using blast chambers for finishing metal?

[cowanrg]

so, im always thinking of trying to get a great finished look that is easy and consistant finish method.

i did a factory tour of boulder amplifiers and they use a simple blasting method to finish their metal. the finish looks GREAT, is durable, doesnt need anodizing, and is easy to do. they have a full walk-in blasting chamber with a tow-behind compressor. obviously thats overkill.

i was thinking of a small blasting chamber:

http://www.harborfreight.com/cpi/cta...emnumber=45411

or

http://www.harborfreight.com/cpi/cta...emnumber=38440

then add a compressor (or if you have one already), and it looks like some sort of dust collector or shop vac. a compressor and a shop vac/dust collector is standard fare for most of us. i dont have a compressor, but was looking for an excuse for one...

is there something im missing? with some fine sand (cheap?), you could get a great finish on aluminum. just an idea, let me know whats wrong with it, or if anyone else has already done this!

[Magura]

Well, to begin with the statement that a bead blasted surface is durable and don't need anodizing. That is just about as wrong as it could be. A bead blasted surface is about as fragile and prone to scratches as they come, so anodizing is obligatoric. Once anodized, it's ok.

The blaster uses glass beads, those are not cheap, not at all.

The blasters that actually work are fairly expensive, like 2000 USD, since they have to have a component that seperates the broken beads from the good beads when reusing them. Besides that you need a fairly big compressor to supply a constant pressure, plus some pressure gauges which are not of the cheapest kind, again to get constant pressure. Ohh, and I almost forgot to mention that the compressed air have to be fairly clean, which is fairly hard to sort on small scale as well.

I have been working with a number of different bead blasters, and my conclusion to that have been that only the best is good enough for making a decent looking aluminum surface. I have a 1000USD unit next door, but rarely use it, instead I travel a couple of hours to get to a good one.

Besides all this, you will need to have one for aluminum and one for everything else, especially ferrous metals really messes up the surface of aluminum.

My solution so far have been to have acces to a high quality unit, or simply pay my way out. The el cheapo solution causes too much trouble, and is not really cheap in the end anyway.

Magura