Duotight fittings disintegrated

[Summa_Brewologica]

Another source for John Guest Push-to-Connect fittings is Fresh Water Systems. They also sell 10-packs at a price break. Not sure how things are now, haven't checked there lately.


I was under the impression that the gray fittings are made of Acetal polymer. That could be the issue, maybe superior in some ways but not in every application.

The white ones are Polypropylene.

Now I have another evidence that Starsan attacks plastics. My spray bottle with Starsan self-decapitated:
View attachment 780511

Yes I’m leaning toward the starsan being the cause. I also suspect I was loose with the mix and made too strong a batch in my spray bottle at the time.

As far as spray bottles go I’ve always used glass ones and love them. The spray part, however, is obviously plastic but it seems to be holding up. I usually empty everything out after a week or two since that seems to be the shelf life.

I always use RO water for mixing starsan and wonder if the mix should be measured differently depending on the water source. The directions on the bottle don’t mention anything about that which makes me think it should be good but I’m still curious.

 

[McMullan]

Another source for John Guest Push-to-Connect fittings is Fresh Water Systems. They also sell 10-packs at a price break. Not sure how things are now, haven't checked there lately.


I was under the impression that the gray fittings are made of Acetal polymer. That could be the issue, maybe superior in some ways but not in every application.

The white ones are Polypropylene.

Now I have another evidence that Starsan attacks plastics. My spray bottle with Starsan self-decapitated:
View attachment 780511

I've lost count of the number of spray bottles I've gone through. I'm thinking about spending a little extra for a viton one next time.

 

[DuncB]

My spray bottle with polythene bottle is going strong after 4 years. Back part of handle broke when I dropped it on the floor.
I've had the threaded part of coke pet bottles crack up and leak with starsan in bottle and the red ball lock thing screwed on.

 

[Deadalus]

https://cdn5-ss5.sharpschool.com/Us...c Schools/COVID-19/starsan hand Sanitizer.pdf
Star San MSDS ^^^, you can see what's in it.

Next question is which plastics are good or not with these acids. Off the top PTFE (teflon) and Polypropylene are good, but that can be case by case. I know that some acids dissolve some plastics, enough to be aware of it, but I don't know specific combos.

In the pdf I posted, it says the Duotights were made out of Polyoxymethylene (POM) but that the collars were switched to polyketone. The pdf notes that John Guest fittings are also made from POM but probably a good idea to just double check that against information from John Guest.

 

[Deadalus]

I’ve not had any more failures w Duotight. I’ve seen no issues yet w the Kegland QD/PTC fittings. I continue to Starsan w each use, and that means they are sprayed, connected to kegs, typically in ferm chamber for a week or two, then removed, water rinsed, tossed in drying bin.

That one failure I had was the only one myself since, thought I would just link the two threads. I just switched my jockey box over to Duotights too...

Not to gum the discussion up but I just had a poppet in my Kegland ball lock QD melt/deform. I had the material* identified yesterday for the poppet and was investigating and the material is supposed to be good to past boiling. I did overshoot the temp on the PBW I was running through the system but it wasn't boiling. I still want to check sources further on that material to be sure.

*EPDM and PP/EPDM overmoulded poppet

 

[tracer bullet]

Polyoxymethylene

Funny, I hadn't heard of that, but am quite familiar with Acetal. Anyhow:

https://www.calpaclab.com/acetal-polyoxymethylene-chemical-compatibility-chart/
And... drumroll.... acetal doesn't seem to get along with phosphoric acid, or really an acid it seems.

 

[Bobby_M]

The added seal of the second oring isn't insignificant. I setup my whole kegerator with John Guest fittings but they were too prone to leaks if the tubing was stressed just slightly off axis. I switched to Duotight and less problems.

 

[dmnota]

Popping in here to share my similar experience. Full Duotight setup, from William's. I've only had them for a couple of months, maybe 2.5 kegs' worth. I've had about 4 flares and at least one checkvalve have their collars disintegrate as well. Both inside and outside the fridge. Gas and liquid.
I'm chalking this up to Star San as well because I definitely soaked some of them for an extended period of time. My two regulators seem fine so far. I had no idea Star San was a problem until finding threads like this out of frustration. Debating whether to replace >$50 of new duotight or go back to more reliable equipment. What a waste.

