Coring Options

Bill

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27 Terry Jason
Looking for positive or negative feedback on the following core materials, I am replacing 1/2" balsa..

Gurit T500 Yellow Tan 46 75x23 75x 50 inch Double Cut Boat Core Cell Material | eBay

Baltek 1365 SB 1 2 inch End Grain Boat Balsa Wood Core Material | eBay

Baltex Airlite B 5 00CK 42 x 24 x 3 8 inch Boat PVC Foam Core Material Sheet | eBay

Tracker Marine 147231 Airex C70 75 Green 42 x 24 x 1 2 inch Boat Foam Core | eBay

Diab Divinycell H60 Green 48 x 32 x 1 2 inch Boat Foam Core Material | eBay

I have to make a move now.. this is for the top of my boat. im planning on cutting out old core and replacing with either new balsa or a foam core. I read somewhere that AIREX absorbs water..wondering if anyone has any ecperience with any of these..should I go with regular laminating resin or isothalic or what?
 

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Admiral
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Balsa core, due to its nature as wood, does absorb water. Trees love water after all. BUT if you isolate each section of balsa with resin, then the water cannot get to the cells of the wood.

PVC foam retains water, not actually "absorbing" it, but it can still get in there. It just wont rot the PVC (its plastic, its going to be around for thousands of years if you listen to Al Gore - he invented the internet btw). But the same goes for it, isolation of the squares with resin = no water retention.

If it was my boat, I'd go with the regular GP resin. It's done millions of projects and the price is right (well, better at least - all petroleum products are going crazy these days).

I guess what I am getting at is as long as you don't go pounding holes in all willy nilly with no sealant anywhere any option will suffice for your project. You can buy the highest grade and most expensive products known to man on the civilian market (or military grade black market for that matter) and have them slapped together haphazardly and have the piece fail. Even with regular products with a little time and finesse you can make one hell of a nice piece that stands up to the rigors of daily life and those times when you just HAVE to get home running through whatever Poseidon and Neptune can conjure up with a little help from Calypso.

Preparation and execution. Those are the key ingredients. Everything else is just filler (in this case, literally) :-D Resin is cheap (in the grand scheme of things), pound it to whatever core you decide and you will be fine.
 

Bill

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Thanks Travis, I now have 2 votes for Balsa and thats what Im gonna go with.. I was thinking that when you "decore" good balsa to install say a rod holder you had to decore a lot around it..fill with hull and deck, reglass, refair,repaint..now I see that you just have to drill it out and fill the cut with hull and deck and redrill..basically I had proper balsa decoring way over thought in terms of keeping it sealed up when a hole needs to be drilled etc.

anyways thanks.. Im gonna order the balsa and a few maybe 3? 5 gallon buckets of resin?
 

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Admiral
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If you go 2:1 weight wise resin:glass you should be alright, takes about 3/4 of a pound to do a sheet of core nice and wet into all the kerfs, there will be extra so be able to scoop some of that up and keep your wet edge going, use it to hot coat the back (scrim) side of your core material.

Plastic sheeting under your wet-out bench (plastic barrel works really well) can help you collect the cast off resin. Work smooth and steady, getting slap happy only makes you grind later.
 

Toolate

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What is this "hull and deck" filler that everyone is talking about?

Separating the balsa pieces is one really simple but excellent idea. Never heard of it and balsa cored a few things but never occurred to me. This way you have a chance at containing a leak instead of flooding your whole core. Smaat.
 

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Admiral
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Hull & deck is boat magic in a bucket! It's a putty polymer that when cured is pretty damn hard. Fills in the gaps and voids when you assemble things and you can fair with it pretty nicely too when needed. Anything you're going to glass over can benefit from hull and deck.
 


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