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alpinelakespilot2000

Well Known Member
I just did a practice lay-up of fiberglass for the first time and have a couple questions. My knowledge of fiberglass is limited to what Sam James offers in "Fiberglass 101." I layed up four layers of BID cloth on top of each other with West Systems epoxy between each layer. The finished results look like:

Top side-
In low places on my sample piece, the epoxy left an almost glass-like, hard, glossy and smooth finish. Presumably, the low spots allowed the epoxy to slightly pool whereas on the higher edges, the texture of the cloth can be felt through the epoxy. Are both of these normal and OK? Will both finish the same?

Bottom side-
In places where I layed up over waxed clear packing tape, the bottom surface is smooth and glossy. In places where I layed up over waxed electrical tape, the surface is smooth but with a matte finish. Not sure about why the difference, but is one better than the other?

Any other general suggestions? Thanks.
 
alpinelakespilot2000 said:
I just did a practice lay-up of fiberglass for the first time and have a couple questions. My knowledge of fiberglass is limited to what Sam James offers in "Fiberglass 101." I layed up four layers of BID cloth on top of each other with West Systems epoxy between each layer. The finished results look like:

Top side-
In low places on my sample piece, the epoxy left an almost glass-like, hard, glossy and smooth finish. Presumably, the low spots allowed the epoxy to slightly pool whereas on the higher edges, the texture of the cloth can be felt through the epoxy. Are both of these normal and OK? Will both finish the same?

Bottom side-
In places where I layed up over waxed clear packing tape, the bottom surface is smooth and glossy. In places where I layed up over waxed electrical tape, the surface is smooth but with a matte finish. Not sure about why the difference, but is one better than the other?

Any other general suggestions? Thanks.
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Steve, from your report it appears you left too much epoxy in the lay up. Next time try using a plastic or rubber 6" squeegy to remove the surplus glue. Once the glass is wetted out, extra epoxy serves no purpose but to add weight to the lay up. There should be no pooling of epoxy.

In the beginning when Burt Rutan was promoting composit building airplanes, he had us do a 9x9 lay up and take it to a grocery store for a weight check. I've forgotten what it should weigh but my first lay ups were twice as heavy as they should be. Good squeegy work will remove all surplus epoxy and the fibers will be very clear and well defined and not submerged in glue. The bottom of a lay up over wax paper will appear glassy with little or no fibers showing. This is normal.
 
Thanks guys. I went out and layed up another sample and found the squeegee method to take out a lot of excess epoxy. I can already tell this sample will show the texture of the cloth much better with no residual gloss. The peel ply should also help with this and I think I will need to use some anyway in the process of getting a good seal on my aft canopy track. For some reason, I don't remember Sam James suggesting getting rid of the excess in his video, but maybe I didn't watch it close enough. In any case, it sure makes a lot of sense. Thanks for the tips.
 
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Steve

I bought the James video first as well. It is helpful, but I think the video from Mike Arnold is much better. If you want to add to your library, you can check them out here http://www.ar-5.com/

Good Luck,
 
Having come over from the composite world, I can offer a few tips.
I use 3mil plastic sheet from Home Despot or Lowest. Cut the plastic sheet a couple-3 inches larger than your glass all the way around. Lay one sheet down, put your glass on top and wet it out. Then lay another plastic sheet on top. Use a plastic body filler squeegee to first work in the epoxy and then squeeze out the excess into the plastic overage. Then cut away the overage and toss it. You now have a very portable layup. Take the layup to the work and remove one of the plastic sheets. Place wet side down on the work. Remove other plastic sheet. Lightly squeegee to make sure you have full contact. Then blot up a little more with Bounty paper towels. Bounty works best for this.
Then clean up with acetone.
 
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RE:Truth

gpiney said:
Having come over from the composite world, I can offer a few tips.
I use 3mil plastic sheet from Home Despot or Lowest. Cut the plastic sheet a couple-3 inches larger than your glass all the way around. Lay one sheet down, put your glass on top and wet it out. Then lay another plastic sheet on top. Use a plastic body filler squeegee to first work in the epoxy and then squeeze out the excess into the plastic overage. Then cut away the overage and toss it. You now have a very portable layup. Take the layup to the work and remove one of the plastic sheets. Place wet side down on the work. Remove other plastic sheet. Lightly squeegee to make sure you have full contact. Then blot up a little more with Bounty paper towels. Bounty works best for this.
Then clean up with acetone.
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I can say Greg is right on. He and I come from the same world and fiberglass work becomes a habit like breathing......not the epoxy/dust/glass :D .......
Steve Rahm who developed a plans built fiberglasss aircraft has a great video........now if I can just find it :eek:

Frank @ SGU RV7A Engine/FWF FINALLY ;)
 
gpiney said:
Lightly squeegee to make sure you have full contact. Then blot up a little more with Bounty paper towels. Bounty works best for this.
Then clean up with acetone.
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Good idea, Greg. It sounds like a clean method.

I take it to mean that this works for multiple layers so long as you do a good job with the squeegee to make sure each layer is in good contact with the previous layer. It seems like, since you would have already squeezed out the excess epoxy onto the plastic sheet, you would need to pay a little more attention to insure that good layer-layer contact.

Going to make my first attempt at a rear skirt with this method later today and planning on four layers of 8-9 oz. BID cloth. Thanks for the idea.
 
Steve,

With my method you would do all four layers at once.
Stack the BID one on top of the other (on first sheet of plastic) and add epoxy. Then add second layer of plastic and use squeegee to wet out and remove excess like I describe above.
 
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