Sandblasting wood

Jeff Gorman wrote:

> I'm concerned about the risk of scattering aluminium oxide particles about
> the workshop, on the surface of my specs and so on.

First of all, use the right grit! Aluminium oxide or silicon carbide,
depending on material. You might even use commercial beads, or even
ground almond shells (make your own in a coffer grinder) for decorative
use on soft wood or plastic. DON'T use sand. It's only needed for some
particular tasks on cast iron, and it has a serious dust breathing
hazard (sand particles flake and make tiny sharp shards).

"Scatter" is a problem because odd grains will get _everywhere_. If
you're also a silversmith or a telescope maker, that's a problem. On a
small sandblaster though, it's not a big deal. You're only using
lightweight "dust" grains rather than beads or shot and these don't
have enough inertia to travel far with any energy. You'll find the odd
one in things, but you won't etch out the windows.

You certainly need some sort of blast cabinet. For odd bits of glass
etching at a friend's place, we just do it outside in the yard and then
sweep up the grit afterwards. The grit is lost, but then grit's cheap
and grit with glass shards in it is a respiratory problem anyway. Not
much fun on a windy day though. Up at my Dad's place, where most of
the sheet steel blasting gets done, then there's a converted '50s
fridge (with doorlock) as a blast cabinet. There are powerful lights
high up in the top and a grit recycling hopper at the base. Both of
these use pressure-pot blasters and they're still very heavy on air
consumption.

For smaller blast cabinets, just improvise. I've used cut down plastic
oildrums before now, and even cardboard boxes. White opal polythene
drums are excellent, as they let light in.

Do get plenty of light inside the cabinet.

Do make a tall cabinet. Mounting the lights high up is the easiest way
to make them grit-proof. Even if you have to make the cabinet taller.

Do use clingfilm (maybe two layers) over the glass panels in front of
lights or windows. It's replaceable and stops the main panel getting
etched. Don't put it directly over lights though, because of the heat.

Do allow plenty of ventilation out of the blast cabinet. If you don't,
the grit will leave through the light fittings, the seals or you might
even blow the door off its catches.

Do get some extra-long Herriot gloves from a farmer's shop. Don't seal
glove sleeves around the cabinet though, as the pressure forces the
gloves out of the cabinet and your arms along with them.

If your blaster has a "lance", then allow a few holes to jab it in
through. Make a 2" or 3" clamping ring and stick a disk of heavy rubber
sheet between, with an X slot for the lance.

A foot-actuated air valve (for a pressure pot blaster) is ideal.

Nova wrote:
> Prometheus wrote:
>
> > Second-easiest answer is that Grizzly makes a small bead blasting
> > cabinet that you could get cheap.
> >
> > http://www.grizzly.com/products/g0476
> >
>
> Harbor Freight has a similar unit for $80:
>
> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38440
>
> --
> Jack Novak
> Buffalo, NY - USA
> [email protected]

With these small bench top cabinets the slope of the base is not steep
enough for the media to fall to the bottom for recirculation. They need
periodic agitation and banging which is a real PITA. They also need
loads of ventillation, the supplied filter is not sufficient and clogs
literally within seconds. I used a ventillation hose going directly
outside.

On 10 Jan 2007 05:45:56 -0800, [email protected] wrote:

>
>Nova wrote:
>> Prometheus wrote:
>>
>> > Second-easiest answer is that Grizzly makes a small bead blasting
>> > cabinet that you could get cheap.
>> >
>> > http://www.grizzly.com/products/g0476
>> >
>>
>> Harbor Freight has a similar unit for $80:
>>
>> http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38440
>>
>> --
>> Jack Novak
>> Buffalo, NY - USA
>> [email protected]
>
>With these small bench top cabinets the slope of the base is not steep
>enough for the media to fall to the bottom for recirculation. They need
>periodic agitation and banging which is a real PITA. They also need
>loads of ventillation, the supplied filter is not sufficient and clogs
>literally within seconds. I used a ventillation hose going directly
>outside.

Good to know- I've only used big industrial ones, and hadn't
considered that the smaller ones might not work the same way.

"Jeff Gorman" <[email protected]> wrote in message
> As an experiment, I've bought a Badger Mini Sandblaster kit with the
> intention of grain to produce an 'interesting' surface on the tops and
sides
> of small boxes.
>
> I'm concerned about the risk of scattering aluminium oxide particles about
> the workshop, on the surface of my specs and so on.

If they're small enough projects, what about a totally enclosed area with
slots to put your hands through and a Plexiglas or similar window to see
through?

On Sun, 7 Jan 2007 09:08:36 -0000, "Jeff Gorman" <[email protected]>
wrote:

>As an experiment, I've bought a Badger Mini Sandblaster kit with the
>intention of grain to produce an 'interesting' surface on the tops and sides
>of small boxes.
>
>I'm concerned about the risk of scattering aluminium oxide particles about
>the workshop, on the surface of my specs and so on.
>
>It would be interesting to know how others cope with this situation -
>possibly by means of some form of enclosure - extraction by a vacuum cleaner
>hose I wonder?

Easiest answer it to do it outside.

Second-easiest answer is that Grizzly makes a small bead blasting
cabinet that you could get cheap. There are a couple of benefits to
that- First, the sand stays in the box, and not all over your shop or
yard. Second, the sand is recycled from the bottom, so you use less
of it. And third, they have gloves built in, so the likelyhood of
getting pelted with high-speed sand is very low.

You could build your own, but by the time you bought the materials, it
would cost a lot more than just buying a cheap one.

If you're really in a pinch, and can't do any of the above, you could
try stapling thick plastic up in a corner of your shop to wall off an
area- but even there, the cost of a single roll of plastic is only
about half the price of this one, and won't work as well:

http://www.grizzly.com/products/g0476

The blaster you've got is probably best used outdoors. I've used
similar setups (with a hose that dropped into a bucket instead of a
glass jar) to prep porch railings and the like for paint, and they
work good for that- but they make an awful mess. Shouldn't be a
problem if you've got a driveway and some sawhorses, though.

Prometheus wrote:

> Second-easiest answer is that Grizzly makes a small bead blasting
> cabinet that you could get cheap.
>
> http://www.grizzly.com/products/g0476
>

Harbor Freight has a similar unit for $80:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38440

--
Jack Novak
Buffalo, NY - USA
[email protected]