7 replies to this topic

[sibhs]

Here are some tips for using the 20 gallon portable sand blasting units.  This is stuff I thought might help the next newbie when he thinks he'll just quickly sand blast his car in an afternoon. Please feel free to add your own tips.

 

This is the unit I was using, cost about a $100 from Radum in Canningvale WA. Comes with face/head mask, funnel, gun and hose and a 3 spare nozzles.

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First thing you will find is it needs a lot of air, I bought a another compressor that has 447litres of free air and this just keeps up. 

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It's a messy job but is very effective in removing paint, bog and rust. Make yourself a room or use plastic to keep it in one area.

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I used garnet as my medium, and to do my car I would estimate 10 bags is enough. This is for all areas except the flat panels, those I did with paint stripper. I liked to fill the pot (two bags) then when that runs out fill it again with two more, then start to reuse the stuff from the ground.  I scooped it up into a bucket then sifted it through a double layer of flywire mesh (fibreglass stuff) into another bucket. Then using the funnel filled the pot. After 3-4 times use it start to become very dusty and less effective, this is a good time to sweep it up and start fresh again. I spent about 15-20 hours on this car but a few hours was down time sorting these issues mentioned below. 

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This cost me $20 a bag but some places can charge up to $32, it's only sand, should be $3 a bag

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A full pot can last 30mins if you have the mixture right, I angled the sand tap to reduce the sand air mixture.

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The unit runs really well with new sand but as moisture gets in the line and lumps of stuff make there way through you start having more stop start issues.  I found by turning the air off to the hose it diverts more pressure to the pot it then spews out sand which unblocks the nozzle then turn the air back on.

This lever going to the red hose.

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Now parts wear quickly, the issues I had was the hose where it connects to the tap wore a hole 3 times so I cut that section off and refitted. Try and keep hose straight near this section and once you stop blasting I would turn the air tap off to stop the pressure building and splitting the hose.  The bit the hose slides over got a hole in it when I was almost finished, this is part of the unit that combines the air and sand, still haven't fixed this problem properly. Nozzles get larger and use more air and eventually break in half. Face mask gets sand blasted which makes it very difficult to see, I would polish the plastic shield everyday which helped but in the end I just used safety goggles and you learn to angle the gun so you don't get a face peel.

The gun nozzle stop, (dead mans) I think it's called would wear quickly if you didn't hold it open fully, very tireing on the hands, maybe devise a tap near the end and get rid of that system. I cut the metal stopper off the rubber block and spun it 180 to keep going.

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Make sure you release the pressure in the pot before refilling, I used the pressure relief valve for this.

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I can't think of any other way to quickly remove paint in spots like this.  This area takes about 1.5 secs.

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Once finished move the car out and sweep and blow out the sand, spinning the car many times.

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Hope this helps someone.

 

Marty

Edited by sibhs, 04 June 2013 - 11:54 PM.

[sibhs]

Don't forget to wear a good quality dust mask.

 

One of the hardest things was seeing what and where you are blasting, good lighting essential.

 

Don't blast in one spot too long, keep the gun moving over the area until all paint removed.

[r2160]

Thanks for the tips. I have been considering doing this myself as well.

 

How many CFM is your compressor rated at? Did it run out quickly or did you do, say, 30 seconds, rest etc

 

cheers

Glenn

[sibhs]

Mine is 447 cfm of free air which is the rating you take notice of. I think it's around 600cfm of normal. <br />It could keep up without stopping but only just. <br />Compressors need to rest as well depending on duty cycle, mine needed 10 minutes in every hour. This is so they don't burn out. <br />If I had free transportation to sandblasters and they charged under a grand, I'd pay it. It's costly, messy and time consuming but it's done to my satisfaction. <br />I can't imagine the pro's blasting then cutting out seam sealer and blasting again. It all takes time. <br />Marty

[sibhs]

Yes, small compressor will do an A4 size area before it needs recharging.