Sandblasters

[Lurcher]

Hello there,
Anyone on the forum used a sandblaster? Have been reading up on them and seen an American website, the one with "The Belle" on it and thought they look the business. Looking around the web they seem pretty expensive for an occasional user though. Any thoughts on it? Has anyone made up a DIY one?
Cheers
Lurcher

 

[Don]

I used one when I worked for british gas, we used it to clean joints that were leaking before repairing them,it used it a material which was non- sparking! obviously. I think it was copper slag , It was a bit fierce and blew holes in anything thin or weak and was prone to blocking up if a bit damp, but it did a great job on cast iron which I think it was mainly designed for.

 

[kernowcam]

I have a small sealey grit blaster. i think the link will take you to it.
Its basically a pot, rubber hoze and a gun to which the air line attaches.
I believe machine mart do the same without the pot, adding a metal tube to go into your bucket of grit instaed for a lot less... prob a better option.

http://www.sealey.co.uk/PLPageBuilder.asp?gotonode=ViewProduct&method=mViewProduct&productid=9212

the unit works well if you get things right. It is brilliant for shifting rust. forget underseal etc. I would suggest paint stripping first and finishing with a blast. dont expect to clear large areas. on some items ie door or bonnet catches on my land rover which are plain metal have cleaned up really well. I give them a coat of clear laquer to finish them.
You really need a 3hp compressor.
you need dry grit. i use local sand from a quarry for £2.00 / 25kg bag. this gives a lovely smooth matt finish.
Glass beads or slag are more agressive and give a rougher finish.
I would not dream of paying for grit from say machine mart etc which seems v high priced.
If your air is not dry it will clog the system which is frustrating.I put a spare reg/ water trap near the gun which solves this one.
I find a high pressure is good - 120 lbs
I collect the sand by laying a sheet on the ground and sieve the grit on return to the bin. Second time around the grit seems to 'flow' better.
With my gun if larger grit gets through i undo the feed pipe put a hand over the exit nozzle and reverse blow the lump out to carry on.
hope this helps.

 

[nellway]

sand blaster

I bought a small compressor with range of tools over the internet and get very frustrated with it's lack of oomph, but using the sand blaster to get into the nooks and crannies of my Aston chassis has been really useful.

I recycle my grit too - but am now probably blasting with more rust granules than sand!

In the best fashion sense, I pinched a plastic shower cap from the wife, just the job for keeping the grit away from the follicles.

 

[kernowcam]

forgot to mention, get a dust mask organised and eye protectors. do the job outdoors away from the house as the grit goes everywhere.

 

[Don]

Just a thought,would sand contain salt? after all would,nt sand from a quarry have been a beach a few million years ago? and we all know salt does to metal.

 

[kernowcam]

The quarry where i get mine is above a beach but does not contain salt. i checked with the guy for the reasons you mention. his is extracted from a sand clay mix and i believe the sand is a by product. My other worry was the possibility of silicon dust from the sand which is why i use a mask. The sand gives a lovely matt finish ideal for primering.

 

[malcolm]

A few of us have been tempted to club together to buy a compressor decent enough for sand blasting.

We've got a couple of guns - one is a Macahine Mart job that looks like a spray gun with a pot for the sand. It's great for doing really really tiny things. The other came with one of those sandblasting cabinets and has a tube to suck sand from the pit at the bottom - but that needs way more air.

How much compressor do you need? I've a feeling that 3hp (14cfm) wouldn't be up to the job. My current compressor is a cheap 8cfm thing with a 50l tank and it doesn't even scratch the surface.

 

[Lurcher]

Thanks for all the replies.
Think I'll go down Ians route and give that method a try.
cheers
Lurcher

 

[sclurgess]

you can hire them if you only plan on using it once

 

[nellway]

Sandblasters PSI

Malcolm, I don't think that the Machine mart guns will be strong enough if we get a powerful compressor, the ones we used at the college were very robust. So much so that all the face masks were opaque from the flying grit.

When the dimwits on Dream Machine stripped the paint of ABW, they did so with a sandblaster, and caused the front wings to cave in!!

 

[rtbcomp]

Gritblaster

I've got a ACE Gritblaster and a Clarke 14cfm compressor. The kit is quite good, but that compressor is working very hard and only maintains 80 psi when blasting. After an hour or so the air temperature can get quite high and hold moisture. Hot air is less dense than cold and doesn't work nearly as well.

The biggest downside is that you have to release two nuts & bolts to refill the pot. The nuts & bolts, lid seal, hose, mixer T-Piece are all consumables, the carbide nozzle lasts well.

Don't use sand - it's illegal, I use J-Blast Supafine, basically a copper slag as mentioned earlier.

I do the work in a sealed shed, a Clarke dust extractor mounted externally removes the dust. Lighting is from 12v headlamp bulbs, with a 21w bulb mounted at the nozzle.

I recycle the grit, sieving it a couple of times in the airstream of the dust extractor to remove dust. After you've recycled it a few times dust is a big problem, it is as fine as talcum powder. I collect as much grit as possible in buckets on the floor to save sweeping up.