I also just invested in Value Brew's "Locking Clips." These were definitely not introduced to any StarSan and are also prone to snapping. I'm really turned off the entire Duotight concept.

 

[DuncB]

I am puzzled by this outbreak of issues with Duotight, mine as I say have been fine, I don't use those brew locking clips and I've got a mix of connectors bought in Australia, New zealand of varying ages.
I'm not sure I bothered to starsan the gas side at all. But posts and ball locks get sprayed each change of keg / at line washing.

 

[Summa_Brewologica]

I need to be clear: duotight fittings are great products. This issue which I am 99% sure is starsan related, is not really their fault. They have written somewhere not to use bleach to clean their fittings. I don’t think starsan classifies as bleach but maybe they mean for this to be included. Either way, in my case, Im fairly convinced I made too strong a mix. Im happy to spend an extra $3 on a fitting when I order my next set for a spare that I can experiment on if it will help anyone.

I never soaked any fittings gas or liquid. But I did spray everything down and since it was my first experience with duotight I may have been excessive with spraying down the gas fittings (with probably a heavier starsan mix by accident) while looking for leaks. Anyone who first puts these together probably understands the skepticism as they fit together too easily and it almost feels like there is no way that something that simple could seal that well but they do.

So I think the lesson from this really is to just pull back on the starsan. I don’t think they need soaking (gas or liquid) just a spray bottle with a simple spritz before hooking everything up should do.

Edit: starsan in its concentrated form might be considered bleach. If anyone has spilled a bit on a countertop without realizing it or similar probably knows what I mean.

 

[Summa_Brewologica]

Popping in here to share my similar experience. Full Duotight setup, from William's. I've only had them for a couple of months, maybe 2.5 kegs' worth. I've had about 4 flares and at least one checkvalve have their collars disintegrate as well. Both inside and outside the fridge. Gas and liquid.
I'm chalking this up to Star San as well because I definitely soaked some of them for an extended period of time. My two regulators seem fine so far. I had no idea Star San was a problem until finding threads like this out of frustration. Debating whether to replace >$50 of new duotight or go back to more reliable equipment. What a waste.

I also just invested in Value Brew's "Locking Clips." These were definitely not introduced to any StarSan and are also prone to snapping. I'm really turned off the entire Duotight concept.

I’m curious, did you by chance notice a “musty” smell from the affected fittings?

 

[DuncB]

I would say that starsan is not bleach, bleach is sodium hypochlorite wheras starsan is phosphoric acid and other chemicals it is acidic. Bleach is alkali.

I think a spray with starsan and then a spray with water to wash it off the surface would work well.
Use soapy water to check for leaks is perhaps the moral of the story.

 

[dmnota]

did you by chance notice a “musty” smell from the affected fittings?

Hmm. I didn't notice anything especially unique about the smell. Though, on many of them is a dark brown - almost like a burn - discoloration on the outside where the collar meets the body (if that makes sense). Originally I thought it was probably beer stain but I'm guessing not, now

I'd like to try a fresh set but my LHBS doesn't have them, and all others have a minimum for free shipping. Anyone aware of the most economical place to get a few to try them StarSan-free?

 

[Summa_Brewologica]

I would say that starsan is not bleach, bleach is sodium hypochlorite wheras starsan is phosphoric acid and other chemicals it is acidic. Bleach is alkali.

I think a spray with starsan and then a spray with water to wash it off the surface would work well.
Use soapy water to check for leaks is perhaps the moral of the story.

It may not be bleach but concentrated star San absolutely bleaches.

 

[Summa_Brewologica]

Hmm. I didn't notice anything especially unique about the smell. Though, on many of them is a dark brown - almost like a burn - discoloration on the outside where the collar meets the body (if that makes sense). Originally I thought it was probably beer stain but I'm guessing not, now

I'd like to try a fresh set but my LHBS doesn't have them, and all others have a minimum for free shipping. Anyone aware of the most economical place to get a few to try them StarSan-free?

I had the same “burn” look on mine. I’m just gonna order through Williams, again.

 

[IslandLizard]

on many of them is a dark brown - almost like a burn - discoloration on the outside where the collar meets the body (if that makes sense).

Could you post a (closeup) picture of those fittings showing the discoloration? Have any of them broken into pieces?

