Quote:
Originally Posted by wyatt
Jim,
I see in post #250, you detail a lot of the materials used. I was wondering where you got your materials. I can get the lumber easily enough, but things like the fiberglass cloth and epoxy resin I am not so sure of. I wouldn't be going for a showroom finish, but I do like the idea of being able to get smooth complex curvature easily from the foam.
Also, you say that Elmer's wood glue can be used in lieu of epoxy, but it has to be sealed. Would sealing with a topcoat (or two) of pigmented epoxy work, or are there better/cheaper ways? Thanks in advance!
Wyatt
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Hi Wyatt,
If I recall correctly, U.S. Composites was where I got the cloth and epoxy resin. I used #6 cloth and this is what I have used many times before. For small, tight areas, I selected the thinnest they had at #2 thickness.
If you choose to do multiples layers, like in high stress areas (think mounting), then I would wet out the cloth with resin, and save the Elmers for areas with just one layer. Doing this you can still cover 80% of the tail with Elmers.
Yes, in many ways Elmers Wood Glue is easier than epoxy to work with.
1) A full size motorcycle fairing was made with foam and glass cloth wetted out with Elmers Wood Glue. It is still going strong to this day.
2) In pure bending loads, the Elmers glue has 75% of the strength as epoxy does. This was measured by a two inch thick foam slice that was 2 inches wide and 14 inches long. One sample was wetted out with Elmers glue and the second with West System epoxy. After allowing to sit for several weeks, both samples were tested by loading each beam in the middle and checking for deflection. The Elmers glued piece flexed only 25% more with the same load. From a real world practical standpoint strength wise, they are both equivalent for our purposes.
3) The Elmers glue does need to be sealed in some way to keep rain from contacting it. All the layers of primer and finishing coats on the motorcycle fairing has worked great. The only caution is chipping. If a rock gets kicked up in the road and hits the paint, it can and will cause chipping which needs to be sealed to keep the Elmers glue safe.
4) The Elmers glue wets out the cloth very nicely and adheres well while drying. In this respect it's actually better than resin in my experience. In contrast the West System epoxy is thinner and I have to wait longer to keep the cloth adhering around tight bends before moving on to other areas when bonding the cloth to the foam. If working with a hair dryer, the Elmers glue gets thick very easily and will hold the glass in position very nicely.
5) I would have no reservations about using Elmers on the tail of the car, especially if construction costs were a major concern.
6) A sealing coat of epoxy over the Elmers glue sounds like a good way to seal things up. The epoxy is harder than paint and probably more chip resistant as well. In my experience, the paint can chip off in big chucks (1/2" dia.) if hit by something off the road just right.
Hope this helps, Jim.