So lately only over the past 6 weeks or so I’ve been having a huge issue with air voids in our laminates under the gel coat. Because of this I now make all of our parts with out gel coat. Once we demold the parts we now sand, spray with vinyl ester duratec, sand, and clear coat with HPC15 by Sherwin Williams.
Anyways to keep it short and simple. We infuse, have zero air leaks, and when we demold there are air voids here and there. We’ve been using the same resin for 6 months and been mixing it the same way for 6 months and have never had problems up until recent.
To describe the procedure… We wax and PVA the mold, gel coat with duratec vinyl ester clear. We then wait till its mostly cured, and put the fabric in. Usually 5 layers of carbon with a little super 77 to hold it down nicely. Release coated peel ply goes over the top with one layer of flow media layered after that. Sometimes we’ll put a second layer through the center to speed up flow if not a full second layer. We vacuum at full force and infuse with a nicely sized hose. We use two resins. One is at 210cps and the other is at 350cps. Always catalyzed with MEKP or MCP slow hardener. We let cure at room temperature, and then post cure in mold under vacuum at 130 - 150. We demold later that day or the next day.
We are getting ready to make some big parts, and I’d much rather just sand the gel coat and clear coat instead of having to gel coat the entire cf piece after demolding, wet sand, then gel coat again to fill up remaining pin holes, then sand and clear once or twice.
Any ideas? Thanks!