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DIY Braided fuel lines?

Subwaybob

Well Known Member
Did anyone buy the Aero Equip kit from Vans and make your own braided fuel/oil or brake lines? Seems like that would save a ton of money doing it yourself...
Thinking this is easier than the aluminium lines and the fittings are perfect.
 
Do yourself a big favor and call Tom at TS flightlines. I'm on my second plane using all of his lines after butchering a bunch of tubing. After the investment in the tools to make the bends and flare equiptment it's not that much more in cost. His customer service is impecable!
 
I second the suggestion to call Tom. You won?t regret it.

Bevan



Do yourself a big favor and call Tom at TS flightlines. I'm on my second plane using all of his lines after butchering a bunch of tubing. After the investment in the tools to make the bends and flare equiptment it's not that much more in cost. His customer service is impecable!
 
Professionally-fabricated lines are great. Tom and Steve will do a wonderful job of them.

Keep in mind that standard Aeroquip lines (Aeroquip 303) have a fairly short service life - some say 5 years, some say 10 years. Go with conductive Teflon with stainless overbraid and you move away from those life limits.

Also, be aware that one can get that fancy conductive Teflon / braided stainless line from racing shops and can fabricate one's own hoses. It's pretty much tool-less, save for a cutoff wheel in a Dremel tool. I made my own brake lines using "Earls" branded fittings and hose - pretty inexpensive and yet produce a professional-looking hose. The assembly technique is nearly goof-proof as well.

This fancy hose is also available with a clear protective sheath over the outside as well, making it quite good for applications where the abrasive nature of the stainless over-braid might be a concern.

I wouldn't fabricate another Aeroquip 303 line if I had an alternative.
 
To answer your question, the kit Van's sells is fine, but you can also buy excellent stuff from places like AN Plumbing and do it yourself - definitely in the spirit of building your own aircraft.

While I'm sure the folks advertised here do a fine job, I've made my own brake, fuel and oil lines for a couple airplanes now. It's pretty easy with the modern fittings and very doable in the garage with wrenches.
 
I made all of my FF lines. I used the aeroquip racing hose, aeroquip fittings for teflon and Earls fittings for rubber. I used rubber for the fuel lines (-6 only) and teflon for the fuel sensor / return line and everything else. I could not source any carbon lined teflon, so used rubber on the fuel lines that pass volume. I used all steef fittings, except the sensor block, but all lines to it are secured by adle clamps near the alum fitting.

In addition to cost savings, you are able to make better fitting lines, especially in tight areas, by making your own. You can put one end on and lay it out exactly how you want it and then mark for the cut. Measuring for custom hoses is hard, because you can't always gauge how the hose will lay/bend, especially with teflon, as it is very rigid in rotation.

I used aluminum for everything behind the firewall, as well as brake lines. I just didn't see the benefit to braided hose for the brakes.

Larry
 
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I made all the lines for my -6 using Earl's fittings and teflon lined stainless lines.

On the -10, I didn't feel like fooling with it and had Tom make the lines.

It all comes down to time vs money. Either way works.
 
Don't forget that you'll also want to build a rig to do high (really high) pressure testing, safely, of your lines after fabrication.
 
i did my own with no special tools and they all went together as advertised.. don't leak now. time will tell.
 
I've rebuilt my 'homemade' hoses twice due to service time by using the same fittings. Only expense was new hose stock.
 
Don't forget that you'll also want to build a rig to do high (really high) pressure testing, safely, of your lines after fabrication.
Can you please direct us to a rig for high (really high) pressure testing, safely. My plan is install and test on the aircraft (on the ground of course) for leaks visually at service or working pressures (not max limit). I used my Google skills and found what one might consider for hose testing, a lower pressure leak test like this:

Video: https://www.youtube.com/watch?v=sVA2xryBCpo
Kit: https://www.holley.com/products/plu...umbing_tools/pressure_test_kits/parts/D016ERL

Fuel and Oil are lower pressure. If it can handle 120 psi without leaking air, that is a good proof test.

Brake or hydraulic lines have higher working pressures. I never tested my brake lines except to install and check for leaks. It takes specialized test equip for high pressure hoses to limit test them.
https://www.youtube.com/watch?v=RF14UzayPXw (warning music is awful)
https://www.youtube.com/watch?v=CETjDJ48Mkk

Testing is good idea. Up to the builder how.
 
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Testing thoughts:

I built a test rig from a rotary actuated hydraulic cylinder. I turned a wheel and a piston moved, creating pressure. It was an industrial component we were throwing out at work. The screw action gave good control over pressure. I added the appropriate AN fittings and a pressure gauge. It worked fine and my hoses have held up well for ~20 years. I still have the test rig in my hangar. (Anyone interested?)

On the other hand, what's the highest pressure/force situation on our hoses? Let's use a -8 oil hose as an example. The pressure in that hose might hit 100+ PSI, so let's assume we test to 200 PSI.

The forces involved are PI*R^2* PSI = 3.14 * .25in^2 * 200 PSI = 40 pounds. That's the force which would be applied to push the fitting off the hose at 200 PSI on the system. The forces get MUCH smaller with smaller diameter hoses because the cross sectional area of the hoses goes down quickly.

