Tungsten Nozzles for Sandblaster

[rtbcomp]

The ceramic nozzles supplied with these blasting pots wear out very quickly, the solution is to replace them with easily obtainable tungsten carbide ones. This is how I did it

In the picture below we have, left to right, top to bottom.

1) Tungsten carbide nozzle, 10mm OD, 3mm ID and 52 mm long
2) Oilve from a 10 mm compression fitting (Screwfix 35490). Use the fitting as a tool to fit the oilive to the nozzle.
3) 3/8 BSP compression nut, the hole may need reaming out very slightly.
4) 3/8 BSPP (parallel) nickel plated brass barrel nipple
5) Steel tube, 10mm OD 1mm thick and just longer than the nipple

The above items will allow the new nozzle to fit into the existing ball valve on the end of the hose, if like me you've dispensed with the valve, the following items will allow the nozzle to fit into the hose itself. If you have a 10mm ID hose just shove the nozzle up it and secure with a Jubilee clip.

4a) 14mm - 3/8 BSP mickel plated brass hose tail.
5a) Steel tube, 10mm OD 1mm thick and just longer than the hose tail.

This is what you do.

1) Secure the olive onto the end of the nozzle. Do this in two stages

a) Insert the nozzle into the compression fitting as you would a piece of pipe. Tighten the nut just sufficiently to allow the olive to slide up and down the nozzle with moderate finger pressure, i.e. it will stay put.

b) Push the olive to the very end of the nozzle, put it back in the fitting and tighten fully. See the next picture.

Next we need to line the nipple or hose tail as appropiate. I did this by sliding the tube into the fitting and peening each end over with a hammer. Try to get the nozzle end as flat and as flush, or even recessed into the countersink, as you can.

You may need to open up the hole in the 3/8 compression nut slightly, the nozzle should be able to turn freely in it.

To prolong the life of the steel sleeve, turn the fitting through 180 deg. occasionally, it wears down one side rather than uniformly.

This chap is selling nozzles on Ebay http://shop.ebay.co.uk/merchant/pete_booth

 

[rtbcomp]

The finshed item

 

[stormin]

I've just bought one of the 3mm tungsten nozzles from Pete Booth. Asked about larger ones but he doesn't do them.
I've experimented with a home spun steel nozzle of 6mm bore the other day and pressure is still up at 90 psi with my 130cfm compressor. Only troubled is the grit tended to get damp. I think the built in water seperator is struggling to keep up with the higher airflow.
I've also recently purchased a large filter regulator kit so I may fit this upstream of the inlet to the pot to help and T off for an air-fed mask.

 

[stormin]

RTB,
If your running the nozzle straight out the end of the blast pipe with no ball valve, how are you shutting off the supply?

 

[rtbcomp]

RTB,
If your running the nozzle straight out the end of the blast pipe with no ball valve, how are you shutting off the supply?

Just turn the air off at the pot, it takes some time to run down but as I'm in a blast room no media is wasted. I have a cunning plan to fit a lever to the pot that closes the bottom valve and air supply simultaneously, whilst maintaining the setting on the bottom valve when it is re-opened.

As for a bigger nozzle, the one you've got will have worn to 3.5mm in about 12 months if you use it every day!

That moisture trap isn't brilliant, I get some dampness creeping through. The place I got my helmet from sells filters to provide breathing air, but I don't know whether it will handle the flow to the pot as well.

 

[irondarren]

rtb ii used to have one of the sealey sand blasters that had a tungsten end, i shuffed loads of grit through it before some little soul nicked it

 

[stormin]

Just turn the air off at the pot, it takes some time to run down but as I'm in a blast room no media is wasted. I have a cunning plan to fit a lever to the pot that closes the bottom valve and air supply simultaneously, whilst maintaining the setting on the bottom valve when it is re-opened.

As for a bigger nozzle, the one you've got will have worn to 3.5mm in about 12 months if you use it every day!

That moisture trap isn't brilliant, I get some dampness creeping through. The place I got my helmet from sells filters to provide breathing air, but I don't know whether it will handle the flow to the pot as well.

Don't suppose you got any that you've worn out to 3.5mm or larger then?

 

[rtbcomp]

Don't suppose you got any that you've worn out to 3.5mm or larger then?

