Kmelander
05-16-2020, 09:31 AM
You know you need one. If your like me, you don't want to pay the $ for a decent one. My solution was to build one.
Started with a 17 gal. compressor off CL for $40. Cut the top off to invert for the fill valve. Made a pop-up valve from EMT tube, plate steel and a 2" toilet tank rubber seal. Made the seat out of a rear diff bearing race.
Welded a cast iron fitting on the bottom for the media injection. Built an injection assembly out of spare fittings and black iron pipe. Welded the tank to a $40 steel hand cart. Put some legs on it for stability and plumbed it up.
Had to order the blast hose and specialty fittings from Pirate Sand Blasters. The hose was pricey. Got the blast head and ceramic nozzles from Northern Tool.
This is a pressure pot blaster. It works really well with silica media. I've tried it with household baking soda with terrible results and ran out of patience. It would likely work better with true soda media but probably still not acceptably without modifications.
Comments and things I might have done differently:
1. I would have ordered carbon steel fittings to weld. The cast stuff sucks to weld. Had to chase leaks.
2. I used a regular ball valve for the media metering. It's a poor application at best. it meters terribly and the sand destroys its seals. It now leaks by. It's manageable but...micro fiddling with an 1-1/4" ball valve to get the media flow correct is aggravating. A gate valve might work better. A proper media valve probably best.
3. I used a single regulator with a combination of valves to control the pot and hose pressure/flow. I'm not sure about this but I think a separate regulator for the pot might help performance. It could just be the terrible application of the ball valve for metering that was pushing me in this direction.
4. The concave bottom of the vessel is not quite enough to keep the media flowing efficiently when it gets down to the last 10# of media. I think I could overcome this issue with a pot vibrating device but that has it's own set of issues. For now, I just have to keep the pot full of media. It holds 100# of silica easily which lasts for 20-30 min. of blasting. I need a break after that long anyways.
5. Once I get it dialed in, I won't stop till I'm done or I run out of media. Stopping the flow loads up the hose with media because the media valve does not close. Those specialty valves are costly.
6. Once dialed in, my 5HP - 60 gal compressor will actually cycle! This surprised me because I worried about having enough air to drive it. I use 3/32" (I think) nozzles and run the blasters regulator at 90-100#. I did have to buy 1/2" air hose to feed it. The blaster regulator is a high flow unit.
Started with a 17 gal. compressor off CL for $40. Cut the top off to invert for the fill valve. Made a pop-up valve from EMT tube, plate steel and a 2" toilet tank rubber seal. Made the seat out of a rear diff bearing race.
Welded a cast iron fitting on the bottom for the media injection. Built an injection assembly out of spare fittings and black iron pipe. Welded the tank to a $40 steel hand cart. Put some legs on it for stability and plumbed it up.
Had to order the blast hose and specialty fittings from Pirate Sand Blasters. The hose was pricey. Got the blast head and ceramic nozzles from Northern Tool.
This is a pressure pot blaster. It works really well with silica media. I've tried it with household baking soda with terrible results and ran out of patience. It would likely work better with true soda media but probably still not acceptably without modifications.
Comments and things I might have done differently:
1. I would have ordered carbon steel fittings to weld. The cast stuff sucks to weld. Had to chase leaks.
2. I used a regular ball valve for the media metering. It's a poor application at best. it meters terribly and the sand destroys its seals. It now leaks by. It's manageable but...micro fiddling with an 1-1/4" ball valve to get the media flow correct is aggravating. A gate valve might work better. A proper media valve probably best.
3. I used a single regulator with a combination of valves to control the pot and hose pressure/flow. I'm not sure about this but I think a separate regulator for the pot might help performance. It could just be the terrible application of the ball valve for metering that was pushing me in this direction.
4. The concave bottom of the vessel is not quite enough to keep the media flowing efficiently when it gets down to the last 10# of media. I think I could overcome this issue with a pot vibrating device but that has it's own set of issues. For now, I just have to keep the pot full of media. It holds 100# of silica easily which lasts for 20-30 min. of blasting. I need a break after that long anyways.
5. Once I get it dialed in, I won't stop till I'm done or I run out of media. Stopping the flow loads up the hose with media because the media valve does not close. Those specialty valves are costly.
6. Once dialed in, my 5HP - 60 gal compressor will actually cycle! This surprised me because I worried about having enough air to drive it. I use 3/32" (I think) nozzles and run the blasters regulator at 90-100#. I did have to buy 1/2" air hose to feed it. The blaster regulator is a high flow unit.