Microballoons? Cork? Straight up Epoxy?

[K.T.]

I'm inching closer and closer to getting my first restore underway. Picked up the epoxy, polish, and Dremel bit.

I have a question about filling in the handle, though. Should I use microballoons, chopped up cork, or something else as a filler with the epoxy? It seems that that much straight epoxy might shrink or warp in weird ways when drying.

Also, where does one buy microballoons? Thanks!

 

[Ruck]

are microballoons the same as colloidal silica? If so... boating supply store/websites.

 

[Schwert]

No idea what microballons are....

I would use cork. Easy and free.

Straight epoxy fill works perfectly too.

My technique is to overfill, then redrill to the perfect floor. This works very well with cork fill as it tends to want to float in the pool of epoxy unless physically jammed into the hollow.

 

[Jim]

You can use just about anything from birdshot to wood flour.

Sawdust works great.

 

[Not The Original Kermit]

microballoons are small hollow glass spheres or phenolic resin commonly mixed with epoxy resins and glues as a filler for seams and other areas. mostly used by RC airplane buillders and other modelers in their hobbies although they are used in other areas as well.

makes the epoxy lighter and easier to sand after it has hardened. I'm not a brush restorer but I dont' think microballoons would apply well in this instance as they are pretty pricey and something cheaper would probably be a better answer because weight wouldn't be a concern but most major hobby supply stores would carry them.

Just adding my two cents as a modeler.

 

[Jaymo]

Could always mix talc with the epoxy to make a putty.

 

[Jeapeacock]

I am in the process of restoring a brush as well. And after reading and taking advise of people here...I opted for straight epoxy. The main reason I decided on just epoxy is the size of the whole and the epoxy I found is a auto/marine that is also made to fill gaps/wholes. So it should not shrink and is designed to bond with the hard plastics/fiberglass/Bakelite. Plus it adds just enough weight to the handle with out being to heavy.

I also just started using Meguiar's PlastX and wow it gives a solid shine as the last step on polishing. Sadly I am waiting for my knot...hopefully it will be here soon.

 

[Brownbear]

Don't understand why you would want to fill the handle. Is it cracked and in need of reinforcement?

If it needs to be filled straight epoxy would work fine, microballoons would work but make it lighter. Since some guys seem to want the weight the microballoons would be counter productive. Wood flour works fine and is cheap. Dry sand would work as would lead shot or sinkers.

But if it is Catalin you run the risk of ruining the translucence that makes it so pretty.

 

[K.T.]

Hmmm.... thank for the information, guys. It sounds like straight epoxy would be better for me if there's no strange shrinkage issue. I want a bit of heft in that handle.

Yes, it's true about the catalain handle. I do have two of those lined up for restore and I don't plan on filling those at all. I do want to preserve that light transmission (interestingly, both my catalin handles screw off and have a hollow chamber inside).

The two handles I'll be filling are a two-piece EverReady that's made of solid colored white and blue plastic, and a Rubberset paintbrush handle with a solid colored black collar.

I'll subscribe to K.I.S.S. and just go for straight epoxy if that will work without any issues.

Thanks!

 

[Brownbear]

The good thing about straight epoxy, although it doesn't matter for the brushes you describe, is that most set to a translucent amber, which probably would let light shine through provided you didn't put thickeners in it.

The only downside to pure epoxy I can imagine would be heat build up during the cure that might overheat the plastic handle. Catalin won't be affected, but plastic might. But for the volumes you are using it won't generate enough heat to be a problem. I've seen a pint of epoxy in a tub get so hot it smokes and would burn you (my bad, beginner boat builders goof), but that is a greater mass with more heat potential.

 

[Luc]

One idea that I found neat was a magnet at the bottom of the handle. Those who have a metallic cabinet could stick their brush under... That is if your magnet is at the very bottom of the handle!

 

[Rudy Vey]

I always use cork slices to fill a too large hole and also to "micro"-adjust loft height. The magnet in the bottom, or close towards the bottom inside the brush, is also a good idea. Have done this a few times, just make sure you use a strong rare earth magnet.

 

[alabamalawyer]

The only downside to pure epoxy I can imagine would be heat build up during the cure that might overheat the plastic handle.

This is a concern. I recently filled a plastic handle with epoxy and it got hot to the touch as the epoxy cured. Luckily, it did not melt the plastic and everything worked out ok, but it is an issue to be considered.

 

[Jeapeacock]

This is a concern. I recently filled a plastic handle with epoxy and it got hot to the touch as the epoxy cured. Luckily, it did not melt the plastic and everything worked out ok, but it is an issue to be considered.

What I did to help this out is, I did a fill in three stages. With smaller amounts of epoxy it cut down on the warming as it cured. In fact it only got warm to the touch rather than not.