Off Topic. Sand blaster

Lawson Cox

Lawson Cox

Well-known member
I have an old gravity fed sand blaster. It has worked fine for years. It was working fine as I was cleaning up my transmission case and then it just quit blasting sand and started blowing air/sand up from the bottom of the hopper. It just reversed cycle somehow. I thought it may be the old dry rotted hose so I replaced everything. Same thing. I have 1/2 a transmission case to finish and I'm NOT going to invest in a new sand blaster just to finish that job. Manufacturer is out of business. Bead blasted a few small things in the cabinet while I pondered this enigma. (I can't put transmission in bead blasting cabinet.) Any ideas as to a solution?
 
Sounds like maybe the air passage in the gun is blocked, pushing air pressure backwards from the gun into the sand hose. Take your gun apart and see if anything amiss in it.
 
Sounds like the gun/blast nozzle is so worn internally that it no longer is able to siphon media. May need new nozzle.
 
Place your gloved hand over the nozzle tightly and operate the trigger with your other hand on and off in bursts a few times. This should unblock the sand hose. Regards, KEVIN.
 
51 MERC-CT said:
Sounds like the gun/blast nozzle is so worn internally that it no longer is able to siphon media. May need new nozzle.
Click to expand...

I checked the nozzle and it looked pretty good. One drill size larger than a new one. I changed it anyway. I'll check it out tomorrow.
 
koates said:
Place your gloved hand over the nozzle tightly and operate the trigger with your other hand on and off in bursts a few times. This should unblock the sand hose. Regards, KEVIN.
Click to expand...


YUP....what Kevin said! Squeeze your thumb tightly over the orifice and burp the gun a few times! DD

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koates said:
Place your gloved hand over the nozzle tightly and operate the trigger with your other hand on and off in bursts a few times. This should unblock the sand hose. Regards, KEVIN.
Click to expand...

Kevon. I replaced the sand hose but it still works in reverse. Changed to a new nozzle which I will try out tomorrow.
 
swedishsteel said:
Sounds like maybe the air passage in the gun is blocked, pushing air pressure backwards from the gun into the sand hose. Take your gun apart and see if anything amiss in it.
Click to expand...

About all I know about the gun is how to change nozzles, which I have done but haven't tried it yet. Will do that tomorrow. I can't see any way to do much else, but I do see a large nut toward the rear of the gun. I'll remove that and take a look see.
 
Lawson Cox said:
I checked the nozzle and it looked pretty good. One drill size larger than a new one. I changed it anyway. I'll check it out tomorrow.
Click to expand...
Inspect the internal casting.
Had one that was so eroded internally that it would not siphon the sand from the hopper.
 
V8COOPMAN said:
Second verse....Same as the first!

Squeeze your thumb tightly over the orifice and burp the gun a few times! DD

.
Click to expand...
As quoted in first post, " then it just quit blasting sand and started blowing air/sand up from the bottom of the hopper."

It is already blowing back into the hopper?
 
34PKUP said:
As quoted in first post, " then it just quit blasting sand and started blowing air/sand up from the bottom of the hopper."

It is already blowing back into the hopper?
Click to expand...

Yes. I changed nozzles and will check it tomorrow after my first great granddaughter's second birthday party, then I will venture into the unknown and remove the large nut and see what lies beneath
 
Lawson Cox said:
About all I know about the gun is how to change nozzles, which I have done but haven't tried it yet. Will do that tomorrow. I can't see any way to do much else, but I do see a large nut toward the rear of the gun. I'll remove that and take a look see.
Click to expand...


When you take off the large nut, don't let the spring in there go flying.:eek:
It is just the spring that pushes the trigger back to off position. ;)




.
 
When you take off the large nut, don't let the spring in there go flying.:eek:
It is just the spring that pushes the trigger back to off position. ;)

Also, if the nozzle gets pushed into the gun to far, and covers up part of the siphon hole,
that the hose goes on, that would act as if the nozzle is plugged.




.
 
V8COOPMAN said:
For the THIRD time, Lawson......Squeeze your thumb tightly over the orifice and burp the gun a few times! DD
Click to expand...

When the gun/nozzle is plugged it is already blowing back through the pickup hose, same as putting your thumb over it.

Lawson, to unplug it take the gun out of the machine and put the shop air hose against the nozzle and pull the trigger and blow back through the gun,
with the trigger held open and blowing backwards through the gun should clear it.

Bill
 
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