Laminating resin for hot coat

I don’t have any sanding resin but I have gloss resin could I do a hot coat with laminating resin instead and then finish  with the gloss coat. The glass was done with 8 oz volan it’s been a few day since I glassed it so I’m gonna wipe it down with acitone. I couldn’t get ahold of sanding resin and I don’t want to wait to long.

sorry if this has been covered

Ohhhkay, see, here’s the problem.This is polyester resin, right?

When you put the cloth on, you wet it out with laminating resin and then squeegee out the excess. All well and good. That sort-of-hardens, but it  leaves a weave texture showing.Laminating resin doesn’t completely harden in contact with air. The reason for  using it is so that any further resin will chemically bond to it for the best strength, including more glass like a deck patch or a second layer of cloth on the deck, where the rails wrap and so on.

Then, you put hotcoat to it. It’s called hotcoat because you want it to go off quickly so you use a fairly large amount of catalyst, a hot batch. Though it’s really a filler coat for filling the weave.You flow that on, filling the weave nicely plus a bit more. And the hotcoat seals over the laminating resin, which it chemically bonds to.  But it’s never perfectly smooth, you need to sand it.

And here’s your problem. Laminating resin doesn’t harden enough to sand. So what’s used is a sanding resin, which is laminating resin plus a little bit of styrene wax mixed in, sanding wax or wax addative or surface agent it’s called. That wax acts as a surface film like a soap film or oil film on water, sealing the resin and allowing it to harden enough to be sanded smooth, no lumps, drips or dribbles. 

And that sanded finish is rough enough for the very thin coat of gloss resin to stick to. 

Still with me? 

Okay, if somebody sold you all the resin you need to make a surfboard  then they may have thrown in some sanding wax to add to the laminating resin.  If you didn’t get any, well, if there’s boat shops near you, they may have a little you could buy, if you’re in a big rush, but you don’t have to panic. Just keep the somewhat tacky laminating resin from getting dusty and besmegged. You can also get some at most larger surf shops, any board maker or Fiberglass Supply  Directions for use here 

hope that’s of use

doc…

 

Thanks for the response that really helped. I’ll see about getting the sanding wax. I’ve been doing the board in a pretty dusty spot . Will wiping the board down with acitone suffice?

De nada. 

I would be kinda careful about hitting it with acetone, that will tend to soften the laminating resin and any dust on it  will become a permanent part of your color scheme. And that’s probably not what you had in mind.

A good dusting or a gentle brushing with a relatively soft bristled scrub brush to get the dust out of the weave, with a little assistance with the shop vac, that’s probably your best approach, then maybe cover it with some trash bags or polyethylene sheeting until you can finish up. 

hope that’s of use

doc…

Awesome thanks for you’re help

you can cover your lam with wax paper if you find yourself needing to wait long periods before doing your fill coat/hot coat. this should help with the dust.

personally, sanding resin is nice because the mixture is already done, but if you just buy lam resin and wax separately then you’ll have everything you need for any job. I used to make the mistake of doing repairs with only sanding resin, which is really just hot coat. 

What you need is called surfacing agent (SA). It’s wax dissolved in styrene. Sanding resin is the same as lam resin minus the SA. Poly resin is known as an air inhibited type. That means direct exposure to air prevents complete hardening.  When added to lam resin SA forms a barrier between the resin and the air. It rises to the surface as the resin gels and the wax creates a film on the surface. This allows the resin to harden well enough to sand. Using gloss resin for a sanding coat equals wasting money.

You can get small  batches of SA from Fiberglass Supply. Go to this page and scroll down to the “chemicals” section. Look for surface agent   # E47-5367

http://www.fiberglasssupply.com/Product_Catalog/Polyester_Resins/polyester_resins.html