grit blasting basics?

[monkeymark]

I've thought about making a small cabinet for grit blasting small components for a while. There is plenty of info on here but most from the perspective of those who already know what they are doing.

Does anyone know of any sites that explain the set up within blast cabinets, blast pots etc as it seems there are different methods of grit delivery and I know nothing about them I'm afraid.

I'm very limited for space which is why I'm thinking of making my own as then it can be made to fit into my existing workspace.

 

[brightspark]

theres 2 types syphon gun used in cabinets or pressurised blast pots which can be used open blast or in cabinet using a decent extracta fan. your comp wants to be no less than 14cfm go down machine mart and look at there cabinet and gun . that will give u a good idea what u want and start there theres is a suction gun . ok for light rust removal on smallish parts

 

[rtbcomp]

The best way to build your own cabinet is to look at a Clarke cabinet as BS says, and then build yours exactly the opposite way i.e.

Make it front loading and fit the lights (I use 12v halogen spots) on the sloping front so they face to the rear. If you use a siphon gun get a decent one from Anglo Scott Abrasives and pay extra for the tungsten carbide nozzle.

Edit - remove duplicated detail.

 

[optima21]

my latest DIY blast cabinet is a temporary greenhouse with the gloves duck taped though the opening

I only have a 2.5hp compressor so it takes me a while. I use a syphon tube with a air bleed to make the grit more fluid in the pipe to the gun. the gun I have is made for small compressors and was from Anglo Scot Abrasives a few years ago. its the same a larger consumption guns, but the holes on the nozzles are smaller

http://www.angloscotabrasives.co.uk/blast_guns_page.htm

and a few parts I'd prepared a while ago

 

[monkeymark]

Thanks for the advice guys.

I have a small compressor, and aldi one. A little under powered but was thinking of making a Calor air receiver for a little extra air.

Have a blasting gun. Its a cheap one with a screw on pot below. To save filling all the time I was considering trying it with a pipe to see if it would pick up from a larger grit container (or the bottom of the cabinet like with the machine mart ones) but not sure if it will. May try it with a little sand at work, not to blast with as I know that can be bad, just to see it it will pick up.

None of my equipment is ideal but if it will get me started I'll upgrade as time goes on, as I do with most things.

 

[rtbcomp]

The gun should pick up with a tube, the gun itself is the same whether it's supplied with a tube or a cannister. As said, an air hole will help to prevent too much grit being picked up which could block the pipe. Another way is to make sure the end of the pipe can't get sucked down into the grit, it needs to be about 1/2 to 1 below the surface.

 

[monkeymark]

The gun should pick up with a tube, the gun itself is the same whether it's supplied with a tube or a cannister. As said, an air hole will help to prevent too much grit being picked up which could block the pipe. Another way is to make sure the end of the pipe can't get sucked down into the grit, it needs to be about 1/2 to 1 below the surface.

So basically some way/valve to allow air to enter the pipe between grit and gun?

Hmm, more reading needed me thinks.

 

[rtbcomp]

Yes. On mine there was some steel pipe connected to the end of the rubber pipe where it dips into the grit. All I did was drill a hole in the steel pipe near the rubber and partially cover it with a Jubilee clip, the idea being you could alter the size of the hole by re-positioning the clip.

If you're recycling grit in a cabinet you can fix the steel pipe rigidly so it just dips into the grit. As the grit is recirculating it should stay pretty much at the same level.

 

[optima21]

an extra receiver wont make much difference as it may only hold a couple of minutes worth of compressed air, but with blasting you'll be using it for 15 minutes at a time, so you'll either need a compressor that can shift a large volume of air, or a grit gun that uses a small volume of air. I have an aldi compressor too, so it can be done it just takes a bit of time

if you look at my first picture there is a white tube going into the grit that is connected to the rubber suction tube with a T piece,and into that is plumbing 15mm isolating valve to alter the amount of air used

http://www.screwfix.com/p/isolating-valve-with-handle-15mm/89226

 

[monkeymark]

an extra receiver wont make much difference as it may only hold a couple of minutes worth of compressed air, but with blasting you'll be using it for 15 minutes at a time, so you'll either need a compressor that can shift a large volume of air, or a grit gun that uses a small volume of air. I have an aldi compressor too, so it can be done it just takes a bit of time

if you look at my first picture there is a white tube going into the grit that is connected to the rubber suction tube with a T piece,and into that is plumbing 15mm isolating valve to alter the amount of air used

http://www.screwfix.com/p/isolating-valve-with-handle-15mm/89226

Excellent. I have a few of those valves at work so i'll see what i can do tomorrow for a test.

