I have a 48 inch sandblast cabinet.

It has a gun with about 3/16" opening and pretty fine sand inside.

The sand always was pretty dry to the touch.

However, the gun would always choke on the sand and spit/pulsate,
instead of steadily delivering blasting media.

Then at some point, a mistaken individual added large size blasting
media that mixed with the sand and would completely choke the sucking
tube every time.

So, at this point I realize that I need help. I need to select or buy
a proper gun, proper tube, and proper sand blasting media. I do not
mind spending the money, I want this system to work.

The typical application would be removing paint and rust from an
access panel, for instance.

I have a 10 HP compressor.

Would someone point me towards some resources on what media to select
with what gun, etc.

Thanks a lot

i

"Ignoramus27493" wrote in message
...

I have a 48 inch sandblast cabinet.

It has a gun with about 3/16" opening and pretty fine sand inside.

The sand always was pretty dry to the touch.

However, the gun would always choke on the sand and spit/pulsate,
instead of steadily delivering blasting media.

Then at some point, a mistaken individual added large size blasting
media that mixed with the sand and would completely choke the sucking
tube every time.

So, at this point I realize that I need help. I need to select or buy
a proper gun, proper tube, and proper sand blasting media. I do not
mind spending the money, I want this system to work.

The typical application would be removing paint and rust from an
access panel, for instance.

I have a 10 HP compressor.

Would someone point me towards some resources on what media to select
with what gun, etc.

Thanks a lot

i
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Go to www.mcmaster.com, search for blasting media, and click on catalog page
(page 2685). They have a nice summary of the different kinds of media and
what they are good for. They aren't the cheapest place to buy from, but
they have a good catalog :-). We did mostly tig weld cleanup and making the
finish pretty on stainless steel, but some rusty painted mild steel and a
bit of aluminum. We used mostly glass beads in the 60-80 mesh range, with a
pressure regulator set to about 65-70 psi. More aggressive media like
aluminum oxide will cut faster and leave a rougher finish behind, and will
chew into aluminum, so I'd start with what we used. You will need a 50 lb
bag (or 5 gal bucket) to fill your cabinet, after you drain out all the old
stuff. You can always empty the cabinet, charge with different media, and
then drain that and swap back, so it's not that expensive to experiment.
Just keep some clean 5 gallon buckets with lids to store the media you
aren't using. With a 10 hp compressor you will probably want a 1/8" jet and
1/4" nozzle. The jet is inside the gun where the suction tube enters from
the side, and the nozzle is the tip where the media comes out. The jet will
get worn away on the side facing the suction tube. You can rotate it a few
times to expose fresh surfaces, it will still work so long as the end is
still square. The worst I saw looked like the whole end was cut at a 45
degree angle, and it still worked but the new one was clearly better when I
put it in. I think these are usually carbon steel, hardened. We made a few
of our own jets and nozzles from 1045 and quenched into oil from orange
heat, but we were more playing than anything. The entire inside of the
nozzle will wear away, and as it does it allows more air to pass through and
lowers the blast velocity. You can wear all the way through but it takes a
while, and you want to change it when the inside is maybe no more than 1/16"
oversize. These can be ceramic, which lasts pretty well, or carbide which
lasts a long time and costs a lot more. We had a 7.5 hp compressor that
would never cycle but would keep the pressure up, using a 1/8" jet and 1/4"
nozzle, so start there and let the compressor rest every 15-30 minutes while
blasting. Go to the next page after the media at mcmster and you can see
what they get for replacement parts. You can get cheaper stuff from
Eastwood, and all the usual suppliers like mcmaster, msc, and grainger carry
this stuff so shop around. If you are cleaning stainless steel and really
care about it not rusting you must use iron free media, so new stuff that
has never been used on carbon steel or cast iron or you will embed tiny bits
of steel into the surface that will rust and cause pits. The only way I
finally got people to stop using the blast cabinet on weekends for their
rusty car parts was to scrounge a second cabinet and get it working for all
the nasty stuff. Didn't stop everyone but did cut down the rusting on our
stainless water tanks in the field, sigh. Oh, sometimes you will get
pulsating flow like you saw. There should be a rubber hose on the suction
port on the gun, and a straight piece of metal tube on the other end that
you shove down into the media. If you cover the gun outlet with your glove
and blip the air valve you can backflush this tube and sort of fluff and
resettle the media, which can help. If you have to, you can drill a 1/16"
or slightly larger hole right where the rubber hose ends on the metal tube.
This will suck in a bit of air and can stabilize the suction and media flow,
and you can tune it a bit by covering none, some, or all of the hole with
the rubber tubing. Keep the cabinet closed whenever you aren't using it, to
keep the media as dry as possible. Make sure your takeoff port on your
building air line points up, so no water in the line can get to the cabinet.
I added a combination filter, regulator, and automatic drain water separator
to our cabinet that helped a good deal. Good luck.

-----
Regards,
Carl Ijames