[JimWoo50]

I am trying to decide whether to order the West Systems epoxy product. Will the one quart kit be enough? Slow or fast hardening? What kind of cloth should I use? Is the West System an appropriate product for my canopy fiberglass work? Thanks. Jim

 

[RV_7A]

Step 1 on Jim Andrews site has all the info you will need on what to purchase.
It is an accurate list. I bought all of it and its perfect.
http://rvpilot.com/Fiberglass/fiberglass.html

-Jeff

 

[dan]

I also used Jim's site to get started, but iirc he recommends 8oz Rutan BID cloth. That stuff is just too heavy for a lot of the stuff we do fairing-wise and what not. While I do have 8oz BID that I use for larger/thicker build-ups, I prefer the lighter stuff like the 3.16oz E-glass cloth that Spruce sells. Just my 2 cents.

 

[JimWoo50]

can you mix the cloths?

And how much will I need to complete canopy fairings appoximately? If I order e glass and B-D fiberglass can I mix the two if I run out of one? Is it right to surmise that because of its lighter nature that e-glass is more pliable and therefore more versatile than the B-D? Are tha applications for B-D limited while the e glass can be used in more places? Thanks for posting the fiberglass primer in a previous post it was a big help.

 

[Davepar]

Other notes:

If you live anywhere near water, you can get West Systems epoxy at your local West Marine without having to pay hazmat shipping fees.

You might want the faster hardener, especially if you're working in a cold shop or on smaller projects.

You may think you can get along without the pumps, but they make mixing the epoxy 2000% easier. I also found a useful free booklet at West Marine that describes the various West Systems epoxy products.

Dave

 

[jcoloccia]

Other notes:

If you live anywhere near water, you can get West Systems epoxy at your local West Marine without having to pay hazmat shipping fees.

You might want the faster hardener, especially if you're working in a cold shop or on smaller projects.

You may think you can get along without the pumps, but they make mixing the epoxy 2000% easier. I also found a useful free booklet at West Marine that describes the various West Systems epoxy products.

Dave

Ditto, ditto and ditto. Also, sometimes you can get West Systems through your local hobby shop as well.

The pumps are indispensible, and I find myself going back and forth between the fast hardener and slow hardener depending on what I'm doing and how hot it is.

 

[avaviat]

Are those materials (on the Jim Andrews site) really the preferred fillers for aircraft use? I haven't done any aircraft composites, but I've done a lot of epoxy/glass/filler work on boats. I've gone through perhaps 50lbs of various fillers (and many many gallons of epoxy) ranging from glass microballoons, phenolic microballoons, colloidal silica, microfibers of glass/polyester/cotton, talc, carbon (graphite), various wood dusts, et cetera including most of the patent fillers (e.g. WEST 410)....

In the WEST system world, I'd have thought 410 "microlite" for fairing and filling moderate pock marks and such, then either microfibers or 404 filler for more structural applications. Phenolic microballoons are similar to 410 (though not the same), better than glass as a filler/fairing material (bondo replacement) but not as good for more structural applications. Glass microballoons are cool.

I guess cotton flocking is popular with aircraft? Any pointers to discussions of why that is? I'm not familiar enough with it to know why it would be picked over another material.

Fumed (colloidal) silica is also extremely important for controlling the working characteristics (viscocity, thixotropy) of the uncured epoxy for filling (even when using other filler materials)... the stuff is extremely light and I can't really imagine doing much epoxy work without it. Aerosil/Cabosil are name brands.

 

[osxuser]

I picked up a small "package" from spruce with the slow hardener (Socal ). I plan on using the 5.8oz S-glass for most everything I do. I've seen some pretty good results with that. If I have to I might pick up some lighter stuff later on. I do wonder sometimes, i'm pretty good with fiberglass, why the heck did I start building a metal airplane? Oh yeah, lack of design compromises...

 

[mlw450802]

more glass info

And how much will I need to complete canopy fairings appoximately? If I order e glass and B-D fiberglass can I mix the two if I run out of one? Is it right to surmise that because of its lighter nature that e-glass is more pliable and therefore more versatile than the B-D? Are tha applications for B-D limited while the e glass can be used in more places? Thanks for posting the fiberglass primer in a previous post it was a big help.

Jim,
Here is a link for more info on glass http://www.sweetcomposites.com/Fabric.html

Generally the composite cloth is available in two primary weaves and in many different weights. The two weaves are 'uni' ,which stands for unidirectional and means that the weave predominantly contains strands in one direction, and 'bid' or 'b-d' , which stands for bi-directional where the weave is roughly equal in both directions and at 90 degrees to each other.
Bid cloth is used when compound curves are going to be formed because the weave is so conformable when it is cut on a 'bias'. That means at an off angle to the weave and generally means at 45 degrees.
The primary strength of any layer of the layup is in the direction parallel to the glass strands in the weave in that layer.
If you want to increase stiffness and strength in a given direction, just add more layers of cloth with fiber orientation that is predominantly in that direction.

