Air Abrader: Making Sure The Air Is Dry

[AeroMike]

Hello All, I searched and didn't really see what I was looking for so I need to ask all that deals with air abrasion machines. How do you keep the moisture out of the line?

I know I will need filters but do Ireally need dryers? I have the compressor, I have the Comco dual tank, and before I get going at it, I need ot make sure I have zero moisture when my dolomite comes in. I thought I would ask to see how others have tackled this.

Thanks,

Mike

[steelhead9]

You almost certainly will need an inline air dryer, especially in the summer.

[Malcolmt]

Since my compressor is in the garage I really need nothing in the winter time. I have a large wall mounted desiccator (really a big pipe that is filled with desiccator tablets)I also have water traps on every line. After the desiccator I break out about 10 lines for various tools after the desiccator. I use a single tank COMCO for abrasion. I also have 2 dental units and two of the small Paasche air erasers. I have a rotary air tool and 7 scribes as well but not all are connected at the same time. I bake my powder at 225 Fahrenheit for 1/2 hour to remove moisture then seal it in glass bottles. I do about 4 pounds at a time. I do re-sieve and re-bake my powder. I use mostly dolomite but also sodium bicarbonate , calcium carbonate, magnesium carbonate and aluminum trihydrate.

With the COMCO unit the orifice at the bottom of the tank must be the correct size for the powder you are using. I have two sizes .025 and .040 I believe .025 is what comes originally with the machine.I found the wrong orifice size for the powder I was using to be my biggest issue when I first started with the COMCO.

[sseth]

Mike

I use an inline air dryer with my comco machines and that has done the job well. It is a bit more humid where you are so I would try it and see if it works. They are pretty easy to clean and maintain machines so it will not be a major problem if you do get a bit of moisture. You can dry things out and implement a different drying system.

Seth

[jpc]

I have two air dryers in my line and a coalescing filter. The latter takes oil out of the air immediately as it comes out of the compressor. My compressor is an oil run model. The first air dryer is before the air scribes connector. After that, the line keeps going to another dryer then to the air abrasive. This way there are three air dyers (there's a filter in there somewhere too) n the way to the Swam Blaster. It is a lot drier out here than where you are, so you might want to pay close attention to what malcomt says.

[Uncle Siphuncle]

i never use a drier with my cheap setup. during humid times i push the compressor into the laundry room, close the door most of the way and run a hose out to the blast cabinet. that way i let my home a/c unit manage the moisture for me, at least well enough for my bottom end unit.

[AeroMike]

I figure I will have to bake the powder too with this humidity here in the Savannah area. This just gives me an excuse to get a used oven to put out in the garage......been wanting to do that for a while so I can powder coat smaller items for my motorcycles~!!!!!

Malcomt, do you just spread it across like a cookie tray?

[Malcolmt]

I have a metal baking tray that is the same size as a cookie tray but has walls on it about 1 inch deep and two handles I put about 1/2 inch layer in it. I set it for 225 F for about 1/2 hour then let it cool enough to handle and then put in a glass jar that has a metal lid. I will generally do a couple batches at the same time. Once sealed in the jar it does not seem to pick up moisture. I classify my powder to the screen size it will go through 320, 200, 120 100, I throw away anything that does not go through 100. I save the 320 material for low PSI prep of very delicate material using the smallest COMCO nozzle (.018) I use the 100 for rough prep taking off major matrix. what goes through 200 but not 320 is very good all round prepping abrasive. My screening set up is 30,35,40,50,60,80,100,120,200,320. I need the larger screen sizes because I do reuse my powder. I use fairly high negative pressure on my blast cabinet so I do loose about 20% of the abrasive I use into the vacuum system (Heavy duty metal shop vac with Drywall Filter) I do not reuse the abrasive that gets to the shop vac.

[matt cable]

Hi Mike,

Malcolm's procedure is very similar to what I use. I also have 2 desiccant tubes and a water trap on my air line. Drying the powder, you want to maximize the surface area to dry quicker. I turn the powder over half way through the drying. Something like a brownie pan works well. A cookie sheet might not have high enough walls to avoid making a mess. One other thing you'll have to do every so often is dry out the silica gel desiccant beads. They change from dark blue to pink when they are soaked with water. A similar drying in the oven also works and the color will change back. Be careful with the beads though. The dark blue color comes from cobalt. Wash your hands and don't use the pan/sheet for any food use.

I thought I had moisture issues for the longest time, but it turned out to be more issues with particle size and distribution. You may have more moisture issues during the summer humidity down south.