In short, I guess I'll have to buy a thermometer.
However...
I used 1lb Eps from a building reclaimers and had to glue parts together. This was a lot of effort but meant an almost free blank. This was useful for practicing.
The experience with epoxy this time was not as good as last time I used it. In general it was much, much slower this time. Here's the 2 compared. In both cases the epoxy was weighed for mixing, hand mixed counting to 100.
Board #1:
- lammed in Humidity 70% on most days of the lam. I think approx 25 degree heat in a workshop next to an air conditioned area
- cheap Chinese epoxy used... Unknown brand
-seemed to set hard after each day. No problems of this kind
-painted over the top for uv (but it looked awful)
Board #2:
- lammed in New Zealand
- humidity... A dry day in the first lam, sunny. on the 2nd lam very wet and it was cold overnight.
- epoxy from epoxyglue.com which seems to be the cheapest here
- painted Eps blank, only 1lb glued together
- took over a week to feel harder on the thumb test. Sped up slightly in a hotter car.
- only 2x 4oz each side. Should have done 3x 2 Oz in the top... Quite a thick hotcoat. No pigment used
I thought the epoxy in board #2 was set as it was harder than the week wait before after keeping it in a car.
Then unfortunately one day I forgot to leave the windows open. When I picked the board up it was warm but I didn't think *really* hot - nothing like as hot as a pickup truck bed. The board felt similar to how it was in the first week it was setting. I moved the board to a cool store room.
Now there's an area on the tail, the deck which is quite spongey with the thumb test. I think the Eps underneath has melted...
In the one hand the actual lamination with epoxy went as well as poly. What suprised me this time has been the post curing. It's been a pain in the ass.
I'm now wondering what to do for my next board. Epoxy feels a bit risky now after this experience . Likewise Eps wasn't too bad to use but I'm not sure it was worth it.
The other thing is UV protection. I found the easiest thing is paint the blank and then go over with a non cut lap, non pigmented layer. Trying to do a pigment on a different board with poly ended up with streaks (weighed)...
So I think the easiest thing if wanting to play it safe would be:
-Paint a poly blank
-lam with UV poly, no merk and no pigment, 2x4oz top and bottom
-normal lam, no cut laps
If I'm spending money in a shaped blank though I would like to use Eps. In that situation I guess I could do:
- paint the blank (test some on a test piece)... Using 2lb EPS now and a proper Eps blank
- do a single 4oz lam with epoxy each side. No pigment, no cut lap. Fill coat it to be sure
- then, when the epoxy is still green to help the bond... Do the 2nd 4oz lam with uv polyurethane resin
- hotcoat with uv poly to finish
- give it a week in a hot but not really hot place to cure
This way hopefully the poly would protect the shape and speed things up but I can still use Eps.
I know it would be better to get a fully epoxy method sorted but this way might be a safer step towards that...?
Sorry for a very long post. I have so much to ask. The thing with epoxy is you think you've nailed and then something like this happens.
