has anyone ever dealt with a stubborn hot coat? basically, it wont (fully) cure. the weather around here has been as humid as mainland mex in august but…i’ve let it sit for over a week and its still (a little bit) tacky.
to be honest, i got a bit lazy and i didnt measure my surface agent very precisely when i did this hot coat. bottom line, i dont think i added enough surface agent to my hot coat mix bc board is still a bit shiny and tacky. it never achieved that hazy appearance and hard shell cure, you know? i could pbly just move on and sand it “as is” but i know it would gum up a ton of paper. i’d prefer to get a truly sandable surface before i move on.
thoughts? should i do another hot coat and add more surface agent? alternatively, does anybody have any nifty solution(s) that will save time and materials? jay
yea, i tried leaving it in the sun for awhile to see if it would cure…it helped a little bit but still tacky.
adding a layer of gloss resin sounds like it might work. i’ve never worked with gloss resin…so here’s a couple of fairly elementary questions. are there any major differences in how you use it? will a standard mekp catalyst set it off? add surface agent just the same?
Howzit sostoked, if the wax didn’t rise to the surface you can just rehotcoat or you can try to knock down the gummy resin with 80 grit and a sanding block. Once you get past the gummy surface you can sand it with no problem. Just be ready to use a few sheets of paper. From now on before you catalyze and apply a hot coat look at your resin mix and you should be able to see the wax on the surface of it.Bet you’ll never make this mistake again.Aloha, Kokua
The theory, as I understand it, is simply that the wax raises to the top and blocks off air, allowing the resin to sure. Doc has backed this up with references to using plastic wrap in instances to seal off the air and it’s worked. Based on this just about anything can work… certainly another hoatcoat or gloss would work, but it’s a bit of a waste of materials.
This came up the other day and I never got a chance to address it… but if I found myself in that situation I would try spraying Future on it. I use it to seal all my sanded hotcoats… it should be air tight, it’s thin and sands off easy, and it’s cheap. The only possible problem I could forsee would be if there is some sort of chemical reaction with the uncured resin. I guess the smart thing to do would be to do a test sample… sometimes it’s fun to take risks though.
Howzit Kokua?! Thanks for the tip (on the sequence of steps when mixing a hot coat). You know what…I honestly never thought about that…since no major chemical reaction occurs when mixing only surface agent and resin…i have time…i can wait, watch and visually confirm that the amount of surface agent in the mix is adequate (by sorta watching it settle at the top) before i procede with catalyst, huh? sooooo true, bruddah…i’ll never make that mistake again!! many thanks!
Hey RKelly! You recommended spraying it with Future (to seal off the oxygen, right?). Sounds good. I wanna try it! Couple quick questions.
What is Future? Is it like a finishing sealer? Where can i pick it up? Any chance its available in a single spray can or do i need to get my hands on an air compressor and spray gun and stuff?
I’m flying out to San Diego this weekend to see some old friends so i pbly wont get to try this until early next week (or later if i cant get my hands on Future??)…but should be a fun experiment. Thanks RKelly for the tip! I’ll try it.
Future is a little substance that Herb filled us all on… actually its a floor sealer. It’s pretty much just clear acrylic with a few sents added, but no corrosive chemicals or bleach that you might find in similar products. You can find it in any Target or the like, it’s about $5 for a big bottle that’ll last you many boards.
You can just sponge it on… I spray it, it works better - more even coats and sponging can lead to a white film, but for your purposes it doesn’t matter. The stuff isn’t very strong, and I’m sure other sealers work better as far as adding physical protection… but it seems to get into the pores and form a nice candy shell that can buff out quite nicely - and it doesn’t add any weight. I didn’t start using the stuff until about 6 months ago, but those boards are still pearly white - a massive improvement from my earlier sanded finish boards. Herb mentioned that he also uses it to seal a shaped blank. I also spray a generous helping over sprayed artwork for added protection when masking over.
If you’re selling boards at a production level Future isn’t quite up to par for a final shell, but for the backyard builder it does the trick. The outer coat can scrape off easily but I believe that it stays in the pores and keeps your sanded finish sealed - and shiny.
This gummy hotcoat issue comes up often and I’ve thought about trying this, but I haven’t ever had that problem… I just thought it’d make a nice experiment. I don’t know if it’s a temperature thing, even in the winter here in So Cal it stays in the 50 in my glassing room (garage)… but I shoot my hot coats… HOT.
Enjoy SD its a wonderful city, I’m suppose to roll down and visit the family this weekend too… so if you hit up Blacks or 15th street, maybe I’ll see you out there…