My bead blast cabinet has started "surging". As you are blasting the abrasive stops flowing and then picks back up again. Pick up hose seems to have abrasive in it the whole time. I have owned this for several years but haven't used it much lately. It used to work fine. I have changed almost everything and can't figure it out. It has water trap and new abrasive, gun and nozzles. Thoughts?

Thanks, Jeff

Try changing your air pressure.

Just went out and tried that. Seems to blast best at 80 PSI but still has intermittent abrasive flow. At full line pressure (100 PSI) it surges and at 60 PSI it surges and every ten pounds in between. If you keep blowing air it takes longer to recover than if you let off and then hit it again.

Jeff

Make sure the screens clean too.

Make sure the screens clean too.
What screen? I'm not sure this cabinet has one. I emptied the hose and pick up tube when I changed the abrasive. Could it be a wrong sized air jet?

Jeff

Look in the gun behind the tip .

Are there any possibilities of moisture in your air supply?

i used to have that problem too. its kinda like having too big of a carb. either use a smaller pickup hose or raise the psi

Look in the gun behind the tip .
Replacing the gun should have fixed this.
Are there any possibilities of moisture in your air supply?
Moisture in air supply is a given, but the quantity varies, this problem is over a year old so I can't believe it's moisture.
i used to have that problem too. its kinda like having too big of a carb. either use a smaller pickup hose or raise the psi
Pick up tube has been the same all along, and it still does it at full line pressure. This unit has worked correctly while I've had it but doesn't anymore. When it stopped working right I thought maybe the gun was shot so I bought a new one but not sure what size the old air jet was.
putting the old jet in the new gun doesn't change it.

Jeff

this is usually caused by moisture.....at leat in my cabnet.....the sand gets a little heavy and doesn't feed correctly into to holes in the bottom of the cabnet. i've had some success by limiting the amount of sand (or whatever abrasive you're using) in the cabnet......using just the mininum to kee the holes covered. sometimes i have to reverse blow the air back into the pickup tube to keep it flowing.

Have you changed the air jet inside the gun head?

Usually a nozzle and jet swap tunes 'em up, but if you've done both and have no restrictions anywhere in the entire cabinet, could be moisture.

Gonna have to revisit that moisture thing I guess. I can't believe the sand is the problem unless it was wet when it came out of the bag. I have a moisture trap on the side of the cab and a water drop in the pipe just past it. The water drop has a ball valve at the end but it's defective and will not open. I got to wondering if the whole pipe is now full of water. The sand seems dry as it flows readily and doesn't clump. Maybe now is the time to try that black blast media.

Jeff

it doesn't take much moisture to keep the sand from flowing freely into the pick-up tube at the bottom. i have all the moisture traps on mine also but when you're using it for a while the moisture gets in there. the only thing that will stop that is a refrigeration unit that dries the air. if you also have to much sand in the unit it agrivates the situation because the sand gets a little heaver and packs ever so slightly at the bottom where the pick-up tube is.........just my observations in using mine for 10 years.

MOISTURE is your biggest enemy!

Do you have evidence of moisture?

This will cause surging.

Use air dryers/filters.

Copper lines from your compressor help in pre-condensing the air BEFORE it reaches your blast cabinate.

My old sand blaster had a air hole in the pick up tube, it wasen't a cabinet, if that hole
got stopped up it would spit and sputter, It needed air to run the suction for the sand
it was just a old hopper with a gun and a air hose.

My old sand blaster had a air hole in the pick up tube, it wasen't a cabinet, if that hole
got stopped up it would spit and sputter, It needed air to run the suction for the sand
it was just a old hopper with a gun and a air hose.
I finally went out there and stayed with this until I got it fixed. This pick up has a "vent" in it also, I didn't believe it till I saw it myself. We pulled a Allen head machine screw out of it and it works like a charm now.

Jeff

It isn't just moisture in the air supply that'll cause this. We have the same surging problem whenever it's been really humid for a few days as the cabinet is in the hangar and subjected to the high humidity this time of year. Try taking the media out and leave it inside where it's air conditioned for a few days to draw any moisture out of it, or simply replace the media.