Originally Posted by pauluk Hi All
Just a couple of points, don't be tempted pump it up with air, if you do and a weld fails, it will be like a bomb gong off. If you use water it is safe, because as soon as you get leakage the pressure plummets. Because water is incompressible there is virtually no stored energy to dissipate. For the same reason it is easy to create and maintain high pressures since you only need to be able to pump small volumes. If you use a small bore (say 3/8” bore) hand pump you should be able to create 300/400 psi without any problem |
Pauluk; When you get to the pressures needed for hydroforming water is compressible. I think the number is something like 12% volume reduction at 25,000 psi. You will need a very sophisticated hand pump to get to this pressure region of course.
For inflating stainless steel solar collectors or metal pillows probably between 1000 and 4000 psi would do and a well made hand pump could get to this quite easily. I used to test acrylic filter housings to 2500 psi with water using a home made pump.
Although inflating something the volume of a pillow could be tedious; my pump discharged about 0.2cubic cm per stroke; how many liters in a pillow?