Screwed up solvent weld; please help. Thanks

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limbeh
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Sat Feb 16, 2008 12:50 am

Hi,

I think I just screwed up a PVC solvent weld. I glued the PVC pipe to the fitting without using primer, just with about 3 coats of PVC cement on the fitting & the pipe. I was not able to bottom the pipe. It stopped about 1.2cm/0.5inch above the bottom. Unfortunately, no camera, so I can't get pictures.

The fitting (a tee) & pipe are both JIS (Japanese Industrial standard) AW (pressure rating 284 psi) & are both are 4" nominal diameter. The local PVC pipe manufacturer makes pipes to JIS dimensions, so Schedule 40 is hard to find & expensive.

Unfortunately, the PVC cement can's instructions & labels are all in Japanese, which I can't read. However, I'm quite sure that its not dual purpose, given that the pipe did not turn soft after applying the cement (even after waiting like 10 minutes).

To the more experienced PVC spudgun builders here:

- Would this joint be able to withstand pressure of about 125 psi (max operating pressure of the planned spudgun)
- Can the pipe be removed without damaging the fitting?
Thanks
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MrCrowley
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Sat Feb 16, 2008 12:56 am

You let the glue dry on the fitting for 10 minutes before joining the pipe and fitting together?
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limbeh
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Sat Feb 16, 2008 1:00 am

No. I let it dry for about half an hour before joining the pipe and fitting together.
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MrCrowley
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Sat Feb 16, 2008 1:02 am

Okay I would scrap it, your supposed to join the pipe and fitting as soon as you have finished glueing and priming them. The glue would've dried out a bit, and weaken the weld.
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limbeh
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Sat Feb 16, 2008 1:12 am

There is no primer on the pipe, just PVC cement. The glue had dried 10 seconds after glueing by simply using the brush to spread the stuff out.
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MrCrowley
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Sat Feb 16, 2008 1:13 am

I wouldn't use it.
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limbeh
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Sat Feb 16, 2008 1:34 am

Ok. Thanks a lot.
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SpudMonster
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Sat Feb 16, 2008 2:01 am

limbeh wrote:No. I let it dry for about half an hour before joining the pipe and fitting together.
*facepalmheaddesk*
5cn trfjfrxku dz

now that my "" key is noperational...

Like Mrcrowley said, yo should psh the pipe and firring together as qckly as possible. In my experience, even waiting 10 seconds can case the gle to set p qckly enogh to make it almost impossible to psh the last 1/2 inch or so.

Seriosly, half an hor? <a herf="http://www.burntlatke.com/weld.html">I recommend reading these instrctions on how to solvent weld properly.</a>
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MrCrowley
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Sat Feb 16, 2008 2:08 am

Someone's lost a vowel :roll:



:)
Last edited by MrCrowley on Sat Feb 16, 2008 3:31 am, edited 1 time in total.
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SpudMonster
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Sat Feb 16, 2008 2:40 am

Yo got it. Anyone care to gess which one? Motherfcking thing...
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Velocity
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Sat Feb 16, 2008 11:41 am

I agree that"u" have lost a vowel :sign4:
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STHORNE
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Sat Feb 16, 2008 11:47 am

i had the same problem, cause by old cement (gets thick and dries faster/more brittle). I just started over in fear of it blowing up in my face...

dont even bother trying to use it, just go buy yourself a new jar and trash the pvc you used it on.
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limbeh
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Sun Feb 17, 2008 2:48 am

My cement gets dry from spreading it out lol.....as in by the time the thing spreads out its like dry already......wonder why.

I might as well forget about salvaging the fittings. I'll probably put the screwed up tee together with some equally screwed up parts and use it as a decoy cannon. Interestingly, even though I'm in Singapore, and the teachers know that I'm constructing it, I can construct it with impunity because spudguns are very rare here & few know what they are. Thus, building it in my school is perfect - lots of space for a firing range, nearby swimming pool to check for air leaks, plus lots of projects that can be used to justify its construction.

The big problem with building it in school is that students are generally itchy handed, particularly with things that go boom or shoot stuff. Thus, the decoy. Anyone can help me think up of some booby traps to add to this decoy to teach potential meddlers a lesson?
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benstern
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Sun Feb 17, 2008 4:37 pm

Like what?
Paint that won't dry?

Just to let you know, we don't condone violence.
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Pilgrimman
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Sun Feb 17, 2008 4:41 pm

Your weld has no strength whatsoever. Start over. For more information on solvent werlding, go here: http://www.spudfiles.com/spud_wiki/inde ... nt_welding
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