Sand Blasting Cabinet

[jb-mck]

I was given a HF sand blasting cabinet the other day. I had to build a new blasting gun to replace the stock unit but other than that it was in good order.

The sand that came with the unit doesn't look like sand at all but it may be. It is very fine and looks like small silica beeds. It does not seem to be as abrasive as other blasters I have used. Is this the only meadia I should use in the cabinet or will others work better?

Thanks

[wierdscience]

Mostl likely glass beads is what you have,they are good for fine finishing/cleaning.

If you want more aggresive media look up aluminum oxide or black beauty slag.There is also granulated baking soda,but it doesn't stay sharp as long.

You can also use fine silica sand,but will need a vaccum to keep the dust contained in the cabinet.The cabinet really should have a vacum anyway even if you use one of the other media types,dust of any form is bad on the lungs.

[hssmike]

It's probably glass bead. Glass bead media comes in different grades also. It’s not as aggressive as other media, but it comes in real handy for nice finishing.
Check online at MSC, Enco or any other supply house as they usually have descriptions of their media.


Mike

[Scishopguy]

Re: Sand Blaster

Sounds like it has fine glass beads. These are used to blast aluminum prior to anodizing and for producing a "satin" finish. The trick with glass bead is to keep the pressure under about 30 psi or the beads shatter and turn to dust. I have looked at some of the little HF blast cabinets and they look pretty solid. If I had one I could put it to work.

[Bill Pace]

AFIK you can use any of the blasting mediums - glass bead, "sand" (anymore its AO or mica.. I think) walnut shells, soda, etc. I have 2 of the HF cabinets and keep glass bead in one and a product from TSC (tractor service supply) called "Black Diamond" (I think its Mica) its what sand would have been in years back and quite agressive. The beads come from HF, about $20 for 20-25lbs.

When I've got a nasty piece I throw it in the black diamond and really eat it off and if I'm gonna paint, blacken, patina, etc, I throw it in the beads.

I went for years with out blast capability -- now I dont know how I did with out it, I love those 2 cabinets!!

Which cabinet did you get, the one on legs or the one that sits on the bench?? I got the one on legs earlier this year to gain the larger work space, after using the bench version for 2-3 yrs -- that bigger unit is an awfully nice piece for the (little) money HF gets.

[jb-mck]

Thanks. The guy that had this cabinet bought it new and never used it. He has had it for at least 5 years. When he gave it to me, all the rubber hoses were dried out and brittle. The nozzle of the gun is made from potted metal. When I picked it up, pieces of it decintegrated in my hand. Other than that, the unit is nice.

[jb-mck]

Bill, I got the bench top model, and glad to have it. I think for now I will have to change out the media as reqr'd. I have a small shop vac that should work well at that task.

[Highpower]

I got the one on legs earlier this year to gain the larger work space, after using the bench version for 2-3 yrs -- that bigger unit is an awfully nice piece for the (little) money HF gets.

Bill,
does yours leak like a sieve at the seams like mine does when using glass beads? I'm trying to decide if I should pull the panels apart and seal everything with silicone or something - or if I should just clean the paint off all the edges and go at it with the MIG welder. Those foam strip seals that came with the cabinet just ain't cut'n it...

Really tired of having glass dust all over the floor.

[Jim Caudill]

You guys might want to check out TP Tools http://www.tptools.com/ they are the most well known of the bead blasting folks. They sell all the components to repair/modify any cabinet you might have or want to build. Their website also offers tips on plumbing and drying your high pressure air as well as "dust collecting" from inside the cabinet. I have a Trinco cabinet, but I modified the "arm holes" to use the gloves and mounting rings from TP Tools. Their rings are larger in diameter and MUCH more comfortable on my arms. Wherever you get your gloves, buy an extra left hand one (if you're right handed) as you will wear out 2 or 3 lefties for every right one. Due to freight costs, I usually get my media from a local Grainger supply store. I mostly use a mix of glass beads and aluminum oxide that comes in a 5 gal pail.

[steve45]

I modified my Harbor Freight blast cabinet in a number of ways.

First thing I did was install a light. Pretty hard to use this thing in the dark.

Even with a 1 HP dust collection system, I was still getting a lot of dust collecting on the glass (plastic film, actually). I installed a PVC tube across the top of the window with holes that allow air to enter above the glass and flow downward across it. The PVC goes out through the vent hole on the left side of the cabinet.

I've also changed up the pickup tube to make it a U-tube with a hole in the side (sort of like a venturi), then ran the supply side of the U-tube outside of the cabinet. If you think about it, you're drawing air out of the cabinet with the dust collector, then you're trying to suck media out of the bottom of the same cabinet. The U-tube allows air to enter the pickup tube from outside. It still isn't perfect, and the U-tube sometimes clogs. Put your finger over the end of the sprayer and hit the trigger and it blows the clog outside the cabinet.

[Bill Pace]

Bill,
does yours leak like a sieve at the seams like mine does when using glass beads?

