Sandblaster

[BogMonster]

At the risk of reopening a topic holding legendary status within LR4x4, I could really do with a sandblaster. However it would be very much for occasional use, so I don't want to spend a lot of money. The sort of thing I would use it for would be to clean up side steps and crossmembers prior to painting, that type of thing. Loose rust and paint removal in places that are awkward to get at with a grinder or flap wheel, and too much like hard work to do manually.

What's the view on current available models at the budget end of the market - anything worth having? The sort of thing I had in mind (having never used a sandblaster) was something like this:

https://www.machinemart.co.uk/p/clarke-cpsb1-portable-sandblaster-kit/

Or even a hand-held one (though I prefer the above)

https://www.machinemart.co.uk/p/sb3-gritblast-gun/

However I have no idea if things at this sort of price range are any good or complete carp. I don't really want to spend more than about £100 if I can avoid it.

I have a 3HP AIE industrial compressor with a big tank on it, so air is in fairly good supply.

A second and related question is - how might these things perform with actual 'sand'? I have a plentiful supply of wind-blown clean white quartz sand right on the doorstop, and I just wondered....

[paime]

Can you not just nail the part to the fence and let the wind do the rest down there??

On a serious note, i've tried a Clarke cabinet blaster and thought it was great. I wouldn't use it continually (mostly because the compressor was too small and it ran out of steam quickly) but it was good for getting those cracks and joints clean where you can't get a wire brush or flap disk in.

[Stellaghost]

Have had the clarke one in the past worked fine main issue as with all sand / grit blasters is having enough air I used fine sand with mine and it left a decent finish have the clarke cabinet one now same issues with air regards Stephen

[Arjan]

Blasting cabinets need a huge amount of air - thus a bl..dy big compressor

Esp. if you'd like some big(gish) stuff to play with

Back in Holland, we had a 2000 ltrs (no typo) one one 3 phase and it did the job well.

But it did love electricity....

 

[secondjeremy]

Have a similar cabinet and 3HP Clarke compressor.  OK - uses lots of air and not very quick especially if there's a lot of dirt or rust. Difficult to see what you're doing due to dust - which gets everywhere.  I Still use a professional sandblaster for serious stuff.

[SteveG]

I wouldn’t bother with the handheld one as you’ll be filling it up all of the time. I suspect the pot will be fine, it’s essentially all the blast cabinets are, a tube into base of cabinet to suck up grit/sand. 
 

Downsides of both are that they are one time use of the grit/sand, but if you have a ready supply of suitable sand that solves that issue. I’ve never had an issue with dampness, but I’ve always used a cabinet, so might be an issue if you’re sourcing the sand locally. I’ve found that 90-100psi is optimum for the stuff that I do. My compressor manages to maintain this pressure full time.
 

As to wether your local sand will work, no idea - you’ll have to try it. As it’s white it’s likely to be high in silica, so could be good. You could try a batch direct and a batch dried in the oven to see if it’s any better.

[bushwhacker]

The one with the hopper works but it is hard to keep the blast medium form going every where. Some type of enclosure for smal parts and if doing really big parts bigger enclosure. a larger hopper obviously allows longer run time.

[Gazzar]

I'm not sure that the use of sand is a good option. 

There's a respiratory disease associated with it, I think. I'm going to invest in blasting facilities, as I think I'll be using it a lot in future, but I'll not be using sand, but other media instead. My lungs are bad enough as it is!

American CDC WEB LINK

 

[Stellaghost]

1 hour ago, Gazzar said:

I'm not sure that the use of sand is a good option. 

There's a respiratory disease associated with it, I think. I'm going to invest in blasting facilities, as I think I'll be using it a lot in future, but I'll not be using sand, but other media instead. My lungs are bad enough as it is!

American CDC WEB LINK

 

Silicosis is what you can get especially with high silica sands definitely pays to wear the correct RPE if using it for sandblasting regards Stephen 

[landroversforever]

I believe the use of sand for it is now banned in the UK. 

