Wet blasting

[tom-madbiker]

I'm thinking of making a wet blasting attachment for my sand blaster to minimise dust and so I can use regular kiln dried sand has anyone tried it also I was thinking it might work ok on car body panels as it would stop the sand heating them up and warping them

Tom

 

[rtbcomp]

Regarding using it on panels, I'd still be careful because you'll have the extra mass of the water impinging on the panel. There is also the issue with water getting trapped in seams &c.

 

[maz0]

I'm thinking of making a wet blasting attachment for my sand blaster to minimise dust and so I can use regular kiln dried sand has anyone tried it also I was thinking it might work ok on car body panels as it would stop the sand heating them up and warping them

Tom

Don't you make the attachment for your power washer, not the sand blaster?

 

[henry Kadzielski]

^^^ There are several way to accomplish this, however the best for production and thus speed is water into the air stream. Air is then the propellant and the water is there form one reason only, to reduce the dust. Using water as the propellant uses much water and can also have a significant impact on the job due to it's mass and speed. Now there is several ways of introducing water into the air stream, the most common is to fit a mixing ring around the blast nozzle and and using just the water pressure from, say a tap, to shroud the air stream with water. This uses much more water to reduce the dust during blasting and leaves the surface wet. There are other ways of introducing water into the air stream, firstly using pressurised water (above the are pressure in the hose). This is then injected into a mixing nozzle and mixes inside the nozzle prior to escaping from the nozzle. This has the effect of atomising the water into finer particles and the water is dispersed evenly through the air stream. This process uses much less water and the water can be very finely adjusted to result in just a mist being seen from the blast nozzle. The other method, that I have seen and played with is a 'Vapour blast machine'. This is what looks like a standard blast pot, however is filled with water instead of air. The water grit emulsion is metered through valves prior to being introduced into the air stream. This is probably the best method as the grit particles are impregnated with water, are heavier subsequently breakup with less dust, which is the aim of the entire process, there is much less heat generated by this method. Anyone who has blasted a thin panel will appreciate the significance of this. So there some of the options, all of which greatly increase in cost as you go from option 1 to 2 to 3. Still the most significant way to improve speed is an increase in air speed from the nozzle and the size of the nozzle used. No substitute for horespower

 

[tom-madbiker]

I was thinking of a mixer ring type attachment my compressor is not the biggest but it seems to be adequate (30hp about 100cfm) my main reason would as you say to reduce dust but I did try a bit of mix Ng water and sand in the pot then blasting but found it hard to keep the sand in suspension

 

[tom-madbiker]

Just been doing a bit of research maybe making a series of nozzles in the sand/water tank that blow air to keep the slurry mixed up and in suspension other bonus is the sand does not need to be dry

 

[Shedendman]

Went through all this years ago when i was high pressure cleaning,want my advice,DONT,you'll spend an age cleaning up after you,ever tried sweeping up wet sand?

 

[tom-madbiker]

I have been looking at ways to keep the sand in suspension in the pot I think I am going to try a paddle mixer like a plaster mixer going through a sleeve welded in the top of the pot powered from the outside with a drill or something I have made it to be a reasonable fit so the air loss should be minimal and hopefully being above the slurry level it should not get too much grit in it

 

[brightspark]

I have been looking at ways to keep the sand in suspension in the pot I think I am going to try a paddle mixer like a plaster mixer going through a sleeve welded in the top of the pot powered from the outside with a drill or something I have made it to be a reasonable fit so the air loss should be minimal and hopefully being above the slurry level it should not get too much grit in it

your probably flogging a dead horse but if you like experimenting go for it . if something isn't produced commercially there is a reason for it

 

[Turbo]

I have an attachment for my pressure washer that adds sand into the stream at the nozzle using a venturi. I ran into difficulties keeping the sand fed evenly to the pickup pipe, ended up using an upside down traffic cone!

It did work quite well at stripping the rust of a lawnmower deck but it used loads of sand & it left a real mess of wet sand that goes everywhere when blasting. I also had the problem of the deck flash rusting due to being wet so it had to be sanded manually before painting.

It also works out expensive as you can only use the sand once unless you have a drier! Crushed glass is only slightly more expensive but you get several uses from it with dry blasting!

I would only consider it again if I got a really cheap (free) supply of kiln dried sand, otherwise it would be dry blasting for me.

 

[tom-madbiker]

I'm not quite sure how the commercial ones keep the sand in suspension and I have not found any real DIY versions one thing I have noticed is that the outlet comes out of the top rather than the bottom and the air comes in the bottom so maybe it's a Venturi type thing they seem to be adjusted from lifting the outlet up and down

 

[maz0]

I have an attachment for my pressure washer that adds sand into the stream at the nozzle using a venturi. I ran into difficulties keeping the sand fed evenly to the pickup pipe, ended up using an upside down traffic cone!

It did work quite well at stripping the rust of a lawnmower deck but it used loads of sand & it left a real mess of wet sand that goes everywhere when blasting. I also had the problem of the deck flash rusting due to being wet so it had to be sanded manually before painting.

It also works out expensive as you can only use the sand once unless you have a drier! Crushed glass is only slightly more expensive but you get several uses from it with dry blasting!

I would only consider it again if I got a really cheap (free) supply of kiln dried sand, otherwise it would be dry blasting for me.

When I was researching this for wet sand blasting my series 2 bulkhead the flash rusting was a worry. I found this product which helps prevent it. Ideally you would want to be sourcing you water from a large barrel which would let you treat it. Or have a diluted spray bottle handy that you could spray down the panel with after blasting.

https://www.rust.co.uk/product/rust-inhibiter-additive-bor-8-29

 

[tom-madbiker]

Found a diagram of a commercial one has a Venturi at the bottom that blows up a pipe through the centre adjustment of abrasive is by lifting the tube up away from the Venturi also it has a vibrating motor attached to the side which is run off air

 

[stuvy]

What about gravity fed and an air agitator

 

[HughF]

Lots of plans online for diy aqua blast cabinets. You just feed the regular blast nozzle with slurry instead of dry media. Slurry is mixed up by a swimming pool pump, usually.