SpudFiles

Hello, I have a question about the filling mechanism on a pneumatic "spud" cannon I am planning on building. Forgive me if this was answered before, I searched but didn't find a definitive answer. The schrader "tire" valves that are commonly used for these cannons are from auto parts stores and are meant to be used on car tires, correct? Yet most tires that I am familiar with have a maximum pressure well below the considered safe limit of 100psi for air cannons. Are they still safe to use? Are there any special precautions that should be taken(using some epoxy to keep the valve in place) or just use the supplied mounting hardware? I did a little research in the matter and found that semi tires run higher pressure, but have had trouble finding a valve meant for a semi.

Another quick question, should I use anything on the threads to the sprinkler valve or the threads to the gauge(Locktite, teflon tape, pipe cement)?

Thank you for your time.

I think it should be safe. If tires usually hold 100 psi then the manufactures would make the valves hold at least like 150 to be safe. i have found screw in metal schraders at a farming type store called tractor supply. and you dont really have to put anything on the threads unless you want to use some teflon tape. Dont use pipe cement though incase you want to take the valve off for any reason.

Always ALWAYS use teflon tape on ALL connections in a spud gun. Your fittings will leak even if you don't notice any sound. Even on cobustion cannons, teflon should be used to stop charring.

Don't use lockite, it sucks and leaks.

Go to a harware store and get a threaded schrader valve and thread it into your chamber. Also use teflon tape after the threads are made in the chamber. This valve is just easier to work with. Either one will hold a lot of pressure.

There is no problem going even up to even 200 psi. The "safe 100 psi" is just a common pressure that works well. The sprinkler valve usually can only handle 150 and many psi guages can only go to 100 before being damaged unless it reads over 100.

to answer your frist question, yes.i have canon that has a ruber tire valve, i don't no whut it's rated to, but i have put 100 psi on it without it brakeing. just use teflon tape on those threads

Thank you all for the quick replies.

I found a site that sells different valves,
http://automotive-hardware.com/1-piece- ... p-106.html
That one is rated "High Pressure" but the site doesn't say what "High Pressure relates to.

http://automotive-hardware.com/1-piece- ... p-110.html
This one appears to be made to take the higher pressure, as it is bolted in.

http://automotive-hardware.com/tire-sup ... c-5_6.html
That shows a list of all the valves sold.

Any comments?

Again, thank you for your help.

I use it on all my pneumatic cannon and it works perfect ....

http://automotive-hardware.com/1-piece- ... p-116.html

Cpt.Rollhart,
Is there enough thread on that valve to get a nut on the inside? It seems like if not fitted correctly that could become an unwanted projectile. Again, I am new so I am just going off my intuition as I don't have a great deal of experience.

Again, thank you.

What are you even talking about? you don't put a nut on self-taping fittings

Alright, it was only a question.

ive taken a 40 psi rated scauder valve to 300 psi by accident and it held fine.

Will a valve from a BIKE tire hold any pressure? How high can I take one of these?

P.S. Inner tubes from bike tires are a good source of rubber.

Yes they will hold pressure.I've had one on my pneumatic and it was fine at past 300 psi.
B.T.W. you can sleeve pipes with inner bike tube if you cut it into rings.
Gives you a matte black bump-proof finish.

Raceing wheelchairs genuinly use 24"/26" x 1/4" rear tires, fluid filled pumped up to 100/150psi depending on users confert. So if your cutting valves out of inner tubes, i would use 1 of them, per square inch they are probly the strongest.

look for a product called an "air valve" at places like lowes, menards etc. i looked for schraders for months, but then i walked into an aile and bumped a shelf, and the air valve felll into my lap lol. look for air valves.

~FLINCHY~