So, I've got a couple of different plans that I've found online, and am now building a "hybrid" of two machines that I've seen. The general plumbing seems basic enough, but I wanted some advice. I'm sure tons of you have used sandblaster more extensively than I so I though I'd ask some general house-keeping quesitons. The first: I've got a 5 HP 17 CFM Rol Air compressor. I run a 3/8 inch hose from the compressor to whatever power tools I'm using. In this case, my soon to be completed sandblaster of justice! My question is, I've used/am using several 1/2 inch joints, ball valves, and bushings in my plumbing. I reduce/convert back and forth between 1/4 inch and 1/2 inch plumbing. Should I have stayed with the the 1/4 inch (Closer to 3/8 inch hose that I've run to the unit)? So, in short, what is going to be the pressure loss of running with a little larger pipe for joints and such? (If any at all?) The second question is regarding the sandblast hose to buy. I've found some "cheap-O's" online in the range of $20-30, but don't believe they're really going to be of any value. I'm leaning towards a Marco sandblast hose, that's 3/8'' ID and 10' long. It's $70. Or, purchasing 25' of Goodyear hose from EVCO that's a 1/2'' ID. I'd probably cut it in half and use one 12 foot hose until it wore out and replace it with the the other half. Which leads to my last question. What is that going to do for pressure from the machine, to the gun? 3/8'' necked up to 1/2'' for 10-12 feet before I reach my gun? Any response will be greatly appreciated. Thanks.
The larger lines and valves are better than going smaller. Shorter lines are also better. You didn't say @ what PSI your 17 CFM is at. Single stage or two stage? I doubt you'll have enough volume of air to run much of a blaster. I'm at 18 CFM at 90 PSI and it's not enough to run my small HF pressure pot blaster for very long at a time. I can do a little clean up of parts, but send out anything of any size. The other issue is dry air. Any moisture in the air and the blaster will plug up.
It's two stage. The Rol Air says that it will do 17.5 cfm at 175 PSI. I don't know how realistic that will equate to pressure wise. What about the change from the 3/8" line from the compressor to the sandblaster, and then bumping up to 1/2"? I was thinking that the shorter the blast hose from the sandblaster to the gun the better. Thanks
It's done. I had a lot of fun putting it together. Wonder if I'll have as much fun using it. Here are some pics. I basically spent as little money as I could, within reason, while still building it strong. I recycled an old compressor tank. I've got about $40 in plumbing fixtures, ball valves, t joints, nipples and such. I spent $45 and ordered a Kuryakin (sp?) hose from the local hose shop. I spent $5 per wheel, and $10 for the 5/8" rod I used as an axle. I think the washers, and coder pin were maybe another $5 at Checker. The air seperator was a b*&ch! It was the smallest/least expensive unit and it still cost me $40 at EVCO. Fetchers. I think I paid another $10-15 or so on barbed couplings and 5 feet of 3/8 hose at EVCO. And lastly I spent $25 on a deadman valve blasting gun from our favorite store, Harbor Frieght. I also spent $20 on 80 grit media from them as well. All in all I think I spent about $170 and have what I think is a pretty sweet little media blaster. It's looks like it's comparable to a $400-500 blaster I'd get elsewhere. But the fun was in building it.
And some of the final shots. I don't think I had even tested it for a minute before I realized people weren't joking when they say media gets EVERYWHERE!!!!
I did pretty much the exact same thing as you... I started with a 30 pound propane tank and welded it up to a hand dolly... Went with 1/2" fittings all the way, used 15' of air brake line and managed to get through the sandblasting of my entire body of a 47 Chev truck. The only thing I had to replace was the butterfly valve at the bottom of the tank since throttling it pretty much ate the nylon seat of it. What I can say was that 17 cfm @ 100 psi was not enough. Starting out with full pressure, it worked great, then petered off after a bit.... not so bad if you're only doing small stuff, but when it's big fenders and cab... well ya. Since I couldn't rent anything around the 25-30 cfm range... I ended up with a 90 cfm diesel rental @ $75 /day for 4 day... got it all done. Used crushed glass as the media, no warpage whatsoever, and I'm a newbie at it. But yes, extremely messy... I did mine inside the garage. BIG word of advice... dry, dry, DRY AIR! Once that stuff gets wet, it doesn't blast for crap! Good luck and enjoy! Ted.
i have a small blaster i picked up second hand some years ago. pot size is about 40 litre capacity. run it with a 65 cfm 15 hp ingersoll 2 stage. cycles in and out between 95 and 135 psi. works fine for 5 minutes or so until i've used up the main tank that the pump is on ( around 200 litre) and also another upright tank of about 300 litre capacity. i'm running 1 inch id line from the compressor all round the shop and out to a ball valve round the side of the shop just for the blaster. run half inch id hose from the pot to the nozzle which is only 5/16 dia. kicks arse if you could keep the pressure up to around 120 - 130 psi. even with this set up there is not enough air. works good but another 40 -50 cfm would be ace. keep in mind the manufacturers bullshit their figures somewhat on cfm ratings. my 65 cfm is really only good for around 50 odd cfm "free air delivery" .rough rule of thumb is around 3.5 times the horsepower driving the pump . in other words running at full noise is what it will actually produce after the tank reserve is used up or something along those lines. water is your main enemy as the warm air condenses in the lines. clogs up the grit where it comes into the air flow at the bottom of the pot. make yourself a cooler out of copper tubing in a drum of water with a drop leg to catch the water that it will pull out of the warm air. as you can see in the pics the tide is a little low in that cooler of mine, could do with a little drinky i have run this rig for over 5 hours straight doing a pile of stuff in one hit. had 1 guy blasting and i was keeping the pot full of grit then swap over after an hour or so. no water problems at all. without the cooler about 10 minutes was it before you had grit flow issues. i'm also running an air supplied blast hat off a tripple filter setup as well while blasting,uses a bit of wind too. if your going to blast a lot get one or improvise, blastings not good for the hearing or the lungs........or the neighbors for that matter...... cheers ....
I was going to make my own after years of using the bucket-o-sand. But then I found this one at a yard sale for 30 bucks, new in the box. He says it was a present, but I think he realized using it would be too much like work. I added the wheels and the t-handle. They make it easy to move around and the handle is handy for storing the hose. It holds more than 2 bags of sand, and goes through them fast. Needs a proper deadmans valve. This one bites my hand regularly. Moisture is a problem. I'm going to have to look at different designs for a separator.
Everything I read said to make sure to keep your media dry. So, that's why I spent the 45 on that air separator. I hope it does the trick. I also am going to be super careful when I bleed off the excess pressure in the pot. I've already noticed that when high volumes of air escape through a small 3/8 in ball valve it creates a significant drop in temp, and water has been condensing/freezing around the valve. I just don't want it inside the pot! I'll keep you posted as to the junk I blast with it. I'm stoked like a mother fetcher though! YEHAW!
water trap at the pot is good. but if the air going through that is still warm and cooling it will still be a problem after a short period of use. just my 02 cents worth
Dawg; you can't. It must be cooled before it gets to media. Look up PA-Blaster for some great ideas. Buffalo Bill.
The Jalopy Journal