Hmmm -- no, actually it doesnt! -- and I'm somewhat surprised, as I have had problems with the bench version, getting it stopped. I've only got maybe 2 very small leaks on the leg version! On the bench, I took it apart and silicone caulked all the joins - the glass window was the worst - I've been into it 2-3 time trying to get it stopped leaking. It still leaks worse than the leg cabinet... On the leg cabinet, I did keep the caulk gun handy on assembly and would use it on any suspicious join. (I keep glass in the big cabinet)

Speaking of the leg cabinet -- the gun that came with it was designed differently from the bench and I could not use it - it would stop up after only 2-3 mins. It seems that where the air/media joined in the gun head, the gun created a venturi effect causing the air to condense turning the medias super fine dust to mud, stoppping it up. Unscrew the tip shake/blow the mud out, work again for 2-3 mins and stop again. I had one of those blaster rigs that you stick the pick up tube in a bucket of sand, and I rigged the gun off it up in the cabinet and havent had any more problems....

[Bill Pace]

First thing I did was install a light. Pretty hard to use this thing in the dark

By all means! the cabinet is almost useless without light!

JB, you'll definately wanna add a light to yours .... I got mine at wallyworld. Its shown as an under cabinet add-on light for kitchen, etc, - flourescent, 18 or so inches with a switched cord for the huge sum of 8-10$ - I pop riveted it in.

[tdkkart]

Unfortunately there is probably no "one size fits all" in blast media, what you use is highly dependant on what your goals are. If I had my druthers and a big enough shop I would have 2 or 3 cabinets with different media.

Here's what I've had experience with:

Black Beauty: very aggressive, too aggressive for my uses(mostly aluminum), takes off anything but tears stuff up pretty good. Will leave a rough surface on steel parts. Breaks down slower than glass beads. Also a bad idea for use on stuff like internal engine parts, if you don't get it all cleaned up you've got troubles.

Glass beads: Good general purpose, fairly aggressive, yet doesn't tear stuff up too bad. Will remove staining from cast aluminum parts. Again, not a good idea for internal engine parts.

Ground walnut shells: good for delicate stuff, soft enough to use on internal engine parts without potential damage. However it is dusty as hell and breaks down quickly. Moisture causes big problems since it soaks up water.

Plastic media: This is my favorite so far, reasonably aggressive yet leaves a nice finish. Does not seem to break down very quickly and produces very little dust, yet is soft enough for internal engine parts. However it is expensive.

Baking soda: One of our brain surgeon engineers at work decided to use baking soda for circuit board blasting. What a friggin mess. Even in an industrial cabinet with a very strong vac/reclaimer we have a layer of soda dust on everything within 50 feet of the cabinet. The dust seems to a it corrosive as it stains aluminum surfaces.

I too recommend TP Tools for parts and media. Their shipping is reasonable for 50lb boxes of media.

[Scishopguy]

Blasting

As I have mentioned before, the pressure setting you use is very important when blasting with any media but glass bead in particular. If you have rust scale, flaky paint, or just general crud, high pressure is reasonable but most of the time it just causes trouble. It wears your nozzles out faster, scars the surface of your parts more, breaks down media (especially glass bead) and can cause other problems you might not think of. One of my assistants had the idea that if 30 psi was good, 125 psi was many times better. We had medium glass bead in the cabinet and he was reconditioning a set of aluminum heads off his wife's car. He blasted the heads and went to machine the gasket surfaces and could not get a decent finish. The tools kept getting dull before he could finish the cut. As it turned out, the pressure was high enough to embed the glass bead in the surface and he had not cut deep enough to get below the layer of glass. It also goes without saying that the dust produced was more than the vacuum system could keep up with. He didn't believe any of us about the pressure and just blamed it on a crappy casting. None so blind as those who won't see!

[gnm109]

I've been using a blasting gun with carbide tips for the last ten years or more with no noticeable wear to date. You can get both tips (inner and outer) on the internet for $35 and you probably wont need another set.

I've used glass beads, walnut shells, soda and lately, I switched to copper slag. I like that the best. It's $9.00 for a 100 pound sack. I have to screen it before loading my H.F. cabinet but it lasts a long time. I would never use straight sand. I have a pressure blaster for big items and I do them outside with regular sand blasting sand.

I have three CFL bulbs inside of mason jars for inside lights. The only problem I have is changing the inner plastic sheet to protect the tempered glas 12X24" window on the front.

I run it at 90 psi but I have a compressor with 21 SCFM. It takes a biig compressor to keep up.

I also use a large Cyclone brand dust colector to keep the field of vision clear when I'm using the cabinet. I used some modified stainless steel dog bowls for arm holes since they are larger. The gloves are $5.00 a pair at H.F.

The H.F. Cabinet is a good place to start if you want a cabinet. With modifications, they are quite good. Don't tell Don I said that. LOL.



Here's a picture.