I have made several mold and tried several process but none really gave me a standout performance when releasing.
My molds coated with a feather fill primer and sanded up to 1000 grit.
so, do you guys have any recommendations for the buffing, polishing and waxing? What types of products do you guys like to use?
thanks!
Your mould is coated with primer, or your plug is coated with primer and then you make the mould off that?
Primer filler generally doesn’t polish up nicely, unless it is made for the job like Duratec surface primer. You can of course spray your plug with high build primer, and just sand it flat to a high grade like 1200 before pulling the mould off that satin finish. Then you can sand the mould up to 2000 or 3000 grit, and compound from there. I would recommend going up to 2000 grit as a minimum, as tooling gelcoat is quite hard and can be difficult to polish up to a full gloss, even with a machine polisher. I’ve had success from 1200 grit and compounding, but 2000 is just quicker, even with harsh cutting compounds like the Pai Crystal NW1.
its Feather fill which polishes up nice. I am just trying to figure out how to take it one step further since i have an infusion that i want a really nice fish on out of the mold.
Feather fill just means it’s thinned more than a regular primer filler, so that doesn’t necessarily mean it polishes nicely. If yours does then ok, sand it up to 2000 grit and compound.
There’s no real secrets to getting a gloss finish. It takes the right products and a good bit of practise.
Correct but what buffing and polishing compounds have you found that work best? Meguiars polishing compound?
post #15 here shows the last part that was made but you can see that it doesnt have a very clear finish.
http://www.compositescentral.com/showthread.php?t=9855&page=2
Meguairs is rubbish. Best I have used is the Pai Crystal range. Outstanding stuff, and it’s black so if you have any pinholes it will hide them rather than highlight them.
Alternatively, 3M is also ok. More meant for paint work than our sort of work, so it takes a bit longer.
yeah i cant even get that stuff locally. I will see if i can get the 3m stuff… but that may not be available.
Generally you would do a med cut then a fine cut? Any steps after that apart from applying a mold release?
I would do a hard cut, then a medium cut, then a soft cut. After compounding I always clean the mould with MEK, to ensure that the release agent won’t have any issues.
cool i just want to make sure that the polishing compond doesnt mess up all the sanding time i put into it.
Lastly you apply a mold release and a pva?
any tips for infusing on glass? Just mold release and pva?
and thanks for your help!
Yeh it can be tricky, I do think there is a bit of an art to sanding and compounding. I’ve by no means mastered it, but I have had better results and worse results and I try to just repeat what works.
I only use semi-permanent release systems, no wax. PVA I used to use to make moulds, but I always sprayed that. I would definitely advise spraying it if you can, it’s infinitely better than brushing or wiping it.
Using glass can be tricky, as a lot of release waxes don’t actually work on glass due to how slick it is. What happens is you apply the wax, and then when you buff it off it actually comes off entirely and none stays on the surface. I do however know for a fact that TR-108 release wax works on glass, and works well with PVA. I would always recommend using a chemical release agent on glass though, much much better system.
I started using this method. I finish the plug with rattle can primers to bring it to perfectly flat sanded up to 400 grit. Then I paint it with 2k clear made by spraymax. 2k is a 2-part urethane that comes in a rattle can. After it dries, you can buff to a perfect finish. Can pull beautiful glossy parts off it.
Wet sand the mould (we use washing up liquid in the water and change the water when changing to a new grade of paper). Wash the mould down after each ‘grit’ of abrasive paper.
When polishing/buffing change the mop heads when you change compound and wash the mould down with warm soapy water before changing to a less course compound.
It helps to keep the mould wet when buffing.
The secret to a high gloss mould is time!