Resin cure and heat dissipation.


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Daveb
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posted 4 Years Ago Merged HOT
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Hi,

I am making a resin river table that is 47mm thick. I am planning on pouring about 10mm at a time to avoid as many air bubbles as possible.

The question I have is this. If I let each 10mm pour get to the B cure stage before pouring the next layer, will I have a problem with heat build up, or would most of the heat have already dissipated by the time it gets to the B cure stage?

Any help would be appreciated.

Many Thanks

DB
Warren (Staff)
Warren (Staff)
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By the time the resin gets to the B stage, then the heat will be reduced enough for it not to be an issue.  

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
Daveb
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Hi,

I recently posted a question and got the answer I was looking for. So firstly, thank you very much.

Secondly, I have a query regarding the sealing coat on an epoxy river table.

As previously mentioned, my table is going to be about 47mm thick. I am aiming to do each layer I pour about 10mm to avoid air bubbles.

If I apply the thin sealing coat to the waney edge and it fully cures before I have poured all my layers, will the sealing coat prevent my river from properly bonding to each piece of wood?

Do I need to key it with 80 grit paper prior to pouring the last couple of layers?

Do I need to seal about 10mm each time I pour a new layer? Or do I seal the entire 47mm in one go?

Many Thanks,

DB
Matt (Staff)
Matt (Staff)
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Hi Dave,

Thanks for your post. This is a classic question actually and so we really should do a sticky post or add this advice to the product page or documentation somewhere!

So, you're dead-right to ask about the state of cure of the seal coat because - at the end of the day - this is what your main pour is going to be bonding to. The answer, as is so often the case with these projects, all comes down to the details of the timing. You're planning to do your main pour in 10mm layers, whereas it's more common, using GlassCast 50 epoxy casting resin to make up 50mm in 2 pours of 25mm. As a plan though, more thinner pours is fine and it does serve to 'de-risk' the project (you certainly won't have risk any exotherm problems pouring just 10mm per layer) and by pouring only 10mm per layer it will also make it less likely that you'll have any stubborn air entrapment. 

The only downside to the multiple thinner pours is the extra time waiting for each pour to reach its B-stage which, as you've pointed out, means that the seal coat on the wood will be FULLY cured by the time you're on your third of four pours. This gives you two options, both of which would work just fine:

1. 'Refresh' the b-stage on the seal-coat each time you do a main pour by painting some of the resin from the pour up the sides again.
2. Allow the seal coat to fully cure before you do any pours and then key it using a relatively coarse abrasive such as 120grit abrasive paper.

I hope this helps.

Matt Statham
Easy Composites / Carbon Mods - Technical Sales
Daveb
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Matt,

Thanks very much for the reply. I will seal coat the lot and key it before doing the main pours I think.

Thanks very much.

DB
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