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Insufficient PVC cement job

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Insufficient PVC cement job

Unread postAuthor: The_Kangsta » Sun Jul 20, 2008 11:39 pm

Hello guys,
I am building a 1 inch stock that will be pressurized to 120+psi.
Will a single coat of cement be sufficient to hold up that pressure? Because i didnt want globs spilling down. And also, it wasn't a totally even job either, because some parts of the glue were *slightly* thicker than other parts. Am i just being paranoid or will this be a threat for injury?

Also, is there any fabric that can protect against burst?

Thanks

ps the normal ring of excess cement was present, and i did a 45 degree turn to ensure no air bubles.
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Unread postAuthor: MrCrowley » Sun Jul 20, 2008 11:42 pm

Sounds like you didn't use primer and you used that glue that was possibly expired and/or dry.

So I wouldn't use it past 50psi personally. But it's really up to you.
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Unread postAuthor: koolaidman » Mon Jul 21, 2008 12:09 am

well, as far as thickness goes it really doesnt matter as long as you did in fact twist it. It sounds fine as long as you used primer and it wasnt extremely old and viscous.

Actually, my first pneumatic had a 1" stock and i glued it very poorly. I dropped it and one of the sockets popped out at 80 psi. Its now a pile of scrap and I think I have since improved.
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Unread postAuthor: jrrdw » Mon Jul 21, 2008 5:01 am

Good solvent welding improves with pratice. If I where you I would hook up a air hose with a remote valve/off/on hook up to test it. What exactly do you mean some pieces where thicker then others?
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Re: Insufficient PVC cement job

Unread postAuthor: Ragnarok » Mon Jul 21, 2008 7:58 am

The_Kangsta wrote:Also, is there any fabric that can protect against burst?

Anything cross-woven out of steel fibres or Kevlar - maybe.
Even then I wouldn't be too sure of it - any fabrics, even Kevlar, are notorious for having little stab protection, because of sheer concentration of force on only a couple of threads.

Essentially, no fabric you are likely to have handy is really up to the job.

If you're worried enough to think that you might need such a shield to protect against bursts (which it almost certainly won't protect against) I wouldn't be using the launcher.

I think MrC maybe right. The cement was probably past it's prime, and your joints may well not be safe.
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Re: Insufficient PVC cement job

Unread postAuthor: paaiyan » Mon Jul 21, 2008 9:21 am

I'm going to have to agree with Rag here, if you have to ask about reinforcing it with fabric, I personally wouldn't trust it.
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Re: Insufficient PVC cement job

Unread postAuthor: The_Kangsta » Mon Jul 21, 2008 9:26 am

Ragnarok wrote:I think MrC maybe right. The cement was probably past it's prime, and your joints may well not be safe.


But i just got the cement that day!!--because the old one i had was extremely old and viscous.

And also, i did the primer properly so it should probably be fine. ?
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Re: Insufficient PVC cement job

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Unread postAuthor: paaiyan » Mon Jul 21, 2008 9:28 am

Can you take a look at the can and see when it was manufactured or when it expires?
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Unread postAuthor: TurboSuper » Mon Jul 21, 2008 9:29 am

Sounds fine to me. For added burst protection I guess you can sleeve it another layer of pipe...but that's just more trouble than it's worth. NSF-PW pipe shouldn't break a sweat at 120 PSI.
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Re: Insufficient PVC cement job

Unread postAuthor: Ragnarok » Mon Jul 21, 2008 10:30 am

The_Kangsta wrote:But i just got the cement that day!!--because the old one i had was extremely old and viscous.
And also, i did the primer properly so it should probably be fine?

Then I'm left a little confused by what exactly you're worrying about.

Check the can manufacture date - if that's all OK, if you used proper fittings, and if you cleaned, primed and glued according to procedure, then left it for 24 hours before pressurizing, the results should be safe enough, at least to moderate pressure.
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Unread postAuthor: The_Kangsta » Mon Jul 21, 2008 10:34 am

paaiyan wrote:Can you take a look at the can and see when it was manufactured or when it expires?


it says 6/03 on both of them, the 1 that already dried up and my new can
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Re: Insufficient PVC cement job

Unread postAuthor: jimmy101 » Mon Jul 21, 2008 11:23 am

The_Kangsta wrote:Will a single coat of cement be sufficient to hold up that pressure? Because i didnt want globs spilling down. And also, it wasn't a totally even job either, because some parts of the glue were *slightly* thicker than other parts. Am i just being paranoid or will this be a threat for injury?
...
ps the normal ring of excess cement was present, and i did a 45 degree turn to ensure no air bubles.

By "single coat of cement" do you mean you only put the glue on one part of the joint instead of both parts? You should apply glue to both parts.

The eveness of the glue application shouldn't matter too much as long as the entire joint had some glue on it to start with. When you inserted and twisted the pipe, given the pretty tight tollerance between pipe and fitting, the glue should have evened out.

PVC glue really doesn't expire so the date on the can is pretty irrelevant. The glue will dry out if the can isn't closed tightly which makes the glue to viscous. Too-thick glue is not good.

As long as you got the pipe fully seated in the socket, you used primer or primer/cleaner (not just cleaner), and there was glue everywhere on at least one of the pieces you should be OK. It would have been better if there was glue on both pieces. It sounds like the joint is OK, not perfect, but OK.

BTW, there are easy ways to control where the excess glue (and primer) goes. Get a roll of painters tape (often blue colored) and wrap it around the pipe a socket depths distance from the end of the pipe. The tape does two things; (1) it marks how far the pipe needs to be inserted and (2) it protects the pipe outside the joint from primer and glue. I find that marking the distance with the tape works better than making a pen or pencil mark on the pipe since the primer tends to wash away the mark. The tape will give a nice crisp primer line right at the end of the joint. I use the painters tape instead of regular tape since it doesn't leave any sticky residue when removed.
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