a scuba tank will be super thick. probably a NOS tank too.
I wouldnt want to be drilling that. Plus they may not even all be a weldable material.
either way if it can be done i can figure out a way to do it i just need to know volume. does anone know that?
If its that thick you shouldn't have any problem drilling and tapping it. Also I thought that they were aluminum so it should be weldable. He's going to be using them for airtanks so he probably won't be running more then 200 psi, not the 1000-2000 psi they normally see. A little pricy to test on them but you could always get some air tanks and have them painted like NOS bottles, just an idea.
As far as volume goes take one apart fill it up with water and dump it into a gallon jug, there you go. You might be able to contact NOS and they might be able to help you also.
first buy a math book, second buy a book on the stress of metals...Then figure out how to do the math... Or just use some ragular tanks dude
Calculating an approximate volume would be pretty easy. 1/2 a sphere will get you a pretty close number to the round part of a tank, and the rest is just a cylinder.
well i will see about getting some used ones and try the whole water idea, good thought. and as far as using normal tanks and painting them like nitrous bottles defetes the point in trying to make tanks out of nos bottles. it was to be different. thanks for the help guys.