I thought I knew what I was doing.

garrisonm89@yahoo.com

garrisonm89@yahoo.com

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Apparently I have no idea what I'm doing. I mean how hard can it be to understand how a sand blaster works. I've got a 60 gallon air tank and a 5 horse 2 stage motor. I've got the air turned up to 140 psi. And though I don't really have the volume I'd like to have it's really not there and I have to quit blasting every couple minutes to let the compressor catch up. When I first started blasting the parts the blaster was doing a great job. I didn't put the parts in without cleaning the grease off them first and making sure they were dry so as not to introduce grease into the glass beads. I was really happy with the job. And then everything went south. All of a sudden it wasn't cleaning the parts worth a s%#t. So what happened? The gun isn't plugged, the air is still keeping up as good as it ever did. The sand isn't bridging under the syphon tube. So can the glass beads wear out? The ceramic tip looks like it's still new. I don't think I have much more than a couple hours worth of use on the blaster. So please, all you guys who know about this stuff please let loose with some advice.
 
Try putting your finger over the gun tip and pull trigger. It should back flow and clear the feed line. You may have some crap in the nozzle.
 
Glass beads will pulverize and turn into dust. At what point this happens depends on the size of the beads and air pressure. Higher air pressure will speed along the break down of the beads. I remember years ago thinking that turning up the pressure on the cabinet would clean the parts faster, and it did for a while until the beads broke apart. Even at "proper" air pressure, I recall having to change the media as it could only be recycled for so long, and then it became ineffective. You may want to ask your supplier for recommended pressures. Also make sure that your air supply is as dry as you can make it. I hope this helps.
 
Jay Ess said:
Glass beads will pulverize and turn into dust. At what point this happens depends on the size of the beads and air pressure. Higher air pressure will speed along the break down of the beads. I remember years ago thinking that turning up the pressure on the cabinet would clean the parts faster, and it did for a while until the beads broke apart. Even at "proper" air pressure, I recall having to change the media as it could only be recycled for so long, and then it became ineffective. You may want to ask your supplier for recommended pressures. Also make sure that your air supply is as dry as you can make it. I hope this helps.
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Good points Jay. I apparently followed your line of thinking and left the pressure up thinking it would do a better job. Tomorrow I'll throw a regulator in line, change media and give it a try.

Jack please understand I'm a little bit leery about putting my finger over the end of an air gun that's cranked up to 140 psi or for that matter any psi. Especially when I consider the fact there are glass beads mixed in with the air. However I understand you methodology and maybe it would be worth a try if I could put something over the end of the gun to create the back pressure you're speaking of.

Another point to make is that I live in Minnesota where the humidity is lower than the Sahara deserts once winter gets here. But there again I'll drain the tank down again and when I put the regulator inline I'll make sure there's a water trap included.
 
My bead blaster recommends air pressure at 40 - 60 psi. I think you are using too high a pressure. Did you get an owners manual with it?
 
Mike, 140 is way to much. Ours is set at 80, but we have a bigger unit and that is what the manual says. Also, we have good (read over $400) air line dryer right before the cabinet. Plus the glass beads do wear out, especially at 140 psi. They will turn to dust and you do need to replace them frequently, sometimes I will change them out in one weekend.
 
I use black bueaty carbon,and I routinly put my gloved finger over the nozzle and disloge bigger particals. It doesn't hurt.
 
I use my palm to clear it.It dont bother you unless you have a hole in the glove where you block it off. ken ct.
 
Definately lower your air pressure. Blows by too fast to pick up glass beads. You did not mention if you had an air dryer on your feed line. Farmall49 is right on. Moisture is generated by compression and water may be making its way down the line to the gun. Everything has to be clean and dry. Good luck!
 
I'm surprised the air pressure is that critical but there is definitely a benefit to turning it down in the fact I won't be blowing right through the volume of my compressor in a hurry. The reason it was as high as it was is to keep up with a sand blaster I used outside to sandblast a boat trailer. The sand wasn't recycled and the air pressure was set right at the limit to keep from blowing the pop off valve. It didn't take much to clean that old trailer right up. But now I realize a sandblast cabinet where the media is recycled is a whole different deal.

I'd never have a problem holding a gloved finger or the palm of my hand over the tip of the nozzle as long as it was the glove used in the sandblast cabinet. Along those same lines I wouldn't have a problem running my bare finger or the palm of my hand across the nozzle as long as there wasn't any air coming out of it. But in every machine shop I worked in and during school I was told of the hazards of high pressure air and the effect it can have blowing it against your flesh. Now I figure I've got close to 50 years in different shops and I've always been told not to shoot compressed air against your fingers or your hand or any part of your body and I actually worked in one shop where if they saw you blow metal chips off yourself with compressed air they would immediately discipline you and would take it as far as firing you if you were stupid enough to do it more than once. Most air nozzles you purchase are purposely set-up to keep you from being able to blow full pressure out the end of them and the nozzle is drilled to keep from allowing it to. And I know damn near every fool who's ever worked in a shop will tell you it can't hurt but believe me there's a reason for all these safety practices and where there's smoke there's fire. I've seen disregard for safety result in some very bad scenarios and I won't push my luck. Sorry if I've offended anyone if I've carried this to far but everyone has there own beliefs, habits and ways of doing things and trust me when it comes to safety there's small chance anyone is going to change me.
 
