RR Epoxy Hotcoat Confusion

General Discussion
1

I just completed shaping my first two boards (eps) and I’m getting ready to glass using RR epoxy. I’m confused with how much resin/hardener/additive F to use for the hotcoat. In Greg Loehr’s epoxy glassing 101 video and on a thread here in the archives it states that the hotcoat requires a little more than 1 ounce of resin/hardener mix per foot and gives an example of a 6 foot board needing roughly 7 oz per side plus 2 cc of additive F per ounce of hardener.

However, in the video it shows mixing 12 oz of resin and 6 oz of hardener plus 1 cc of add F per side for the hotcoat of a 6’4" fish. Am I miscalculating or not understanding the ratios? I was hoping someone might be able to make it clearer for me. I sent Greg an e-mail, but figured I would post it here as well. Thanks for any input. This realy is a great website and can’t wait to finish up my boards.

2

I just hotcoated bottom of 6’6" w/ RR. Used 8 oz resin + 4 oz hardener + 8 ml additive F. Had maybe a few tablespoons left over. ( Which I needed as it started to pull some fisheye funny biz on me so I just sort of blopped on big drops as needed and surface tension was enough to hold them in place. A little extra sanding to do but otherwise good.) If there were zero problems and I really brushed it out 7 oz resin plus appropriate amts of the rest would maybe have been enough but with basically not a drop extra. Maybe…

3

Another novice here, and I haven’t seen Greg’s video, but I know one great thing about epoxy – you can always mix more later if you need it, because you have so much working time.

So start off with the lesser amount, and see where that gets you. That way, there’ll be less waste.

Also, the amounts that pros generally use are far less than what you and I will use – so again, try to use the lesser amount, but plan on using more.

Can’t speak to the add F issue, but the amounts in the Epoxy & EPS thread have yielded great results for many…

4

kgus,

I think the amount shown in the video is an editing mistake, but I’m not sure. If this is your first hotcoat, it’s best to use a little more resin than you think you will need.

Until you get the hang of it, use 1 to 1.5oz of resin per foot of board, before adding the hardener. You’ll have some extra, but until you get brush technique down, you’ll spill a lot off the rails, hence the extra needed.

So, for a 6 foot board: 6 oz resin, 3 oz hardener, or 9 oz resin, 4.5 oz hardener. I would go with the larger values for your first, and if you are very comfortable with it, then move down from there.

As far as AddF, use 1cc per oz of resin (same as 2cc per oz of hardener). When your technique improves, you can cut that down by half (0.5cc per oz of resin, 1cc per oz of hardener). AddF really helps you out.

Consider also warming the resin to make it flow easier. I do it every time, especially if hotcoating in lower temps. Use as few brushstrokes as it takes to get the job done, and no more. You’ll just add bubbles. To help with the bubbles, go over the coat with a heatgun after you walk it out. Also, after the heatgun, I take the brush and go all the way around the board by the tape apron to take care of any sags/drips that formed. Then walk away and pull tape about 60-90 mins later.

Oh, don’t forget that your bare hands should not be touching the laminated blank. That’s asking for fisheyes/separations. If the lam was done more than 24 hours ago, or cured in a cold room, hit it with some 80 grit sandpaper to scuff it up.

prepwork is key with epoxy…

Good luck, let me know if you have any more questions…

JSS

5

Thanks for the advice. I’ll stick to the ratios he has posted in the archives, but will definitely mix a bit more based on my inexperience. Thats what makes this website great. More experienced guys telling you of pitfalls to avoid before you even realize you need to avoid them. Thanks again.

6

Hi -

Have you heard of the accelerator additive X-55? I’ve been adding a spot of it in various stages and it speeds things up when it’s cold.

According to MSDS it contains muriatic and hydrochloric acids which may negate some of the so-called safety aspects of RR epoxy. I don’t know if it affects yellowing or anything like that. I like having a crisp cure several hours sooner than without it.

7

hi,

I had the same issue with greg’s 101… after reading a lot in sway’s i figured out there was a mistake in the dvd .

work with the amounts you saw in the archives, it’ll work fine.

warm up the resin in a microwave for not more than 30 sec, then mix with hardner and additive F , it worked for me and results were great.

as for hotcoat-

when finished hot coating, take a heatgun or a regular hair fan, blow over the surfboard slowly to iluminate those small pins/bumps.

then set a big fan to blow air all over the board until it dries. this will help to flatten the hotcoat and get rid of most of the fisheyes.

good luck

8

Hope I’m not adding to the confusion…

I was told that a three gallon kit would do 6 short boards. I’m sure there’s plenty of people out there that can do this. I did four boards with my first three gallon kit. But I do things like fin box installs ,glass on fish fins ,tail patches and second hot coats. Tail blocks too. I also let alot of stuff land on the floor. The second three gallon kit did three boards and a few major repairs. Two of the boards were 8’ long with second hot coats. Just bought my third three gallon kit this week,plan on getting four boards out of it.

About 15 oz of total mixed product is what I would use for your size board…but I don’t mind stuff landing on the floor and my wife would kill me if she caught me putting resin in a microwave oven. I’m sure you could do it with less

I did a major EPOXY delam/broken board repair two weeks ago. After every thing was hot coated my wife let me keep the board inside the house for a few days so it could cure. No smell. No way that would happen with poly.

Have a great day

Ray

9

John, I don’t know much about the additive x-55, but I’ll research it. I’m doing all my shaping/glassing in my garage which is attached to the house. I don’t want it to affect my 2 kids, 2 dogs and pregnant wife, so Lee that would mean the microwave trick would be out. Sounds like a good tip. Maybe I could get a cheap one for the garage. I’m on Long Island and its now definitley below optimum glassing temps. Has anyone had any luck with space heaters?

Ray, I got the 3 gallon set for two 6’ 1" fish and a 9’ 6" longboard. I think that should be enough to go heavier on the mixing for spillage, etc. Thanks again for all the great insight.

Ken

10

Microwave is no smell no fumes. But go a short burst at a time. 5 sec or so and then GENTLY swirl the container. As soon as resin is a little more fluid you are there. If bucket starts to feel warm you likely should let it sit and cool for awhile. Heat resin only NOT HARDENER AND NOT MIXED TOGETHER.

I did it yesterday w/ my chemically sensitive (you have no idea!!!) wife standing right there. No problem. Just don’t spill it on the stove or she’ll have your head. though it does clean up pretty easily.

11

“I was told that a three gallon kit would do 6 short boards.”

Yes, but with many qualifiers. You need to stretch the resin so far, that only clear boards need apply. Any colors on the foam will show you the froth/bubbles and ‘silver slivers’ that stretching the resin gives you. Try this: glass a black panel. You will be amazed at the amount of bubbles/froth left by overworking, and the worst part, the lack of fiber saturation if you pull the lam too dry, causing the ‘silver slivers’. Basically, I think you squish the resin out of the fiber bundles with the squeegee, and when the fiber bundles spring back to shape, air backfills where the resin once was. I had no idea how sensitive to squeegee pressure the lam was until I messed around with some panels for another project… I glassed on top of dark plastic; the white foam simply covers it up well…

Now I completely understand why bammbamm uses a softer urethane squeegee. I’m gonna have to make one for myself…

JSS

12

When I hot coat with epoxy I only use enough to barely fill the weave. There isn’t any epoxy slopping over the tape and on to the floor. Maybe a beers worth or less to do a 8 1/2 ft board.

epoxy is so much more “sticky” than poly you can really stretch it without loosing that wax film that poly requires to set up properly…Hope that make sense?