Fuel Tanks - What did you do?

I'm at the point in the build where I need to do my slow build fuel tanks. I watched the Beck Video on an RV-7 and he does one tank over the course of several days.

I know the tanks need to be throughly clean while working with the pro-seal and working over the course of days would seem to induce unwanted debris getting onto the parts which might cause leaks with using the pro-seal.

I'm looking for a method that worked for the majority of builders who didn't encounter any leaks when done.

I would prefer to do the assembly over the course of several days working in stages but don't want to chance leak protentials.

Thanks,

Mike,

I found the tanks to not be nearly as bad as a lot of people think. Yes, the proseal is a bit stinky and sticks to EVERYTHING but you can overcome that.

Tips:

- Make sure you have lots of mixing sticks, cups and rubber gloves. (More than you think)

- Use an apron to help keep your clothes clean. Gives you something to wipe your hands on sometimes.

- *USEFUL* Find yourself some large syringes to apply proseal with. This is a very clean way of applying proseal in places, particularly the baffle. The baggie method sounds messy to me.

- *USEFUL* Use masking tape wherever you can. I used it along side of every line of rivets for the ribs and stiffeners. It reduces the mess, creates nice clean lines. It actually reduces the amount of proseal you will use. It really doesn't take much to create a leak free tank. I've seen pictures of proseal gone wild in tanks. Fuel can only leak through the rivet holes, so why put proseal 1/2" on either side of the ribs/stiffeners?

- Make, prep and fit all your parts. I stored the small pieces in baggies to keep them from getting too dirty before using.

- A quick swipe of MEK soaked rag will clean any dust off that settled between sessions.

Links:

Prosealing process for tank ribs

Prosealing the stiffeners


Have fun!

Mike,
I am in the process of working on my tanks now. What I did was MEK everything down before I started - ribs, skin, baffle, and all of the misc parts. Now when I install a rib or anything, I MEK everything down again to get any contaminates off that might of accumulated since the last session. I have so far been working on my tanks for about 10 days now and have another 5 or so to go.

Another thing I did was to dab a little extra proseal into each rivet dimple with a toothpick before inserting the rivet. I figure it can't hurt.

To follow up on what Matthew stated, a syringe is great to form the fillets around the parts. I went with a smaller syringe - basically so I can actuate it with one hand. If you go to the pharmacy counter at Target they should give them to you for free - I have scored 20 of them for free so far. Also, I prefer electrical tape over masking tape for blocking unwanted proseal. Electrical tape lifts better for me.

Also, I cut a bunch of Q-Tips in half and use them to clean up after sealing. This works very well because if you try to clean up too close to proseal with a rag, you end up making a bigger mess. With Q-Tips, you can really control what you are doing.

All of this comes from a guy who hasn't finished his tanks, so take it with a grain of salt.

Good luck.

Alternate Prosealing Method

Mike,
Here's how I did mine. Read through Rick's method, it's really easy. I can't say how much easier as this is the way I did both of mine. As of last evening, I have no leaks in the second tank. Keeping my fingers crossed.



http://www.vansairforce.com/community/showthread.php?t=7602

Fearless said:

...at the point in the build where I need to do my slow build fuel tanks.....I would prefer to do the assembly over the course of several days working in stages.......

Click to expand...

I am nearing completion of the RV-8 fuel tanks, building them the identical way I built my leakproof 6A fuel tanks. All that remains is attaching the back baffle...I'll do that over the next few days. Fuel tank construction is best accomplished over several sessions in many small steps. Here's a basic breakdown of how I approached the job.

#1. Prepare the inboard and outboard end ribs. Lots of details to attend to. Get all the parts ready. This includes preparing the access cover cutout, the air vent fitting, the rib nose reinforcements and fabricating the fuselage attach angle. In my case it also included prewiring and installing the electrical connector through the inboard end rib for the capacitive sending system.


#2. Prepare the skins and all the stiffeners. Rough up the contact surfaces on the skins and stiffeners with maroon scotchbrite and clean with M.E.K. Install them during the same pro-sealing session with the fuel filler neck and drain flange. Encapsulate all shop heads after shooting the rivets.



#3. Using the prosealing installation technique I outlined in another thread, I then (holding each rib in a vise) applied proseal to the rib flanges on the 5 internal ribs and 100% clecoed into place. I started by cleoeing in all 5 ribs by their upper nose, followed by starting a few clecos from the bottom aft and working forward. That way, as I folded the skins into them, the sealer was not smeared all over as the ribs nested into place. The rest of the session was spent in smoothing the sealer squeeze out into an uninterrupted fillet seal around the ribs. Over the next two days I wet installed and shot the rivets. In my case, I found using the holding cradle to be awkward and simply shot the rivets with the fuel tanks lying flat on the workbench. Encapsulating all the shop heads was tedius work but has to be done. For this step, I mostly used a broken off "Q" tip stick. Not shown is a floor standing 1000 watt light stand flooding a lot of hot illumination into the tanks during this phase of assembly!




