Hello everyone, I’m in the costruction of something like 20 moulds, I use high temperatures epoxy formulates, they got a long geltime (2h 30min) so when making a 10+ layers laminate it would take days to complete. I have a job and I also need to sleep, how can I do?
Is it a good idea to make the core layers, let them cure during night and then sand and laminate? Better use peelply? Or better take a vacation day and don’t sleep?
Vacuum infuse the mould laminate. 10mm thick in one shot?
I cannot vacuum bag the plug cause it’s made of polystyrene (the core) and I’m not skilled in infusion
What temperature are you using the moulds at?
120°C, I’m laminating at 20°C, I think that I need a small box heated at 30-35°
If you can operate at 100C or less then you can use polyester tooling resins etc which are much faster and cheaper?
Yes but I need to operate at 120°C not less 
If you have the facilities to cure at 120, can you not use the same facilities at 35-40?
Heat is definitely the easiest solution when trying to rush any resin system.
I suppose epoxy is the only answer then. The heavier the fabrics the quicker you can build thickness.
Infusion is the way to do it, next time you should make the plugs in another way to allow for it.
Is there a trick to making plugs and flanging for infusion molds? All the molds I’ve made the flanging is real delicate and would never allow for infusion…
If you are making a part from scratch then it’s easier, you just design the flanges in and make them part of it.
If you are copying something like an OEM vehicle panel then it’s harder. You essentially have to set up your temporary barriers, splash a quick mould, splash a part with solid flanges, then infuse your mould.
That makes sense. I was wondering if I was missing something, haha
You can really only make them firmer with more support. Some insurance can be to do your gelcoat and first skin wet laid by hand so that you have a vacuum integrity even if a flange should flex. Then set up for the infusion with the bag taped to the outer edge of the skinned layer.
But hand wetting the first layer after the gelcoat won’t trap air when infusing?
I strongly advice you to use the method Hanaldo suggested: It’s the only way to have the necessary vacuum integrity and a vacuum bag that doesn’t pull apart the flanges spoiling all the job.
Thanks everyone, but how you deal with gelcoat? You apply by brush, than laminate first layer and than infuse?
I’ve had the worst luck with applying gel coat by hand. What I use now is a tooling gel cup gun. I’ve been lucky enough to not measure even though I have a thickness gauge. Maybe it’s just the tooling gel I use but it’s the only way I can get good results.
Thank you but what I mean is:
I apply gelcoat, let it gel, apply the first layer (I use 25g/m2). Than I put down the next layers and infuse. Is it correct? Or do I need to let the layer to gel? Will I get air trapping issues this way?
My laminate will be:
Gelcoat
25g/m2
49g/m2
80g/m2
110g/m2
160g/m2
230g/m2
600g/m2 (3 layers)
Why using 25, 49, 80, 110 g/m2 ?
I was using 25,49,80,110 in hand layup because it seems easier for me to evacuate small air bubbles (maybe just in my mind).
Now that I’m trying to infuse I was thinking that starting with very thin fabrics will help me to evacuate the smaller air bubbles near the gelcoat. Is that correct?
Moreover: I’m making moulds, they will go in an oven at 120°C and maybe I will use countermoulds to add pressure, so my primary problem is to avoid small bubbles near the surface and I think that this is more important than a low fiber/resin fraction (right?) So… maybe shutting off the pump when finished infusing could be a good solution?