Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 49 users online :: 5 registered, 0 hidden and 44 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

pvc cement question, kinda

Post about things you have launched or thought about launching. Also post about various materials used for building cannons. No posts about explosive projectiles!
Sponsored 
  • Author
    Message

pvc cement question, kinda

Unread postAuthor: GORILLASAPIEN » Thu Jun 28, 2007 5:37 pm

Hi all,
my question is, i used primer and glue to create a pneumatic chamber, and when i pressure tested it, the seal between the fitting and the pipe sprung a leak, why? I followed all the directions given (what with the wet primer and quarter turns and all) and, is there anything i can do, short of re-doing it completely, to repair the leak from the outside.

i considered maybe drizzling super glue or even more pipe cement into the leak with negative pressure in the tank
  • 0

User avatar
GORILLASAPIEN
Private
Private
 
Posts: 15
Joined: Tue Apr 17, 2007 6:00 pm
Location: Gainesville, GA
Reputation: 0

Unread postAuthor: Jumpin Jehosaphat » Thu Jun 28, 2007 5:43 pm

Did you let the weld cure?
Check that it is PVC primer, PVC glue, and PVC pipe (if anything says ABS you used the wrong kind)
You could attempt to seal the leak, but it may just happen again, or other parts of the same seal may be bad.
Depending on where on the chamber the bad seal is, it may make more sense to just cut off that fitting and replace it. For example if it's an endcap, it would just be easier to redo it.
  • 0

User avatar
Jumpin Jehosaphat
Sergeant Major
Sergeant Major
 
Posts: 188
Joined: Wed Jun 06, 2007 8:20 pm
Reputation: 0

Unread postAuthor: Flying_Salt » Thu Jun 28, 2007 5:44 pm

You must not have used enough primer and glue. When you press the fittings together, a little bit of glue should be visible. Also what some people like to do is use a padded mallet to tap the fittings together. They should be pressed together as far as possible.

This Solvent welding course can also help.
  • 0

sgort87 wrote:I hereby present Flying_Salt with The one and only <a href="http://www.geocities.com/sgort87/ghetto">Ghetto Award!</a>
User avatar
Flying_Salt
Brigadier General
Brigadier General
 
Posts: 779
Joined: Mon Oct 09, 2006 4:57 pm
Location: Texas
Reputation: 0

Unread postAuthor: GORILLASAPIEN » Thu Jun 28, 2007 5:56 pm

thanx for the quick replies guys, yes all parts were sch 40 pressure rated pvc, and i used purple primer and glue for pvc from a company called oatey. The parts in question were a 4 inch diameter pipe and a reducer fitting. Does the glue ever go bad, because it occurs to me that the can in question may in fact be over two years old.
thanks again guys

also, the parts fit together pretty tightly without glue and bottomed out when assembled with, yes thank you, lots of glue.
  • 0

User avatar
GORILLASAPIEN
Private
Private
 
Posts: 15
Joined: Tue Apr 17, 2007 6:00 pm
Location: Gainesville, GA
Reputation: 0

Unread postAuthor: boilingleadbath » Thu Jun 28, 2007 6:05 pm

Some people have successfully used the technique you suggested in your original post - using low pressure in the tank to draw glue into it, although epoxy may be a better option.

As a note, leaks tend to indicate weak solvent welds, so be weary of failures.
  • 0

User avatar
boilingleadbath
Moderator
Moderator
 
Posts: 1642
Joined: Sat Mar 12, 2005 10:35 pm
Location: Pennsylvania, USA
Reputation: 0

Unread postAuthor: hi » Thu Jun 28, 2007 6:28 pm

i find that i have to go around about 5 times with primmer and get it really purple, then go around 5 or 6 times with glue. epoxy would work to seal it. if it leaks you either did it wrong or you pressurized it before it dryed.
  • 0

"physics, gravity, and law enforcement are the only things that prevent me from operating at my full potential" - not sure, but i like the quote

you know you are not an engineer if you have to remind yourself "left loosy righty tighty"
User avatar
hi
Major General
Major General
 