Anyway, in the -8 sized hose with the 40 pound test load, would it be appropriate to attach a 40 pound weight to the fitting to see if that holds in tension? That won't prove the fitting doesn't leak, but it will demonstrate that the fitting won't blow off under pressure.
 
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There is absolutely nothing wrong with a builder making his own hose assemblies. LOL, early on when I was just getting started on VAF, a certain famous member here told me he enjoyed making his own. Fair enough, then we did a price comparision and found that his time was more valuable than the effort to make his own assemblies, versus tested teflon ones. Including buying various styled hose ends to get the routing correct.

To answer Larry's post, finding conductive teflon hose from an industrial source is tough. Most 'race car' hose suppliers dont use it. Ours, -4 and larger when used for fuel and oil are conductive. Those for brake systems with a clear chafe cover are not-----brake fluid doesnt flow to make the brakes work, its compressed, so it doesnt pick up static electricity. Thus a conductive liner for brakes isnt necessary. High quality suppliers like Earls and Goodridge have excellent components for the builder that wants to do their own assemblies.

Pressure testing---slightly more involved than just a leak check at 120 PSI under water. You want to take it to the rated working pressure OF THE HOSE, then a safety margin, usually 2 times the working pressure. Before I spent the money on a large test bench (Hydraulic Technology, Inc) I had a hydraulic ram pump, gauge, and an old parts washer cabinet and made my own. MESSY is the operative word. Made a bunch of adapters for the different sizes. Served the purpose.

WE get calls all the time from builders that have made some assemblies and for one reason or another have issues. Its all part of the 'education and recreation' of building your own plane. Most of the time its because they cant test the assembly before installation, only then finding a problem. Steve and I have spent alot of time, effort and money to help builders, both experts and novices, and provide them with quality tested hose assemblies they can rely on. WE take this very seriously, as it should be.

NOT an infomercial, but we chose to not use a push lock hose and fitting assembly, but a reliable crimped fitting teflon assembly. Crimped fitting, because we can control the crimp OD due to possible manufacturers variances. A resuable hose end should be matched to the same manufacturers hose, because presumably they were engineered together. Over the years, we've seen variances in hose OD in even the same manufacturers hose. WE use TEFLON because of its fluid temperature rating, capatibility, and generally lighter weight as compared to rubber lined lines.

Again---nothing wrong with making your own hose assemblies. For those that chose not to, we are here to help.
Tom
 
There is absolutely nothing wrong with a builder making his own hose assemblies. LOL, early on when I was just getting started on VAF, a certain famous member here told me he enjoyed making his own. Fair enough, then we did a price comparision and found that his time was more valuable than the effort to make his own assemblies, versus tested teflon ones. Including buying various styled hose ends to get the routing correct.

To answer Larry's post, finding conductive teflon hose from an industrial source is tough. Most 'race car' hose suppliers dont use it. Ours, -4 and larger when used for fuel and oil are conductive. Those for brake systems with a clear chafe cover are not-----brake fluid doesnt flow to make the brakes work, its compressed, so it doesnt pick up static electricity. Thus a conductive liner for brakes isnt necessary. High quality suppliers like Earls and Goodridge have excellent components for the builder that wants to do their own assemblies.

Pressure testing---slightly more involved than just a leak check at 120 PSI under water. You want to take it to the rated working pressure OF THE HOSE, then a safety margin, usually 2 times the working pressure. Before I spent the money on a large test bench (Hydraulic Technology, Inc) I had a hydraulic ram pump, gauge, and an old parts washer cabinet and made my own. MESSY is the operative word. Made a bunch of adapters for the different sizes. Served the purpose.

WE get calls all the time from builders that have made some assemblies and for one reason or another have issues. Its all part of the 'education and recreation' of building your own plane. Most of the time its because they cant test the assembly before installation, only then finding a problem. Steve and I have spent alot of time, effort and money to help builders, both experts and novices, and provide them with quality tested hose assemblies they can rely on. WE take this very seriously, as it should be.

NOT an infomercial, but we chose to not use a push lock hose and fitting assembly, but a reliable crimped fitting teflon assembly. Crimped fitting, because we can control the crimp OD due to possible manufacturers variances. A resuable hose end should be matched to the same manufacturers hose, because presumably they were engineered together. Over the years, we've seen variances in hose OD in even the same manufacturers hose. WE use TEFLON because of its fluid temperature rating, capatibility, and generally lighter weight as compared to rubber lined lines.

Again---nothing wrong with making your own hose assemblies. For those that chose not to, we are here to help.
Tom

If you get bored today call me! 214-213-2451 Otherwise I'm going to call tomorrow when you're open to price them out anyway. Just exploring my options.
 
I made my brake lines from Earls braided Teflon supplies. It?s not hard but you need to figure out the technique. I see these as lower risk items. For fuel and oil lines I?ll be buying premade and pressure tested lines.

It?s really not cheaper to build your own, well maybe a little bit. The main thing is you get them exactly as you want. The learning curve cost $$ too.
 
Only automotive and motorcycle experience (so far)


Braided oil hose is easy (and I would assume fuel).

Brake hard line is easy.