 

[vw1]

my latest DIY blast cabinet is a temporary greenhouse with the gloves duck taped though the opening

I only have a 2.5hp compressor so it takes me a while. I use a syphon tube with a air bleed to make the grit more fluid in the pipe to the gun. the gun I have is made for small compressors and was from Anglo Scot Abrasives a few years ago. its the same a larger consumption guns, but the holes on the nozzles are smaller

http://www.angloscotabrasives.co.uk/blast_guns_page.htm

and a few parts I'd prepared a while ago

my latest DIY blast cabinet is a temporary greenhouse with the gloves duck taped though the opening

I only have a 2.5hp compressor so it takes me a while. I use a syphon tube with a air bleed to make the grit more fluid in the pipe to the gun. the gun I have is made for small compressors and was from Anglo Scot Abrasives a few years ago. its the same a larger consumption guns, but the holes on the nozzles are smaller

http://www.angloscotabrasives.co.uk/blast_guns_page.htm

and a few parts I'd prepared a while ago

When you say it takes a while how long did it that you on the struts ? ? as I was going down the pressure washer root but think it is going to work out quite expensive . Apart from your compressor how much did this set up cost?

 

[optima21]

probably took about an hour to do a strut, but that was after the worst of the rust had been removed using wire brushes in drills. ( I was using a 6 x 4 temporary greenhouse for doing the blasting in with a decent face mask).

gloves £12, duck tape £5, blaster and pickup £40, small greenhouse £10, reusable grit £30

and this is my first version from about 10 to 15 years ago, using the same blaster and pickup......the engineering is a bit ghetto, so you could say I've made a ghetto blaster.

I'm on my second lot of blasting media in about 10 years of use (probably needs changing again), but the marigold emperor gloves I've have been using for years needed replacing every couple of years as they would perish and rot/split. earlier this year I bought some gloves that arn't latex, so hopefully they should last longer

http://www.ebay.co.uk/itm/251420238215

 

[Rig Pig]

That's a nice simple setup, I'm tempted to make one now!

 

[vw1]

probably took about an hour to do a strut, but that was after the worst of the rust had been removed using wire brushes in drills. ( I was using a 6 x 4 temporary greenhouse for doing the blasting in with a decent face mask).

gloves £12, duck tape £5, blaster and pickup £40, small greenhouse £10, reusable grit £30

and this is my first version from about 10 to 15 years ago, using the same blaster and pickup......the engineering is a bit ghetto, so you could say I've made a ghetto blaster.

I'm on my second lot of blasting media in about 10 years of use (probably needs changing again), but the marigold emperor gloves I've have been using for years needed replacing every couple of years as they would perish and rot/split. earlier this year I bought some gloves that arn't latex, so hopefully they should last longer

http://www.ebay.co.uk/itm/251420238215

Thanks mate works out a lot cheaper than pressure washer set up ..i may do the greenhouse set up for now see how i get on . Any idea where i get the grit and blaster gun from please ?

 

[richie00boy]

Looks good! Do you have the steel nozzle or tungsten?

Looks like you are using aluminium oxide from Machine Mart for the media - what grade is it?

 

[vw1]

Will this kit be ok ? or shall i stick with your diy set up?

 

[optima21]

the gun I use is the BHE7 gun with pickup on the link in my first post, and thats supplied with a steel nozzle,but its still going strong as I use it infrequently. as has been mentioned earlier dust extraction may be required as it can be virtually impossible to see (like driving in thick for with main beam headlights on) so good lighting helps too (I normally have a small torch held on the gun so I can see what Im doing). also if you do you plastic boxes etc,its best to have a replacable panel in them (either glass or polycarbonate) as they get blasted too and become impossible to see through.

as for abrasives, thats a whole minefield in itself, as there are loads of different types for different applications, best to do some research on that, of just have a look through the http://www.angloscotabrasives.co.uk/ website

my setup works for me, and its all a compromise, but for others it would be completley useless, if I have the space, and money, I'd have a large compressor, full sized cabinet with dust extraction

 

[optima21]

Will this kit be ok ? or shall i stick with your diy set up? View attachment 46727

this looks to be the same one, check the reviews out and see for yourself,although it says it needs 3.5cfm of air at 50psi, so Im guessing thats low consumption, but as the pressure goes up, the air consumption would go up faster

http://www.harborfreight.com/portable-abrasive-blaster-kit-37025.html

 

[vw1]

the gun I use is the BHE7 gun with pickup on the link in my first post, and thats supplied with a steel nozzle,but its still going strong as I use it infrequently. as has been mentioned earlier dust extraction may be required as it can be virtually impossible to see (like driving in thick for with main beam headlights on) so good lighting helps too (I normally have a small torch held on the gun so I can see what Im doing). also if you do you plastic boxes etc,its best to have a replacable panel in them (either glass or polycarbonate) as they get blasted too and become impossible to see through.

as for abrasives, thats a whole minefield in itself, as there are loads of different types for different applications, best to do some research on that, of just have a look through the http://www.angloscotabrasives.co.uk/ website

my setup works for me, and its all a compromise, but for others it would be completley useless, if I have the space, and money, I'd have a large compressor, full sized cabinet with dust extraction

Well space it tight for me so was going to have same set up as you and do it out side .. or i may go for the pot blaster unit as above in my post .. Many thanks.