Sandblasting 101?

[Patrick Cooley]

Hi all,
- I brought a small sandblast cabinet from Harbor Freight.
- I purchased some of the green mask from Laserbits.
- I lasered the mask on the glass. Worked great.
- I then tried sandblasting the piece. Worked pretty good... except..
- I blew through the mask in a few areas, and I didn't do a good job with a consistant frost in all areas.

Couple of questions for you experts...
What air pressure do you use?
How far away do you hold the piece your blasting?
I have a 1/4 inch nozzle, is that too big?
Any other helpful hints?

My Epilog does a decent job on most glass, but sometimes I want a little heavier frost.

Thanks in advance for the help.
Pat.

[Wil Lambert]

Hi all,
- I brought a small sandblast cabinet from Harbor Freight.
- I purchased some of the green mask from Laserbits.
- I lasered the mask on the glass. Worked great.
- I then tried sandblasting the piece. Worked pretty good... except..
- I blew through the mask in a few areas, and I didn't do a good job with a consistant frost in all areas.

Couple of questions for you experts...
What air pressure do you use?
How far away do you hold the piece your blasting?
I have a 1/4 inch nozzle, is that too big?
Any other helpful hints?

My Epilog does a decent job on most glass, but sometimes I want a little heavier frost.

Thanks in advance for the help.
Pat.
What abrasive are you using? I use Silicone Carbide in 150grit. You can use AO (Aluminum Oxide). AO will work we but break down faster.

Pressure any wear from 20-30 psi - 60 depending on the design. 20-30 will be a good start point and will get you the feel of blasting.

Blow out is cause by keeping the nozzle in one place too long. You must keep the nozzle moving at all times. The best way to blast is in nice even straight patterns. Similar to your laser rastering. Just move back and forth from one side to the other of the piece.

The 1/4" nozzle is very big from small glass items. Best to sue 1/8" or a 3/32" nozzle. Make sure to get carbide nozzles if you plan to blast a lot. The ceramic ones wear fast.

Check out the sand carving site for more info. The are just as friendly there as people are here.

cuttingedgesandcarving.com/forums/

Wil

[Patrick Cooley]

Thanks Wil,
I'm using AO 150. Do glass beads work well?
I was using 80 psi. Not sure the Harbor Freight will work much below that? I didn't want to invest in a big unit with pressure pot until I could justify the cost.
I'll try a smaller nozzle as well.
Thanks for the tips.
Pat.

[Mike Null]

Pat:

Stick with AO or SC. SC is better and you won't get nearly the static electricity. The reason you need so much pressure is that you are probably using a syphon system. The syphon system is nice in that you don't have to refill it but for good artistic blasting the pressure pot is a requirement.

Then you will blast at 15 to 30 lbs.

I think HF has them at about $150 or you might find one made by Rayzist or another of the domestic brands on ebay or Craig's list. The HF one is a little small.

The nozzle on one of those should be carbide or at least ceramic and about 3/32".

Good luck,

[Patrick Cooley]

Thanks Mike... I'll stop by HF this weekend and pick up a pot.
Pat.

[Mike Null]

Pat:

Both AO and SC are re-usable and will collect at the bottom of your cabinet. When you refill your pressure pot filter the abrasive with a fine screen. The smaller nozzles get clogged easily.

[Evan Stockton]

OK, so bringing this thread back as I'm just now finding them on the boards...I have a huge favor to ask anyone with the time & inclination to answer...Ready? OK, here goes:

I love the idea of creating wooden signs via sandblasting - I feel like I have the skill and the patience to learn, and I can't put into words how excited the prospect makes me. The problem? I take "newbie" to whole new levels! I've never worked with an air tool, so I'm completely lost as to what I would need, which I should choose should there be multiple options, you name it - I don't know it! lol

Would anybody be will to list what an absolute beginner would need to sandblast? Heck, include wood types 'cause I'm a moron on that, too! lol

I don't want to irk anyone with my self-depricating humor, but I really mean it - Anyone willing to write and list what you wished someone had told you when you first got into sandblasting? I'd be forever in your debt!