But due to the much higher pressures, and smaller size (I already had experience with oil lines, and figured the smaller size would make screw ups in manufacturing easier).

I didn't trust myself for brake lines. I just bought premade sections for my truck (correct ends on both sides) and motorcycle (an3 both ends, supply your own adapter). The motorcycle line also came plastic covered in a color of your choice (can see braiding thru cover).
 
for me they were much cheaper. how can a brick and mortar business hand you a finished product that costs no more than the ''raw materials''? i am not saying the service isn't worth it, but it costs more.that's the way it works.
 
I built my first set. Took them to a hydraulics shop who tested them to their rated pressure, not to the application. It cost very little to have them tested. I think it was $3 a hose.
If you build them correctly, no reason they shouldn?t hold at their rated pressure plus safety factor. I am of the opinion that they need to be tested to their rating to insure they are properly assembled.
When these ?timed out?, I shipped them to Tom as patterns and he copied them in Teflon.
I assume Tom tests them to their rating. Tom?
 
for me they were much cheaper. how can a brick and mortar business hand you a finished product that costs no more than the ''raw materials''? i am not saying the service isn't worth it, but it costs more.that's the way it works.

Buying power..... but you?re probably right.
 
Jon and all----we usually test to 2000 psi for -3 to -8, convoluted -10 750, convoluted -12 500. The -12s are normally breather hose assemblies, but we test them anyway if they have fittings on both sides.

Tom
 
To answer Larry's post, finding conductive teflon hose from an industrial source is tough. Most 'race car' hose suppliers dont use it. Ours, -4 and larger when used for fuel and oil are conductive. Those for brake systems with a clear chafe cover are not-----brake fluid doesnt flow to make the brakes work, its compressed, so it doesnt pick up static electricity. Thus a conductive liner for brakes isnt necessary. High quality suppliers like Earls and Goodridge have excellent components for the builder that wants to do their own assemblies.

So do Earls and Goodridge carry conductive Teflon hose or no?

Thanks,

Erich
 
for me they were much cheaper. how can a brick and mortar business hand you a finished product that costs no more than the ''raw materials''? i am not saying the service isn't worth it, but it costs more.that's the way it works.

Buying power..... but you’re probably right.

JonJay- Tom and I buy and manufacture our own components in very high volumes. This allows us to keep control over the quality as well as help keep pricing in line. In addition, we have built a very efficient and high volume shop. We keep our overhead as low as we can by not having a fancy website and doing everything in house that we can.

Regarding hose pricing.... here is an example

-6 hose 90/str with firesleeve.

EARLS SPEEDFLEX


1. Earl's Speedflex conductive teflon hose (Very high quality) - 24" - $12
2. Earls Speed Seal Hose end 90 degree Stainless fitting - $63.02
3. Earls Speed Seal Hose end Straight Stainless fitting - $24.76
4. Milspec AS1072 Firesleeve - 24" approx $22 from Spruce.
5. Firesleeve Bands - about $5 for two of them from Spruce.

1. Total $126.78 for the hose assembly components.


2. ASFlightlines Assembly- -6 with firesleeve 90/str 24" flare to flare - $117.04


3. ASFlightlines Integral Firesleeve Assembly - $134.60

4. Vans Aeroquip Build it yourself Hoses- These are not conductive Teflon, but rubber assemblies. They are also the most expensive of the options.

1. 2 feet of -6 hose $32
2. Right Angle Fitting $71
3. Straight Fitting $30
4. Firesleeve $29
5. Firesleeve bands (Not sold on Vans but about $5 from Spruce)
Total $167

Different configurations and sizes may vary, but when you are comparing the same quality components, our pricing is very competitive with what it would cost to build yourself. With that said, those same hoses can be fabricated for half the cost, but won't be conductive teflon with true stainless ends, milspec firesleeve, etc..... Every one of our assemblies undergoes a hydrostatic pressure test prior to shipment and comes with a 10 year warranty.

There are lots of builders that choose to fabricate on their own for the experience of learning. We fully support that. But for those that want professional hoses fabricated with the highest quality components at a fair price, we will do our best to earn your business.

For those that are interested in how we assemble our hoses....

http://aircraftspecialty.com/howwemake.html

Part 3 of the conductive teflon hose video series shows crimping and pressure testing utilizing a fully automatic CNC crimping machine.

Over the last year Tom and I have made some significant investments in additional equipment and will have some new announcements in the coming months.

If anyone wants to talk about hoses, please give either Tom or I a call. We are both builders, and spend most of our days talking with other builders about custom solutions for their aircraft. It's extremely rewarding to be able to be a small part of so many of your projects. We have a massive database of different aircraft/engine/servo/mag, etc... configurations that we can draw from to help you with your fuel/oil systems. However, if none of our "stock" kits fit, we will help you configure the perfect custom hose setup for your project.
 
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Never heard of conductive teflon hose.

What's it used for? Why?


Ed,

Great question. Teflon material allows you to have a hose that won't degrade over time like rubber lined hoses. This is why it is "on condition" replacement, versus rubber hoses that need to be changed because they get brittle over time and are affected by certain fuel additives, ethanol, etc.

