How I fixed getting no suction of media in blast cabinet

[Lewis_RX8]

So anyone with a cheap sandblast cabinet that relys on sucking up media from the base due to what I believe is the venturi effect?

These are the types of gun I am talking about , The air comes in at the back end with the trigger opening up the air that then passes over the pickup hose creating a vacuum in it that then pulls it up from a pickup pipe that runs along the base of the cabinet.

I spent half my day trying to change every little bit of my cabinet to get it working again all sorts of tips different media , fresh media old media etc and couldn't work out what was causing my problem as all I did is change the media turn it back on and it just wasn't working at all not sucking up anything. Only when I took apart the gun I noticed the smoking gun lol

Well inside that gun behind the ceramic nozzle there is this air nozzle , It is made of brass and shaped in a taper , it screws into the trigger body of the gun and sits above the pickup hose and when the media is picked up it must swirl around it hitting the brass constantly as it gets pulled up wearing it away. As it wears the sandblaster becomes more and more inefficient when it loses the shape , Once it blew through completely it stopped any suction of media so my cabinet was just blasting out air and the smallest amount of media dust.

The wear is clear in this photo

It worn through the tapered part and punched into the inner hole where the air travels to the tip of the brass nozzle

I then quickly made a steel one on my lathe , filed some flats on it and it seems to work fine and will hopefully be more wear resistant compared to brass

Hopefully this saves someone else from another few hours wasting cocking about with these cheap cabinets

 

[Lewis_RX8]

This is the cabinet new although mine is quite well modified

 

[Edward Teach]

I changed my 'suction' hose from outside to inside,
I could not see the point of pulling medium from outside, when the cabinet would have plenty inside to reuse.
ps: it does not get used often.

 

[Lewis_RX8]

I changed my 'suction' hose from outside to inside,
I could not see the point of pulling medium from outside, when the cabinet would have plenty inside to reuse.
ps: it does not get used often.

What do you mean like to an external pot?

On my cabinet the media hose is connected to a little pickup tube that then sits in the bottom of the V shape made by the cabinet so it all falls back down and gets sucked up again I suppose.

I think some people use blast pots that take it from outside the cabinet.

 

[Edward Teach]

My cabinet had a suction/medium hose going outside the cabinet,
I changed it to how you describe yours to be.
ps: my cabinet was second or third hand when I acquired it.

 

[Ross365]

I've got the same style of gun an my Switzer cabinet .

 

[Lewis_RX8]

I've got the same style of gun an my Switzer cabinet .

I would say take it apart and check it now why you remember might save you a day of irritating fault finding lol , you may see it worn away slightly I have used this cabinet quite alot of hours now so explains it

 

[Cuthy246]

Have pretty much the exact same cabinet. Run it with a pressure pot although I am looking to use the suction gun so I can run some lighter media for ally. Getting bits together to do a better pick up/metering valve than the silly tube it came with. Something along these lines, supposed to give more reliable feeding.

 

[graffian]

I then quickly made a steel one on my lathe , filed some flats on it and it seems to work fine and will hopefully be more wear resistant compared to brass


View attachment 349941

Hopefully this saves someone else from another few hours wasting cocking about with these cheap cabinets

The air nozzle is behind the pick up hole in mine, well I can't remember bead cutting in to it so it must be.
Bead has cut the cavity in my gun up quite a bit and worn a hole through the top of the gun casting.

 

[brightspark]

if u make another steel one use carbon steel and harden it heres a home made gun i made

 

[Ross365]

As I don't have a lathe, I just searched ebay, expecting only to find the complete guns for sale. But no! These nozzles are available at £9.99 for two here. So, thanks RX8 (from a another Gen7 man) for sharing your experience . The removal of that nozzle would not have been high on my action plan for resolving that problem.

 

[Lewis_RX8]

if u make another steel one use carbon steel and harden it heres a home made gun i made

View attachment 349990 View attachment 349991

Ah yes that would make it last a lot longer and who cares if its brittle it won't get knocked or anything

As I don't have a lathe, I just searched ebay, expecting only to find the complete guns for sale. But no! These nozzles are available at £9.99 for two here. So, thanks RX8 (from a another Gen7 man) for sharing your experience . The removal of that nozzle would not have been high on my action plan for resolving that problem.

Great find, That's why I posted up this warning making sure my suffering would not be in vain and stop anyone else from that mind racking fault finding experience

 

[DennisCA]

I had this problem last night, ain't getting nothing out of my suction blaster cabinet.

I have just bought a sand blasting tank however and was thinking of converting the cabinet to pressure blast. God the "gun" that came with this is prmitive and clunky looking though. They all seem to be like that. So I am wondering if I could just plug up the hole for the media and run both media and and air through the old suction gun.

 

[DennisCA]

I am thinking this might be better and simpler. Just a nozzle, the control is outside.

 

[brightspark]

I had this problem last night, ain't getting nothing out of my suction blaster cabinet.

I have just bought a sand blasting tank however and was thinking of converting the cabinet to pressure blast. God the "gun" that came with this is prmitive and clunky looking though. They all seem to be like that. So I am wondering if I could just plug up the hole for the media and run both media and and air through the old suction gun.

it wouldnt work the air jet is at the back of the gun

 

[Coo]

Oooh... great info, will check mine that started to fail.

Cheers !!

 

[DennisCA]

it wouldnt work the air jet is at the back of the gun

I was thinking of running the whole thing through the air jet and ignore the suction part. But I don't think it'll work very well, probably better to do as in the video, a hose with a nozzle, valve elsewhere.

 

[brightspark]

are you going to use a pressure pot instead of the suction gun

 

[DennisCA]

Yes that's the idea, connect the pressure pot to the blast cabinet. Almost got it tonight but lack proper fittings. This kit came lacking some needed kit, wrong kind of fittings (c-type)

 

[brightspark]

heres mine i just poke the blast jet through the hand porthole and just turn the pot on and off by the ball valve on the supply