Gloved hand on the nozzle will clear it with no harm as there is no velocity to speak of until the blast exits the nozzle. Glass beads are great if you are cleaning fine carb parts and stuff like that but for just general cleaning you will have excellent results using kid's white sandbox sand that you can get at any of the big box stores like WalMart, Lowes, or Home Depot. It's really cheap and cleans like mad. When your glass beads start to fail the dust packs in tight and plugs the gun in no time. Your air pressure is WAY too high. Cut it in half or even lower regardless of what media you are using.
 
John Otis said:
Gloved hand on the nozzle will clear it with no harm as there is no velocity to speak of until the blast exits the nozzle. Glass beads are great if you are cleaning fine carb parts and stuff like that but for just general cleaning you will have excellent results using kid's white sandbox sand that you can get at any of the big box stores like WalMart, Lowes, or Home Depot. It's really cheap and cleans like mad. When your glass beads start to fail the dust packs in tight and plugs the gun in no time. Your air pressure is WAY too high. Cut it in half or even lower regardless of what media you are using.
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Makes sense, however the idea originally state was; "Try putting your finger over the gun tip and pull trigger." Now that it's become extremely tiresome responding to the reasons why I won't do what the original idea stated I think I'll let this one lie. As far as turning the air down, it's already done. But John you said something that finally got through and made sense. I guess I'm fairly dense and lord knows if a persons going to ask a question on this site every expert in the world (yes the world) is going to crawl out from their respective rocks to have an opportunity to help. But it never occurred to me that "glass beads start to fail the dust packs in tight and plugs the gun in no time." So the fact I put a regulator inline and cranked the pressure down to an intelligent level, then putting in new media to cut down on the amount of dust, the situation has been dealt with.
Thank you everyone who made safe suggestions regarding methods to correct my problem. It once again proves this is without a doubt the best place to turn for information on our old T's.
-Mike
 
redmodelt said:
Check what the sand is made of before you use it;
http://www.osha.gov/Publications/silicosis.html
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Yeah, I know. I'm very aware from reading several bags of the stuff (silicon) over the last couple years. I use it in my pressure unit when I sandblast outside and I always wear a facemask when using it. I'll continue to use the glass beads for the rest of this job anyway. I'm blasting transmission components and really don't need anything as abrasive as silicon. I've used the black beauty and it's way to aggressive. I think I'm going to look into an air dryer as farmallcub49 suggested. I really don't have a problem with moisture now but in the winter my compressor becomes a fawcett because of our high humidity. It's weird in Minnesota, Wisconsin and Michigan. In the summer it's unbelievably humid and in the winter it's dryer than a popcorn fart. At any rate thanks redmodelt. As you have probably gathered by now I try to be as safety conscience as possible in the shop. I've been burned, broken and have bled too much in my lifetime. Hell I drive a model t because I'm afraid to go over 41 mph.
 
We have a scat blast cabinet.It is a good one and pretty good size.I have to REGULARLY lift off air,cover nozle-blast or a second, uncover nozle and blast away.I PROMISE it is totaly NORMAL. I would not lie to you! Now get back to work...haha
 
fordman67 said:
Now get back to work...haha
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Damn, slave driver. Boy am I ever gonna catch a ration when I actually do put my gloved finger (sandblast glove) over the gun, clear it and then tell all you monkeys I actually did it and it worked. Or maybe nothing will get said.
I kid you not, they were just talking about an electric prostate heater on the TV; and they were in southern California. Unbelievable. I mean we need stuff like that in Northern Minnesota, but in Calipornia? Come on!
 
Another thing, the glass beads wear out the tip. We have a blast cabinet with a cyclone to get rid of the dust. I tried reusing the spent glass only once and that was the last time I will do that. All it did was clog up the works and didn't do much cleaning. Spent more time blowing the line out as suggested above.
 
The kid's play sand that I used was ground up marble waste that was less harmful than silica. (I think). It also seemed to be less affected by humidity than the bagged beach sand that you can buy. Anyhow it's 40 years later and I'm still breathing easily.
 
Your problem is probably in the pickup tube. I have seen lots of problems in the area thru the years in different cabinets. Pull out the line (should be a steel line) in order to be able to inspect it properly. The open end should be out of the glass media in order to create a proper air flow and a vacuum at the pickup hole in the line. I have had to reshape the line and sometimes make a new line in order to accomplish this. Next make sure that the media pickup hole is not worn too much. The hole wears pretty badly with use especially when using sand. Also, we used to have lots of problems with the glass clogging and clumping with grease, moisture and debree. Sometimes a wire screen helps out in that situation. The glass beads are a lot easier on the metal than sand but with use the glass pulverizes into powder and this makes the problem worse about stopping up. These cabinets are pretty simple and there is not very many things that can cause your problem.
I hope this helps.
 
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