The bigger portion of this is Conductive versus Non conductive Teflon. This is a critical point. When you have a fuel line hose carrying gasoline at a relatively high flow rate, static charges build up. The static charges can arc to the stainless outer braid. Over time this will cause pinholes in the teflon hose and the hose will begin to weep. (Like those garden soaker hoses).

A conductive hose has a layer of carbon impregnated into it that allows this static to dissipate through the fittings and not cause these issues over time.

Take care,

Steve
 
conductive Teflon

So do Earls and Goodridge carry conductive Teflon hose or no?

Thanks,

Erich

Earls does have conductive Teflon -4 and above. As far as I can tell they do not offer conductive Teflon in -3 size. Perhaps no one makes conductive Teflon hose in -3 size because it is normally for brake lines where there is no flow.
 
So do Earls and Goodridge carry conductive Teflon hose or no?

Thanks,

Erich

Erich,

For those builders that are interested in building hoses themselves, Earl's Speedflex is a high quality solution for a conductive Teflon assembly with stainless ends. It won't result in much of a cost savings (It might be more expensive in some situations), but is a great option for those that want the experience of fabricating their own hoses.
 
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And advantage of DIY is that tricky hose where you need to trial fit to get the length just right, and get the clocking on angled end-pieces just right (angled pieces on both ends).

I dislike swivel ends because they always seem to eventually get an oil film on them from a leak that's short of a drip.
 
I purchased my-6A that had been flying about 500 hrs. About 50 hrs later I was climbing out and began to smell fuel. Really smell fuel. Shortly later my feet started to feel wet. Checked under the panel and my fuel line going to the firewall was pissing a stream on my feet. Turned off the electrical boost pump, and the stream stopped. Now got worried that the engine driven pump would be sucking air. Declared a precautionary landing, and got on the ground ok with my shoes and carpet soaked in fuel. I had visions of my legs on fire before landing.
As it turns out, the builder decided to make his own using Earls parts. He misassembled the end fitting, and obviously never pressure tested it.

Flex lines must be pressure tested to pressures not likely available in your shop.
 
And advantage of DIY is that tricky hose where you need to trial fit to get the length just right, and get the clocking on angled end-pieces just right (angled pieces on both ends).

I dislike swivel ends because they always seem to eventually get an oil film on them from a leak that's short of a drip.

Ed,

We DO NOT use swivel ends for that exact reason. We warranty the hose assemblies for 10 years, and a swivel end will eventually likely start to leak.

What we do for these clocking or complicated fit issues is to send the customer the raw hose and fittings and let them do a mock up with the actual components. Once they are marked to the exact lengths and clocking, they come back to us for final assembly, pressure testing and shipment.

This is not normally necessary, but for some very critical lengths and clocking, we do utilize this method.

Also, we have master "clocked" hoses for certain setups so that we are able to duplicate it the same every single time. This is for hoses that we utilize often for standard type set ups.

Steve
 
I purchased my-6A that had been flying about 500 hrs. About 50 hrs later I was climbing out and began to smell fuel. Really smell fuel. Shortly later my feet started to feel wet. Checked under the panel and my fuel line going to the firewall was pissing a stream on my feet. Turned off the electrical boost pump, and the stream stopped. Now got worried that the engine driven pump would be sucking air. Declared a precautionary landing, and got on the ground ok with my shoes and carpet soaked in fuel. I had visions of my legs on fire before landing.
As it turns out, the builder decided to make his own using Earls parts. He misassembled the end fitting, and obviously never pressure tested it.

Flex lines must be pressure tested to pressures not likely available in your shop.

Dan,

We hear these kinds of stories often. Here is a video of a rubber lined hose failure. This hose had been in service for many years and developed a leak in the rubber liner. The owner was noticing fuel smells in the cabin. As soon as a little pressure was applied on the hydrostatic pressure test bench, it began to leak like a sieve. At the extremely low pressures it was normally under, it was only weeping slightly versus spewing fuel out.



https://www.youtube.com/watch?v=uu__Wt0ImLk&feature=emb_logo
 
I’ve fabricated fuel hoses in the past but would definitely not do it again. You really need to know what you’re doing when you fabricate your own fuel, oil or brake hoses. There are a lot of potential pitfalls and the consequences of a hose failure can certainly be fatal in a very ugly way. The trouble for many amateur builders who attempt to fabricate their own hoses is that they don’t know what they don’t know. This is definitely not the area of the build where you want to try and save a few dollars.

There is no greater area of ignorance in the fabrication of home built aircraft hoses than in the requirement for pressure testing of the hose. Some home fabricators don’t test at all because they have no equipment to do so...that’s really putting your life on the line. Others will connect the hose up to their compressor and pump a couple of hundred psi into it....that’s entirely inadequate as a test and super dangerous as well...you do not want fittings flying off like ballistic missiles. The pressure testing must be done hydraulically. If the builder doesn’t have an hydraulic pressure tester then he needs to have the pressure testing done by someone who does. And that tester needs to be using the right type of hydraulic fluid so that the hoses are not contaminated. This is not necessarily straightforward.