 

[mlw450802]

I guess cotton flocking is popular with aircraft? Any pointers to discussions of why that is? I'm not familiar enough with it to know why it would be picked over another material.

Jon,
Cotton flocking is used whenever a fill needs to be structural and not just aesthetic in nature.

-mike

 

[RV7Factory]

Some Links

You have already been given a link to Jim's page, but I have tried to compile a short list of Fiberglass links on my Resources page. If you come across any others, please let me know, I would like to add them to the list.

 

[dgrayent]

Flat, smooth sheets

If, for some reason, you might want a FLAT SHEET (floorbords, etc.) OR a piece that might eventually be bent to a slight simple curve, you can do your layup on a piece of clean, unwaxed window glass (or mirror) with the peel ply over as many layers you of weave (saturated in resin) you want. Roller or squeege out, well to the sides, the excess air bubbles and resin. Wait a day. Remove the peel ply and and pry the piece off the glass. It is REALLY flat and smooth as glass on one side. Trim the piece to your needs.

The dacron covering (Ceconite, Poly Fiber -- same stuff) for fabric planes makes pretty good peel ply. Maybe you know someone who has done a rag-and-tube plane?

 

[rv8ch]

Fiberglass

I do wonder sometimes, i'm pretty good with fiberglass, why the heck did I start building a metal airplane? ...

Come on over to my place - you can finish off my cowl and other little bits of fiberglass! Seriously, I'd really like to know how people get good with this stuff. Is it just a lot of practice, or are there special tricks you need to know? I guess my major problem is that I have trouble drawing a straight line with a ruler - forget about shaping a compound curve.

When I see airplanes like Cory and Patti Bird's Symmetry, I'm just in awe.

http://www.eaa.org/benefits/sportaviation/0411_symmetry.pdf

 

[avaviat]

Jon,
Cotton flocking is used whenever a fill needs to be structural and not just aesthetic in nature.

-mike

Interesting. I'm guessing that it changes the working properties as well as providing a semi-structural fill? So by using cotton flox you can skip the colloidal silica? Or am I missing something?

I guess what I'm really saying is I have a whole bunch of glass and phenolic microballoons, milled glass, chopped glass, powdered graphite, colloidal silica, talc, even a few tubs of WEST patent fillers and so forth from the time when I considered working on sailboats to be a fun and rewarding way to kill a Saturday...

Is it worthwhile to get some cotton Flox and learn how to use it, or should I stick to the materials I'm used to and have gotten very acceptable results from in the past? I'm betting milled fiber and colloidal silica will do the same job as cotton flox? Any resources with the properties of each?

Thanks!

 

[avaviat]

If, for some reason, you might want a FLAT SHEET (floorbords, etc.) OR a piece that might eventually be bent to a slight simple curve, you can do your layup on a piece of clean, unwaxed window glass (or mirror) with the peel ply over as many layers you of weave (saturated in resin) you want. Roller or squeege out, well to the sides, the excess air bubbles and resin. Wait a day. Remove the peel ply and and pry the piece off the glass. It is REALLY flat and smooth as glass on one side. Trim the piece to your needs.

I once laid up the plug for a mold on a glass substrate and had one of those murphy moments where everything that can go wrong does. The epoxy adhesed to the glass so well that prying the plug up ripped chunks of glass out of the surface. Nice little conchoidal divets pulled out of the glass on one side, and the (double strength window pane) glass broke on another side. I spent a couple hours trying to get the glass off the plug, ruining it in the process.

 

[mlw450802]

Is it worthwhile to get some cotton Flox and learn how to use it, or should I stick to the materials I'm used to and have gotten very acceptable results from in the past?

dunno. My experience with the stuff is from the 80's when I was partner in a build of a Q2 so I am not an expert. Just parroting the reasons spelled out in the instruction manual at the time.

I'm betting milled fiber and colloidal silica will do the same job as cotton flox? Any resources with the properties of each?

Thanks!

You sound as though you have more experience here than I do. Perhaps the other fillers you mention were somehow nastier or more irritating than the cotton?? It was pretty benign. I know that the dermatitis I got while working for the year or so on the Q2 made me shed like a snake after practically every layup session. This occurred after about a year of exposure and I am not looking forward to the glass work on the RV. I'm saving every last bit till the end, hoping I can finish before sensitization sets in again.

-mike

 

[avaviat]

LOL... I have the worst sort of experience... I've done something similar but with totally different goals and constraints... which means I've learned a set of biases that may be totally incorrect.