I've made a helmet from an upturned plastic bucket. Air is fed in via vacuum cleaner hose from a Metro heater fan, slow speed is adequate. There is slot to see through, protected by a double layer of clear polycarbonate, cut from a plain sided drinks bottle. A plastic carrier bag forms a seal between the helmet and my jacket, gaffer tape plays an important part in its construction!
The outer layer of plastic has to be replaced often.

For the future I'm planning making a pot from an old gas bottle and adding valves so I can back-flush blockages.

Don't do petrol tanks, you can get sparks from the grit hitting the metal and static electricity, although the proper blast hose should dissipate static.

 

[Robbus]

I've got one of those 10 gallon pressure pot jobs you'll find on Ebay, running it with a 3hp 100l compressor, I set the compressor to buid up to 140-150psi and then regulate the air to the blaster pressure pot at 60psi, even so it doesn't take long before the compressor has to start up to catch up which is pretty annoying. You can get twin motor compressors (for obviously more money) that run on single phase and should spend less time filling up. Obviously the bigger the tank, the better and the higher FAD from teh compressor the better.

For steel blasting I just used Wickes patio sand, get about 3/4 good recycles out of it before it's broken down too much and is then pretty dangerous to health. For aluminium (did a gearbox) I use the glass beads from Machine Mart, contrary to the earlier answer, these are not as aggressive as sand and give a nice satin sheen to the aluminium. Every now and then the thing blocks up which is a pain as it has to be shut down and the nozzle taken apart, then you have to faff around setting up the right media/air flow ratio again.

I built a large cabinet out in the garden to do the blasting in and to make recycling the media a bit easier. Need to get some lighting in there though as most of the time I have to do it with the door open which somewhat defeats the purpose! Damn stuff does get everywhere!

Cheers,
Rob

 

[rtbcomp]

I've lost count of how many times I've recycled my grit, it's quite fine now but will never give sheen on ally, you do need beads for that.

Blocking is a PITA. I've added extra valves to my pot so I can blow air back through the hose into the pot. Before refilling the pot I invert it to get rid of any debris, I've found bits of rubber and fibrous material from the hose in there! Also by having seperate valves to control the air into the top of the pot and the hose I can adjust for different media. I use ordinary lever operated ball valves, gate valves would give finer control, but they rend to jam.

 

[Lippyp]

Frosts do a self build kit that has all the bits and plans you need to build a blast cabinet from a sheet of ply http://www.frost.co.uk/item_Detail.asp?productID=8066&frostProductName=DIY Cabinet Kit.

 

[rtbcomp]

I started out under a carport with tarpaulins at each end, then built a cabinet but by far the best is my shed. OK it takes longer to get kitted up, but you can do small jobs in a shed, but you can't do big jobs in a cabinet!

I regularly do motor scooter frames and I'll have to do my Landrover roof soon

 

[lexi]

Blasting with sand is a no no health wise. Dry sand forms into silica dust on impact and can get into lungs unless you have air fed mask. The best sand is Kiln Dried sand which is washed of all impurities like salt loam or even coal.
I`ve only used the sand with water through a powerful jetwasher where it is quite effective. Like most things you need a BIG compressor for good results. Over 3 hp Iwould say.
Alex

 

[malcolm]

I picked up a compressor with a 300L tank and belt drive, but it's only got a 1.5hp motor. But we've got 2 other compressors knocking about, and with a few T pieces we ought to be good for a realistic 20cfm.

Do you guys actually get a decent blasting effect from your set ups? My cheap Machine Mart gun can remove a small area of thin paint given enough time, and I've not tried the gun that came with the cabinet, but the end of the nozzle is 3/8 inch diameter and I've a feeling it was designed to run off a more beefy supply. A RR Trent engine maybe?

Haven't spent a lot on the set up (just accumumated bits when they were offered for cheap) but it would be interesting to know whether a decent blasting gun would make a difference if the ones I have dodn't do the job.

 

[rtbcomp]

Do you guys actually get a decent blasting effect from your set ups? My cheap Machine Mart gun can remove a small area of thin paint given enough time, and I've not tried the gun that came with the cabinet, but the end of the nozzle is 3/8 inch diameter and I've a feeling it was designed to run off a more beefy supply. A RR Trent engine maybe?

Yes, mine is very effective. I've cleaned really rust wheels with J-Blast Supafine, and it will easily strip paint. Don't forget there are many different paints out there, some fly off, some need work. Powder coating won't budge.

I've never tried a gun type, I suspect they'd be difficult to get into cramped spaces.

This is the one I use http://www.acegrit.co.uk/acegrit/gritblaster/page3.html

 

[Silas (son of Silas)]

I can't remember what make my blaster is, but it sounds very much like your ACE RTBComp. It may will be the same. I also use J-Blast as it's what they recommended when I bought it. It's the big red one they always used to advertise in Practical Classics (they may still do)

It's one of those things that you can't really imagine just how useful it is until you own it. I really can't be arsed with rust removal and it makes it so much quicker. All I need is a good method for stopping the grit getting EVERYWHERE....