barb fittings & wire banding for large PEX?

[pybyr]

as I keep moving forward with planning and construction of my system, I'm going to need some moderately long, moderately large diameter lines, around 1.25 to 1.5 inch, between the primary loop and the 1200 gallon tank, and then also between the primary loop and the water-air HX

to me, big iron in long lengths is klutzy to work with and support, especially through somwhat crowded existing low-ceiing old farmhouse basements like mine.

copper in these quantities is going to be scary on cost.

so, I keep coming back to PEX,

but I am finding a relative lack of fittings of any sort in the bigger sizes, and an even bigger lack of fittings that don't either cost an arm and a leg or require some unusually exotic tool that itself costs several arms and legs.

I think I have heard of OWB folks using barb-fittings, like you'd use with black poly pipe, and then hose clamps, with pex. But of course, OWBs generally run no pressure other than the weight of the water. the hose clamps wouldn't help me sleep well at the more significant pressures of a regular domestic system.

but then I got to thinking of a tool that I already own from other projects and that can clamp things tighter and more uniformly than regular worm-screw hose clamps:

http://www.clamptitetools.com/

I can use stainless wire with this tool, and could run a bunch of wire bands around the pex, quite tight, after a barb fitting is inside

I'd appreciate feedback on whether I may be onto something, or whether this is a direction best avoided.

thanks, as always, for all the great experience and ingenuity and support 'round here

 

[pybyr]

bump- pros, please?

 

[atlarge54]

I have 4 of the barb and clamp fittings on my system on the 1" pex. Use two quality clamps on each fitting and retighten after the system is warm and you should be ok. I was amazed how loose the fit was when new, the fittings would practically drop into the pex. My system is approx. 12 psi.

 

[free75degrees]

That thing looks cool either way. I wonder if the wire may be so thin that it would dig through the pex. Pexalpex might help to avoid that if it is a problem. Have you tried a test fitting? It would be interesting to do a test and see if it could hold the pressure without leaking. Even then you wouldn't be totally sure that it could last and would be able to produce large numbers of good fittings, but it would be a start.

 

[in hot water]

I would stick with copper or threaded steel. At those temperatures and pressures pex can get very soft and hard to keep connected with all but the proper connection.

An 1-1/4 line gushing 190F water is a sight to behold.

hr

 

[pybyr]

That thing looks cool either way. I wonder if the wire may be so thin that it would dig through the pex. Pexalpex might help to avoid that if it is a problem. Have you tried a test fitting? It would be interesting to do a test and see if it could hold the pressure without leaking. Even then you wouldn't be totally sure that it could last and would be able to produce large numbers of good fittings, but it would be a start.

I haven't tried a test fitting yet, but that's a good idea.

I could mock up a short length and put an air fitting on it, and then

what are folks' reactions/ suggestions on whether it's really necessary to use the large diameter stuff in order to conduct a valid test-- 'reason I ask is that I already have a 3/4 brass hose barb fitting and some 3/4 pex on hand

I'm sure that larger diamters would introduce some different variables- just not sure whether the variables that change are ones that'd matter?

 

[pybyr]

I have 4 of the barb and clamp fittings on my system on the 1" pex. Use two quality clamps on each fitting and retighten after the system is warm and you should be ok. I was amazed how loose the fit was when new, the fittings would practically drop into the pex. My system is approx. 12 psi.

thanks for the insight based on experience- when you say "barb" are you referring to the true hose barb type (with serrated sloping rings) as is used with black poly or flexible hose, or are you referring to the "nub" type barbs as are used for some of the clamp-based PEX systems?

thanks

 

[atlarge54]

I have 4 of the barb and clamp fittings on my system on the 1" pex. Use two quality clamps on each fitting and retighten after the system is warm and you should be ok. I was amazed how loose the fit was when new, the fittings would practically drop into the pex. My system is approx. 12 psi.

thanks for the insight based on experience- when you say "barb" are you referring to the true hose barb type (with serrated sloping rings) as is used with black poly or flexible hose, or are you referring to the "nub" type barbs as are used for some of the clamp-based PEX systems?

thanks

It's been about 4 years since installing, but I'm pretty sure there were no sharp edges on the "barb" ends. What kind of price is involved in larger pex? It seems like I paid $5/ft for 1" pex years ago. At the time it seemed overpriced compared to all my other pex at $80 for 250' of 1/2" with oxy barrier.

 

[pybyr]

I have 4 of the barb and clamp fittings on my system on the 1" pex. Use two quality clamps on each fitting and retighten after the system is warm and you should be ok. I was amazed how loose the fit was when new, the fittings would practically drop into the pex. My system is approx. 12 psi.

thanks for the insight based on experience- when you say "barb" are you referring to the true hose barb type (with serrated sloping rings) as is used with black poly or flexible hose, or are you referring to the "nub" type barbs as are used for some of the clamp-based PEX systems?

thanks

It's been about 4 years since installing, but I'm pretty sure there were no sharp edges on the "barb" ends. What kind of price is involved in larger pex? It seems like I paid $5/ft for 1" pex years ago. At the time it seemed overpriced compared to all my other pex at $80 for 250' of 1/2" with oxy barrier.

