some fiberglass questions

[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]

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]

Originally Posted by 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

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]

Originally Posted by JimWoo50

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]

Originally Posted by avaviat

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