Blush?

Builder's Forum
1

Curious what others’ experience has been with MAS LV epoxy and amine blush.

I mixed a small batch (2 pumps each, resin & fast hardener) to first-coat two small items yesterday afternoon.

(These items were made from a different brand of okoume marine ply than what CLC provided in my kit. Made up of four laminations of 6mm, I used MAS to bond them into a workpiece of the needed thickness several weeks ago. No apparent problem with that process.)

I did the coating yesterday in my basement, around 4:00 PM. This morning at 8 I found the resin had cured hard yet was slightly greasy/sticky to the touch.

(I noted some face-grain areas had a blotchy appearance despite the hard cure, like what I’ve seen in pics asking about what went wrong. Not evident on end-grain.)

Since I began my kit assembly I’ve had zero issues with mix problems: used clean, new mix containers each time, count each resin+hardener pump (1^1+2^2...) carefully, stir well for full three minutes.

Only suspects:

Temp in basement from mix application to this morning was 60.7F at 4:00 PM down to 58.1F @ 6AM, then up to 61.7F by 8 AM. Humidity was higher than I’d expected: 56.1% @ 4 PM, up to 56.9% @ 8:15 PM then down to 53.6% by the time furnace went on again just before 6 AM then up to 54.9% by 8.

And a new bottle of LV resin I opened day before yesterday. I used some for the first fill coat after a fiberglass wet-out on my kit build. After 36 hours that has no stickiness, seems to have cured fine but that was with slow hardener, and not cured in the basement last night. Where I’m assembling my kit the humidity has ranged anywhere from 37.1% to brief spikes to 55%, averaging 36.3% since early Nov. last year. Temps 53-62F w/avg. of 57F. I’ve seen no evidence of what I’m calling blush whatsoever in that location.

I washed the two items in warm, soapy water, then towel-dried. No stickiness was apparent after this.

So my presumption is that MAS - though generally described as amine blush-free - may yet experience blush under certain conditions having coolish temps and elevated humidity?

2

   SP, I had exactly the same problem last winter. Cool basement, MAS, fast. Same thing with West but not quite as bad. Really vexed me, took me too long to figure out what the problem was. Read something on WB forum about blush happening a lot with slow cure times/cool temps.

Soap and water. Humm, seems to be a theme right now ;-)

3

Soap & water's a pretty reliable fix for lots of things we get outselves into, yes....

Thanks for confirming what my suspicions were leading me to believe needed attention, namely turn on the dehumidifier in the basement well before I plan on doing anything further with this combination.

In light of that, for those that truly desire to keep tabs on their working environment's climate conditions, I recommend they look at SensorPush.com. I bought first one remote sensor last August, then upon seeing how granular the data feedback it gave me via Bluetooth (and with their app for my iPhone and iPad) I bought five more sensors and their wireless server.

Not cheap but very effective at doing what they're supposed to do.

The sensors work when you're in close proximity (Bluetooth after all) so if you want remote monitoring access the server connects wirelessly to any wireless hub so as to make truly remote monitoring possible from anywhere you can get on-line.

RH in the basement was 53.5% @ 6 AM, temp 58.1F.  I turned dehumidifier on around 11:30 AM, with humidity @ 55.3%. As of now that's dropped to 48.4%, temp @ 61.3F.