Perhaps the biggest ignorance in pressure testing is the pressure itself. I keep hearing builders say how they tested home made fuel hoses to say 200 psi because that’s “way beyond operating pressure”. The correct pressure to test a hose to is the proof pressure of the hose. That is the pressure that ensures that the hose has no defects and that the end fittings are properly fitted. Typically the fittings will be checked after proof pressure has been applied to ensure that they are not slipping. The proof pressure on a fuel hose varies depending on the manufacturer, the type of hose, and the hose size...but for a -6 hose it might typically be around 1500 psi. Testing to say 200 psi is virtually useless. It’s typically not the operating pressure of the hose that causes the end fitting to fail....it’s the flexing of the hose in the end fitting caused by differential movements.

And finally, there is a broad misconception on Teflon hoses that they last forever and never need to be replaced. That is not necessarily true. Teflon hoses are “on condition”. That means that they have to be inspected at predetermined intervals to ensure they are still functional. If they pass pressure testing they can be returned to service. The big problem with Teflon hoses is that they form a cast (a shape, a curvature) and when the hose is pressure tested that cast needs to be maintained to prevent the hose from straightening out under the pressure. That is not always easy to do.
 
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Ed,

......
What we do for these clocking or complicated fit issues is to send the customer the raw hose and fittings and let them do a mock up with the actual components. Once they are marked to the exact lengths and clocking, they come back to us for final assembly, pressure testing and shipment.

......
Steve

From this I'm assuming I could send you an old hose and say

"Please duplicate this" but better........................
 
From this I'm assuming I could send you an old hose and say

"Please duplicate this" but better........................

Absolutely. We do that all the time too. Our lead times are fairly quick anyways, but we try to prioritize AOG aircraft. If we know hoses are coming to us from an aircraft mid conditional inspection, we get those done ASAP to minimize aircraft down time.

If you ever need anything we will do our best to earn your business.
 
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Dan,

We hear these kinds of stories often. Here is a video of a rubber lined hose failure. This hose had been in service for many years and developed a leak in the rubber liner. The owner was noticing fuel smells in the cabin. As soon as a little pressure was applied on the hydrostatic pressure test bench, it began to leak like a sieve. At the extremely low pressures it was normally under, it was only weeping slightly versus spewing fuel out.



https://www.youtube.com/watch?v=uu__Wt0ImLk&feature=emb_logo
Tom made my replacement hoses, for every flex line on my airplane.
I wasn?t chancing it. Great product and even better service.
 
These recurring threads about DIY vs buying fabricated hoses should definitely have their own section in the “Never Ending Debates”.

I don’t want to take away from what I’m sure are very professionally made and tested hoses advertised here, but if you are interested doing it yourself, the fact is that you can make quality hoses on your own, easily and with normal shop tools. No Fear, Uncertainty and Doubt required.

As for the high test pressures, we test utility gas lines, steam lines, hydraulic lines and many other high pressure systems in the utility industry to ASME standards, which generally require hydro testing at 150% of the operating pressure. You can certainly test your lines at higher pressures, but you won’t be able to convince me that an oil system that is fully relieved by 100 psi needs to have hoses good for 10,000 psi. That’s a safety factor of 100. And then consider that nuclear power plant pressure systems are designed to a minimum safety factor of 2, with some as high as 5.

While you can have a confident feeling that your oil, gas and brake lines are tested to a certified standard, created back when fluid lines were all made of natural rubber - just know that it’s unnecessary. And it still won’t guarantee they won’t leak.

I test my lines using 150 psi compressed air, the earl’s test kit and a 5 gallon bucket. Works great.

BTW, if you buy the fittings and hoses from ANPlumbing, they’ll assemble them with crimps and test for you at essentially the price you pay for the materials. It’s a nice low cost option if you don’t want to do it yourself.
 
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I?ve fabricated fuel hoses in the past but would definitely not do it again. You really need to know what you?re doing when you fabricate your own fuel, oil or brake hoses. There are a lot of potential pitfalls and the consequences of a hose failure can certainly be fatal in a very ugly way. The trouble for many amateur builders who attempt to fabricate their own hoses is that they don?t know what they don?t know. This is definitely not the area of the build where you want to try and save a few dollars.

And definitely don?t ever try to build your own plane. That?s strictly for experts and would lead to certain death.
 
We didnt make up the pressure ratings on the hoses, nor the testing pressures.
We took the Certified hose working pressures of hoses that were used for the applications and adapted it. For example, a -6 303/111 hose (666/124 teflon) used for fuel is rated at 1500 psi. Now in most of your injected applications, youre looking at 29-31 PSI with the boost pumps. (SDS and EFii run +- 49 psi.) But the hoses used to plumb them in a certified application were rated at 1500, so thats the spec we used. So you can see that the pressure test margin is not excessive, but over the working pressure.

Since oil systems can run 80-90 PSI on occasions, the same basic hose (303/111 for certified applications) was used. Again---it's what was designed for the application. So similar hose, similar HOSE working pressures, similar test pressures. Even carbureted fuel systems at 5 psi use a 303/111 hose rated at 1500 psi in certified aircraft.

