safe?

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Thu Dec 28, 2006 5:32 am

Ok, so I am in the process of building my first cannon the chamber is 4"x2'
abs pipe, said rated to 425 psi but I don't beleive it. All I have left to do is attach my 2 inch 6 foot long sch 40 barrel. I have two questions

1. how do I glue abs to pvc? do I use abs glue or pvc glue?

2. is it safe to use starter fluid in my gun?
I will post pics when I'm done, I will test it friday
User avatar
Insomniac
Sergeant 3
Sergeant 3
Posts: 1297
Joined: Mon Dec 18, 2006 3:47 pm
Location: Australia

Thu Dec 28, 2006 5:53 am

I wouldn't trust abs for a pnumatic, apparently it weakens after several shots. Also, I've heard gluing abs to pvc is bad, but if you must, there is a special glue for it, that bonds both plastics. I would just stick with pressure rated pvc.

As for using starter fluid, I'm not sure but I think others have used it without a problem.
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Thu Dec 28, 2006 5:57 am

it's a compustion not pneumatic.
User avatar
Insomniac
Sergeant 3
Sergeant 3
Posts: 1297
Joined: Mon Dec 18, 2006 3:47 pm
Location: Australia

Thu Dec 28, 2006 6:03 am

Oh man I'm a dumbass. Who uses starter fluid in a pnumatic??? :lol:
Abs should be fine for a combustion, so long as its not cellular core (has tiny air bubbles mixed in) Where you are attaching the abs to the pvc, I would put a few screws through both layers of plastic , 'just in case' That way, if the join breaks it will just leak, and won't go flying.
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Thu Dec 28, 2006 6:22 am

put a few screws? the chamber is abs and the barrel is pvc. maybey I will just go pick up a abs barrel instead of useing pvc and having to go get special glue but I have both pvc and abs glue. another barrel is only like 8 bucks for a ten foot peice of 2 inch abs.
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Thu Dec 28, 2006 8:47 am

Oh and one more question

what kind of noise will this thing make?
User avatar
medievalman
Specialist 3
Specialist 3
Posts: 319
Joined: Tue Dec 05, 2006 5:52 pm
Location: Central Minnesota
Contact:

Thu Dec 28, 2006 9:08 am

please dont double post.

and its kind of hard to tell what noise it will make, you will have to shoot it to find out. and getting special glue will probably be cheaper than buying a new barrel, and the glue can be used again, so i personally would get the glue and the put some screws in. the screws would also act like a screen, preventing the spud from going into the barrel, so it would serve a double purpose.
User avatar
Bluetooth
Corporal 4
Corporal 4
Posts: 863
Joined: Tue Jun 27, 2006 7:57 am

Thu Dec 28, 2006 9:32 am

Just buy the ABS barrel like you said it's only 8 bucks more and if you mean about how loud by what kinda noise. If you stand near the front of the barrel when you shoot it it'll probably leave your ears ringing.
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Sun Dec 31, 2006 6:08 am

I have one more question, when I put my ignition system in is it safe to the screws (4 in all) directly into to the wall of the chamber, it's going to have dual sparks. will the screws weaken the wall of the chamber
User avatar
frankrede
Sergeant Major 2
Sergeant Major 2
Posts: 3220
Joined: Thu Jul 20, 2006 9:47 pm
Has thanked: 1 time
Been thanked: 1 time

Sun Dec 31, 2006 1:03 pm

Cell core for a combustion is fine insomniac, sometimes its prefered stupid.
And for the glue its by the pvc glue and its called transition or something like that.
Current project: Afghanistan deployment
User avatar
Bluetooth
Corporal 4
Corporal 4
Posts: 863
Joined: Tue Jun 27, 2006 7:57 am

Sun Dec 31, 2006 1:58 pm

Cellular core is not preferred, ABS is.
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Fri Jan 19, 2007 10:41 pm

OK so my gun has been finished for a while. I dry fired it today (no projectile) I was wondering there is a tiny crack looking thing by the screw holes. the were ther before I fired it and did not change in size. oh by the way it is f!#$ing loud. back to my question, on the inside it looks like a chip of plastic is coming up(thinner than a peice of paper) and on the out side it looks like a really really really tiny crack, at a glane I thought it was a scratch on closer inspection it looked like a crack about 1/2 or 3/4 of an inch long and thinner than a peice of hair. I will try and get some pics but it is really hard to see. but if I run my finger nail over it I can hear when it slide over it.

will my chamber hold up when I test fire it tommorw, by the way it has with stood 5 dry firings and has not chanded in size. to compare sounds it is louder than my 30-30 and my 338 mag. but it's a different kind of sound higher pitched its more of a sharp crack rather than a boom, loud none the less. maybe the sound was different beacuse I was in my house :D
User avatar
chaos
Sergeant 3
Sergeant 3
Posts: 1205
Joined: Wed Jan 17, 2007 8:31 am

Fri Jan 19, 2007 10:50 pm

post some picz please would like 2 see wat it looks like

thnx

C@SE-G
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Sat Jan 20, 2007 12:55 am

the cracks look 100x worse than they are and some of them you can't even feel them with your finger nails. and that little circle where the screw was is not really there, the camera magnifies them because of the flash
crsaz
Private 4
Private 4
Posts: 62
Joined: Thu Dec 28, 2006 5:21 am

Sat Jan 20, 2007 3:53 pm

Image
Post Reply