Switching blast media in cabinet? And what about smaller nozzles?

[gasket999]

Thanks to the lovely people at Machine Mart, I've rearranged my VAT-free night until payday

Thanks to the great advice from other forum members and the info already available from the site I've decided on a DIY-blast cabinet (the frost/anglo scot design if I can get a set of plans - I already have plywood sheets) with a 10 gallon pressurised shot blaster.

Hopefully my 14CFM/50L compressor will be up to it.

The things I'll want to blast will be heavily rusted steel parts, thinner steel panels as well as some aluminium and steel engine/machine parts.

As such I'll need to use multiple types of blast media (glass beads for aluminium, J-Blast superfine for the rest, maybe others) and I'll want to change them quickly, is it easy to change the media and if so, is contamination from stray bits of media left in the cabinet/pressure pot a problem?

Finally - the machine mart pressurised blaster I'm getting comes with 2, 2.5, 3 and 3.5mm ceramic nozzles. Everything I read on the forum mentions using 3mm nozzles for DIY use, the worry being the lack of sufficient air from home compressors - but wouldn't the 2.5mm or 2.0mm nozzles require much less air and as such be much more suitable for me and my small compressor? I appreciate progress would be much slower but I'm in no mad rush.

Many thanks, yet again.

 

[gasket999]

Oh and as I'll be doing some paint spraying the air for the blaster will be arriving via a half inch regulator filter so should be reasonably dry.

 

[rtbcomp]

The smaller nozzles require finer media. The ceramic nozzles won't last 5 mins with grit, you'll be best advised to switch to tungsten carbide. They'll be OK with glass beads.

Don't forget to protect the plywood - some people use rubber sheets or steel (from old washing machines/fridges)

I wouldn't worry too much about contamination, empty the pot by removing the nozzle, close the bypass valve, open the bottom valve fully and slowly open the main air valve to expel the media. You'll need to shake the pot gently as it becomes nearly empty.

 

[brightspark]

if your using the blast pot for j blast superfine u would need to empty it thoroughly to then use beads . after using beads back to j blast isnt much of a problem. i have seperate cabinets for both and also use a suction gun for beadblasting ally . its not good policy to mix beads and j blast in the same pot as it contaminates the beads and isnt suitable for cleaning presicion alloy parts without surface damage

 

[gasket999]

That's really helpful thank you.

I'll be careful to empty the pressure pot properly prior to using bead and to give the cabinet a wipe out first (the tip re: metal sheeting will make it a wipe-clean surface)

I'll keep my eye out for suitable tungsten nozzles for the MM blaster, just hope my compressor's up to it.

 

[brightspark]

That's really helpful thank you.

I'll be careful to empty the pressure pot properly prior to using bead and to give the cabinet a wipe out first (the tip re: metal sheeting will make it a wipe-clean surface)

I'll keep my eye out for suitable tungsten nozzles for the MM blaster, just hope my compressor's up to it.

ace gritblasters sell the 3 diffrent carbide nozzles there about £17,00 each just google ace gritblasters and the site comes up. there on ebay as well dont bother with the ball valve set up on the end just hold the jet on end of blast hose with a jubily clip and work the pot of the main shut off tap

 

[rtbcomp]

ace gritblasters sell the 3 diffrent carbide nozzles there about £17,00 each just google ace gritblasters and the site comes up. there on ebay as well dont bother with the ball valve set up on the end just hold the jet on end of blast hose with a jubily clip and work the pot of the main shut off tap

Yes, the valve at the nozzle lasts slightly longer than the ceramic tips!

Some pots are fitted with a lever that seems to block the tip, not had any experience of these, but they look a bit cumbersome.

 

[stormin]

You will need to thoroughly clean the pot to remove all Jblast, I mean remove the top cap and poke a rod in there. I recently found remnants of sand in mine despite having run nearly 3 tonnes of Jblast through since the last sand fill.

The curved bottom shape of the gas bottle shaped cheap pots isn't ideal for clearing all the media. You tend to refill with grit before it's all actually run out.