What went wrong when setting fin box?? Rookie USA Help Please

General Discussion
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First Timer Failure=== Epoxy resin with Epoxy Board. Lined box with fiberglasss cloth as instructed and done by many shapers… used 2 ounces of resin… Help Please.

 

I pulled out box after I noticed it wasnt a strong bond after curing for 15 plus hours… What to do next??

 

Thank you Pat

 

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Hello patboon5, welcome to the jungle so to speak…sorry to hear of your troubles. The spider webs of material left behind and the lack of a beaded texture makes me think that the epoxy exothermed hotter that the melting point of the EPS foam, something like 165 degrees F.  Was the 2oz per fin box? If your hole was larger than normal then there would be more epoxy in there to exotherm and melt the foam.

 

 

 

 

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Jrandy,

Thank you for your response and words of wisdom= I had a huntch it heated up way too much… Yeah 2oz per fin box- dope!! and yes hole was larger than normal… Back to the drawing boards I suppose. All part of the learning curve…

 

Best,

Pat

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You are welcome Pat. I have learned much from the folks here and a bunch the hard way myself. All is not lost. Do you have a plan for recovery? If it were mine I’d clean out the melted foam and clean off the outside of the pulled fin box. Then I would make a replacement piece out of EPS or PU foam, and use clear/white Gorilla foaming PU glue to glue it into place (no exotherm and expands to fill cracks). Remark box location, rerout to fin box spec’s, reset box with cloth and just right amount of epoxy. Some people do the epoxy in two separate pours or apply ice bags to area to counteract exotherming.

That lam looks pretty wild, when you get through this detour could you show us the rest?

-J

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Awesome advice for the recovery phase- I will do those steps and bring her back to life once again…  I will definately show the wild lam swirl- I was thoroughly impressed I was able to do that good on first try :slight_smile:

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Great advice from jrandy.  You can always lay a couple of “ice-paks” on top of the box if for any reason you are worried about exotherm.

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thanks mcding for the response too

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Put some wax paper between the wet ice bag and your box, too. So it doesn’t get it all wet… I like to glass fins  onto EPS because of my own exotherm adventures. Mike

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Yeah I learned about Exotherm on boxes the hard way.  Had to install 10 or 12 handles in a bunch of Focus SUPs on Maui.  First two went from a simple rout out and install to a major ding repair.  Luckily I was also installing deck pads that covered the ugliness.  Lowel

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Jumping in here a bit late.  When I do boxes, plugs etc in EPS. After prepped for work I put the board in the sun for a bit…just warm…not hot.  Then I bring it in to the shop and place a ziplock bag of ice under the board, below the work area. Two good things happen here.  1) the ice bag keeps the EPS from therming and melting the EPS foam. 2) the cold draws a difference of presure, and the boards sucks air in. This keeps the boxes from doing the volcano thing.

if the boxes continue to do the volcano thing I add ice bags to the board further and further away from the hole.

I think EPS melts at something like 165 degrees, so when it therms in the box hole, if you place your hand under the work area and its too hot to touch…then it’s too late.   Just have a few ziploc bags of ice around before you start, and you’ll never have this problem.

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Thanks resinhead for the added knowledge…

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thanks rooster- Will try that too

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thanks rooster- Will try that too

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oops

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