How do you remove the peel ply layer of a resin infused part? If the part is cured, will the nylon release from the surface of the composite (carbon for example)? Or does it need to be removed before fully cured?
You can remove the nylon after it’s cure. Nylon does not bond to the laminate.
Sweet 
While i have you here…
Is there any problem with leaving the bag under full vac overnight for cure?
Also, if one did not have access to a gelcoat gun and needed to lay down some gelcoat (not epoxy hehe), can an HVLP gun be used? I have a new one in the box I picked up many moons ago but never used. What size nozzles do I need and I saw someone mention thinning out the gelcoat w/ acetone?
you want to keep the gelcoats viscosity the way it is because that is one of the properties of it so it will stick to the sides of the mold without pooling in the bottom. How big is you mold? You can just brush on the gel. I have left my things going overnight before but it does wear on your pump. I usually leave things bagged for about an hour and a half. A lot of people pinch their lines and release vaccum but I am infusing so i want to keep the suction.
I’m going to have to disagree with EMI here for a little bit. You can thin down the gelcoat with acetone. If you spray it up to 18-20 mils you’re going to be ok. If you thin out the gelcoat and brush it on, THEN you’ll see that it’ll start to run off. Acetone evaporates as you spray it out of the gun. It doesn’t stay on the mold, at least not for long. I would much rather spray the gelcoat and get a consistent finish then brush it on. Unless you can brush it on perfect without any brush strokes, then it’ll show up in the final part. Not pretty.
As far as how big the nozzle should be, I think anything 1.8mm and up will do. 2.0mm is good and anything 2.2mm and above would be best.
Sorry again, it would be bests to leave the laminate under vacuum while it’s curing. However, you can go ahead and turn off your vacuum pump once the laminate has gelled up completely. No need to hurt the pump by leaving it on all night.
good call. I have never sprayed it out of a HVLP gun before. I did not know the acetone would evaporate when you spray it out, good info to know. Keep at it and if in doubt always ask. Evan has an answer for everything
I don’t know how to get my bills to pay themselves yet. So no I don’t have the answer to everything.
but when you do find out, share the wealth 
Thanks evan!
I was thinking about putting a few valves inline to the pump so I could just close off the line and remove the pump w/o loosing vac. Fish tank valves might work, I know they make el-chepo manual boost controlers :lol:
Roughly how much should I thin out the gelcoat before spraying w/ lets say a 2mm nozle? Just enough to get it through the gun (trial and error) or a base % of the total weight?
Thanks!
James
I go as high as 20% acetone sometimes. You’ll have to play around with it a little bit. I’m no expert in the spraying anything department so I can’t go into it in details.
If you were laying down clear gelcoat as the first layer in a vac infusion, could you do it with a brush instead of spray? I’m not sure if the strokes would show through, since they gelcoat should conform to the surface of the mold while still liquid(ish).
Yes, no?