BYYB Forums

Here's one for ya,

Has anybody ever tried recycling their sanding dust making it into filler.  I just got done long boarding a couple of taped joints and ended up with a cup and a half of nice fine fluffy white powder.  Rather than tossing it, I saved it in an empty filler can and intend to use it on a future joint.  I'm not too worried about it being compatible with epoxy because it is epoxy.  If anyone has done this, how was it to sand later, and was it particularly tough or brittle? 

I worked pretty hard to make this stuff, so I kind of like the idea of using it. 

Al

Sanding dust is usually quite course compared to wood flour or other fillers, but it can work in fillets and joints. They don't finish well, because the particulates are big and epoxy dust doesn't sand easy, but if under some tape or hidden in a locker some place who cares.

I use to make my own wood flour, with a grinding stone and everything, but it takes quite a while, needs a lot of sander dust and moisture content is a difficult thing to control. I've also ground up bits and pieces of old boats, like transom skins from core replacements, etc. This filler worked well and moisture wasn't as big a problem, but it's a difficult filler to sand, though quite strong.

So the answer is yep, you can use it, but it tends to be clumpy and isn't easy to sand, so put it under  some tape in a fillet or use it inside a joint. If you want a light weight filler, sanding dust isn't the way to go. Baby powder. Yeah, plain old baby powder make s a good light weight filler and it's a lot cheaper than balloons. Us old school builders have put pretty much everything into epoxy at some point, including most body parts. A relatively recent innovation I'm using in epoxy is stone dust. Pulverized rock - decomposed granite to be specific. I'm using this to reinforce the leading edge of keels, centerboards, rudder blades, skegs, etc. Really tough stuff when cured and it's inert, so moisture can't screw with it.

Thanks for the reply Paul,

I was sure an old head like you would have tried something like this before.  In this case, I tried it just for grins.  I'm the kind of guy that will make a mistake intentionally just to see how bad the outcome would be.  I was using 50 grit on my long board, and when I swept up the dust I noticed that it looked just like the silica filler I had in cans.  I swept up about a cup and a half of dust so what the heck.  Later in the day yesterday I mixed up some in a batch of fillet goo along with sanding filler and some odd bit of silica.  The fillets laid down normally and this morning seemed to sand okay.  I don't make big piles of sanding dust normally, so this won't  be a thing in my shop, but for now it seems to be a good way to get rid of that nasty stuff.

I'm going to see if I can get my hands on some taconite powder that they make by the ton up here and try that in goo.  Taconite is one of the hardest rocks known, and in the  mines they grind to face powder fineness.  If I can get a reliable source, I will try it and let people know about it. 

Al