Cold forming plywood question

[tvrgeek]

OK. I have a buck to the shape I want my board.
After the second one, got a vacuum pump that works.
Made a platen and bag. All working ( doing a veneer right now)

I was able to convert some 3-ply birch to two ply. Much more flexible.

Question: For addition dimensional stability, would it help if I used a layer of fiberglass cloth in the middle layer, well saturated with the power resin glue of course. Or would I be better off just making it 5-ply with a layer of veneer in the middle. (6 if counting the veneer on the surface)

 

[Woodmolds]

Depending on final thickness, curve, etc. More layers of veneer(thinner plys) the more stable the final product(no spring back). Gut feeling is fiberglass will add nothing and could cause problems later.

These are just my opinions and are not based on science just my experiences.

 

[Phil S]

You might want to consider carbon fiber instead of fiberglass. How big is this piece? I might have some in the freezer

 

[tvrgeek]

Dashboard for a Triumph stag. About 6 high and 16 long. Curve is about 2 inches over the length. Final thickness is about 10mm.

Isn't CF very hard to bond to?

 

[Phil S]

I checked the supply but I have prepreg CF, which means it is pre-impregnated with epoxy resin. We keep it frozen at 0 degrees and it must be used very quickly when it thaws. Real hard to send to you frozen.
Upon further review, a biaxial weave fiberglass in a 6 to 10 weight will work. Laminate it with a slow curing epoxy - Something from West or System 3, not the polyester epoxy from the big box. Use 25 min, better 27 vacuum for 8 hours. Hope this helps

 

[tvrgeek]

I had thought about using West to do the glue up, but testing showed too much bleed-through on the veneer, so using the powered resin glue. West is also more flexible than the resin glue. Having the epoxy available just a pump away was real handy. Might just do one as you suggest and one with the resin to see how they compare. Nothing beats testing when learning new things.

 

[Roy G]

What was the original piece made out of? Was it a plywood or solid? I know the interior of a car varies greatly in temp but how strong does this replacement need to be?

Roy G

 

[tvrgeek]

It was 10mm ply. Some water damage caused some de-lam. Imagine that, A British car that leaks. Redoing mostly as I am moving the gauge positions slightly. Otherwise I would have just re-veneered. None of the pieces are structural other than holding up a switch.

 

[tvrgeek]

Making progress I guess. Basic glue-up for the cluster only sprung back a mm or so, and I can deal with that. Double side veneer is next.
Here is my dirt cheap vac rig. Shower liner as it was a lot cheaper than clear vinyl! MDF platen with cross cuts on the inside. Also the original cluster panel.