Hi guys, building a mold and have decided to go with LRTM instead of infusion. I am going to use UV cure vinylester resin so have to make the top mold as clear as possible. I’ve seen some have tried using clear gelcoat for this but said it was too brittle for serious production. There is a polyester resin called 249 laminating surfboard resin that is crystal clear. However, it is UV stable to prevent yellowing. Here’s my question : Will the UV stabilizer in the 249 stop my UV light from passing through the top mold to cure the laminate inside? I don’t want to use epoxy because it can’t be sanded and finished afterwards like poly or vinyl ester resins can. Thoughts?
Yes, the UV inhibitor blocks your UV rays.
Also you do not want to use epoxy on a tool for polyester production. The epoxy will not cope with the styrene attack.
Use a good quality transparent tooling gelcoat, as thin a top mould as you can live with, and think about the detailing around the resin chanel.
This is why UV cure resins never became popular. Many issues with cure.
The uv inhibitor doesn’t block light from getting through. It’s used with uv cure powder all of the time in repairs, glassing boards, fin panels etc…you’ll be fine. The only thing is that with the uv cure and a lot of resin in a small area, the bugger tends to kick off super hot. When we first started using the UV cure some knucklehead put a bucket of the stuff in the sun and it smoked, and melted the bucket so…heads up!
http://shop.fiberglasshawaii.com/resin/polyester_resin/uv_resin
If you don’t mind, how thick of a laminate did you use the UV resin on successfully?
I’ve used it on different projects where the resin is up to 3" thick and has tint mixed in. Pigments will block the UV rays and only the top layer will partially cure. As far as laminating it with cloth, I’ve done it successfully while making 1/4" fin panels using 6oz cloth.