[BogMonster]

I'm not in the UK, and it's windy here

[cackshifter]

Sieve the sand with a flour sieve before use, and keep it very dry.If you can catch it, it is reusable if sieved.  A wet trap before the blaster is a good idea. In the UK the sand for going in between brick paviors is good, but as above silicosis is a risk to using sand.

[Anderzander]

I’ve had a day trying to get my set up working for the first time.

I’ve a 3hp compressor, a small blast cabinet I have made a pair of legs for, and a blast pot. I’m running Archifine in the blast pot at anywhere between 20 and 50 psi - and have found it hard to get it working well.

The hose with the pot, that I routed into the cabinet is too stiff to flex in a confined space. So I’m looking for a replacement for that. 

I need a lot more light !  The plan for that is to buy a cheap 12v LED light bar and put that in the cabinet.

My Hoover was doing a great job pulling through a shrouded filter in the cabinet - and keeping the dust down - until it stopped working. I’m hoping that’s just the thermal protection in it because it had been running for so long.

Getting the metering and flow right wasn’t easy - I ended up on the smallest nozzle, the air on full, and the metering valve not fully open. That helped control the amount of media coming out and slowed the dust down a bit too.

The layer of film over the window was a bit of a disaster - media got behind it at one point and I couldn’t see anything, so I pulled it off. I’ll need to replace that and read somewhere that florists film is a good cheap replacement.

So - I’ve had some positive results and some struggles. I found it worked great when direct on metal - but a couple of parts had a layer of baked on grime on them and it didn’t want to shift that - however picking that away with a sharp implement and then blasting brought some good results.

So I need a more flexible hose, lots better lighting, a better hose, and hopefully not a new hoover.

[David Sparkes]

If it's steel & rust you are cleaning (not aluminium sheet, or glass) treat 60 psi as your minimum pressure, If it drops below that, stop work until the receiver fills to maximum pressure.

Do not have any sort of filter on your 'hoover', the target is to maximise fresh air throughput; any filter will block with dust and restrict the flow.
Ventilation to remove dust is an entrirely different subject to pressurised air carrying the blast media. Ensure you have a large hole to admit fresh air; ideally place this hole so the fresh air entering the cabinet washes over the inner face of the viewing window.
Have the inlet to the extractor fan below the height of the mesh worktable; this will ensure the dust moves downwards away from the viewing window.
Florist film is good the protect the viewing glass, but you still need to draw the dust away from the film.

Grimy surfaces, and thick paint, absorb the energy in the grains of the blast media. Clean off as much as you can before putting the unit in the cabinet. Leaving thin paint is OK, it's the five coats of brushed on paint that need prior application of paint stripper.

Regards.

[Anderzander]

23 minutes ago, David Sparkes said:

If it's steel & rust you are cleaning (not aluminium sheet, or glass) treat 60 psi as your minimum pressure, If it drops below that, stop work until the receiver fills to maximum pressure.

 

Thanks David.

The stuff that came with the pot had said blast at as low a pressure as you can - and aim for between 15 -50 psi. My experience matched your suggestion though - so that’s encouraging.

 

25 minutes ago, David Sparkes said:

Do not have any sort of filter on your 'hoover', the target is to maximise fresh air throughput; any filter will block with dust and restrict the flow.

Ventilation to remove dust is an entrirely different subject to pressurised air carrying the blast media. Ensure you have a large hole to admit fresh air; ideally place this hole so the fresh air entering the cabinet washes over the inner face of the viewing window.
Have the inlet to the extractor fan below the height of the mesh worktable; this will ensure the dust moves downwards away from the viewing window.
Florist film is good the protect the viewing glass, but you still need to draw the dust away from the film.

The Hoover is sucking through a filter - the one that came on the cabinet - but throughput makes a lot of sense. The hoover is an old ‘drag along dyson’ - so would hopefully survive sucking in airborne media. 
 

