Desk top sand blasting

[ron61630]

Looking for a compact desktop sandblasting cabinet, and all the associated gubbings  Cabinet will be used for smallish parts up to 300mm long so something like 300x300x300 would be ideal. Also hints on suitable compressor and gun

Thanks

[andyhigham]

You will need quite a large compressor, blasting is very air hungry.
www.sandblasters.co.uk/bench-top-sand-blasting-cabinet-sbc90---blast-cabinet-for-blasting-smaller-part-130-p.asp?gclid=EAIaIQobChMIyarr6ZGNgwMVyIBQBh3eRQ43EAQYASABEgKiJvD_BwE

[oldnorton]

I have used a bench top style one for several years, but had to extensively modify my Clarke item. Yes you need the biggest 13amp compressor, make a new blast gun jet to reduce the airflow, attach a Henry vacuum cleaner exhaust extract, with baffle plates and dismantleable blast media filter, fit a toughened glass viewing window (the plastic ones are hopeless). If your choice of bench top model comes with all that you are good to go!

[chris vine]

Anglo Scot abrasives used to make a kit and supply guns.
I have one of their guns, it is excellent. Unlike the clarke ones which have soft nozzles so only last a short time.

Chris.

[chris vine]

Ps I think the Clarke guns are only intended to work with glass bead media. Maybe they are fine with that.
Maybe their guns are different now??

[steamer5]

Hi Ron,
I’ve had a bench top blaster for quite a few years, as you get them they work, but not that well!
As Chris says I’ve run mine on glass beads since getting it. Best thing throw the suction tube away! Put in a bottom pickup… as mentioned above Anglo Scott’s used to supply these, I made my own from pipe fittings, you need to extend the legs a few inches. There are plenty of you tube videos on mods to the bigger units… sorry can’t post any pictures of what I’ve done as I’m away from home.
But as a quick list, a cyclone on the exhaust to the vacuum, removed the air inlet filter, put a plenum on the air out, sloped the inside ends to the center, bottom pickup, still using the gun as supplied with the smallest nozzle. One of these days I’ll replace the plastic window with tempered glass, make a smaller nozzle plus air nozzle, fit an air inlet plenum & some form of vibration to encourage the beads to migrate to the suction pickup( there’s just not enuff slope for it to fall / slide on its own.

Cheers Kerrin

[andyhigham]

I have a desk top blaster, I wish I'd bought a floor standing one! As Kerrin said the pick up arrangement is woeful.

You need a really good extract system, ideally sucking more air out than the gun puts in, otherwise media gets blown out through the door seals

[chris vine]

The problem with the pickup tubes (solved by the simple Anglo Scot system, made of pipe fittings) is that they don't let any air into the pipe where it comes out of the hopper.

If you have an air bleed into the pipe, then the grit gets transported along in a steam of air.
With out the air, you get gobs of it and blockages all the time.

You would have thought that the people who sell these things in their thousands would have worked this out by now...

Chris.

[doubletop]

Dec 14, 2023 23:09:30 GMT chris vine said:

The problem with the pickup tubes (solved by the simple Anglo Scot system, made of pipe fittings) is that they don't let any air into the pipe where it comes out of the hopper.

If you have an air bleed into the pipe, then the grit gets transported along in a steam of air.
With out the air, you get gobs of it and blockages all the time.

You would have thought that the people who sell these things in their thousands would have worked this out by now...

Chris.

Mine would do that and I would disassemble to gun to try to rectify. I then thought maybe it was the media at the pickup end not flowing properly and tried to free it up. Then a moment of inspiration, before I start I put a blast of air backwards down the nozzle of the gun which loosens the media at the pickup. No problems since I started doing that.

Another problem in times of high humidity water caries over from the compressor and causes the media to bind in the ceramic nozzle of the gun. Of course, a water trap helps, but so does the reverse blast down the nozzle before starting.

I have owned two cabinets:-




The problem with this one was the seal on the lid, media escapes around the seal and straight into your face necessitating goggles and a face mask.




This one overcomes the leakage of the lid as it has a door in the side. The problem with both the cabinets is the level of dust that when being used that prevents the operator seeing the job.



I fixed that on this second cabinet by adding the filter unit which was available separately from the supplier. It was not meant for this model but was relatively easily adapted with some stand offs for three of the four mounting lugs and adaptor for the vent. I 3D printed mine but one could easily be turned. It transformed the machine.

(I did try one of the cyclone units Kerrin suggested but wasn't really happy with the result thats when I went for the commercial filter)

Pete

[SteveW]

Things to consider:
The big one is you need a lot of compressed air at pressure for even the modest of grit blasters. I used the Clarke Spot Blaster from Machine Mart and my 1-1/2HP compressor couldn't keep up. You need high volume at high pressure. Think 3HP compressors else its a blast, wait, wait, wait, blast repeat cycle.

Remember that if you are hosing 10cu feet a minute or more of compressed air into a small box it's going to make its way out again and likely still carrying a payload of abrasive dust with it. You can't stop it plus the stupid little filters you see on the back of blasting boxes just bung up very quickly then it blow out all the joints. A better solution is a free flowing labyrinth filter. Do not do this anywhere near precious moving parts or surfaces.

Minimise the number of small orifices in the hoses, keep the compressor well away from the blasting area and maybe use a secondary tank close by. I replaced the stupid little screw-down tap on my Tiger compressor with a cone/cross hole type. The flow improved immeasurably.

Use a soft and flexible rubber hose inside the box to feed the gun else you'll be fighting a tough plastic hose in a confined space.

Use of a water trap is a must to remove water from your air source else you'll get little hard nodules of grit bunging the gun up.

Wear tough gloves. I converted an old CRT TV box to a grit blasting box, used a spare bit of secondary double glazing for the window, DPC plastic sleeves hot glued onto industrial rubber gloves through holes in the box with yards of duct tape and did everything in my greenhouse well away from my workshop and compressor.

Use high quality dust masks or respirator and goggles for your own personal safety. Also for any rubber neckers. Don't under estimate this one.

Consider buying spare grit blaster nozzles at the outset if you intend doing a lot of this. I was surprised how much wear there was and how much bigger the little hole in the nozzle ended up when I'd finished.

I did a thing here years ago on my experiences but I couldn't find it today.