Sand Blaster Cabinet Problem

[DavidAU]

I have a home workshop sand blasting cabinet with a problem. It is the type that stands about 5 foot tall and you open it up and feed the parts in the end. Although it works good and I'm using grit in it, it is forever sucking itself dry.

It has got a tapered bottom so the grit is meant to move down and be picked up for the gun but unless I keep wacking it on the outside with a rubber mallet or opening it up and poking the sand with a stick it runs out of sand supply fairly quickly. The sand / grit is dry and I have a water trap on the air supply line.

Anyone else have this problem and has come up with a "fix"?

[Carsnz123]

The sand blasting cabinet I use has the same problem. I have found that pulsing the gun like you're spray painting helps. I have heard that one of the reasons this happens is the finer particles in the mix can become packed down too hard around the gun pickup for it to be sucked up.

[Friartuck]

Two tips: 1) occasionally place your finger over the blasting gun's tip to force air down the suction tube to break up the grit in the lower cabinet, and 2) consider reducing the suction a little to not draw out all the airborne grit. Add small amount of tape over the vacuum inlet, possibly some course steel wool in the vacuum hose, or limit the air inlet into the cabinet. These have worked for me.

[MyJetstar1]

I have found the sand blasting cabinet to be one of the most neglected pieces of equipment in the shop. Many feel that if there is media in the bottom of the cabinet, it's all good. I've seen guys use the same media for months, lol! Remember, it is like sandpaper, in that it will eventually wear down.

Here are a few tips, that may be redundant to you, but may help the beginner with some common issues. First, the part must be clean. No grease, excessive rust, large loose chunks of paint, etc. The cleaner the part, the longer your media will last. Make sure your dust evacuation system is clean and functioning properly. Empty the dust often, and allow the vacuum to run a little bit after completing the part, so the dust just doesn't settle back into the bin. Also, on occasion, turn the vacuum on, and stir up you media to remove excess dust. The dust is what is contributing to your media sticking to the side of your media bin. Be sure to sift you media often. I do it twice. Once with a screen to filter out large chunks, and then rub it over a small screen to allow dust and too fine media to fall through. You basically just move it around on the second screen, leaving mostly the better media.

Then the blaster, itself. Over time, the hose where it connects to the pick-up straw will wear thin. This allows the hose to suck shut, and restricts the flow. Check it on occasion, as I have seen them literally wear through. And finally, check and maintain the tip. when the tip is worn out, it will allow too much media, and make it difficult for gravity to keep up with the demand for media. Also, make sure the unit is grounded so you are not subjected to unnecessary shock therapy, lol!

Be sure you are using the right media for the job. Too fine on a really rough part will just break it down fast, and of course, too rough could do irreparable damage to the part.

Hope this helps, and happy blasting!

[joe_padavano]

Two things. First, as noted, if the sand is not completely dry it will clog. Holding your finger over the tip of the gun and quickly tapping the trigger will "backwash" the suction tube and usually clear the clog. Second, if the problem is that the sand gets a hole around the bottom of the pickup tube, you can get a small motor-drive vibrator that bolts to the outside of the cabinet to keep the sand shaken down into the sump. TP Tools is one of many vendors who sell these. Also, keep in mind that the metal pickup tube does wear out eventually due to the sand moving through it. You might need to replace it.

[Matt Harwood]

It may not be that your media isn't sifting down, but I bet your pick-up tube is getting clogged. Mine does this too, and sometimes knocking the funnel with my knee will knock it loose, but more often, I'll put my thumb over the nozzle and pull the trigger, which diverts the air down the pick-up tube, clearing it out and it works fine again.

Hope this helps.

[DonMicheletti]

What you are experiencing is called "rat holing" when the sand forms a hole at the pickup. Some better commercial units have a vibrator on the feed hopper to address the problem. It works perfectly.

[tom_in_nh]

Good comments - I would like to add that it is a good idea to store the media in a five gallon bucket with lid, when not in use. Will hold 40-50 lbs of media.

And another tip - you do not need 90+ psi of shop air - adjust to 50 - 80 psi.

Good luck

[Beltfed]

As the co-owner of a small metal refinishing business I can't say how many hours I've spent looking into a blast cabinet. The problem we had was about the same. The grit would creep up the sides at the front corners and starve the suction hose. For years we used the rubber mallet trick. I then came up with an idea on how to push the grit back to the bottom. I got two inline push button valves. A couple of feet of copper tubing and hose. Drilled two holes at the sides below the work grate and plumed it in. Now I just hit the button valves just a second and it blows the grit back to the bottom. Keep the vacuum going as it blows up the fines in the grit.

I use two commercial "Empire" blast cabinets. The vacuum filters are very expensive as is the vacuum motor. Don't ask me how I know this, but never use an air hose to blow the dust out of the filter. There is a membrane in it that you will puncture and dust will pass through and eat your motor.

BTW some good ideas above. I really like the one about putting your finger over the nozzle. I'm going to use that one for sure.

[Restorer32]

We've been using an Empire cabinet for 35 years. It must have thousands of hours on it. Takes a lot of hours to wear out a carbide nozzle with glass beads. We can't add to the advice above. Thumb on the nozzle is our go to cure.

[auburnseeker]

Get the vibrator motor as recommended. I have the large 791 I think it is Detailer cabinet with the upgraded dust collection system. Once I put the vibrator on it was like night and day. I use black beauty. Pretty aggressive on steel. leaves a great finish for priming. I wash all my parts with water and promptly air dry then cook on my stove to be sure they are dry before priming. The adhesion is great. For fine stuff I use soda. Infact I just bought a small cabinet to get the soda out of my big cabinet as it causes all kinds of problems. I've had my Cabinet about 6 years. I have the bolt on extension as well. I use 120 PSI air which seems to work best with the carbide nozzle I have. When ever I get a clog, I do the blow back through the feed tube as mentioned. It always cleans it out. If it persists I have a pan under it and I drop the media and sift it through one of TP's screens. I always seem to find the problem, chunk of rust, flaked paint, Hunk of soda etc. I filter it right in the cabinet and back to work. If you are blasting anything with heavy scale I chip it with a hammer first. The scale always takes forever to get off blasting it and always causes the gun to get clogged. I also upgraded to the foot pedal control. I'm overall very pleased with the cabinet. I just wished they had charged me the 50.00 extra when I bought the cabinet and included the vibrator as standard equipment.

I bought the reclaimer as well but all it's good for is helping to keep the larger dust from getting to the filters. It's pretty much useless to reclaim any usable media. Maybe if you are using walnut shells or something it might work.

Edited March 9, 2015 by auburnseeker (see edit history)

[Luv2Wrench]

Vibrator on the side of the cabinet works better than you would think it does... it really should be standard equipment.