Been working on a cub that belongs to the local Lions Cub as I get time and feel like it. Yesterday I decided to sand blast the hood Cubguy47 had provide to replace theirs which was in pretty bad shape. I have one of the cheap Harbor Freight pressurized sand blasters, which works good but uses a lot of air. I have a stationary air compressor the delivers 10.7cfm at 90psi, and a portable that delivers 5.5 at 90 psi, and have my airlines set up so I can run both of them when I am sandblasting. Even with that, they do not quite keep up with the blaster, but do come close. I got out all my rigging, the blaster, a poncho, respirator, hood, gloves, etc. and fired up. After about 20seconds my air pressure was too low to blast, so I stopped and checked the gauge on blaster and on both compressor tanks. All checked ok, so I started again, and got the same results. When I looked at all the gauges all was ok, so I concluded that for some reason I had a restriction in an airline, and the blaster which is a pressurized tank type would fill with air, but would was not receiving air fast enough to maintain pressure. I use a 25 foot hose to feed a 50 foot reel mounted on one wall. It was close enough that I could bypass it with a single 25 foot hose, so I got out the extra hose to run it out to the blaster. When I started to connect the hose I realized I had not opened the valve to feed air from the big compressor into the line.
Opened the valve and all was well.