#4. Finished installing the capacitive plates, installed the soft aluminum vent tube and then prosealed and shot the end ribs into place.

#5. As mentioned, installing the rear baffle is all that remains of the fuel tank assembly process but trust me, that task is child's play compared to some of the steps that preceeded it.

If I ever do it again, I will probably go Rick's route. FWIW.

Thanks for the input

Thanks for all the replies.

Rick - If I understand the method you use, you set the piece in place first with clecos and proseal and then a day later after removing the clecos you fill the rivet hole with proseal and then place the rivet in position sealing the rivet hole and then set the rivet.

So there is no problem with the new proseal bonding with the previous set proseal?

Fearless said:

.... is no problem with the new proseal bonding with the previous set proseal?

Click to expand...

In my experience.....no.

Fearless said:

...So there is no problem with the new proseal bonding with the previous set proseal?

Click to expand...

I used Rick's method also and if you shoot rivets the next day after prosealing, it's still a bit tacky. Not quite "cured" at all.
If you do the first prosealing when the garage is only 40 degreesF or so, I think you could wait a week or at least it seemed that way on my second tank.
No leaks either!

-mike

I just finished my tanks. My process was pretty simple.

1. Scotchbrite all the surfaces to be prosealed and clean with MEK.
2. Assemble and cleco the tank skin and all ribs in the cradle.
3. Take one rib out at a time, do a quick wipe of the rib flanges and skin (where the rib touches) with MEK to get any dust, etc.
4. Butter up both the rib and the skin with proseal (I used about 20g per rib). 5. Push the rib into place (there's plenty of proseal even if it moves a bit during the install) and cleco every other or 3rd hole.
6. Rivet from the leading edge back removing clecos as you go. I always had little gobs of proseal squeeze out into the dimple in the skin, so I'd just smear it around a bit with the rivet before I installed and shot it. (so I didn't need to add more with a toothpick as mentioned above.)
7. Wipe up any excess and cover the shop heads with proseal.
8. Repeat for the next rib.

The end ribs are pretty similar, and by the time you get to the baffle you'll have it all figured out


You don' t have to use big gobs of proseal, but don't skimp on it either. my only leak was around one of the access hole cover plates, as I was trying to use up the last of a batch of proseal on that cover without mixing up any more (so it was too little and too tacky by then). The second tank I just mixed up some more and had no problem that time.

I did saved this thread for future use so no need to search for it. Tanks, rumored to be most messy job of the plane, sounds not pretty easy and I really can't undestand how this job would be "so messy" at all. However, some moderator might answer this, what this thread still has to do with "VAF Classifieds"?

Thanks for everyone for gathering this great piece of tank building.

My Bad - Wrong forum

I thought I was in the general forum area when I submitted my post.

I'll try to be more alert about what I'm doing the next time.

Doug, if you read this, please move these postings over to the general area.

Sorry,

Tank input.

After two sets of tanks, the best tip in the world is the use of small freezer bags for dispensing Pro-Seal. They are a bit smaller than a sandwich bag, mix the black death and spoon it in to the bag, seal up and snip the corner to use as a bakers bag. You get much more control and vastly cleaner work! It stores well on the bench and does not stink up the shop as well. I found the tip somewhere in the RV world online, hope it helps.

Steve

What is everybody's experience in dealing with the fumes from proseal and mek when doing the tanks.

Bill,
The MEK fumes are way worse than proseal fumes. Both products recommend respirators. I don't find the proseal fumes all that abnoxious - in fact I was sick of wearing the respirator one day when I was riveting a interior rib ans took it off while prosealing - it did give me a headache, so I wear a respirator now whenever I am dealing with proseal. The way I figure it is why expose your lungs to this **** if you can avoid it. Ventilation is also nice.

billdianne said:

What is everybody's experience in dealing with the fumes from proseal and mek when doing the tanks.

Click to expand...

In the production environment, many of us were exposed to proseal and in far, far larger quantities than contained in all the RV's that have ever been built, day after day, year after year. As anal as the company was about exposure to toxic fumes, there were few cautions issued about proseal exposure. Respiratory protection was hardly ever used. That said, there was the occasional employee who over time developed an allergic reactions to sealer but such instances were very rare. Now M.E.K.......that is a horse of another color. We had respirators with filters on them that specially targeted M.E.K. fumes. Those fumes should be respected and you will do your long term health a favor by at least having a fan circulating fresh air when M.E.K. is in use.