YES YOU CAN use a hose with a much lower WP and have even seen Tygon used, believe it or not. WE chose to use teflon not only for the pressure ratings, but for the fluid compatibility. Fuel is a great example---we never know what additives are in fuels that may react with the liner materials in a negative way. Like the 701 hose in the video that Steve posted. That hose was sent to me to test. The owner though he had a hose end leaking at the screw in collar. As you can see, it wasnt the case. Fuel had deteriorated the liner of the hose to the point where it was leaking THROUGH the liner out out of the reinforcement braid. LITTLE PRESSURE--I think it was 1 psi---just enough to get fluid flow.

When I got started in this, I wanted to give experimental builders a resonable, reliable alternative to expensive certified hose assemblies, and a faster response time. 10 years later, I think we've accomplished that.

Tom
 
These recurring threads about DIY vs buying fabricated hoses should definitely have their own section in the “Never Ending Debates”.

I don’t want to take away from what I’m sure are very professionally made and tested hoses advertised here, but if you are interested doing it yourself, the fact is that you can make quality hoses on your own, easily and with normal shop tools. No Fear, Uncertainty and Doubt required.

As for the high test pressures, we test utility gas lines, steam lines, hydraulic lines and many other high pressure systems in the utility industry to ASME standards, which generally require hydro testing at 150% of the operating pressure. You can certainly test your lines at higher pressures, but you won’t be able to convince me that an oil system that is fully relieved by 100 psi needs to have hoses good for 10,000 psi. That’s a safety factor of 100. And then consider that nuclear power plant pressure systems are designed to a minimum safety factor of 2, with some as high as 5.

While you can have a confident feeling that your oil, gas and brake lines are tested to a certified standard, created back when fluid lines were all made of natural rubber - just know that it’s unnecessary. And it still won’t guarantee they won’t leak.

I test my lines using 150 psi compressed air, the earl’s test kit and a 5 gallon bucket. Works great.

BTW, if you buy the fittings and hoses from ANPlumbing, they’ll assemble them with crimps and test for you at essentially the price you pay for the materials. It’s a nice low cost option if you don’t want to do it yourself.

Ron,

This isn't a never ending debate like "Primer Wars." I think everyone can agree that the truth is that an aircraft should utilize high quality hoses. High quality hoses can be built yourself,or they can be sourced from a company that fabricates that professionally.

Poor quality hose components/assembly can result in a less than desirable outcome.

We completely agree with your statement that it is possible to build very high quality DIY hoses. We have some customers/fellow builders that want to do so for the experience of building. We have no problem at all recommending brands for high quality do it yourself lines. It's not about saving money, but rather about the fabrication experience.

AN plumbing sells about 15 different lines of fittings and hoses. To the untrained eye, it can be challenging to know the difference between what is suitable for an aircraft and what isn't. The ones that are not suitable for aircraft use may work fine at first, and cause problems down the road.

We decided long ago that we would not compromise on quality. We could fabricate hoses for half the cost of what we do, but the components would not be ones that we would utilize on our own aircraft. We refuse to go down that road...ever.

Regarding pressure testing.....a 150 PSI pressure test will give peace of mind, but will not serve as a proof test for the fittings. We could crimp a hose that would hold at 150 psi that would fail over time under normal operating pressures and vibration.

Putting 150PSI of air pressure into a hose is no problem....UNLESS A FITTING FAILS. In that case, your day will get very interesting. There is a reason that hydrostatic tests are utilized when testing hoses under pressure.

Ultimately, there is no right or wrong answer because there are various paths to reach the end goal. For builders who want to use professionally fabricated hoses, we can help. For builders that want to build their own lines, we are happy to point you in the right direction too to help make sure you are utilizing high quality components.

If anyone has any additional questions, please feel free to contact Tom or I.
 
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the ''untrained eye''. ok, so it was just a phone call to ANPlumbing to get specific recommendations for assemblies to be used in airplanes.
 
the ''untrained eye''. ok, so it was just a phone call to ANPlumbing to get specific recommendations for assemblies to be used in airplanes.

Bob,

That's a great recommendation. The most common question we get is the difference between Teflon and Conductive Teflon. You can tell the difference based on the internal color of the hose. However, we have seen some manufacturers of imported non conductive hose color it the same as conductive. That's why it's important to buy from a supplier you trust. The more questions that you ask of vendors/suppliers, the better informed you can be about the decisions you make. On the outside, stainless braided hoses all visually look about the same. What's inside is what counts. The same thing is true with fittings.... Crimp versus Reusable, Swivel or not, Material (whether its actually a certain material or just a plated coating), and thread type are all things to look into when deciding what to put on your aircraft.

As has been mentioned many times, if you use high quality materials and they are assembled properly, you should have a long lasting assembly.
 
Ron,

Putting 150PSI of air pressure into a hose is no problem....UNLESS A FITTING FAILS. In that case, your day will get very interesting. There is a reason that hydrostatic tests are utilized when testing hoses under pressure.

While I'm sure you have a very nice test rig, it can be done safely at home as well.

The "at home" safe process is to fill the hose with fluid, for the quickest pressure relief, and then use a "Compressed Air Flow Safety Shut Off Valve" on the inlet to the test kit (search on that...about $30 device). One should probably have this handy device to prevent "whip lines" on a compressed air system anyway.

