when i was putting in fin boxes today weirdest thing happened, about 10 minutes after putting them in one of the boxes started making a (squeeling?) noise and then started to lift up out of the board, i pulled it out and then there was some smoke comin from the hole and the foam had gone all yellow. only thing a can think of is too much catalyst? anybody else have anything like this happen?
amature mistake im guessin.. was in a rush so didnt measure the catalyst... hahaha woops
Yep. Cold, wet rags around and under the boxes might help, but too much cat is too much cat.
PE or epoxy? In either case, the more mass in the batch, the hotter it will get. For example…if you use more catalyst than necessary, the volume of resin in the cup will cause it to kick and heat up much faster than if you spread the batch out in a thin layer. So, when doing boxes, plugs, etc…there’s usually a higher concentration of resin than a typical cloth patch or lam.
Best to err on the low side with PE when doing things like boxes. The slower the kick, the stronger bond.
Howzit merritt, Which kind of boxes were they,I had that happen with a box that was an O'Fishal. Aloha,Kokua
sammy, it was PE, i’ve never heard of less kick stronger bond, cheers for the tip ill definately keep it in mind next time! haha
and kokua they were just the fin solutions triplug boxes, not to popular i dont think cause i dont see them around this site much.
these ones… http://www.shapers.com.au/products/Tri-Plug-%252d-Set.html
not sure why only one box came out? do you reckon i might have some trouble with the bond on the other boxes(pulling out of the board) when surfing?
Not “less”, but slower. The chemical process that turns resin from a liquid to a solid involves the formation of linked molecules. If the process is accelerated too much, the links are more random and less uniform. Any glasser with experience will tell you that fast batches tend to be brittle. It’s pretty basic physics, really.
Also when doing fin boxs,, if it kicks too fast you will get resin shrinkage and then separation occurs (how do I know)
and allways prep the boxs
[quote="$1"]
[quote="$1"] i've never heard of less kick stronger bond, [/quote]
Not "less", but slower. The chemical process that turns resin from a liquid to a solid involves the formation of linked molecules. If the process is accelerated too much, the links are more random and less uniform. Any glasser with experience will tell you that fast batches tend to be brittle. It's pretty basic physics, really.
[/quote]
Sammy: If thats true, how do you explain the UV activated hardners? They kick REALLY fast when exposed to direct sunlight. Does that mean UV resin is brittle? If it is why are so many using it for laminating? Just looking for some answers cause Ive been using UV cure hardener in my simlar resin lately. My last personal board was done completely with UV hardener in simlar resin, lam and fill coat.
Like a lot of things, this has been covered here before...
In polyster resin, the little polymers are roaming around free, they can slide past each other; hence it's liquid state. When MEKP is introduced, it immediately sends the little polymers looking for their buddies and they link up to form polymer chains. This turns the liquid to a solid.To get optimum physical properties from the resin, you want these chains to be as long as possible. Too much MEKP can leave some of the polymers un-connected; they didn't have time to hook up before a lot of short chains were formed around them. UV initiators are thoroughly mixed into the resin, so as soon as light hits it, almost everybody can get in line at the same time.
Epoxy is an additive reaction, the two parts that are going to link are kept seperate until use.
haaa’’ mike how can anyone cast doubt on that explanation
**
**
no more needs to be said
cheers huie
well, huie, I could have spelled polyester correctly, haha.
Thanks, MikeD. I would have said it just about the same…
Extemely helpful thread, thanks guys. On some of my boxes after a surf, if i push the fin to the side, i can see a tiny amount of water squeezing out of the other side. Not much, and doesnt seem to be a problem, but i think i know why now. Will cut down the MEKP when doing boxes next time.