PEXSupply.com lists 1.25 oxygen barrier pex at $289/ 100 feet. not sure yet if they will sell lesser lengths

I found some steel hose barb fittings on McMaster.com that, at under $5.00 per fitting, compared to the ridiculous $80- and up fittings for big PEX, make me think that this is something to investigate

as an example, see McMaster's # 5363K55 - and picture that with the wire banding clamps that I mentioned above

 

[BrownianHeatingTech]

I have 4 of the barb and clamp fittings on my system on the 1" pex. Use two quality clamps on each fitting and retighten after the system is warm and you should be ok. I was amazed how loose the fit was when new, the fittings would practically drop into the pex. My system is approx. 12 psi.

thanks for the insight based on experience- when you say "barb" are you referring to the true hose barb type (with serrated sloping rings) as is used with black poly or flexible hose, or are you referring to the "nub" type barbs as are used for some of the clamp-based PEX systems?

thanks

It's been about 4 years since installing, but I'm pretty sure there were no sharp edges on the "barb" ends. What kind of price is involved in larger pex? It seems like I paid $5/ft for 1" pex years ago. At the time it seemed overpriced compared to all my other pex at $80 for 250' of 1/2" with oxy barrier.

PEXSupply.com lists 1.25 oxygen barrier pex at $289/ 100 feet. not sure yet if they will sell lesser lengths

I found some steel hose barb fittings on McMaster.com that, at under $5.00 per fitting, compared to the ridiculous $80- and up fittings for big PEX, make me think that this is something to investigate

as an example, see McMaster's # 5363K55 - and picture that with the wire banding clamps that I mentioned above

I wouldn't do it, but I have liability factors, being in business. If I were you, I'd risk the hose barbs and test it out. Assuming it seems to hold, I'd wait a few days until all the air is out of the system (and watch the fittings closely), then shut off the boiler feed, so there wouldn't be a major flood if the thing does pop (ie, only what's in the system would come out, at most).

And install a low-water cutoff, to protect the pumps and such.

Joe

 

[feelingasi]

just bought 100 ft 1 1/4 for 236.33 as well as a 1/2 3/4 crimp tool (150.71). they also shipped me a 1 1/4 crimp tool to use. I had the 1 1/4 tool for about a week N/C. total shipping was 37.44. and of coarse there is sales tax. call cc allis ask for mark. this place is the biggest true value hardware store in the middle of nowhere that you've ever seen. google it. the place actually does exist, i've been there, great people

 

[jebatty]

I would feel pretty comfortable with the pex and barb fittings, 2 clamps per fitting. Re-tighten periodically until well seated. Use these only where you can easily access the fittings for retightening. I've always used a bit of vaseline on the fitting to help it slide more easily.

I've mentioned this before, but maybe it will help again. I'm using 3/4" high temperature rubber rose, barbs and clamps on curved or snaked runs. Very easy to install. Rated to 200F. In 2nd year of operation and no noticeable softening, deterioration, etc. It is necessary to check and retighten the clamps a couple of times after in operation. My pressure runs up to 20 psi. 3/4" is about $1/foot. Check Ace Hardware on-line + free shipping to a local store.

Larger and higher temp hose is available but is pricey.
http://abbottrubber.thomasnet.com/viewitems/hose-water-hose/paper-mill-creamery-hose?&forward=1

 

[pybyr]

just bought 100 ft 1 1/4 for 236.33 as well as a 1/2 3/4 crimp tool (150.71). they also shipped me a 1 1/4 crimp tool to use. I had the 1 1/4 tool for about a week N/C. total shipping was 37.44. and of coarse there is sales tax. call cc allis ask for mark. this place is the biggest true value hardware store in the middle of nowhere that you've ever seen. google it. the place actually does exist, i've been there, great people

are you referring to PEX supply?

thanks

[EDIT - re- read and answered my own question. I'll look up CC Allis. Thanks for the tip]

 

[pybyr]

found out today that I can get 20 foot lengths of o2 barrier 1.5 HePex, which has a 1.244 actual inside diameter, for just under $50 each through my local vendor- that's gotta be less per foot than copper, and I am assuming less than steel- plus it'll be easier to hoist and hang between the primary loop and the big tank.

I've asked McMaster Carr to confirm that their 1.25 barb fittings are indeed a true 1.25 OD- but pending that answer, this is looking promising

 

[jebatty]

Don't know if you can do this with pex, but if OK, carefully heat the pex a little with a torch to soften it, put vaseline on the barb fitting, and it should slide right in.

 

[pybyr]

Don't know if you can do this with pex, but if OK, carefully heat the pex a little with a torch to soften it, put vaseline on the barb fitting, and it should slide right in.

Thanks for the suggestions. You're supposed to avoid direct flame on the pex, but heat guns are OK, as would be boiling water. I'm hoping to skip any lube if I can, as I figure that whatever makes it slipperier going in may make it slipperier in potentially coming out...

 

[DaveBP]

put vaseline on the barb fitting

Are petroleum products cool with PEX?

I’m hoping to skip any lube

Or you could just use the international standard lube; just spit on it. Works on metric fittings, too.

 

[pybyr]

put vaseline on the barb fitting

Are petroleum products cool with PEX?

I’m hoping to skip any lube

Or you could just use the international standard lube; just spit on it. Works on metric fittings, too.

i'm not sure whether petroleum compounds are officially OK'd with pex, but since pex is basically a super-duper form of polyethylene, which is usually OK with petroleum (at least compared to other things) I think it would be OK, although I prefer to avoid it for the reasons mentioned above.

on the spittle, good idea - PTOOEY- or I could use the fancy variant of that- wire pulling lube, which is non-petroleum and basically dries out and then ceases to be slippery