I guess this could be a plumbing question also. We have been looking at new hot tubs and noticed they all use “blue glue” for white PVC connections. According to a master plumber in NC (and my husband), blue glue is only appropriate for cold water fittings and not an acceptable welding material in this case ie: water temp. in hot tub is usually at least 98 degrees. When we ask hot tub dealers if this is appropriate, we get the same answer-“all the hot tub manufacturers use it!” Are we being too picky? What would be an appropriate glue to use in this case?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Traditional lime wash still has tons of useful applications.
Featured Video
SawStop's Portable Tablesaw is Bigger and Better Than BeforeHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Are you sure you're not seeing the blue-ish primer?
No, it is not the purple primer. They do not use a primer, just the "blue" glue
You got me wondering so I took a look at a bottle I have from Oatey called Rain-R-Shine and nothing on the bottle says anything about working temp of the pipes it's glueing. It's blue BTW.
Go to Oatey's site and it says an application range of 40F-100F. Does that mean to apply in temps of 40F-100F or the proposed application (could be the term means 'use') should be 40-100? I doubt it's the latter, especially so when you look at all their glues for pressure applications say the same temp range.
http://www.oatey.com/apps/catalog/showskus.asp?ctg=1&subctg=1&prodgrpid=164
Intersting thing of note on the bottle in my hand it's temp range is 40F-110F, 10F higher than the data on their site.
It's solvent welding anyway. So would the glue really matter? The purpose of the glue is not to create a joint that joins two individual pieces. It's purpose is to more or less "melt" the pieces together into a cohesive single unit. I don't know, I'm just a hack DIY plumber. But my understanding of PVC is not that you "glue" it. Rather, you "weld" it using solvent cement.
Good point. Now I understand why Oateys website product listing called it Solvents & not glues.
Hello John, this is the husband joining in.
I questioned the spa manufacturers using "Rain and Shine", known as "Blue Glue", because I have had to repair older (+/- 10 years installation) PVC Blue Glue joint failures on outside water piping (max 50 psi) where the joint did not fuse. The joint was "glued", not solvent welded. I literally was able to purple clean/prime the fittings and heavy duty cement them back together!
Years ago, when I asked Hughes supply about this, they had strongly suggested using the purple primer/cleaner if using "Blue Glue." For the link that was sent as to Oatey's, I see that they say the Rain and Shine can be used for non-pressure dwv PVC without primer, unless code required.
My question to the manufacturers was why were they not using the heavy duty cement as, in my experience, it welds the joint rather than gluing it. The response was "... everybody uses the blue glue."
My second question to them was why did they use PVC instead of a CPVC, as the water temperature in the spa is 99 to 104 F (means the water temp coming out of the 5000 watt heater will be significantly hotter than the +/- 100 F temp PVC is rated for. Their answer was similar to the above answer - "... everybody uses it."
We asked a building inspector as to residential plumbing: He said code required purple primer and heavy duty cement. Since "Rain and Shine" is a fast set, he felt that some may use it for a "non-inspected" quick repair (lesser of two evils - no water while waiting for the longer set time v. non-approved Blue Glue.)
So, here we are looking at spas, a relatively expensive purchase and which is not going to be "inspected." Maybe I am being over-concerned (my wife thinks so) but I see a problem with PVC pipe, blue glued in a heated, non-dwv application that is then covered with insulating foam. Felt it was better to ask for comments now, rather than after the warranty runs out (1 year parts and labor, 5 years parts) so I will welcome comments, suggestions, or experiences related to such.
Husband Ringtail,
Did you see this sheet from the Oatey link?
http://www.oatey.com/apps/catalog/instance_assets/assets/Submittal_Sheet/PVC%20Rain-R-Shine.pdf
It's found at the product information link at the previous link. That sheet doesn't say anything about DWV in regards to the use of primer or in pressurized situations, only that it can be skipped if local codes allow (which make me think that Oatey is fine with it holding pressure w/out primer)(I've also been told that primer is only necessary for the larger pipes, but that's unsubstantiated so far).
I hear what you're saying. I'm not a plumber but I've seen the blue used in inspected locations but that's all up to the locals. From what I've read NC is one of the more stringent and standardized AHJs.
I do remember hearing years ago what you're saying about the no blue on high temps but I also believe that chemistry changes and can be changed over time. I'm going to follow what I read at Oateys site; I don't think they've gone through all the R&D and not state a working temp range or omit pertinent usage criteria. Also I think the Big Boxes sell the Rain-R-Shine and the labels on the cans are the only things that most users are going to see. If there were indeed a working temp range I'd think it would (should) be stated there on the label. I took a look at some of the other solvents there and I didn't see any referring specifically to CPVC, just PVC.
I can guess at your 2nd question and that may be that they feel since it isn't pressurized they can use the PVC other than CPVC.
Maybe some real plumbers will chime in.
CheersJohn
Thanks. That link is different from the one above, which does have the dwv clause in it for the primer - that was a "products page" though.
The temp aspect I was referring to had to do with PVC pipe. From memory, I thought that PVC was good in pressurized situations up to only 100 F. My thinking is that:
a) the water coming through the pipe will be pressurized as it is being forced through the sized nozzles. Totally guessing here, but I feel a minimum of 10 psi.
b) the water temp coming out of the heater will be greater than 100 F and therefore I wonder if PVC is a good pipe to use for the long term or does it ensure "built in obsolescence"?
Your input is appreciated!
Just took a look at a pc of Sch 40 DWV... 330psi @ 73* is what's stamped but there's no high-side limit though. I wonder what Sch they use at the factory for the spa tubs? Do they make a heavier sch that is flexible enough for them to route it as the do? I dunno.
I searched for more info using PVC 1120 (which i think is industry-speak for sch 40) but I don't have an ASTM subscription which I'd think would give the standards and maybe even the testing process.
You're logic seems good but the planned obsolescence will cost a lot of money to a lot of people and may cause a lot of damage. I'm thinking that this isn't part of the plan whatever the plan is. I keep my WH @ 120* (kids in the house) but I think a lot of people keep it hotter than that. I wonder what the safety factor is that they used to come up with the numbers and test limits. From my aviation career much of that was tested to 300% rated. Does PVC get the same? I'm figuring probably not.
Thanks to all for your help. As you have pointed out, it looks like the glue and pvc should hold up to it. Next, I'll look into how sausage is made!
Next, I'll look into how sausage is made!
I have two words for that.
Rytek Kutas
“The Hand of providence has been so conspicuous in all this, that he must be worse than an infidel that lacks faith, and more than wicked, that has not gratitude enough to acknowledge his obligations.” —George Washington
Don't get worried about the color, it's an additive so you know you're using a one step glue.
If you look at all of Oatey's glues, they are ALL recomended for 40 to 100 degrees.
& don't woory about regular sch 40 PVC either.
We plumb spas that are custom concrete poured on site, with sch 40 PVC for above ground & sch 80 for below ground piping.
Here is a spec sheet from Lasco¯
Any more question or concerns feel free to ask.
Thanks Bill, was hoping someone like you'd post.