Interesting fiberglass advice

[jsharpphoto]

A friend of mine who builds cosplay sci costumes gave me an interesting tip about finishing one-off fiberglass parts. Let me know what you guys think.

In instances where you are working with one-off parts or not using a gel coat...

"Do all of your sanding and body filler work to get your raw fiberglass surface as perfect and ready for paint as possible. After it is all smooth, mix up another batch of resin and hardener, and brush it over the entire part, to seal and harden any exposed fiber cloth. Then as soon as it starts to cure (dry to the touch but still very tacky) start laying down light dusting coats of rattlecan primer (either "sandable" or "high build filler primer")."

I guess the idea is that the primer bonds to the resin as it cures, eliminating the need for adhesion promoter and creating a chemical bond between the primer and fiber glass.

Any thoughts? He doesn't build anything that has to stand up to much abuse, but it sounds like it makes perfect sense.

 

[SONICJK]

I suppose it would work, but i dont really see the need?
I've never had any issue with primer not sticking to glass...

 

[J-Rod10]

I hit all my parts with primer when I finish them. Seals them off from air, and aids in curing them. Though, I've never had any issue with it sticking after it's cured, either.

 

[Sonreir]

Same. Never had any adhesion problems.

 

[SONICJK]

I hit all my parts with primer when I finish them. Seals them off from air, and aids in curing them. Though, I've never had any issue with it sticking after it's cured, either.

So you're saying you primer wet? like the OP is suggesting?

 

[jsharpphoto]

That's good to know. What about the idea of doing a finish coat of resin after the sanding and bodywork?

 

[J-Rod10]

Yep. Soon as I get done laying my last layer, they get hit with a coat of primer to cut the air supply off, and speed up the cure time.

I don't follow the bondo it, same it, then dab more resin on it. You've just added a lot more sanding by doing that.

Though, I guess if you are using it as a part, rather than a plug, it would create a tomb around the bondo and keep it from cracking as easily.

 

[jsharpphoto]

that's my thinking, kind of to encapsulate the bondo. maybe it doesn't need to be an all-over coat, just over areas of significant body work..... but if you have significant body work on a one-off FG part, you did something wrong.