Small Balsa Core Damage - filler vs foam?

[nfbr]

I have a small area of balsa core (2" x 4") that has water damage and is an odd shape.
I don't have foam handy.

Is there a filler I can mix with epoxy that would give flexible lightweight properties like foam? Then I can glass over the top. It's a locker floor, non structural.

[psk125]

Microballoons should work for such a small space. There are all sorts of different kinds. Look at the West System fillers for examples. Some people even use sawdust- and that ranges from fine to chunky too, depending upon the sandpaper or blade that creates it.

[JBP]

I often use microballoons to make lightweight fillers. A super light filler is microballons alone mixed to about the look and consistency of "Fluff" marshmallow spread. It is very soft and sands very easy. I've used it as a substitute for foam core, but it would probably be fine with balsa too. You can make it stronger by adding silica/cabosil.

[Rumrace]

I see everyone is on micro balloons and Systems West you can buy a small piece of balltech cut to fit. Foam is fubar. The baltech will connect and make the structure strong while Epoxy will make a wet locker water proof. I have a cedar saw dust bag in mine

[Rumrace]

Plywood and foam your using as a glue surface. With age both stink and delaminate with age.
Baltek the resin travels between the cubes locking both surfaces and encasing the structural material in a water proof case

[nfbr]

Originally Posted by JBP

I often use microballoons to make lightweight fillers. A super light filler is microballons alone mixed to about the look and consistency of "Fluff" marshmallow spread. It is very soft and sands very easy. I've used it as a substitute for foam core, but it would probably be fine with balsa too. You can make it stronger by adding silica/cabosil.

I'll try this. Do you find it has a little flex? The current adhesive filler in the boat is strong but brittle. It doesn't act like wood / foam.

I'm wondering about Flex epoxy from West

[garyfdl]

Originally Posted by nfbr

I have a small area of balsa core (2" x 4") that has water damage and is an odd shape... It's a locker floor, non structural.

That small you should be able to dry it out with heat lamps, saturate with thinned epoxy, and glass over.

Problem solved.

[thinwater]

Originally Posted by nfbr

I'll try this. Do you find it has a little flex? The current adhesive filler in the boat is strong but brittle. It doesn't act like wood / foam.

I'm wondering about Flex epoxy from West

No. It does not wet out fabric well and you don't want flex in a resin that is bonding to glass fibers. Think about how the fibers work. G-Flex is not for laminating.

[bullislandken]

Thanks for that info. I have been loving the g-flex but that makes sense. It is not for fiberglassing or laminating.

[nfbr]

Originally Posted by thinwater

No. It does not wet out fabric well and you don't want flex in a resin that is bonding to glass fibers. Think about how the fibers work. G-Flex is not for laminating.

Agree
But to make lightweight filler wit might work well?

[Chotu]

Honestly?

This is 4“ x 2“? In the bottom of a locker?

It doesn’t matter what you do. You can do like the builders of the 80s and just throw the wrappers from your lunch from yesterday in there, then drop some glass over it.

This is a long thread for 2“ x 4“. Ha ha ha.

Just mix up some microballoons, stuff it in there, drop some glass on there with neat epoxy and be done.

Or throw some plywood in. Or if you have some core material sitting around, throw that in. Throw in some pink insulation foam. You can throw anything in there. It’s so small it doesn’t even matter. And it’s in a non-structural location.

I’m the king of overthinking boat stuff. The absolute emperor. But I can safely say this one is being over thought.

[thinwater]

Originally Posted by nfbr

Agree
But to make lightweight filler wit might work well?

I'm with Choto on this. It's just not going to matter, and no, I would not use G-Flex for this. Either a foam or balsa scrap, a bit of plywood, or a lot of low density filler.

[nfbr]

Originally Posted by Chotu

Honestly?

This is 4“ x 2“? In the bottom of a locker?

It doesn’t matter what you do. You can do like the builders of the 80s and just throw the wrappers from your lunch from yesterday in there, then drop some glass over it.

This is a long thread for 2“ x 4“. Ha ha ha.

Just mix up some microballoons, stuff it in there, drop some glass on there with neat epoxy and be done.

Or throw some plywood in. Or if you have some core material sitting around, throw that in. Throw in some pink insulation foam. You can throw anything in there. It’s so small it doesn’t even matter. And it’s in a non-structural location.

I’m the king of overthinking boat stuff. The absolute emperor. But I can safely say this one is being over thought.

Last place someone did that was the deck.
The difference in flex cracked at the join, and water got into the ply, rotting out about 2 sqr ft
So I’m anxious to find a filler that acts like balsa for flex.

Once glassed over, its not a big deal, but keeping water out of balsa is a hassle.

[FPNC]

Pretty much any ground up material can be used as a filler.

Micro-balloons, fumed silica, glass beads. These are good but hard to find in small quantities.

Pecan shell flour, silica clay, kaolin clay, fine sawdust, corn starch, talcum powder, asbestos. All of these will make a good filler for epoxy or polyester resins. Plain talc is actually used quite a bit to thicken commercial resins.

You would be surprised as to what kind of weird and economical stuff the commercial resin providers use in resin to make it more thixotropic and create resin putties.

[Chotu]

Originally Posted by nfbr

Last place someone did that was the deck.
The difference in flex cracked at the join, and water got into the ply, rotting out about 2 sqr ft
So I’m anxious to find a filler that acts like balsa for flex.

Once glassed over, its not a big deal, but keeping water out of balsa is a hassle.

You are making yourself crazy over the tiniest thing. This thread is going to make you more crazy. Trust me here. I am talking from a huge amount of experience going crazy over little things like this. Lol

Why is the bottom of your locker flexing? Do you jump up and down in there a lot? It does not matter what you put in there because it is non-structural. This is not the deck. This is a little place in the bottom of a locker that is 2” x 4”.

You want something that acts like balsa? Put a scrap of plywood in.