Hey guys, I just finished laminating my board, and I had a question before I did the hot coat.
Now, what do I need for the hot coat? I looked at Shaping 101, and it said that you needed a chemical known as “cavacil” (I think that’s what it was), and you mix it with the resin, so that the resin thickens for the hot coat? Is this true? Is “cavacil” just a fancy word for “catalyst”, which is the resin hardener? Do I have to have cavacil to do the hot coat? Is it completely necessary?
I was very confused by this whole thing, because the chemical “cavacil” sort of looks like that powder UV catalyst. So please, be a good guy and enlighten an idiot on this subject.
Thanks for telling me to search. I searched in the archives like you said, and found nothing that I was really looking for. I typed in stuff along the lines of “Hot coat glassing instruction” “glassing procedure” “hot coat procedure” etc., no good results.
Can’t you just tell me what I need? It’s not like you couldn’t have spent the same amount of time typing “Go find it yourself” rather than just telling me.
Cabosil, it’s a thickener, but not like catalyst. It just changes the viscous qualities of the liquid resin. Add enough cabosil and the resin will resemble jelly or mayonnaise. It’s apparently added in small quantities to sanding resin so that it won’t run as much, and sit thicker on the board as it hardens, filling in the laps and weave better. As far as I know, it’s not crucial…
Easy there fella, don’t bite the hand that feeds you,
You’ll get that response here if your request is too broad in scope, or if the info is already in the archives or elsewhere. I realize the issue here is complicated by the fact that one of our members is called “hotcoat” and anything he has posted about comes up on the search…
try these, and read the glassing and hotcoat chapters carefully. Then come back with specific questions and we’ll be glad to help.
Just a suggestion: if there is a word you don’t know, try the glossary. If you don’t know the spelling, the index is alphabetically organized – look under C for cabosil (or H for hot coat).
although we may get there someday, Swaylocks’ doesn’t have a “step by step, let’s show you how to shape/glass your board” section. However, all the steps have been detailed, some many times over. The trick is finding them in the archives, because people seem to get tired of typing out basic stuff repeatedly, so respond with “check the archives”. Sometimes that’s hard because you may not know the right buzzwords to search under. Other times you just have to read a lot. (However, that’s often very educational, because different people do things different ways…)
Howzit JLW, If all this is confusing you just buy some sanding resin for the hot coat. The other way is buy some surfacing agent( strene and wax), add it to your laminating resin, mix really good, catalyze hot and apply it to the lammed board,now it’s sandable. Since we don’t know how big the board is it’s hard to give you instruction on the proper mixture amounts for the hot coat. Aloha, Kokua
You don’t need a resin thickener such as cabosil (fume silica, very bad to breathe) or other. Just laminating resin, some surfacing agent (really only styrene monomer with a little parrafin/wax dissolved in it) and catalyst. I seem to recall being told that laminating resin is thicker (more viscous) than finish resin, but it’s been so long since I’ve used finish resin that I’ve forgotten how it feels.
The cabosil would thicken the resin; I’ve never used it nor felt the need to. The surfacing agent thins it slightly anyway.
A cheap brush is usually stiff and will serve well to spread the hot coat, and lay it out as thin as you want. More pressure on the brush = thinner hot coat.
I do thin out my finish coats, though, using a little styrene.
Howzit JLW, If all this is confusing you just buy some sanding resin for the hot coat. The other way is buy some surfacing agent( strene and wax), add it to your laminating resin, mix really good, catalyze hot and apply it to the lammed board,now it’s sandable. Since we don’t know how big the board is it’s hard to give you instruction on the proper mixture amounts for the hot coat. Aloha, Kokua
Howzit JLW, Don't laminate with sanding resin because you'll never get a hot coat to adhere to the lam job. Sanding resin is only for hot coating. What you refer to as styrene wax is Sufacing Agent which is added to lam resin to make it sanding resin. Where ever you bought your resin should carry it if they sell surfboard materials. If there are any glassing shops in your area you could see if they will sell you some also. Aloha, Kokua
I’ll defer to the more experienced guys, but isn’t there a way to rough up a waxy weave without cutting into the fibers, like sandpaper would, by using one of those scotchbrite pads?
Damn, I think i used sanding resin for the regular laminating coat. Now, is there any way to solve this, or is my board pretty much not hot-coatable?
If you used laminating resin for the glass layup the board would remain tacky to the touch for days. If, however, you used a sanding resin with wax already added the wax would float up to the surface of the lamination and seal it; making the layup dry to the touch within an hour.
If it is the case that you have glassed it with sanding resin (with added wax in styrene), then yes, you will have problems getting subsequent coats to adhere. I would suggest scrubbing it with acetone, attempting to get the layer of wax off without damaging the weave of the cloth. GLOVES, VENTILATION!
Someone answer this, this is important, it’s my first board and I dont want to mess it up.
Also, guys, I had another idea. What if I were to add another layer of fiberglass with regular resin (not sanding resin), then I put the hot coat on top of that layer?
Here is a suggestion to what I think you are asking.
I you are worried about hitting the weave while sanding your hotcoat you can either do a second hotcoat or do a gloss coat this will take away all those little weave spots. Remember to make sure the hotcoat is sanded completely before you do this (no shiny spots should be seen)
In your shoes I’d… sand the lamination lightly to get the wax off the surface (100 grit sandpaper would be fine - nothing too aggressive). This will allow any further application of resin to adhere to the lamination. Do that - leave no spot unsanded, but don’t go deep into the cloth.
Then - I’d wipe with acetone. No need to douse it, just wet a rag and wipe the whole thing down 2 times. What you should be left with is a surface of slightly roughed-up resin that is wax free.
From here you can either hotcoat or laminate another layer without worry.
you may damage the cloth a bit, but the important part is not to go nuts with the sanding - you just want to get the surface wax off and rough it up a bit.
If you watch “Glassing 101” carefully you’ll see Cabosil (Fumed Silica?) is being used for the leash plug. If you used Cabosil for the hot coat I don’t know what the result would be, but I don’t think it would be good.
For hot coating you will need standard laminating resin mixed with 1-3% styrene wax solution as well as your catalyst.
The reason hot coating gets it’s name is the amount of catalyst that is used, and the fact that using MEKP (standard hardener) invloves an exothermic reaction. (A fancy word for heat).
I’ve heard that if you add enough MEKP the resin literally gets hot.
1-2% hardener is standard for laminating, adjust accordingly for hot coating depending on how much time you want before it hardens.