Guyson Blast Cabinet not pulling media…

[Infront]

Would anyone be able to guide me with my small Guyson blaster?

Obviously it was well used when I got it. I have changed every part of the gun including new witches hat and 6.4mm tungsten. I have also changed all the hoses, new pressure regulator and anything else that could be considered consumable / service items.

I’m running 80/100 aluminium oxide.

The issue issues I have is based around the siphon / pickup or lack of action therein.

It did initially pull some media through and I could blast but it was so unreliable that I changed all the hoses as they were pretty stiff. This made no difference.

My model has an air inlet regulator as part of the siphon tube which is adjustable to regulate the flow of media, this projects through the front of the media sump.

I’ve lost quite a lot of media because it blew out of the air inlet / mixture vent.

I’m currently using a 105cfm compressor through 1/4” PCL fittings varying the pressure up and down to see if I can get a tune out of it… I can’t…!

It has stopped blowing the media out of the front now as I lowered the amount of media in the sump to below the air inlet vent. Still nothing.

My question is, what is the best / most satisfying way to burn / blow up this machine?

Pics of the siphon tube coming shortly.

 

[oldbikedavey]

Still have my setup round at my nephews unit.
Larger bore air feed hose will help a lot, and the bigger the reservoir, the better.
Those things use a rare old chunk of air, believe me......

 

[Infront]

I have thought that, but a quick check suggested that 1/4” fittings and ~10mm bore pipe would flow plenty. Obviously 1/4” fittings could be the start of my issues in that last statement.

 

[Brad93]

ours works fine on ¼" fittings although is slightly different.

Have you set the ceramic the correct distance in the torch. There has to be enough room to generate a venturi but not too much

 

[MetalMonkey]

Standard pcl fitting are way too small imo, my cabinet has 3/4" pipework to the compressor with a high flow regulator and xf fittings. That sounds like a road compressor or rotary screw, is that correct?

 

[Infront]

Standard pcl fitting are way too small imo, my cabinet has 3/4" pipework to the compressor with a high flow regulator and xf fittings. That sounds like a road compressor or rotary screw, is that correct?

Yes, it’s a rotary screw compressor.
My friend has a ‘similar’ cabinet and swears it has the same connections.
I totally agree that 1/4” seems small considering the fittings on the machine, but on the flip side the machine itself is tiny. It’s hard to believe it can need so much air.

 

[Infront]

ours works fine on ¼" fittings although is slightly different.

Have you set the ceramic the correct distance in the torch. There has to be enough room to generate a venturi but not too much

Yes I keep fiddling with the nozzle position, though it seems there is a natural position within the rubber.

 

[Brad93]

sounds silly but have you tried purging the gun.

hold your hand over the end of the nozzle then press the air for 5 seconds or so.
Media inside the pipe will be blown back into the hopper, then remove your hand and try again

 

[Infront]

sounds silly but have you tried purging the gun.

hold your hand over the end of the nozzle then press the air for 5 seconds or so.
Media inside the pipe will be blown back into the hopper, then remove your hand and try again

Sadly that didn’t work. I’ve just tried lighter media to no avail. I took the pipe off the top of the pick up tube and put my finger over that to see how much suction there was. Nothing amazing, maybe underwhelming. It didn’t suck the gauntlet to it. It did change tone a little. I doubt it needs that much..?

 

[Infront]

There are a couple of marks inside the smaller tube, I think it’s just surface rust. I’ve run a pick down it and checked it with a light. I think it’s fine.

 

[dave h 2]

Gun pic please.

 

[bricol]

6.4mm - is that the bore of your nozzle? I would think that would need an enormous amount of air to work effectively.

 

[Erie Fred]

As you replaced both the sand nozzle and the air jet, are they the right combination to work with each other ?

 

[dave h 2]

Gun pic please.

The Clarke SB3 grit blast gun will choke it's self because it picks up so much grit (unless the tube is smaller these days) it can't get out of the nozzle. I had to sleeve mine down to reduce the grit flow.
Running what you seem to have is a bit like putting a 350 Chevy v8 into a 2CV.

 

[Infront]

6.4mm - is that the bore of your nozzle? I would think that would need an enormous amount of air to work effectively.

Yes. It seems a generic size for a guyson cabinet.
Quantity of air is not a problem. Getting it to the gun is the issue.

 

[Infront]

As you replaced both the sand nozzle and the air jet, are they the right combination to work with each other ?

Yes, I have spoken to Guyson, they said they didn’t know much about the air syphon type. I then asked about the nozzle and jet sizing and it seems they list 5 or so sizes for the air jet, but most seem to just use the one size. It sounded like they don’t even bother carrying other sizes.
6.4mm nozzle again is fairly standard on a guyson. Other sizes listed are 5/16” ~ 8mm.

 

[Infront]

Gun pic please.

It’s a Guyson 400 gun. Air in the top media below. Currently has a ceramic nozzle, but I have a tungsten one also.

 

[Erie Fred]

Maybe have a look in here:

https://guysonstaging.wpengine.com/wp-content/uploads/2015/01/Guyson-Model-400-Suction-Blast-Gun-2.pdf

IIRC there is a specific 3 to 1 or something ratio, as too big of an airjet will over blow the
sand nozzle, resulting in little/no suction.

 

[bricol]

The Clarke SB3 grit blast gun will choke it's self because it picks up so much grit (unless the tube is smaller these days) it can't get out of the nozzle. I had to sleeve mine down to reduce the grit flow.
Running what you seem to have is a bit like putting a 350 Chevy v8 into a 2CV.

And your problem with that is . . .

https://www.autosport.com/national/news/club-racer-building-v8-powered-citroen-2cv-special-saloon/10567323/

 

[bricol]

Yes. It seems a generic size for a guyson cabinet.
Quantity of air is not a problem. Getting it to the gun is the issue.

Is your 105cfm real cfm, or compressor displacement?

Hodge Clemco suggest 80.8cfm at 100psi is what 6.4mm nozzle will use.
PCL claim 43cfm through a 1/4" fitting.
So I suspect you aren't getting enough air flow to the gun.

I'd be pulling the fitting out the hoses and clipping the hose directly to the pipe nipples to see.