The pro-seal we use is rated at a 2 (the same as acetone and isopropyl alcohol). Now the Quick-Seal is nasty stuff, its a 3, the same as Chromium 6. Where I work (a Boeing supplier) they almost exclusively use pro-seal and there is no PPE required (STUPID). FWIW, I try to stay as far away as I can.

TIP

Before installing the baffle plate, be careful to put the bead of proseal just forward (touching or tangent to) of the line of rivet holes. The soapy water test reveals all. Leaked like an Elbonian submarine, 3 places.

Avionics arriving today,
Steve

Cleveland Tank Dimple Dies?

I like the method that Rick 6A proposed and will go down that path.

My new question is did anyone use the Cleveland Tank Dimple Dies on the tank skins and ribs? Because of the use of proseal would having a deeper dimple be advantageous.

Thanks,

I think even Van's says to use the special tank dimple dies. You should use them.

Get two boxes of nitrile disposable gloves. Wear two pair at a time.

Cut paper shop towels into small squares.

Wear a disposable Tyvek painting suit.

Can you find Van's reference to tank dimple dies? As far as i know, they are not mentioned in "Section 5S Fuel tank Sealant" nor in my RV-10 Section 18 Fuel tanks plans.

I think they really *SHOULD* include the use of fuel tank dimple dies - or at least a disclosure, warning or special note about its use being beneficial.

It is too late for me. I researched it but like a dummy, i ignored it. I thought I could get away with just countersinking a bit after dimpling. It still was not enough.

I am sure the tank dies would have saved me a bit of grief, especially, on the few rivets per rib on the curved leading edge part. I remember having to work extra hard at getting those rivets to set straight.

Definitely, go straight to tank dies.

Jae

What is the reason behind tank dimple dies? As rib is well sealed against skin and shop heads are covered with ProSeal I really don't understand what rivet type (470 or 426) or dimpling would affect leaking. Unless you did you job badly and either shopheads or rib-skin connnection leaks... so it's kind of a double protection or?

Asked about the Avery about the fuel tank dies, as they were out of them, they suggested that countersinking would do the same job.

jchang10 said:

Can you find Van's reference to tank dimple dies? As far as i know, they are not mentioned in "Section 5S Fuel tank Sealant" nor in my RV-10 Section 18 Fuel tanks plans.


Jae

Click to expand...

Huh, your right I could have sworn. Anyway that was 5 months ago and I couldn't find anyone at the time who did NOT use the special tank dies so I forked over the cash and used them.

Pirkka said:

What is the reason behind tank dimple dies? As rib is well sealed against skin and shop heads are covered with ProSeal I really don't understand what rivet type (470 or 426) or dimpling would affect leaking. Unless you did you job badly and either shopheads or rib-skin connnection leaks... so it's kind of a double protection or?

Asked about the Avery about the fuel tank dies, as they were out of them, they suggested that countersinking would do the same job.

Click to expand...

"Tank dies make deeper dimples to allow for the layer of tank sealer between the rivet and skin.
Rivet will set flush with the skins surface.
Spring back angle on die faces.
Minimizes skin deformation.
Skins remain very flat!
Precision made on our CNC machine.
Stainless Steel- Heat treated.
Polished dimpling surfaces.
Don't make 14,000 mistakes on your plane!
See also DIE-KIT.
We guarantee these dies work better than any others or we will give you a refund! "


http://cleavelandtoolstore.com/prodinfo.asp?number=DIE4263T

The methods worked - Left tank no leaks

I want to thank everyone who made recommendations and suggestions to my original posting. I did the balloon test on the left tank yesterday and happy to report no leaks.

After two boxes of gloves, almost a quart of pro-seal, lots of popsicle sticks, and a couple of weeks worth of work - it is done.

I used Rick's method on the inner ribs. I prosealed around the reinforcement ring and sender unit hole when riveting the nutplates on (Orndorff video - maybe). I used the medium compound tite-seal on the gaskets for the tank access plate and sending unit. I didn't want the proseal mess if I have to get back into the tank for any reason.

Thanks again,

What is the consensus on buttering the ribs before installing them. Butter just the rib? Or butter the rib and the skin?

Thanks,
Bill

I just buttered the ribs - not the skin. No leaks...

Just the ribs

I also just buttered the rib flanges while doing my left tank. I did the same on the flanges for the rear baffle.

I didn't metion in my earlier post that I used the Cleveland tank dimple dies.

Now on to the right tank.

NO MEK fo me.

I used alumiprep and scotch bright on both of the surfaces to be sealed, rinsed the parts and then blew them dry with air before applying the sealant. NO MEK, it was a little more work but a lot less hassle.

I worked full time fixing planes for years, I can tell you, the effects of MEK are cumulative and it will find its way into your body any way it can.

All you need is sterile, clean, dry, aluminum surfaces when you apply the proper amount of sealant and you will get a good job.

Have fun (as if thats possible with sealant) !