resin

is there a difference between hot coat resin and laminating resin if so what

Parafin wax in Hot Coat. That is all.

to elaborate a little:

the wax agent in sanding resin (the hotcoat resin) rises as the resin kicks, giving it a sandable finish when its cured. laminating resin, after cured, will always remain tacky, and will gum up in your sandpaper if you try sanding it.

… I learnt the difference after mi 10th board…

Swaylocks didn’t exist 10 years ago.

My understanding of polyester resin chemistry is that it is “air inhibited”. This means that the surface exposed to air will not completely cure.

We dissolve a bit of paraffin in styrene and call it “surfacing agent”. Added to lam resin, during curing the paraffin (wax) is supposed to rise to the surface, seal it from air, and allow full cure. This full cure allow the surface to be sanded without gumming up the sandpaper.

The requirement that the wax rise to the surface has me a little nervous using UV cure resin for hot coats and finish coats. I worry that the wax won’t rise quickly enough, but so far, I brush it on, cross stroke, long stroke then clean up the brush before I take the board into the sun for the great 90-second cure. I have not had this method fail - yet - and I won’t push it any faster, either.

You can also achieve surface hardness when doing patch work, but containing or covering a lam resin patch with a bit of sheet plastic, mylar,wax paper, or acetate. Acetate in particular will leave a very flat shiny finish when peeled away from a cured ding. Makes one want to think about how to do a full board surface with this stuff…