I use water, also in the water filled bucket, so if there is a failure the pressure relieves quickly. In the spirit of actually experimenting...I purposely partially assembled a fitting with only slight compression on a test hose. At 150 psi, the fitting did finally come off after waiting about 10 minutes, but it was a "pop" and that was it. My take-away was that the Earl's Speed Seal system is a pretty solid design.

And yes, I agree, the whole process should be about the "experience of building".

I personally enjoy doing the whole thing, from the big things like the airframe and engine, down to hoses and servos - all the way down to those little HD pins on the Garmin D-sub connectors. It's all part of the process of recreation and education.


Bob Noffs: not sure if you were being serious or not, but just in case... here's the link for AN8 hoses. Pick your ends and length...

AN Plumbing AN8 pre-made hoses
 
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the link for AN8 hoses. Pick your ends and length...

AN Plumbing AN8 pre-made hoses

They say made in the USA and testet to 1000PSI... So please educate me where this would be worse than me learning to bend and flare solid lines for break lines? (they carry them in -6 and -4 also) EDIT: AN Plumbing told me that these are not suited for our needs. If anything his recommendation was speed seal... This is among other things what Tom and Steve said...

Also:
Since this topic is really interesting. How does ONE satisfy the "condition" of a Teflon SS braided hose? I mean lets say every year you look at them and from the outside they look the same. I assume this is the reason Cert. hose just get replaced every X years to be sure? What is the proper method to determine when the hose need to be replaced?
 
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Lets compare apples to apples----conductive hoses verses non conductive. Aluminum nuts, and brass collars, and probably brass stems, verses 304 stainless steel fittings and stainless collars. GRANTED---- some guys are shopping to get the lowest possible costs available. Some like the whole process of building their own hoses, engines, avionics, etc. Absolutely nothing wrong with that in my view. Actually we welcome it in alot of cases. BUT---we've found that the majority of builders dont want to do those jobs. They want to do the install, and move on. So there are vendors that specialize in such things as hoses and fluidlines, engines, avionics and wiring harnesses, fuel tanks, and yes even building the airframe.

WE set out to fill that void----and its not for everyone. We are NOT the cheapest, nor the most expensive, and dont want to be either. We have MANY friends on VAF that have never bought anything. Yes we are still friends, and talk to them as if they spent a bunch of money. Its about people, and products and offering what we have and can do.

Tom
 
While I'm sure you have a very nice test rig, it can be done safely at home as well.

The "at home" safe process is to fill the hose with fluid, for the quickest pressure relief, and then use a "Compressed Air Flow Safety Shut Off Valve" on the inlet to the test kit (search on that...about $30 device). One should probably have this handy device to prevent "whip lines" on a compressed air system anyway.

I use water, also in the water filled bucket, so if there is a failure the pressure relieves quickly. In the spirit of actually experimenting...I purposely partially assembled a fitting with only slight compression on a test hose. At 150 psi, the fitting did finally come off after waiting about 10 minutes, but it was a "pop" and that was it. My take-away was that the Earl's Speed Seal system is a pretty solid design.

And yes, I agree, the whole process should be about the "experience of building".

I personally enjoy doing the whole thing, from the big things like the airframe and engine, down to hoses and servos - all the way down to those little HD pins on the Garmin D-sub connectors. It's all part of the process of recreation and education.


Bob Noffs: not sure if you were being serious or not, but just in case... here's the link for AN8 hoses. Pick your ends and length...

AN Plumbing AN8 pre-made hoses


Ron,

If you're using the Speed Seal system with Speedflex Conductive Telfon hose and Stainless hose ends, it is a very solid system. That is the one we recommend to customers who want to do it themselves. You won't save any money by going that route, but you will be able to say that you built all your own hoses. I agree with you.....this stuff is fun and some people thoroughly enjoy it. Others don't.

If you are filling your hose up with fluid ahead of time it is a hydrostatic test, which is the correct way of doing it. You don't have a method to purge the air from the line before testing but with a 150psi test it won't much matter. The video of the test showing how to use their equipment does not show a hydrostatic test, but rather just filling the line with compressed air. That is a good way to turn an improperly attached fitting into a projectile.

The link to the AN8 pre-made hoses is something completely different. We could absolutely build hoses with those components and sell them at that price, but we choose not to for a wide variety of reasons.

There are places to save money, but I can tell that you are a person that is concerned with quality. If you weren't, you wouldn't be utilizing Speedflex hose and Stainless Ends.

As Tom mentioned, we have both spent hours talking to builders who never buy a thing from us. Ultimately, we want to see safe airplanes being built. Experimental aviation is a community with the opportunity to make lifelong friends.

They say made in the USA and testet to 1000PSI... So please educate me where this would be worse than me learning to bend and flare solid lines for break lines? (they carry them in -6 and -4 also)

Also:
Since this topic is really interesting. How does ONE satisfy the "condition" of a Teflon SS braided hose? I mean lets say every year you look at them and from the outside they look the same. I assume this is the reason Cert. hose just get replaced every X years to be sure? What is the proper method to determine when the hose need to be replaced?

