Diesel engined compressor wanted

[Stormin]

Kiln dried sand works OK on sheet metal such as body panels, but tends to leave a fine coating of dust in places. For heavier gauge metal the glass grit you've used is better. I've been meaning to try that next as it's slightly cheaper than copper slag / iron silicate / j blast.

Yes as Martyn says 100 psi is the ideal pressure for blasting metal. On my Compair I had to raise the pressure at the regulator on top of the seperator slightly to get upto 100psi.
The volume of air required is set by which size nozzle you run. If you have too large a nozzle for you cfm you will never achieve 100 psi line pressure and blasting will not be as efficient. Efficiency also tails off as the nozzle wears.

Centurywise have a table of available cfm versus nozzle size to run here:-
http://www.centurywise.co.uk/content/pdf/Guidetoblastcleaning.PDF

You can't go much more than 1/4" nozzle with the small 20 gallon blaster as the supply pipe is too small. I think the requirement is the supply pipe must be minimum of three times the area of the nozzle to achieve the grit speed at the nozzle. When you are blasting at the correct settings the air is near supersonic speed at the nozzle and makes a distinctive very loud roar.

[Julian]

Kiln dried sand works OK on sheet metal such as body panels, but tends to leave a fine coating of dust in places. For heavier gauge metal the glass grit you've used is better. I've been meaning to try that next as it's slightly cheaper than copper slag / iron silicate / j blast.

Yes as Martyn says 100 psi is the ideal pressure for blasting metal. On my Compair I had to raise the pressure at the regulator on top of the seperator slightly to get upto 100psi.
The volume of air required is set by which size nozzle you run. If you have too large a nozzle for you cfm you will never achieve 100 psi line pressure and blasting will not be as efficient. Efficiency also tails off as the nozzle wears.

Centurywise have a table of available cfm versus nozzle size to run here:-
http://www.centurywise.co.uk/content/pdf/Guidetoblastcleaning.PDF

You can't go much more than 1/4" nozzle with the small 20 gallon blaster as the supply pipe is too small. I think the requirement is the supply pipe must be minimum of three times the area of the nozzle to achieve the grit speed at the nozzle. When you are blasting at the correct settings the air is near supersonic speed at the nozzle and makes a distinctive very loud roar.

I thought that about 100Lbs seemed to be a typical pressure. However me being me, I remembered my 'O' level physics classes and that the kinetic energy of a body (ie the grit) is proportional to the square of the speed. 125psi is the blow-off pressure of my blaster pot so I adjusted the compressor to provide an upper pressure of 120psi. If the grit speed is proportional to the air pressure (though it may be a bit more complex) then it has almost as much (1.44) as 1/2 the energy again than 100Lbs

Anyhow, I'm very happy indeed with my new compressor, never before have I had more air than I know what to do with

The glass grit is fine, very good at removing layers of paint and scabby rust.

Cheers, Julian.

[martyn williams]

When I worked at the rail depot in Cardiff we had two shotblasters,one cabinet and one the size of a house.Shame that place shut down as I put many tractor parts through the blaster
What I tend to do these days is use nitromorse and a wire brush on the more delicate bits like engine blocks etc and sanding discs on the flat surface items and the blaster on the more sturdy stuff like track frames etc
Martyn

[Julian]

When I worked at the rail depot in Cardiff we had two shotblasters,one cabinet and one the size of a house.Shame that place shut down as I put many tractor parts through the blaster
What I tend to do these days is use nitromorse and a wire brush on the more delicate bits like engine blocks etc and sanding discs on the flat surface items and the blaster on the more sturdy stuff like track frames etc
Martyn

Nitromores, I'm afraid, it total shite these days as they've taken out the main active ingredient due to EEC regs I think. There are alternatives. There was a good discussion about this on the Stationary Engine forum a while ago: http://www.stationary-engine.net/forum/showthread.php?t=24545&highlight=paint+stripper

Julian.

[martyn williams]

Bloody EEC