I was getting my board ready for a repeat hoatcoat and there are some areas that need another coat but have already been sanded with 300grit. Should I scuff them up again with a lower grit to make it stick?
yes. 100grit will work
I would. I glass and hotcoat with epoxy, and always sand with 100 grit, if the prior coat has cured. That's just me, I know some guys here go with much finer (higher) grits.
Just to clarify I am using PE resin.
it's not how scuffed up the surface is.
it doesn't matter what grit finish it is.
...............................it's about how pure,clean,non-corrupted.
herb
“.it’s about how pure,clean,non-corrupted.”
O Herb. something true rare to find.
More critical with epoxy than with poly,
but never the less ~ keep finger off once sanded!
Mahalo, Rich
Hot coat is a filler coat using PE resin(lam resin/styrene/catalyst)
Filler coats(Pe or Epoxy) are done over a just laminated/just past sticky side of a surfboard. Why do you sand prior to any filler coat???
So a PU/ PE board and others eps/epoxy boards you sand the whole board 3 times???
[quote="$1"]
Hot coat is a filler coat using PE resin(lam resin/styrene/catalyst)
Filler coats(Pe or Epoxy) are done over a just laminated/just past sticky side of a surfboard. Why do you sand prior to any filler coat?????
So a PU/ PE board and others eps/epoxy boards you sand the whole board 3 times????
[/quote]
You are correct about the purpose of the hot coat, but I had some burn throughs after my initial hotcoat sanding. I didn't really notice them until I went to clean the board and it really showed after I got the dust off with a little denatured alcohol. I was having some issues with my hotcoat initially and thought it didn't cure due to the temperature I was working in, but it cured over 24 hours and then I just did alot of sanding to get rid of some small dips.
Consider doing a gloss coat next time… they really don’t add much weight and, for me, the pros out-weight the cons