First two epoxy boards ended up with big craters as the hot coat dried. Using RR epoxy with the fast hardner. Resin mix was weighted, made sure to use the right amount of add F, even wiped boards down with desaturated alcohol, used nitrile gloves when handling. Room temperature was 75-80, mixed resin for 5+ minutes. Still got these big craters. Heated up the resin on one board, didn’t heat up the epoxy for the other, same problem both.
Any ideas of what could be causing this? Do I need to babysit the board more and give several more brush strokes as the resin gets thicker?
Lots of posts on this - some last week. Some sort of contaminant e.g. even the oil from your skin, on the board causes it. Most people here say don’t use any sort of solvent to clean down your board because it can be contaminated.
As its been said before, if you insist on wiping down your lam coat, only use **A NEW SHEET OF SANDPAPER!!! NOTHING ELSE!!! **And your hot coat is adequately mixed in a **NEW CLEAN BUCKET!!! **Thinned with nothing but 2% **ADDITIVE F **or FIBERGLASS HAWAII EPOXY SURFACING AGENT!!!
In my experience, this right here is your problem. Do some searching and you will find others that agree. I watch my resin as long as I can and drip excess resin in the “craters” if they appear.
Moisture makes epoxy crater (repel) like a mother $%#@er and it looks like moisture has gotten onto the board. It’s most likely either from your wipe down or just general humidity. However you might be able to fill them just by using a double hot coat seeing you used Add F?
As for when I struck this problem (several times), no Add F was used so I was stuck with a boatload of sanding. In fact, now that I look back on it, I probably could of sanded a boat with the amount of time me it took to deal with same problem you’re having.
So go with the double hot coat. If it doesn’t stick, it doesn’t stick and you’re going to have to sand anyway. Level or not! Have fun…
I’ve done a few in epoxy and always wiped down with DNA with no problem. I did have a similar situation like yours on one board. Turned out that my air compressor was spewing oil vapor into the air as I was working on a fin with an air grinder. Sanded the whole thing down and did the hotcoat again with no problem. You definitely have a surface contamination problem there for sure.
I don't think the manufacturer would advise ''wipe downs'' with any solvent, and he recently pointed out (on here) that none of the solvents are 100% pure anymore. There will be a residue left (of who knows what) that can produce fish-eyes or bond problems. It may not happen every time, which leads to the ''well, I did it that way with no problems'' comments.
You are certainly right Mike. I stopped the practice as well. Just trying to relate that there are other reasons for surface contamination. There are pure solvents out there but they are incredibly expensive and unecessary. Question comes to mind though. If the workspace is prone to contaminating the surface is there any prep besides a light sanding that is recommended?
I see what you were trying to point out, there certainly are other sources for contamination. Eliminating them is the key. I would defer to the manufacturer's recommendations for use re hotcoat prep.
Just sanded the two boards for 5 hours starting with 40 grit. Don’t want to make that mistake again, I’ll try the second hot coat without the cleaner.
Does every centimeter of the board need to be sanded? There’s still about 15 1/8" round spots that are hard to get to. Thinking the same thing might happen again in these spots.
Come back tomorrow and decide! Trying to think straight after five hours of sanding two surfboards is like holding your breath for half an hour. It doesn’t happen.
Awesome.....Stingray has an ear to ear smile on his face right now. A shitty grin I must add....don't read my posts......don't do the steps I have learned from Swaylocks.com and have posted here......don't read that Stingray thread about how to glass a board with epoxy
It's great art...leave it alone and tell all the chicks that you planned it ..........chicks love art.....and what about golf balls?
Maybe your board will be faster and have more lift................
There's some good stuff in the FAQ thread at the top of page. Stingray has a step-by-step for hand-lam with RR epoxy, maybe he could insert a link on this thread too.
Something else to consider: if you wiped down with DNA before the lam was completely cured, the alcohol can react with the epoxy and “slick” it up, causing the hot coat to bead. This can exacerbate surface contamination issues.