I just put on the hot coat and sanded it down but now it looks really dull in some spots and in others it still looks real glossy, how do I get all of it to look glossy again?? If this is possible. Do I just sand it down with 240 grit or such???
In most cases the hotcoat shouldn’t be shiny at all. That’s the job of gloss resin. If you are not going to gloss coat, then you can finish the hotcoat with anything from 320 to 600 grit. If you try to polish it out, it will get somewhat shiny, but never as good as a gloss resin would.
Mostly, hot coat finishes have a matte finish. Doug
If you used a long solid sanding block or a large electrical disc sander those shiny spots may be slight depressions that need to brought up to the level of the rest of the hot coat. I call that procedure “spot coating”. I mark beside the depression with tape, sand them with a small piece of sandpaper, re-hotcoat those areas, then sand to blend.
Ride on. Tom
if you are going to gloss coat those dull spots will brighten right up after the gloss coat dries. In either case you’ll want to get the whole board dull. Even if you are not going to hot coat, at the early sanding stages it is all dull the brightening will come with the finer paper and polish.
I agree that the bright spots may vary well be low spots that your sanding has passed over. If so dull those spots as well before recoating to ensure a good bond.
No need to sand your hot coat to 240 before gloss cloating. Seems most people here are sanding hot coats to between 100-200 grit before the gloss.
(others chime in here if I missed).
100 grit works well
uh did i hear something about hotcoat wont get as shiny as gloss?..yeah it will ,it just isnt as easy i guess,its all the same resin you know…you can polish hotcoat just fine if you know how to sand …but i dont know how,but i know its possible cause ive seen it done…ive always heard gloss is no good, just polish hotcoat …but if i was an expert id not be typing on my compooter…
Have, I disagree with you on the ability to get as goood a polish with sanding resin as with gloss. I’ve done ding repairs using gloss for the final stage, and I’ve used sanding resin. The sanding resin can shine up almost as good as gloss, but it never seems to get to that final stage of high shine. It seems to be softer.
Dings repairs ok, but getting an entire board’s worth of hot coat to polish up to a high shine…?
But here’s a news flash: I don’t know everything. If somebody has a different experience, let us know. Doug
I don’t have the time to wait for gloss resin to cure hard enough for sanding/polishing. I use regular sanding resin and add styrene and SA which cures in about 3-4 hours. I sand to 600 then polish and get an equal or better shine than gloss. It seems less brittle than gloss also.
From my understanding of polyester resin (UPR’s):
The addition of *more styrene (or catylist) is used to modify/adjust pre-hardening properties of the resin. Once hardened, gloss and hot coat resin are structurally the same exact thing.
Best,
Herb
Yep, I polish out hotcoat all the time…but glossing is way easier to polish out. Gloss cures harder than sanding resin. So if your going to polish sanding resin you have to run through the grits better, and more throughly, 150-1000. I only polish out sanding resin when I do 60’s restoration work. Ding repair is a sanded hotcoat flat patch with a spray of UPOL over the top, then a polish out with 600 grit.
Glossing resin only really shines when you have a foam buffer pad and fine polish, otherwise it’s just resin thats somewhat harder to scratch.
-Jay
Some brands of gloss resin are marketed as having UV inhibitors.