I have been building a skimboard using eps and epoxy. I have been using TAP Plastics epoxy and used the slow cure for my laminations, (2:1 ratio w/6oz glass two layers), no problem, did it in my garage which is 60 degrees. I then switch to the medium hardener (4:1 ratio), carefully mix it which is suppposed to also cure at this temp. I do the hot coat at the same temp, and now 6 days later its still tacky. I have looked through the past posts and I have some hope that eventually this thing will cure. Are there any things I can try, like heating the thing in the car or something or in a box with a heater blowing on it that may spped it up? Or am I probably screwed? If I am screwed what are my options for salvage, clean it with acetone or something and re-do it?
Yikes! 6 days later and it's still tacky? Well, your last ditch effort should be heating it up a bit in hopes of forcing a reaction. However, if the mix ratios are wrong or it wasn't mixed thoroughly- fuggeddaboudit! You can't fix this problem the same way you do with poly - completely different chemical reaction, so none of those poly tricks apply.
If a night in a hot box doesn't fix it, it's probably not worth salvaging. You can build a new one in much less time, using less materials than it will take to attempt to salvage a bad epoxy hot coat.
Good luck cthulu. Hope it kicks for you, but if not, write that one off to experience and move on.
Im not familiar with this brand of epoxy
but
I find it odd that the ratio's are different
I would think it should have been the same ,,,2 to 1
can you scrape it off? if that doesn’t work sand away.
throw it away.if it doesn't kick properly you're screwed. clyde beatty told me it's the only down side of working with epoxy.
Most epoxies crosslink… so if you really felt brave and didn’t mind the effort your at the hotcoat stage so you could try and remove as much as you can and then carefully mix a small batch correctly and roller this on with a small paintroller, leave it to cure in a warm place and then if the surface does harden forget about it for a while, like a few weeks perhaps months because epoxies cure for ages and longer is better.
Thanks for the comments. I checked again this morning, nearly a week afer and still tacky. I think I will try it with a heater on it tommorow and if that doesnt work, maybe try scraping it off as a last ditch effort. The ratios are different, but I did a test batch previously with a black tint and it did take a few days to become completly dry but it did dry. I felt the slow reaction time may have been the tint. So I went ahead with the hot coat. I guess this will be my last use of TAP Plastics epoxy. At least its only a skimboard made with a Home Depot eps foam, only loss is the glass and epoxy cost really.
I guess I should have read the temp info on the medium hardener closer, says lower temps can lead to incomplete cure, heres what the TAP website says on this stuff, its "marine grade epoxy"
B-Side Hardener • 109 • Medium
Medium cure, 5 to 5.5 hours. 30 to 35 minute pot-life. Clearest of the hardeners for a transparent finish. The mix ratio is 4 to 1. Use for adhesive, laminating, clear finishes. This hardener is the most sensitive to temperature. It should be cured at no lower than 77ºF. Ideal cure temperature is 80º-85ºF. Lower temperatures will produce blushing and potential incomplete cure.
Heres what it looked like before I hot coated it
Well I was able to rescue the skimboard from the bad epoxy cure, I took a razor and scraped the sticky epoxy off, then I sanded it with 40 grit sandpaper. I hotcoated it again last night using slow cure hardner and it cured fine. Something with the TAP medium cure hardner that requires 70 degree or warmer for hardening taht caused the problem. Glad I didnt have to toss the thing!