SpudFiles

i just recently made a barrel out of a piece of 2.5 in pvc wire conduit (it was the only 2.5 in pvc that i could find without paying alot of money online for it, it was only $10...). While working with it, i found that it has a rigidity/insulation layer in the middle that appeared to be made out of fiberglass. This layer at least seams as if it would effect the way it acts under ddt. I was wondering if anyone has tested wire conduits pressure abilities, or taken it to its limits and seen how it fails. If the fiberglass in the middle contains shrapnel, and the pvc holds up to high enough pressures, the conduit at least appears to be a cheaper and viable material for combustions.

i see that you are asking about its pressures, but are you planning on using it for chamber or barrel? for chamber just using 3 inch or 2 inch



if its not rated for pressure dont use it

i've been using it as a tennis ball barrel for my large combustion, and would probably use it in other barrels in the future. But i was wondering if anyone has, or would willing to do some pressure tests to take the conduit to the bursting pressure, and determine a safe load for it, to see if it could possibly be a viable chamber material (as it is much cheaper where i am).

Have you tried a plumbing supply store, where I live they sell the stuff really cheep i can get 10 feet for five bucks + you need fittings. So if you can get your hands on the pressure rated stuff it would be a good investment.

I'm in the process of making an advanced combustion chamber from this stuff, so that should generate nearly 100psi. I don't know if you plan on going any higher then that, but I think that's as far as I'd trust it anyway

8tonsemi wrote:Have you tried a plumbing supply store, where I live they sell the stuff really cheep i can get 10 feet for five bucks + you need fittings. So if you can get your hands on the pressure rated stuff it would be a good investment.

if your talking about pressure rated pvc (supply line), i work at a hardware store, so i have access to cheap (plus a discount) pvc or abs, the conduit is just alot cheaper, which would be helpful in larger diameter pipe.

locknloaded, make sure to post the cannon if it doesn't ddt, how large conduit do you plan on using (smaller the pipe, the more pressure it should take).

I would use it for a simple spray n pray or a tennis ball barrel like you have done but thats all I would trust it for. I would rather spend the extra cash and be safe...

i wouldn't trust it without knowing how strong it is, and when it will break, it would jsut be interesting to know how strong it is

Just to clear this up, DDT is not going to occur in a normal combustion. You've got your definitions mixed up somewhere; it refers to a flame front accelerating to hypersonic velocities and deforming anything that happens to be in the way.

Seeing as I've used paper towel tubes with a few wraps of duct tape as a barrel for a propane cannon, I think you'll be relatively safe. Glue on some end caps to hydro test it. Also, hit a section of the pipe with a hammer to test how easily it shatters.

thanks for the info, i'd never been given a formal definition of ddt (beyond what it stood for)
i'll go 'shatter' test some conduit that i have.

EDIT: test successful... it shattered just as pvc would be expected to shatter, but it took a pretty solid hit from a 6 lb sledge hammer to break it.

boyce123 wrote: if it doesn't ddt

I really really doubt you will get a advance combustion to ddt, it a pretty hard for it to happen if you don't try go for it.

i thought i would get alot of people fearful of using non-pressure rated pvc, but it seems people hold more faith in conduit here than i initially did. It would be interesting to see more cannons made out of it.

Pvc doesnt scare me at all. As long as you follow the guidelines and never go beyond the maximum pressure and solvent weld properly, you will never have a problem, but thats only my opinion.