sand/shot blasting

[bogtrotter]

anybody got any exconomical solutions for blasting large bits of metal/machinery prior to painting without spending 000's on a compressor and blasting set up???

[martyn williams]

I would find a company that will blast your items.I found a local firm that were very cost effective and also primed the metalwork.
Some firms have a mobile set up for very large items.
I would google it to find a company near to you.You may be surprised how cheap it can work out without spending lots on equipment.
Another way is to use an angle grinder fitted with sanding discs, slower and harder way to do it.For large items I would use a specialist firm.
Hope this helps
Martyn

[Stormin]

I built my own blast pot from a converted propane cylinder, copying the design of a well known make. I started off with one of the Ebay 10 gallon pots but found it a bit small. They are good for small areas but you really need bigger hose and nozzles and a much bigger compressor to make decent progress.
I bought a road compressor (135 cfm) off Ebay for a good price and spent a few hundred servicing it up. My set-up probably stands me at about a grand which is I reckon the minimum you could get away with spending for "real blasting". Other option to keep costs down would be self built or Ebay pot and hire/borrow a big road compressor as necessary on weekends.
Decent grit runs a bit expensive when you get going to I use copper slag bought by the tonne for about £220 delivered on a pallet. You can get through half of that in a day. You may think of using sand because it's cheap but it doesn't cut as fast and is more expensive in the long run.
There's some good threads on blasting on the Mig welding forum http://www.mig-welding.co.uk/forum/forumdisplay.php?f=40
and details of my home built blast pot http://www.mig-welding.co.uk/forum/showthread.php?t=10682

[agrimax]

Don't use sand.It can give you silicosis--wrecks the lungs. ie it's deadly!

[Jeremy Rowland]

Don't use sand.It can give you silicosis--wrecks the lungs. ie it's deadly!

It's okay to use sand but you must wear a decent respirator mask, you can buy em with the filters for around £20 - £30 but as above don't use sand without respiratory protection cos it ain't good for you.

Jeremy

[Julian]

I built my own blast pot from a converted propane cylinder,]

I've got one of those cheap syphon feed ones from Machine Mart with a pot that holds about 20Kg's or so of sand.

What I have found is that the air consumption figures quoted by MM are hopelessly unrealistic. To be effective the thing needs air at 150psi. I use 1/2" bore garden hosepipe to supply the air, via a 1/2'' quick disconnect fitting from a receiver. (the same as tyre fitters use with 1" drive windy guns) I use 4 electric compressors all feeding the receiver via separate lines and fed with electric from two separate ring main circuits in my workshops. I have a 3HP, two 1.5hp and a 2 hp all working. The trick is to adjust all the motor cutouts to 10 bar (receivers all marked up as 10bar SWP) and tweak the safety valves if needed.

That gives an aggressive blast and the compressors will keep up with demand.

I've always used kiln dried silica sand, (and decent mask) but it's a bit fine and I need something better really. What I need is dried builders ''sharp'' sand perhaps, but not sure where to get it from.

Julian.

[martyn williams]

I use kiln dried sand but I have found that a good angle grinder fitted with a sanding disc is better,don't make a mess and a bit quicker.
We had a fantastic sandblaster in work that worked very well.put a D2 through it

[Julian]

We had a fantastic sandblaster in work that worked very well.put a D2 through it

I've got my D4 to blast soon. I was thinking of having someone around with the proper kit - like the guys that blast the sides of narrow boats prior to painting. But there's so many areas that you don't want to be hitting with supersonic sand that I'm in two minds about what's best.

Julian.

[martyn williams]

I would just do the running gear,bonnet and all removable tinwork.I used a wire brush and nitromorse on the engine block and the fiddly bits.Took a while but did not damage anything.I did my D4 in sections using etch primer as I went along.
Martyn

[Stormin]

I built my own blast pot from a converted propane cylinder,]

I've got one of those cheap syphon feed ones from Machine Mart with a pot that holds about 20Kg's or so of sand.

What I have found is that the air consumption figures quoted by MM are hopelessly unrealistic. To be effective the thing needs air at 150psi. I use 1/2" bore garden hosepipe to supply the air, via a 1/2'' quick disconnect fitting from a receiver. (the same as tyre fitters use with 1" drive windy guns) I use 4 electric compressors all feeding the receiver via separate lines and fed with electric from two separate ring main circuits in my workshops. I have a 3HP, two 1.5hp and a 2 hp all working. The trick is to adjust all the motor cutouts to 10 bar (receivers all marked up as 10bar SWP) and tweak the safety valves if needed.

That gives an aggressive blast and the compressors will keep up with demand.

I've always used kiln dried silica sand, (and decent mask) but it's a bit fine and I need something better really. What I need is dried builders ''sharp'' sand perhaps, but not sure where to get it from.

Julian.

The simple and cheap pressure pots are far more effective than the syphon feed ones,less blockages and a far better grit feed.

To all those still thinking of using sand, Forget it! Proper blasting grit is far far better for productivity, it's properly dry so less likely to clog, it's also far tougher and sharper edges so has more effect on the metal or rust for less air pressure. The used product is also easier to clean up less dusty as it doesn't break down on impact like sand does. Once you've tried it you won't go back to sand.