Hi,
up to the stage of hot coating my first two boards but don’t have access to any styrene surfacing agent, sanding resin etc… Will the board be too soft with just a resin coat over the lam stage? Or is there another alternative to the regular SA?
thanks in advance!
Dan
If you want to be able to sand the board smooth without it gumming up your sandpaper, you have to keep oxygen away from the surface of the resin. That’s all the wax is doing. It’ll be lumpy as all heck and a pain to sand, but you can brush on your filler-coat and wrap it with plastic stretch wrap, Saran-wrap, or pretty much any thin plastic film and it’ll cure up enough to sand.
Thanks so much! I shall try that 
how much extra hardener should I use?
You don’t need to get the oxygen off when the resin is wet. You can slip the gelled board in a vac bag for an hour too.
Yeah I was thinking to let it set for a while then throw the plastic on top!
Long long ago, in a galaxy far far away, I saw no less a personage that Pat Curren , shave thin flakes of paraffin into a small amount of acetone that was added to lam resin to make it sandable. Just one of many ways to skin the cat.
That would be great but you have some disagreeables in this thread…
http://www.swaylocks.com/forums/replace-wax-styrene-surfacing-agent
might make a small batch up first to test it out! Have you done this yourself or have an idea of percentages I need for wax and hardener?
I’ve used waxed paper on ding repairs and on top of a fin panel and squeegied out the air and it works perfectly. Might be a bit much to do on an entire board but where there is a will there is a way.
No, have not done it myself, just reporting something that I observed. If I did try it, I think I’d melt the wax first, and then add it to the acetone before mixing with the resin.
I wonder if you could just melt some paraffin (gulf wax used for canning) and add that to lam resin? I may try that just for the heck of it. or I wonder of you could put melted wax in styrene? Hell they make SA somehow. It can’t be rocket science.
Who makes SA??? I bet the guys at Fiberglass Hawaii know the answer.
Or…maybe they use another kind of wax. Somethingl like Johnsons paste wax? Questions questions
Surfacing Agent is paraffin wax and styrene. Don’t know if would work with acetone but have made my own by mixing shavings of paraffin wax and styrene.
Nice, I’ve got my hands on a candle kit that is mixed paraffin and styrene. do you remember how much you used? Also how much hardener? First go at this… Thanks
5% paraffin wax to styrene and about 2oz surfacing agent per gallon of resin.
Thanks Oahu! I’m sure I could find this but on Friday morning after visiting the in laws I am a little lazy… How much extra hardener should I put in? Used 2% on my lams. Thanks heaps already (again)!
I’d reccomend using a standard catalyst chart for poly resin. I usually kick the hot coat a little hotter than my lams since I don’t need as much working time. For me the surfacing agent doesn’t noticeably affect the reaction so I don’t add any extra catalyst other than what I’d normally use for a given amount of resin for the working time I want and also taking the ambient temp into consideration. Others might have another opinion but this is what works for me and I’ve never had any problems.
Excellent! Thanks for the help, have everything I need now to finish off my first couple of boards :)
What sort of time limit do you have on sealing the hot coat? Can you seal it much later on or does it have to be before it sets hard?