After I pull parts from my molds there is a print of the 2x2 twill on the mold surface. Parts are coming out without issues, I was wondering if this is an issue and if so what can I do to avoid this?
Is the mold surface dented or just printed? If I remeber right you use Adtech 820 for your infusion? Adtech 820 will leave a fabric print in semi-permanent release agents like Frekote 770nc. I’ve never tried it on just wax but maybe the same things happen. I remedy the issue by clear coating the mold or using a different resin.
I never have print through in the mold because I gel coat before putting the fabric in. I’m scared to infuse with out gel coat :(. I don’t want print through in our molds. I spend lots and lots of time polishing the molds and keeping them nice.
The mold surface is just printed. It seems to come off after waxing for the next part.
Maybe I’ll try a gel coat sometime. I am interested in one that can be brushed on.
Almost any Gel-coat can be brushed on but you having greater chance of not have pin holes and entrapped bubble from infusion when you thin the gel-coat properly and spray it in the mold.
Thanks. What are some gel coats being used that I can get in the US? Do you let it dry before laying your dry fabric?
The print happens because the dry fabrics are compressed to the wax and that seems to be a print through to the mould. After waxing again it is gone.
Use a gelcoat that has a tack free surface and does not need any afterwork before infusion. The best systems are polyurethane systems, some polyesther gelcoats also work. Epoxi systems will not work for your aplication. It should be an In Mould Coating!
Don’t worry about pinholes if you brush your gelcoat, pinholes will only happen if you don’t work with full vacuum and do not degas your resin.
Thanks, that’s what I thought because the marks go away after waxing again.
I may give gel coating a try in my next infusion, but I need to find out what gel coat to buy and the process. Just need my order of MTI hose trio arrive :).
Marine clear gel coat and duratec polyester or vinyl ester top coat. Those are the three I use. when I use the marine clear I reduce it 37% with duratec high gloss additive.
So can I brush this on and then lay the fabric, or does it need to become tacky or totally dry? Is the marine clear gel coat made by adtech?
I too get some print through of the core using Adtech 820. I only used wax as a release.
I’m not sure if its made by adtech, but if you order it from Fiberglass Coatings Inc. You’ll be getting good stuff. The ft. Luderdale bran mixes their own clear brushable gel coat. I’ve used it. If your not spraying gel coat, then you’ll want to use one that is designed to behe brushed on. If you’d like I can forward your info to the management there and they can walk you through the gel coats.
Is this print-thru on the mold surface or part surface?
Maybe I’m not sure what print through is. What I’m seeing is on my part surface. I can see where the edge of the foam core is.
I may be using the wrong term as well, I just see exactly what DDCompound said, its the dry fabric leaving a print in the wax, but its comes off when you wax again.
Kevin, you might be demolding the part too soon. Try letting it cure longer before demolding and see if that helps. Being that you are making a sun roof, you are going to want to heat cure the part in the mold. Direct sunlight will effectually post-cure the sunroof out of the mold and further progress the cure. Ideally you want to achieve a complete cure before demolding. This will make fabric and core print-thru even worse. See thisrecent post that I made on how to reduce or eliminate print-through issues.