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High Grade PVC cement....for machined assembly

MwTech Inc

Titanium
Joined
Feb 6, 2005
Location
Fishersville VA
Googled but .......maybe there isn't any.....???

Job requires gray PVC cap to be glued onto pipe, needs a perfect seal.
There is zero pressure ...... but cannot leak ..never leak.....air included.

Is there high grade PVC cement made?????
 
I'll reverse it- Are there any low grade PVC cements made? AFAIK, they're all about the same stuff. Cleanliness and technique are what's important. Not sure if a primer is appropriate or would help, but I use it on all my PVC plumbing.

Being a bit of a PITA, there are no perfect seals and pressure is never zero. No matter what you do, it will certainly leak helium at a slow rate.
 
Googled but .......maybe there isn't any.....???

Job requires gray PVC cap to be glued onto pipe, needs a perfect seal.
There is zero pressure ...... but cannot leak ..never leak.....air included.

Is there high grade PVC cement made?????

Since you want one end of the pipe to be perfectly sealed and a pipe has 2 ends, then maybe you should use whatever method is used to perfectly seal that other end. After all why have a perfect seal on one end if the other end isn't perfectly sealed?

If this is a customer request and they say to glue a cap on, glue a cap on, actually it's called solvent welding.

Check out this video for proper solvent welding of PVC Piipe.

 
Probably should have added some more info.........lol

Have installed PVC piping up to 10", never, thank goodness had any leaks with those jobs. (20 psi systems)

Yes I know I said "perfect" seal, but as close as I can get is what I'm after.

So no problems doing it, I was just asking if there was a "better" glue than regular ol plumbing stuff.

Seems not, so far anyway so Oatley it is I guess.........
 
There are many different pvc cement types, depending on pipe size, wet or dry, and ambient temperature, among other things. Choose carefully.
 
If you want it fast just use MEK.

it will instant bond.

Most of the pvc glues currently may have some mek with other "safe" stuff.

Purple primer is a must!

The old stuff was mostly MEK with a carrier and would self prime.

Current stuff is safe meaning little if any solvent so it will not cut into the surface so the primer does this.

There are some that work fine with water and others have slo set.

If you have a commercial irrigation supply they sell in bulk and may have a good blend.

Sent from my SM-G781V using Tapatalk
 
Purple primer is purple just so the inspector can verify that primer was used. No other special magic.
 
If you want it fast just use MEK.

it will instant bond.

Most of the pvc glues currently may have some mek with other "safe" stuff.

Purple primer is a must!

The old stuff was mostly MEK with a carrier and would self prime.

Current stuff is safe meaning little if any solvent so it will not cut into the surface so the primer does this.

There are some that work fine with water and others have slo set.

If you have a commercial irrigation supply they sell in bulk and may have a good blend.

Sent from my SM-G781V using Tapatalk

I would add that you need to manage the cement. I think most joint failures are a result of using cement from the can that is low on solvent from the cap being off and contamination from dropping the dauber on the ground and continuing to use it.

This is the driving factor for the different temp ratings and evaporation ratings.

We had a rule when doing the piping on big pool projects and water parks that all cement was dis-guarded after 4hrs. These projects had some pretty good sized piping and much of it was under concrete so a leak after the fact was completely unacceptable. It was amazing how much better the joint quality was with the four hour rule.
 
So straight MEK will work?? Interesting.......

I'll have to get some and try that out.

more info......there are no liquids involved at all.......just sealing two ends of a 14" long pipe.
 
As some others have said, just making sure you get complete coverage of the bond area, with a surplus of cement, along with priming on a clean surface, should be about the best you can do.

PVC cement (such as Oatey) has several solvent components, such as tetrahydrofuran (THF), cyclohexanone, MEK, and acetone. There is also PVC dissolved in the solvent mix to thicken and fill the joint. It's interesting to see the variations of proportion of these solvents in the different products as specified on the MSDS info. I had always thought that PVC cement was almost entirely a THF-based material with PVC dissolved into it, but that is not so much the case. In the case of the purple primer, the two major components are acetone and cyclohexanone, with THF and MEK being smaller players.