I sent you a PM
 
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Since this topic is really interesting. How does ONE satisfy the "condition" of a Teflon SS braided hose? I mean lets say every year you look at them and from the outside they look the same. I assume this is the reason Cert. hose just get replaced every X years to be sure? What is the proper method to determine when the hose need to be replaced?

See my Post # 32. Obviously you can't tell if a steel braided teflon hose is failing by just looking at it in situ. It has to be pressure tested to proof pressure at regular intervals. If it passes pressure testing it can be returned to service.

Do I think that the typical RV owner doing his own maintenance will do that pressure testing...probably not.
 
I use water, also in the water filled bucket, so if there is a failure the pressure relieves quickly. In the spirit of actually experimenting...I purposely partially assembled a fitting with only slight compression on a test hose. At 150 psi, the fitting did finally come off after waiting about 10 minutes, but it was a "pop" and that was it. My take-away was that the Earl's Speed Seal system is a pretty solid design.

And yes, I agree, the whole process should be about the "experience of building".

Pressure testing your hoses to only 150 psi is not best aviation practice and in fact it's very dangerous. It is recommended that hoses be tested to proof pressure for a good reason. But hey, it's the Experimental category so builders can do whatever they like.

When you test a hose to proof pressure you ensure that the end fittings are secured to a level that will preclude the possibility of the fittings failing under normal levels of vibration and flexing. Testing the hose to 150 psi does not provide that security. All you're doing is satisfying yourself that the actual operating pressure of the hose will not push the end fitting off....but it's not the actual operating pressure on fuel lines that represents the real threat....it's the vibration and movement of the flexible hose into the fixed end fitting.
 
Pressure testing your hoses to only 150 psi is not best aviation practice and in fact it's very dangerous. It is recommended that hoses be tested to proof pressure for a good reason. But hey, it's the Experimental category so builders can do whatever they like.

When you test a hose to proof pressure you ensure that the end fittings are secured to a level that will preclude the possibility of the fittings failing under normal levels of vibration and flexing. Testing the hose to 150 psi does not provide that security. All you're doing is satisfying yourself that the actual operating pressure of the hose will not push the end fitting off....but it's not the actual operating pressure on fuel lines that represents the real threat....it's the vibration and movement of the flexible hose into the fixed end fitting.

I disagree with you. ASME B31.1 is a consensus standard to test pressure systems, and as I said previously, the recommended test pressure is to 150% of the system operating pressure. If the fuel system runs at 75 psi, and oil at 100, then 150 psi is a good test pressure. When assembled and installed correctly, vibration will not cause quality AN fittings to separate. If the hose is actually moving about with vibration enough to cause cyclic failure, it is not supported properly. Simply saying that it is dangerous is not factual.

Now, flying airplanes, let alone building them, is perceived by many as dangerous as well, so based on that, I suppose I have to agree with you that building, testing and using your own hoses is also dangerous. But then again, according to the CDC, two thirds of all injuries happen in the bathtub or shower, so I should probably avoid those too. ;)
 
Ron,

The link to the AN8 pre-made hoses is something completely different. We could absolutely build hoses with those components and sell them at that price, but we choose not to for a wide variety of reasons.

I appreciate the vote of confidence.

The link is to pre-made hoses constructed of Earl’s Speed-Seal braided hose with aluminum fittings, both crimped and pressure tested - to the same pressures I believe you stated. Perfectly adequate for the installation.

And if you’re saying that only steel or stainless steel fittings can be used, then Beechcraft needs to have their type certificates pulled as nearly every fitting on my Baron is a ‘D’ fitting (aluminum). The only steel ones in the IPC called for are on the lower brake hose that connect to the caliper.
 
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The Mil Spec for H8794 hose ends from -3 to -6 use steel nipples and nuts, with aluminum collars. -8 and above use all aluminum fittings. These are the resuables for 303/111 type hose. 'MOST' Certified teflon assemblies will use stainless or CRES hose ends, at least up to -8.

In answer to the question on testing a teflon hose after its been in service, it get alittle complicated. Mot teflon hoses will take a set through temperature and pressure cycles, making it conform to its installation routing. So if the routing has a curve in it, the hose after extended use may stay in that curved pattern. Removing the hose for reinstallation requires supporting the hose so it maintains the installed shape. Dont try and straighten it out, then reinstall it because the liner may fracture and leak. For the same scenario, trying to pressure test a teflon hose that has taken a set, is an issue especially if you try and go to the proof test pressure . The hose will naturally want to straighten out and may fracture the liner. So, most long time inservice teflon hoses are replaced. What that interval is is dependent on the application, the temps and pressures involved, and the amount of movement the accessories have. Obviously, hoses that move under higher pressures like on retract landing gear should be inspected and replaced at high cycles.
For our purposes, most teflon hoses have no service life.
When it gets down to it, the aircraft manufacturer can specify what goes on the aircraft. In Rons case, Beechcraft specified that aluminum hose ends be used, or a Mil Spec equivelant with aluminum hose ends. In the experimental world, the kit manufacturer can specify what to use, but its generally up to the builder to use the specified parts. As we all know---some do, some dont, some opt for quality reliable assemblies from well known sources, some, well lets just say we've seen some pics of hose assemblies that really makes you wonder.

Tom
 
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