I bet you are right about the irritant factor. All of the powdery inorganic fillers (glass microballoons, milled glass, colloidal silica) can cause silicosis-type problems if you breath them too often. Cotton is probably a lot more benign.

Sorry to hear about your epoxy sensitivity. Stay away from the stuff....
Maybe there is another builder around who would do the epoxy work on your plane in trade for help on theirs? If not, hire someone to do the work and supervise from a distance. Sensitivity doesn't go away, and it does get worse with continued contact. I (so far) haven't faced it first-hand, but I watched a boat builder make their life truly miserable by not facing reality about their new-found allergy to epoxy. It was miserable to see them after they did even a little bit of epoxy work.

Thanks,

 

[jcoloccia]

Seriously, I'd really like to know how people get good with this stuff. Is it just a lot of practice, or are there special tricks you need to know?

It's just like doing aluminum work. 90% is in the preparation. If everything fits well and is layed out well, it's easy. If you're randomly cutting pieces of glass figuring that you'll trim it later, and just kinda making it up as you go along, it's WAY harder. In any event, just stick with it as it really does get MUCH easier with a little bit of time and practice...in the end you may even start looking forward to glass work because it's so darn easy once you've figured it out.

One thing, though: use the sharpest damn scissors/knives/rotary cutters/whatever you can get your hands on, and replace/sharpen them when they dull. Just this one thing will make life much better.

 

[mlw450802]

good basic article on composites

Interesting. I'm guessing that it changes the working properties as well as providing a semi-structural fill? So by using cotton flox you can skip the colloidal silica? Or am I missing something?

I guess what I'm really saying is I have a whole bunch of glass and phenolic microballoons, milled glass, chopped glass, powdered graphite, colloidal silica, talc, even a few tubs of WEST patent fillers and so forth from the time when I considered working on sailboats to be a fun and rewarding way to kill a Saturday...

Is it worthwhile to get some cotton Flox and learn how to use it, or should I stick to the materials I'm used to and have gotten very acceptable results from in the past? I'm betting milled fiber and colloidal silica will do the same job as cotton flox? Any resources with the properties of each?

Thanks!

Jon,
I came across this article on the EAA site. Hopefully you are a member because it requires a log-on.
http://members.eaa.org/asplogin.asp?asplReq=%2Fhome%2Fhomebuilders%2Fauthors%2Falexander%2FPart+2+Basics+of+Composite+Construction%2Ehtml%3F

It talks about relative strength and uses for the various fillers.

-mike

 

[DanH]

Pitch the Pumps

Do yourself a favor; eliminate cheap epoxy pumps from your shop. They are not accurate 100% of the time. Air bubbles and partial dispensing per stroke are the primary offenders. Inaccurate resin/hardener ratios result in understrength parts at best. Very few things will piss you off more than layups that do not cure properly, in particular if they were an addition to an expensive factory part.

Instead, look around for a simple beam type gram scale, new or used. With a beam scale you can mix ANY resin/hardener system by weight, a dead accurate method. Bubbles don't matter anymore as they don't weigh anything. You can now choose your dispensers too. Clean squirt bottles from the condiments section work great. Squirt directly into the cup on the scale, no more drippy cans. A gram scale is best because the graduations are 1-10-100 multiples; easy to calculate ratios. Capacity is just right for everything from a little cup of T-88 to a big cup of SafetyPoxy.

About the only downside to mixing your epoxy with a scale is that some fool is sure to peek in your shop and figure you for a drug dealer <g>

Dan

 

[trib]

Interesting. I'm guessing that it changes the working properties as well as providing a semi-structural fill? So by using cotton flox you can skip the colloidal silica? Or am I missing something?



Thanks!

My last experience was with a plastic airplane- a dragonfly. Believe me, it's a lot more fun working on metal! The difference is that the micro and the like are fillers. Ever try sanding pure epoxy? It's very difficult. The fillers provide an easily conforming material which occupies the volume of the space so that epoxy does not. Depending on which one, it also makes it easier to work. If you could occupy the space with microscopic air bubbles in a homogenous mixture, then you'd really have it easier to work. The difference in the cotton flocking is that it has fibers and therefore provides some structural integrity also. Similar to chopping up fiberglass fibers and mixing them. No directional control, however, such as mentioned earlier with bidirection or unidirectional cloth. The reason it is not a good substitute for the micro, is that it absorbs epoxy just like your cotton socks absorb water in the wash. Subsequently, it's pretty much just like sanding pure epoxy. Stick with the micro for filling for appearance. The cotton would be good if you needed to fill a crack or a hole (i.e. for redrilling). Not really any preplanned use for the RV's.