The bottom fills up quite quickly - so on this cabinet I couldn’t put the suction below the mesh - and it’d end up buried quite quickly, but I could easily put it low down on the opposite side to the filtered inlet I’ve been using to hoover from.

The dust reduction I mentioned above was simply from having less media flying flying about in there.

[SteveG]

I bought a couple of cheap 12v led lamps like these...

Ricoy 7inch LED Light Bar 2pcs 240W Offroad Driving Lights LED Pods Spot Flood Combo Beam (2 Pcs 7inch 240w) https://www.amazon.co.uk/dp/B07LBRLZ1H/ref=cm_sw_r_cp_tai_q-77EbXVZ6G37

Now no issues with light 

I burned through a couple hoovers, an old Miele and a cheap fireplace vacuum off eBay. So I then went down a different route of fitting one of these...

https://www.ebay.co.uk/itm/183748043689

duct fan with a brushless motor, used in model jet aircraft. I used heatshrink to place it in the exhaust duct. I had to get a speed controller. No problems so far in 18 months, and it has no problems in running 45 mins straight. I tend to give the compressor a break by then.

As said above, you’ll need more pressure, I’d try at 80 psi and then see how you get on.

i use archifine too, it’s the best media I’ve used so far, just doesn’t seem to last as long as other types.

cheers, Steve

 

[SteveG]

Forgot to add that I sealed the cabinet and viewing screen with foam tape, and yes I use acetate sheet too over the polycarbonate.

[Anderzander]

Great info here. 

Thank you @David Sparkes and @SteveG

Steve - how do you vent the duct that your fan runs in? 

[SteveG]

I use a dust deputy equivalent into a bucket then into duct fan, similar in setup to this...

https://www.howtomotorcyclerepair.com/dustdeputy/

 

[David Sparkes]

OK, clearly more than one way to skin a cat, but I'll pick up on a couple of points if I may.
 

Quote

The bottom fills up quite quickly - so on this cabinet I couldn’t put the suction below the mesh - and it’d end up buried quite quickly,

This reads as though the spent media is being collected in the base of the cabinet. As a blast pot is being used this in-cabinet collection is not required. Remove any bung in the bottom of the cabinet and let the blast media fall straight though into an open collection bucket. Your extraction facility (motor, pipework, etc) should be good enough to ensure that only blast media heavy enough to be reused will fall out. The dust will be sucked out of the extraction vent.

Side point here.
The cabinet should be in negative pressure all the time it is in use; there should be no signs of dust being blown out past the viewing window, access door, or glove ports.
A useful test of ventilation throughput is to leave the gloves crumpled up on the mesh floor.
Switch on the extraction motor.
The gloves should slowly uncrumple then stand horizontally, supporting their own weight.
If the gloves snap to attention in a couple of seconds there is too much negative pressure, consideration should be given to increasing the size of the ventilation input hole.
(The gloves stand horizontal because the atmospheric pressure inside the gloves is higher than the pressure on the outside of the gloves (inside the cabinet), caused by the extraction fan).
 

Quote

The hoover is an old ‘drag along dyson’ - so would hopefully survive sucking in airborne media. 

I am familiar with this style of vacuum cleaner (made by Electrolux in my case), although not in this role. Ensure you remove all filters, both those as part of the normal dust collection elements on the input side AND any 'cleaned air output' section, after the motor. Filters will block, very rapidly. If the air passes over the motor as part of the motor cooling system then the motor will have to be left to take its chances. You will probably find the motor itself is sealed from household dust anyway, so absence of filters shouldn't be a problem.

