help please.....Duratec Sandable Primer for mould surface.

For the normal polyester products no, but they make many specialty products and may have a product that might be better.

 

They spray Duratec over fiberglass/epoxy as a tool serface sometimes, the guys I have been talking to about it (Carbon racecar parts shop) do it all the time. They say just make sure to scuff up the surface really well with 80grit before you shoot. I don't know about putting it right over a solid epoxy surface. I know that poly doesn't have the best bond with epoxy, but it seems to be working for the pro's, so I'm going to trust them on this.

 

I just got off the phone with Denis over at Revchem, he said that as long as the tool doesn't get to hot, Duratec Surface primer would work alright, but it would be better to shoot it with Duratec vinalester primer, sand that, then shoot it with Duratech high gloss coating and wetsand till smooth.

 

VE's do bond better and I recommend the their VE product to many of my customers. I just hate to make claims on bonding polyester or VE to epoxy, because while it does sort of stick, its not near the bond you get when using one of these two products over a substrate of similar chemistry.

 

wa, you need to start final sanding over ONE material-whatever it is-at 80 grit(at the finest)-and not go thru to another material of a different density. If you go thru and keep sanding you will be creating waves. From pictures on your site it appears you may have already done that with coarser grit-and if so-it will be almost impossible to correct. Ideally, you would have used a material that when finished with 36 grit would have been one uniform color.

 

My tool is sanded to 80 grit, and the surface is one material (fiberglass), this is a prototype tool (read "one or two off), not a production mould (its to help me learn the process before I try a real plug and mould), the foam goes on the outside of the first skin and gets faired before the second carbon skin. the hull will spend a most of its time out of water (read "foiler that actually flies). The guy helping me learn owns a carbon shop http://ebscarbon.com/about_ebscarbon.asp, he seems to think my tooling is fine, so get over yourself)..... please go away doug stay out of my threads, please stop poisoning the name of all that foils, you turn people off before they can even get turned on. The only revolution I see is the one against You.

 

For those wondering about epoxy/duratec bond issues, I just recieved this e-mail from Bill Beaver.

"I did use epoxy resin on my mold and microlight to fair it up. Then shot the thing with Duritec Easy Sanding Primer. I haven't had any problem with duritek sticking to epoxy to create a mold surface. Its certainly good enough to pull a dozen parts out of and probably a couple dozen parts.

Cheers,
Bill"

So if your planning to build a simple mould that you want to pull a small run of parts off of, Duratec over epoxy should be fine.