Hello from the US. Sorry this is a relatively long read but if anyone can chime in on my options, it would be much appreciated. (First time writing this my phone froze and the text got deleted) I am currently making a mold for a vehicle hood and ran into a couple problems. I am attempting to turn my car into a full carbon car.

The first problem is, after completing the top half of mold, i trimmed the excess fiberglass using a hackzall to make molding the underside easier. It seems as though the vibrations loosened the hood in the mold. The front corners were sticking off the mold about 2-3mm. Everything else still sat flush.

The next problem is completely my fault 🤦‍♂️. Annoyed by this, and thinking that pva or filleting wax got wedged in somehow, I released the rest of the hood from the mold... after cleaning off the pva and wax, turns out the front corners still sit up about 2-3mm from the mold. I can push the corner down into place but it springs back. Pics will be posted later.

So My first question, is this 2-3mm difference worth scrapping the mold over? Everything else sits flush in the mold except the front two corners. If it’s worth redoing, is it a good idea to resecure the hood in the mold (no idea how to resecure the hood) and start with the underside? That way I can use the already existing flange?

The other question, does anyone have any ideas of how to resecure the already released hood back in the mold? I’m kind of at a loss here. I thought about reapplying pva and clamping the hood in the mold. But the pva will likely not dry of hold the mold down. My other thought was spray adhesive, but I am unsure if this will hold it down/ lead to difficulties eventually removing the hood from mold. If the mold is still worth salvaging I would like to resecure the hood in the mold before preceding.

Last question, is VE resin a better choice to use over tooling PE resin? Will it shrink less?

Unfortunately, I do not have affordable access to the uni molding system. Nor have I found a similar system available in the US. Epoxy is also out of my current price range. The mold bulk was made with unfilled tooling isophthalic poly resin. The manufacture claims it is a very low shrinkage resin meant for tooling. I added layers very slowly (never more than 2 per day) to prevent over heating of the resin.

-4layers of tooling poly gel goat was sprayed for a total of ~22mil
-after 3-4 hours the first layer of .75oz fiberglass mat was applied. The layer was allowed to cure for a minimum of 24hr.
-the surface was abraded and another layer of .75oz mat was added. Cured over night.
-surface was abraded, added a layer of 1.5oz mat. Cured over night
-surface was abraded, added a layer of 1.5oz mat. Cured over night
-surface abraded. Added two layers of 2oz. Cured over night.
-surface abraded added a layer of ~580 gsm biaxial +45/-45 that has .75oz mat stitched on the back. Let sit for 3-4 hours and Added cardboard tubes cut in half with 3 layers of 2oz mat to secure tubes using vinyl ester resin (ran out of poly).

Mold thickness is ~ .34-.40in depending on where the overlaps were.

For bonnets (hoods), you don't actually need an excellent fitment between the outer skin and the inner skin as the adhesive you use should do some gap filling anyway. Obviously you don't want to be too liberal, but 2 or 3mm will work out. So your mould is probably still useable. Given you have demoulded already, use the opportunity to inspect the mould for any signs of excessive shrinking in the surface of the mould, as this is hard to fix. You don't need to secure the bonnet back into the mould super well, as you will need to seal the edges again with filleting wax anyway. Just do the best you can.

Potentially the biggest issue may be that the 2 or 3mm of shrinkage has affected the fitment of your bonnet, as being 2 or 3mm out can make a huge difference to panel alignment. This is really your call, but for me there's no point starting from scratch yet, you may as well complete the inner skin mould and make a part and see. If you later decide you need to remake the first mould, you can still use the second mould to do so, you don't have to remake the entire mould. So it is worth a try.