So im epoxying my board, got the mixing ratio wrong. Not quite enough hardener. Doh!! Im just sealing the 90' edge along rail. ( cosmetic stuff really.)Was supposed to use .5ml n used .4ml hardener 
. 12hrs on its still soft to touch but doesnt stick to finger.
1. Will it ever set?
2 Whats the best way to remove it? Acetone wipe?
Thanks guys
Hair drier or heat gun, carefully warm and it will become quite runny and easy to wipe off. If you can heat it have it become runny but keep it where you want it the extra heat may be en?ugh to activate and speed curing.
Select to expand quotepirrad said..
Hair drier or heat gun, carefully warm and it will become quite runny and easy to wipe off. If you can heat it have it become runny but keep it where you want it the extra heat may be en?ugh to activate and speed curing.
Yep i tried the hairdryer ,gently. Made it runnier. Left it in the sun as i had to bolt to work. See how it ends up.
Epoxy doesn't have the same chain reaction as polyester, mixing ratios have to be exact and mixed thoroughly, get the correct solvent for the brand of resin, messy job but unfortunately it's the only way to get a clean job done unless you can scrape it all off with a blade.
If you need to get it off, scrape heaps then acetone for the last bit is the go.
BUT depends what you were trying to fix in the first place..... was there a split thru the glass? If so, go easy on the acetone as it will seep in and eat the core.
BUT #2 - many painted boards have a solid colour in proper good 2K paint and you can scrub away with any solvent u like ............. but some then use a cheapo paint for the designs over the top of the decent paint, you think its all good and suddenly the solvent is eating away your paint. 
so if there is paint anywhere near it be careful.
Mix larger qty's and be accurate. Don't mix small amounts in two little medicine cups or similar unless you will scrape the sides and bottom forever to make sure you actually got all of one part out into the other container. Syringes are usually best of if you must do small bits, or mix in same cup.
A lot of epoxies will clean off with methylated spirits when not cured- far less aggressive than acetone.
I agree that epoxy is different to polyester regarding mixing ratios, but I would have though 20% variation would not have been a tragic situation.
The other thing is that very thin layers of epoxy can take ages to go off, especially in cold temperatures.
Clarence
I smell a rat here, 0.5mm of hardener sounds more like polyester. even if you're using a 5:1 ratio you're only mixing 3gms of resin total, you're not going to be doing very much with that small amount. Also epoxy is more part A part B, not resin and hardener.
If you've mixed the two systems nothing will happen, it will stay a sticky mess.
I've under mixed part B by 50% and the resin still went off, after a while. You're only 20% off, I'd expect it to set, but may not get as hard as it should, may not sand very well.
If you are talking polyester, that much difference in hardener shouldn't be too much of a problem, unless the hardener is old, there's moisture about or it's cold.
Acetone doesn't work well with epoxy, I get much better results with vinegar, but that's with resin that's mixed properly before it's gone off. It's well worth a try if it doesn't set.
Ok thanks guys. Just checked after day in sun. Still tacky to touch. I use syringes to measure. 4:1 ratio.Only make up 2ml resin at a time. As im only covering the chine edge(90' hard chine) where its rubbed thru to expose epoxy yellow colour thru white board colour.Will try scrape/ sand it off. Keen to sail it in a day or so. BAH!!!! 
As a security safety measure I have minimum amount to mix. Generally 20gm of epoxy. Worked out it was bigger all money wasted compared to going in with undermixed epoxy. Yes had that happen once.
Metho to to wipe out sometimes works
talcum powder rubbed in allows you to sand semiset epoxy
cheers Jeff
Heres what im wanting to return to factory look. Small worn thru colour but watertight. Used a paddlepop stick to apply resin along chine edge. Then profiled as it gelled. Minimal sanding reqd. One side done, ok.
So i used metho to remove the under done resin. Took quite a bit of rubbing to remove... Its a 3.8m raceboard and id done one whole chine.
Back to square one. Day wasted.Ahh well. Measure twice this time 
Thanks Guys for the prompt answers
Ding! Ding! Round Two begins.
MUST SAIL TUESDAY....
MUST SAIL TUESDAY....
Hard to tell from the pics , but it looks like a job that just paint would take care of. If you're not really missing any structural epoxy, I wouldn't even go that route, just paint.