Thanks for reading, and my best to everyone...

[Joe Pelonio]

Evan,

There's a big difference between glass and wood. Mainly pressure and volume. The sign that I showed was actually blasted by a guy that I work with whose compressor is the size of a small room, his booth a large room. He wears an outfit that looks like those government guys in the movie E.T.

I have done small ones, 2-3 sf myself with my 40 gallon compressor and an inexpensive gun, but it takes forever. Mainly because you need 90lbs and it runs constantly so the thermal kicks it off frequently.

Any wood can be used, but for outdoor signs to last I use clear cedar. We used to use Redwood but it got scarce and very expensive.

The stencil is a rubber mask that can be plotter or laser cut. There's a stencil "filler" adhesive thats rolled onto the wood, then the stencil applied.

The actual blasting takes practice to do evenly, and from the proper angles to eliminate ridges, and have a nice texture to the background.

[Keith Outten]

I've done some glass blasting sign work using my blast cabinet and glass beads as the blast medium. Some were so long that I had to blast half the sign at a time through the end door then turn them around to blast the other end. Many were painted before removing the mask, they were building directories and installed using brass standoffs.

I purchased my own vinyl cutter just to make my own blast masks last year. I had a local company cut my first vinyl masks, they charged 16 to 30 dollars per mask which I though was very reasonable. Having my own cutter gives me more control of my schedule and saves a lot of driving time to deliver designs and pick up finished masks.

One thing I have learned about glass signs is that special consideration must be given to the location of light sources. Light coming from the wrong direction will cast shadows through the glass onto the back wall and glare can be a problem as well. In spite of the many problems that must be overcome working with large glass signs I enjoy the work...glass is very profitable :)

.

[Mike Null]

Do not under estimate the importance of a pressure pot for this kind of blasting. A syphon system is not really efficient enough for any kind of sand carving.

[Darryl Hazen]

Evan,

There are quite a few sand"carving" websites out there. THis one has some info on getting started. http://www.amsmith.com/sandblasting/presentations/budget_files/v3_document.htm

There's also a Sandcarvers Forum with plenty of knowledge.

[Keith Outten]

Any suggestions for cleaning a pressure pot. When they are shipped the inside of the pot and all the valves are coated with oil which will interfere with glass beads and walnut shells. I have thought about putting mineral spirits in the pot and let it blow but I doubt it will get all the oil out. I am hesitant to even consider lacquer thinner...under any pressure :)

.

[Charles McKinley]

Hi Kieth,

I'm sure you have the pressure pot clean by now but how about just running a bag of sand through it to clean it out?

We use lacquer thinner to clean out he old high pressure spray guns but not the quanity you would need to put in the pressure pot.

HTH

Chuck

[Paul Phillips]

Evan,
If you really want to do sand blasted wood signs on anything more than an occasional small sign then you will need an industrial set-up. I used to run the sandblasting dept for a large sign company years ago and like Joes' friend, we used a 250cfm diesel compressor @ 150psi with a 300lb capacity blast pot with 11/4" hose, a 3/8" blast nozzle and 80-grit copper slag for blast media, but that was for doing large redwood, cedar and MDF sign blanks all day long. To be able to do it at that level would cost $20,000.-$30,000. at least in equipment, but you can often find large equipment rental places that will rent a decent blasting set-up for less than $200. a day so you can try your hand at it to see if it's really something you want to do. Of course you would have to find an old barn or open field somewhere where you could set up to work because it will quickly overwhelm you shop or garage area.
Hope this helps,
Paul

[Terry Swift]

Thanks all. I'm one of those looking to add sandblasting in a "small" way to my lasering for glass and other items. Seems sand-blasting may have some more "perceived" value so that a decent profit might be made.