They don't wear evenly, I've got a couple that go from 4.3mm to 3.5mm. The least wear occurs at the olive end, I dare say you could fit the olive to the other end and even up the wear. I can spare one of these, subject to a donation to forum funds, if you're interested drop me a PM.

 

[rtbcomp]

They don't wear evenly, I've got a couple that go from 4.3mm to 3.5mm. The least wear occurs at the olive end, I dare say you could fit the olive to the other end and even up the wear. I can spare one of these, subject to a donation to forum funds, if you're interested drop me a PM.

Posted this morning

 

[softlad1971]

This is how modded the original fitting that came with the pot.

I drilled out the fitting with a 10mm drill then chamfered an edge so the olive had some where to bite.

Put the olive on the nozzel

All together. Only cost 10p for a 10mm olive

I can also still use the ceramic nozzels that came with the pot if I ever need to.

 

[rtbcomp]

I did that originally, but the nut and nipple that comes with the pot isn't BSP, so when it wears out you have to replace the lot with BSP fittings. It will last MUCH longer if you sleeve the brass components with a bit of steel tube.

 

[gavuk]

Rtb ,do you find the abrasive choice has any effect on the pressure/volume the pot needs to be set to?...does glass bead require higher or lower pressure than alliminium oxide?.......in recent years i've only really had experience with aqua blasts ,would like to build small blaster for home ,but have limited cfm and funds ........need your expert advice

 

[rtbcomp]

Yes indeed. Glass bead (not grit) needs about 25 to 30 psi, I've never used aluminium oxide. Glass grit works very well at about 55-60, but it does break down each time you use it and the finer it gets you need to put the pressure up, I'm running at about 70 psi on glass grit that has been used about half a dozen times. Pretty much applies to copper slag (J-Blast).

A 14 cfm (3hp) is the minimum compressor you need to be realistic. Mine will maintain 70 psi but I'll be adding another compressor soon to maintain a higher pressure & greater flow. You need more cfm as the nozzle wears.

I was thinking of making my own pot, but the price of those on Ebay hardly makes it worthwhile.

 

[gavuk]

I wouldn't make one myself ,except i have a few ball valves and i already have a few cylinders,i intend to connect up a couple of compressors thru an old propane cylinder just gave away my 19kg cylinder because i have a 47kg spare,is jblast good for alluminium ?never used it ,which do you prefer or which is cheaper ...many thanks Gav

 

[stormin]

I was thinking of making my own pot, but the price of those on Ebay hardly makes it worthwhile.

Haven't seen any of the cheap pots on ebay for a while. I've been thinking of making an enlarged pot using an old propane bottle as I want to use larger pipes and probably a commercial type blast hose in the future.
Don't really want to mess about with my current pot though in case it's out of action whilst experimenting with the new ideas. A bit of extra grit capacity might come in handy too with the greater airflow I should be getting.

 

[rtbcomp]

.....,is jblast good for alluminium ?never used it ,which do you prefer or which is cheaper ...many thanks Gav

New J-Blast may be a bit harsh, I've used worn. It depends on the finish you're going for. If you're going to paint or powder coat a rough surface is best, if you're going to bead blast you want a smooth surface.

I keep my worn grit seperately to use on allly if I'm going to bead blast it ultimately.

J-Blast is much cheaper, but it doesn't last very long (it's designated as single use) and breaks down into dust. If you're going to use aluminium oxide it's best in a cabinet or blast room so you can recover it easily.

 

[gavuk]

Cheers rtb ....great info ......ever thought of changing to aqua blast?,we had a vixen where i used to work ,still used air to keep media insuspension and accelerate water but dust levels where very reduced.........nice bit of kit ,but i didn't have to pay for it

 

[rtbcomp]

I haven't really got room or funds for any more equipment, and hopefully I'll be retiring in a few years anyway!

 

[gavuk]

sympathise with room and funds.....i got 20 +years unfortunatley as i can't see early retirement being an option more like 80 by the time i would reach it.......again thanks

 

[rtbcomp]

To add to the original post.

I've noticed that the nozzle is beginning to creep out of the olive, I've fitted a new olivbe with a bit of Loctite and screwed it up very tight.

I suggest you check this everytime you fill the pot.