grit blast cabinets

[Alan]

Hi has anybody had any use of a clark/ machine mart grit blast cabinet and gun.

Are they any good or shall i battle on with a rotary wire brush

Thanks

Alan

[fostergp6nhp]

A friend of mine has the bench top model, compared to industrial kit its slow but it does work and the result is cleaner than a wire brush will get it.

[abby]

I have one , it was reduced in price because of slight damage. I use it for cleaning castings and it works fine with dry sand but not so well with bead.
It will also clean rusted steel very quickly but uses a lot of air.
For about 5 or 6 minutes of use you will need at least 13 cu ft of air per minute , even with the smallest nozzle.
The viewing window turns opaque very quickly and needs cleaning quite often , a pack of protective covers came with the kit .
I use a vacuum cleaner to collect the dust as the cabinet does not seal very well,
The built in light doesn't work on mine but I have an overhead light anyway so that's not a problem.
The media does not flow to the pick-up point very easily so occasionally you have to tip the thing on its end and you must use a water trap or the gun will clog.
I only paid £100 for mine so I consider it well worth what I paid .

[SteveW]

Alan,

I had some success with the Machine Mart "Spot Blast" unit at around 17 quid but it still uses a lot air. The nozzle jumped a few sizes by the time I'd finished with it. I also use the Machine Mart grit and recycled it over.

I found I needed a water trap else the used grit turned into little nodules and clogged the nozzle.

I cobbled together a big cardboard box and a bit of spare glass into a blast cabinet. It included a set of long sleeves of heavy duty polythene and neoprene rubber gloves taped on the ends. Don't do it with out proper gloves, goggles and breathing mask.

A long air hose is sort of a must if the cabinet seal is poor, I did it in the greenhouse at the end of the garden well away from the workshop. Remember, there's a lot of air going in and it's got to leak somehow so some sort of labyrinth filter would be good to let the grit settle out.

The biggest problem is getting enough air, volume and pressure. My 1-1/2 HP unit wasn't really man enough for more than a few tens of seconds at a time. Then of course I had the problem with the compressor dumping half the air via the regulator. See elsewhere for my reported fix for this.

[GWRdriver]

My experience with a similar model available in the US is almost exactly the same as Abby's. I've only used a sand-like commercial abrasive so far (not masonry sand) and that works well with only an occasional clog. I second Steve on using it away from anything which would be harmed by the abrasive grit dust it generates from an exhaust port although I could eliminate that by power evacuating through the port. All in all I've found an abrasive blast cabinet to be a very handy thing to have. Occasionally I'll pick up beer money cleaning up tools and metal objects for the locals.

I recently had something a bit larger than I could easily handle (a drill press head) commercially abrasive blasted and the folks used plastic beads on it. That material did a beautiful job of removing all paint and grime without harming the machined surfaces in any way. I was astounded. I was told that solid CO2 ( "dry ice") would produce similar results.

[Staffordshirechina]

There is a thread on Traction Talk about just this topic at the moment. Repainting a model engine and how to get bits clean.

link is www.tractiontalkforum.com/showthread.php?t=14683

Les

[caddman]

An associate of mine who works in the aircraft imformed me that walnut shells are used for the same purpose.

Nels

[bambuko]

"...PLEASE NOTE: You Now Need to Be a Signed Up Member to View Posts on Traction-Talk..."

[isc]

Nels, your right, back in the 60s when I was overhauling piston type aircraft engines we used crushed walnut/ we called it prunus(spelling) blasting, for cleaning pistons, and cylinder heads. I seem to have heard that for some uses plastic beads are some times used.

For normal use here in NZ, there are three grades of ground glass(one of a number of ways of recycling old glass).

I have a part built sand blast cabinet, made of a large plastic storage box, its yet to get the hand holes cut in the side and the window fitted in the lid. I,v been using the box on my bicycle trailer in the mean time.
isc

[deverett]

I bought one of the plastic Machine Mart bench top blast cabinets hoping to clean up a few castings and the like. I only have an Aldi compressor and that is not man enough for grit blasting of any kind. So I am now wondering whether to fork out for a larger compressor or to get someone else to do my occasional blasting.

Dave
The Emerald Isle

[isc]

I,v got two compressors, and I'll couple them both into the system, I think they will just about keep up. They both are home made, using old freezer compressors. isc

[ron]

Hi
I used to have the Screwfix version when I was restoring the TR6, my experience was pretty much the same as Abby's plus by the time the resto was finished it was completely clapped out. I have a two cylinder 3hp industrial compressor which ran continuously to keep up and struggled a bit when the ceramic nozzles wore [which happened quite quickly with carbide media]
I would say they are good value for money for light hobby use if you have a big enough compressor, but are not really suitable for anything more serious, if they are available Tungsten Carbide nozzles would possibly be better with carbide abrasive.
Ron

[russell]

I succesfully used a KEW pressure washer with a wet sandblasting nozzle to strip a vintage car chassis. A bit too heavy duty for model use but perhaps one could build a lighter version using something like a boiler feed pump driven by a small electic motor.

Just a daft idea perhaps.

Russell.

[abby]

Actually Russell I think that is a very good idea ,something lke a vapour blaster . I was thinking a bigger pump though giving water volume rather than pressure ,and re-circulated water (would need filter and/or settlement) My use is for cleaning castings , with a sand/air feed it could be more efficient than just sand/air , no dust either but re-using the media might be difficult to arrange.

[russell]

Jan 8, 2011 23:49:08 GMT abby said:

Actually Russell I think that is a very good idea ,something lke a vapour blaster . I was thinking a bigger pump though giving water volume rather than pressure ,and re-circulated water (would need filter and/or settlement) My use is for cleaning castings , with a sand/air feed it could be more efficient than just sand/air , no dust either but re-using the media might be difficult to arrange.

I used fine, dry, silver sand which is dirt cheap so reuse is not necessary. I think high pressure was needed to get sufficient velocity for it to remove paint. I did it in the open air as there were no problems with dust.

Russell.