Posts: 1619
Joined: Thu Feb 01, 2007 9:28 pm
Reputation: 0

Unread postAuthor: GORILLASAPIEN » Thu Jun 28, 2007 6:53 pm

on a previous cannon i tried some epoxy for a leak and couldn't get the epoxy to actually stick to the pvc, i re-read the directions and it was recomended for pvc, but like i said it just flaked off after a thorough cleaning, drying, and a 24 hour dry\cure time. thanx but it looks like i'll just have to call a mulligan on this one :cry:
  • 0

User avatar
GORILLASAPIEN
Private
Private
 
Posts: 15
Joined: Tue Apr 17, 2007 6:00 pm
Location: Gainesville, GA
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: Pilgrimman » Fri Jun 29, 2007 2:27 am

I think your cement may just be old. I had the same problem recently. If the cement is REALLY old, it might even be solid. (This happened to me once.) Heck, I bought some cement once, used it a few times, and only two or so months later, it was jelly-ish goo. Needless to say, I was pissed!
  • 0

User avatar
Pilgrimman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 481
Joined: Thu Jun 28, 2007 1:10 pm
Location: Grants Pass, OR
Reputation: 0

Unread postAuthor: Modderxtrordanare » Fri Jun 29, 2007 2:33 am

Pilgrimman wrote:I think your cement may just be old. I had the same problem recently. If the cement is REALLY old, it might even be solid. (This happened to me once.) Heck, I bought some cement once, used it a few times, and only two or so months later, it was jelly-ish goo. Needless to say, I was pissed!


That also happens when you leave them somewhat open. I have a tendancy to do that. So I've got like 5 half full, solidified jars of glue sitting on my workbench. The happen to fit in a 2" barrel pretty snugly, so they work as ammo now. :wink:
  • 0

Spudding since '05. Proud waster of plumbing and plumbing accessories.

-Wiki
-How-To: Modding a Sprinkler Valve
User avatar
Modderxtrordanare
Donating Member
Donating Member
 
Posts: 686
Joined: Mon Nov 20, 2006 1:22 pm
Location: Texas
Reputation: 0

Unread postAuthor: Pilgrimman » Fri Jun 29, 2007 2:39 am

The happen to fit in a 2" barrel pretty snugly, so they work as ammo now.


OMG! :!: :shock: :!: That's my next gun! *Runs off to build it*
  • 0

User avatar
Pilgrimman
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 481
Joined: Thu Jun 28, 2007 1:10 pm
Location: Grants Pass, OR
Reputation: 0

Unread postAuthor: pyrogeek » Fri Jun 29, 2007 3:12 am

The glue goes bad if you let it get too cold. I stored a couple bottles in my house for a while, they were fine. After it was in the garage when it was freezing out though, it turned into jelly. I had that happen both with some like 3 year old stuff, and some stuff I just bought a couple months prior.

I use heavy duty glue, and clear primer. I get the pipe and fitting good and primed. May brush the primer on for a minute or so until I see a little white coming off onto the brush. Then glue, a generous amount. I haven't had a single problem. Of course, my joints ooze a decent bit and I let it dry so the wet part is up. I'm not super eager to get things done since I can't shoot them where I live, so I may glue a guy together over the course of a few days and it may cure at least a few before getting to fire it.
  • 0

I'm weird, I know it, you don't need to tell me.

pyrogeek
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 457
Joined: Sat May 13, 2006 7:43 pm
Location: moline Illinios
Reputation: 0

Unread postAuthor: GORILLASAPIEN » Fri Jun 29, 2007 5:43 pm

quick update: super glue, vaccum, superglue gel. no problem. tested to 150psi no leaks, works like a dream, pics coming soon. thanx again to every body who responded 8)
  • 0

User avatar
GORILLASAPIEN
Private
Private
 
Posts: 15
Joined: Tue Apr 17, 2007 6:00 pm
Location: Gainesville, GA
Reputation: 0

Return to Construction Materials/Ammo Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'