As it happens, I chanced on an upright 'beats as it sweeps as it cleans' vacuum cleaner. An instrinsic design feature is that the motor is out of the dust-laden air stream; only the impellor is washed by the dust passing through it, and boy, is the aluminium impeller shiny!
I removed the beating roller, covered the hole with a sheet of 12mm MDF, making holes in the MDF to accommodate two smooth bore hoses, feeding these into the cabinet, ensuring the open ends pointed downwards, and were below the mesh floor. Thus the dust, flowing / falling downwards in the cabinet had to turn through180 degrees, anything too heavy failed the turn, thus continuing down and out of the cabinet.
At the outlet of the vacuum cleaner I removed the handle, and the dust bag, using a circa 4" pipe to lead out of the workshop, through a vent normally specified for clothes driers.
The vent is only ~18" above ground level, and far enough away from the garden boundaries, for neighbours not to experience dust laden air.

Although I've thought of a water filter, I've never had to construct one. My thoughts were to duct the dust laden air over a water trough, letting gravity, perhaps assisted by a baffle or two, let the dust drop out of the airstream onto the water. An added refinement would be to duct the rainwater downpipe through the trough, thus ensuring any settled deposit is washed out of the trough.

Regards.

[L19MUD]

4 hours ago, SteveG said:

I use a dust deputy equivalent into a bucket then into duct fan, similar in setup to this...

https://www.howtomotorcyclerepair.com/dustdeputy/

 

I came here to say exactly this. Your hoover won't last long if you don't do this and it is nice and easy to get set up

 

all the other suggestions above match what I have found, namely;

- 100 psi seems good for me

- anything soft (dirt/grease/soft paint) will not come off easily so remove it first

- wait for compressor to refil if you can't maintain pressure otherwise you just waste your time

- Experiment with different media for different things. It's quick and easy to drop it out of the hopper and swap for another type and swap back if you need too

-Lighting is key, I lay an LED light on the top of the screen facing in which helps a lot as it is line of sight

 

Also consider other methods first which speeds up the process. I always chuck things in the electrolysis tank before the shot blast cabinet as I can go any do other things for a day whilst that does it's magic. Make sure it is dry before putting back in the cabinet though

 

[yalan]

Not sure if anyone is using the same Clarke cabinet, but Ifound the problems could be fixed with a new lid,

two mini halogen floods, replacable woodburning stove laminated glass window, massive filter panel and increaced internal volume. 10 years later still going strong.

I use a henry hoover with mine.

https://www.mig-welding.co.uk/forum/threads/small-clarke-blast-cabinet-improvement.20261/

 

Edited June 30, 2020 by yalan

[Anderzander]

Good stuff here - thank you guys.

I’m having much more success upping the pressure. I’ve made a hole for the hoover to draw from and that’s made just the right amount of negative pressure. It’s loads better. Still more to do.

One thing I need to learn is when to replace the media - I notice that the hoover caught quite a lot of media to start with that still felt abrasive To the the touch - so I put that back in the pot. The next time I emptied it - a lot of it felt just like powder. I tipped it back in but then reflected that I should probably be sieving that out.

I still need a more flexible hose - it’s a pain to use as it is. But it’s coming together as a useable set up. I’m very grateful for everyone’s input.

[HoSS]

Have you thought about the Karcher attachment? I've just bought one but the sand hasnt arrived yet so have not tested. But i did do some internet research before and there was some very positive feedback. Theres a video of a guy taking underseal off with one and reports that on bodywork you get no heat deformation of panels. Only thing to watch is dry it quickly to avoid flash rust.

e.g. https://www.youtube.com/watch?v=T89OAbLj_sI

[Nonimouse]

https://www.machineseeker.com/radler+u.+raf-m/i-4020941

We have an ex RAF one of these at the farm. The filter and media catch is 8' high. It's powered by a mobile air compressor, producing about 350cfm and using about 11 litres of diesel an hour. It's useful but expensive. We use silica or iron filings.

Total cost was less than £1k as the whole unit was about to be scrapped and the air compressor was 'spare'. Biggest cost was completely rebuilding the electrics

It's useful being able to do big things

Actually it might be biger than the one in the picture - ours has a turntable. See piccy for size

Edited August 4, 2020 by Nonimouse