That "4-hour rule" note is a good one in the context of doing a lot of PVC assembly. I almost always have to buy new cement for any little bit of OVC work. Very annoying;-)
 
There ARE differences in PVC cements. For 10" pipe you should NOT use standard Oatey general purpose cement. What you want is Heavy Duty PVC Cement. It's more viscous (I think it has more PVC solids in it). The suggestion of "Heavy Duty" is not speculation: look at Oatey stuff on-line, or the Aetna Plastics selection guide. Note that CPVC cement is a different product. Use heavy-duty CPVC for that type of pipe. The higher solids fills in cracks better, and presumably this will give you a better physical joint and seal.

You may wish to use medium set vs normal, if you need more working time. Priming is really, really important when using heavier-duty cements. Primer softens up and cleans the surface. A cement with higher solids and less solvent can then bond strongly.

So. Cut cleanly, deburr the pipe, clean both pipe and cap scrupulously, make sure that you prime, and use heavy duty cement (pvc or cpvc as appropriate). BTW, gray or clear cement doesn't really matter much. When you assemble, hold the cap on with significant pressure for a couple of minutes. This avoids expansion forces and what have you from pushing the cap off a bit. Wipe off excess cement to avoid etching the pipe wall.

Not to be a know-it-all but are you saying that you are gluing a 10" PVC cap onto a schedule 40 pipe? The pressure rating for that is 140psi at 73°F. Note that PVC is strongly de-rated at higher temperatures. At 140°F is 0.22, giving you a rating of about 30psi. If using higher than ambient pressures, I suggest CPVC (at 140°F it's correction factor is 0.5).

Because you're higher than 15psig, if the pipe is more than 30 feet long (probably not!), the ASME Section VIII Bioler and Pressure Vessel code applies. That would require a pressure relief device. If your pressure source is a compressor setup that generates higher pressures (like 100psig), so that a regulator failure gives you full pressure, I'd have a relief device on the thing if there's any chance of getting up around the 140psig rating. You've read stories here on PM about people using PVC for shop air and having it explode. If pressure excursions were frequent, a relief valve reseals but leaks a bit. If excursions were almost never observed, a rupture disc would have almost nil leakage. But if you had an "incident", you'd have to replace the disc, and they're not cheap.

Sorry for the arc into likely non-related design considerations. But the big thing is: use heavy duty cement on a 10" pipe.
 
So straight MEK will work?? Interesting.......

I'll have to get some and try that out.

more info......there are no liquids involved at all.......just sealing two ends of a 14" long pipe.

No, it won't. It won't give you as good a seal, nor will the joint be as strong (you have 1600 lbs force on that cap, remember). You need cement with solids to fill the gaps between the pipe and cap. The bigger the pipe, the more filling capacity you need (which is why 10" pipe requires heavy duty cement0. Also, pure MEK is more likely to etch the pipe walls if you slather it on. Inferior on all criteria that you're seeking to meet.

The analogy is that you've asked "What type of 2 component paint is good for aircraft service?" MEK is like someone saying "Hey! you could use shoe polish! That works!".
 
Bosley....

The actual job is 3" od pipe , not 10".
Since I didn't mention I had experience gluing pipe , I just brought up I have worked 10" PVC on other jobs in my past.
I will need to be explain better in the future....lol


I fully under stand about joining PVC.............I simply wanted to know if there was a "better grade " of the stuff that may be used outside the plumbing industry???

I will also transfer the glue to a dispenser as this is not a "slap glue all over, shove it together and watch it drip off" kind of job.
 
... this is not a "slap glue all over, shove it together and watch it drip off" kind of job.

You insolent bastard! You set up a camera in my shop and have been watching me! :eek:

Seriously now, the guide shows that you could use medium, heavy duty, or extra heavy duty cement. I have to suspect that the heavier duty you go, the better the gap-filling aspect of the cement. The gaps were why I really reacted negatively to using MEK. I think you'd end up with a joint that might end up having passageways in the joint.

Good luck. And no more personal comments about my sloppy technique! :D
 
Also, for priming purposes, in code work you use a different color primer and cement. Purple primer/clear or gray cement. The code inspector can then verify that primer was used.
 








 
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