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Galvanised steel?

Posted: Mon Feb 01, 2010 12:30 am
by subxa001
Hey I've got a question before I begin my pneumatic build, has anyone used this type of metal with their cannon? What exactly are its pressure properties as in advantages and disadvantages?

Thanks in advance.

Posted: Mon Feb 01, 2010 1:04 am
by D_Hall
Sure, I've done it.

Pressure ratings vary with pipe size and schedule.

Advantages are strength (compared to PVC) and impact resistance.

Disadvantage is weight and you shouldn't really weld it (if you're going with steel, might as well go black, not galvanized).

Posted: Mon Feb 01, 2010 1:24 am
by subxa001
The label at the hardware store says "GALV PIPE PIECE 5ZZ PP20 X 550MM" does that give any indication on the pressure rating?

Posted: Mon Feb 01, 2010 1:48 am
by chinnerz
what pressure are you thinking?

Posted: Mon Feb 01, 2010 6:43 am
by kenbo0422
Normally, the hardware stores will sell sch 40. Ask about it before you buy. It seems that the fittings for most of those are actually rated higher than the pipe itself, so go with the pipe rating. If the '20' is your diameter, then you probably have about a 3/4" pipe.

Here is some pipe info for standard wrought steel pipe (sch 40)

Pipe Dimension
(inches) Bursting Pressure(psi) Working Pressure(psi)
1/2 10380 1300
3/4 8610 1080
1 8090 1010
1 1/4 6745 840
1 1/2 6100 760
2 5185 650
2 1/2 5650 710
3 4940 620
3 1/2 5610 700
4 5270 660
5 4630 580
6 4220 530
7 3940 490
8 3720 470
9 3540 445
10 3380 420
12 2930 370

edit: in the finished message this 'chart' doesn't keep the columns lined up, but I think you can still see the information OK.

Posted: Mon Feb 01, 2010 12:35 pm
by Gippeto

Posted: Mon Feb 01, 2010 2:55 pm
by Hubb
In my sig is a link to the Hubb Library. If you follow it, you will find a portable tank calculator. In it, I've put together pipe information, which includes the type you are asking about. It shows the pressure rating, which will give you an idea.

D_Hall pretty much covered the advantages / disadvantages of it. But, for the record, I've used Sch40 galv pipe (1") with unregulated CO2 with no problems.