Anyone got experience with the small sandblasting units like this one
What would be great is to point me at a web site that helps a novice like me
figure out how much sand to put in it, how to pressurize it properly and how
to set the valve levers when it's in operation. I have followed the
instructions but it seems to only really work for about three minutes before
it loses pressure, I know it's something I'm doing wrong but I don't know
what. If anyone has experience with these things I would appreciate some
It is important that students bring a certain ragamuffin, barefoot,
irreverence to their studies; they are not here to worship what is known,
Not that brand, model or size, but experience nonetheless.
First thing is that you really need a compressor that can keep up.
Since you really didn't give any details as far as what type of media, what
you are trying to blast, etc., it's kind of hard to give any advice.
Different media require different settings, but there are really only two
adjustments that need to be made and most times it's a trial and error
thing. The valve after the pressure gage is your tank pressure (as it
appears in the picture). Heavy media like silica require more pressure and
larger nozzles, lighter media like walnut shell require less pressure.
There should be a valve at the bottom of the tank, this will control the
amount of media that is fed through the nozzle. The goal is to make those
adjustments to where the media is barely visible coming out of the nozzle.
BTW, you are keeping a constant supply of air to the tank, right?
thanks for the reply. Right now I'm planning on cleaning some interior
brick in my attic. It's a knee wall and its covered in about 120 years of
Chicago crud. I'm using a media called black beauty
http://www.flatrockbagging.com/sand/abrasive.html and the nozzle aperture is
about the diameter of a pencil lead, is this too small? I've been using the
blaster with the media throttle ( bottom of the tank) open full, so based on
your info I'll throttle it back until I can barely make out the stream,
thanks for that really great advice. I'm trying to get the compressor to
keep a steady pressure of about 60 psi but it keeps dropping off. I'll keep
plugging away though.
thanks for your great advice
I have very similar to that and it works great.
First question is did you buy screened, dried sand specifically sold for
sandblasting? This comes in a plastic lined kraft paper bag. You do not
ever want to use "play" sand, or concrete sand. The moisture content is too
high and the size of the grit varies way too much. Either will glog up the
works real fast. Most welding supply places carry the right sand.
Second, does your compressor put out enough CFM at 100 PSI to keep up? To
work effectively, the compressor really needs to be able to put out a LOT of
air. This usually means a min. 5HP compressor with at least a 30 gallon
tank. My 7HP w/ 60gal tank will run the blaster non-stop - the 3 HP / 30gal
I had before made required me to stop and let it catch up. Looks like yours
has a moisture trap onboard - be sure to check / empty it regularly. Also,
be sure to drain your compressor tank regularly too - I installed a 1/4 turn
ball valve in mine to make it easy, figuring the easier it would be, the
more likely I'd do it instead of having to go and get a wrench....
You MUST wear a respirator if using sand as blasting media - the dust it
generates can cause a serious health condition named silicosis
http://en.wikipedia.org/wiki/Silicosis - 'nuff said.
I fill mine about 3/4 full. Brush off the theads for the cap before
installing it. A shot of dry graphite lock lube now and again will keep it
easy to get on and off.
Here's some info on the valves.
First one, closest to inlet is the supply valve. Turn it on to pressurize
Second valve is the choke /mixer ( one with gauge at top). Set it to about
half for starters.
The valve at the bottom of the tank adjusts the amount of media feeding into
the blast hose. Start it at 1/4 open or less - you want to run this lean
or you're wasting sand.
Then you're ready to turn on the nozzle valve - be sure to have this one
either fully open, or fully closed - don't run it partially open or you'll
be replacing it very quickly.
If you're blowing lots of air but not enough sand, open the media valve
If you're getting lots of sand, but not enough pressure, close the media
valve some and add more air using the mixer valve.
If you get a clog, sometimes you can clear it by turning off the media valve
and turning the mixing valve to full on - if this doesn't clear it,
completely bleed off all pressure before doing any disassembly.....you might
miss seeing your face in the mirror otherwise.....
One last thing - if you're doing the blasting on a dry, sunny day on a clean
( before starting) driveway, you can sweep up the sand, sift it with sifter
made for blasting sand, and re-use it. But ONLY if its bone dry.
I just went upstairs and wrote down the setup details from the setup
the sand blaster is
a.. Abrasive hose: 8 ft. x 3.4'' diameter
b.. Valve material: brass
c.. Abrasive capacity: 20 lbs.
d.. Air consumption: CFM 6-20 @ 125 PSI
e.. Air inlet size: 1/4'' NPT
AND the compressor is
Air america 5 hp 20 gallon Model f5020
displacement 11.9 cfm
8.8 scfm @ 40 psi
6.9 scfm @ 90 psi
What do you think?
Compressor is not large enough... <g> That 6-20 CFM on the sand
blaster is a bit misleading. The lower value(s) are if you are using
it about 10% of the time, basically playing. They give that number so
people who have small compressors will still buy it!
Best bet may be to rent a big compressor (I'd suggest one that can do
20 CFM) for the job.
Bottom line: a 7 CMF compressor won't give enough air.
the output of the compressor only dictates how continuous you can blast.
Even a little dinky compressor with a big tank will work if you don't mind
waiting for it to recover. I have a little itty bitty emglo compressor on
top of an old 110 gallon tank, I can do anything I want as long as I don't
mind waiting. In the case of blasting, air sanding, etc.
"Harry Palmer" < email@example.com> wrote in message
All good suggestions.......
you need a bigger compressor if you want to get serious work done in
reasonable amount of time (& not keep waiting for the compressor)
Compressor mfrs overstate their horsepower & cfm numbers....tool mfrs
tend to get wide ranges with low ends that just don't work.
The combination results in general disappointment in using air tools.
With good tools & the right amount of air....air tool usage is really
One thing not mentioned is provide for media / debris collection
(heavy plastic, drops or cardboard arranged so that all flows into a
trough or container)
otherwise you'll generate a real mess in that attic. I set up a
"blast booth" (only three sides & a top) to corral the sand & debris
I re-used the sand by running it through a series of sieves to get the
junk out. If you're got real messy stuff to deal with, re-use might
not be an option.
thanks for your great advice bob, I'm taking the advice of my betters and
getting an expert in to get this done. I need a lot of other brick related
things done so might as well bundle this in with them. Thanks to you and
everyone else for helping make this decision.
Best solution, IMHO! In the end I think you will be happier with the
results. Blasting is a pain when dealing with one time jobs. Expensive
equipment, major safety issues, and cleanup problems all add up to a
'why bother with this' type situation. Good luck!
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