Physically Small Blaster

[rtbcomp]

Am I right in thinking you only need to weld in pipe and filler fittings, not cut the tank in half (I saw some photos where this was done)?

.......

I think it'll be ok. I made a pressure pot from two cheap saucepans a while ago for injecting waxoyl and tested it at 100psi. I'd test the blasting pot at 150psi to be sure

If you think about it, you don't need to do any welding at all where there's pressure.

With the bottle inverted (ie top = bottle bottom) cut a 3" dia. hole in the top and cut a 5" dia. hole from a similar bottle, this becomes the lid for the 1st bottle. Fix the lid to a bar, one end of which locates in the rim around the 'top' and the other end can be bolted to the opposite side of the rim. Use a gasket between lid & bottle.

The air supply to the top of the bottle connects to the lid using a screwed-in connector, which is held in place with nuts and a gasket.

I hope you don't test the bottles with compressed air, if it fails under test you'll still get a big bang.

You should use pressurised water, it doesn't compress so there's virtually no stored potential energy.

 

[luke123]

Without doubt!! If you don't know if your welds are good enough*. Then don't even think about it



*and by that I mean you DO know what a good weld is

Yeah i now what a good weld is, but what welder mig, tig, arc?

 

[Punx0r]

This may be a daft question, but where do you put the grit in the MM/Clarke spotblaster? In the recycling bag on the front? It just occured to me as I went to order one.

 

[rtbcomp]

Yes it goes in the bag, the connection on the handle is for the air supply.

 

[Punx0r]

Thanks

I'd seen some which were basically identical but had a metal syphone canister between the handle and the bag, which made me think.

 

[awemawson]

I have a spot blaster that I've had for years that connects to a pressure line and a vacuum cleaner. Grit is held in a spherical pot, sucked out by a venturi and blasted, and the nozzle is surrounded by a rubber cup with flexible fingers. The vacuum cleaner sucks grit from within the rubber cup and drops it back in the spherical reservoir. Works well for small areas and comes with a selection of cups intended for car bodywork, so there is one specifically shaped for panel edge for instance. Not used it in years - I'll have to try and remember where I've put it!

 

[Punx0r]

That sounds like an interesting variant - using a vacuum cleaner.

Another newbie question: What media ought I use? Aluminum oxide? Garnet? Is grit size particularly important? The cheaper the better really so I can play about/experiment.

 

[graffian]

That sounds like an interesting variant - using a vacuum cleaner.

Another newbie question: What media ought I use? Aluminum oxide? Garnet? Is grit size particularly important? The cheaper the better really so I can play about/experiment.

The local snap-on man was a mate at one time and I used to visit his garage quite often, when he was repainting his kneeler he was using a snap-on spot blaster someone had ordered;-) It had a vacuum and a sort of brush like shroud.

My spot blaster came with an assortment of media, all the little tubes are probably still around, a mate borrowed it before I used it and he bought a 25kg bag of aluminium oxide for it so I never bothered with the stuff that came with it. It came with ali oxide, bead and steel shot and there might have been one or more other things of media. Ali oxide will probably be best for you.

 

[Punx0r]

Thanks

Someone is sorting me out a 25kg bucket of aluminium oxide, and I've tracked down an old calor bottle for the pressure pot.