Another thing Starsan does is make clear vinyl hoses opaque, they turn white, when soaked/immersed for extended time, say a week or so.
When hung up to dry they return to clear after a few days to a week.

 

[Summa_Brewologica]

Could you post a (closeup) picture of those fittings showing the discoloration? Have any of them broken into pieces?

Another thing Starsan does is make clear vinyl hoses opaque, they turn white, when soaked/immersed for extended time, say a week or so.
When hung up to dry they return to clear after a few days to a week.

I’ve noticed this with my silicone tubing, as well. The part submerged turned completely white like it was dipped in white paint.

 

[scrap iron]

After reading this very informative thread I checked all my Duotight fittings. I bought them from my LHBS less than a year ago and they are all the newer version that Deadalus posted in #24. Thanks for the PDF. I have had no leaks or breakdowns; I did spray them with starsan but I spray rinsed them with water after assembly. I suggest using a spray bottle from a farm and home store that are made to use with chemicals. I've had one from Tractor supply for several years.

 

[Craiginthecorn]

I’ve noticed this with my silicone tubing, as well. The part submerged turned completely white like it was dipped in white paint.

That's a different issue. According to Charlie Talley of Five Star Chemicals in an old podcast interview, that's a component of Starsan binding to the hose. He said that cleaning with PBW would remove it.

 

[matt_m]

I suggest using a spray bottle from a farm and home store that are made to use with chemicals. I've had one from Tractor supply for several years.

The Zep branded ones at Lowes seem to hold up well too. I would assume they are made for cleaning products since that's what Zep does. The cheaper ones at Lowes aren't worth it.

 

[Bobby_M]

That's a different issue. According to Charlie Talley of Five Star Chemicals in an old podcast interview, that's a component of Starsan binding to the hose. He said that cleaning with PBW would remove it.

I don't know about the binding theory because silicone hose that sits in starsan for 1-2 weeks can be snapped in half. It would seem it's taking something away rather than adding it if it becomes that brittle, but maybe that's one of those counterintuitive scenarios.

 

[IslandLizard]

silicone hose that sits in starsan for 1-2 weeks can be snapped in half.

I've never seen that happen, and I'm sure I've occasionally (and unintentionally) left 1/2" thick-walled silicone brew hoses in a Starsan working solution for several weeks. No brittleness experienced either.

 

[dmnota]

Could you post a (closeup) picture of those fittings showing the discoloration? Have any of them broken into pieces?

The Flare has totally failed, the inside pieces coming apart.
The Checkvalve has not broken apart. It was leaking from behind the collar, though.

Another Flare (not pictured) which just failed on my CO2 tank only has slight discoloration on the face.


RE: storing StarSan- I've had this for 3 years. So far so good! https://www.amazon.com/gp/product/B00BCH4WTA

 

[Bobby_M]

I've never seen that happen, and I'm sure I've occasionally (and unintentionally) left 1/2" thick-walled silicone brew hoses in a Starsan working solution for several weeks. No brittleness experienced either.

It doesn't seem to be isolated either. I had several customers over the years order 25 feet of silicone to replace stuff that's old and stained and think, "hey, I'll just get this soaking in some starsan" then forget about it for a couple weeks and then call me to ask why the tubing can be easily snapped in half. Then there's a brewery I won't name that ordered 20 brand new butterfly valves and called a month later to tell me that they are all defective. They were leaking like sieves on both the dump and racking ports on a 20 BBL fermenter. We later discovered that all the seats receded about 1/4" due to a well intentioned month long soak in starsan.

 

[Off Balance Brewing]

I only use duo tight so far for my spunding valve setup, but seems like my QD fitting starts to leak after 6 to 9 months. I guess from the starsan but they are the new versions. I tried adding more tubing to put less stress on the end of the fittings this time. We'll see if they last longer.

 

[Ayzala]

Here is what happened to my cutoff valve, soaked too long in Starsan, and I sprayed Starsan to check for leaks. There was discoloring on the collar.

 

[balrog]

Another thing Starsan does is make clear vinyl hoses opaque, they turn white, when soaked/immersed for extended time, say a week or so.
When hung up to dry they return to clear after a few days to a week.

I've started piping fermenting CO2 through keg to jar of tapwater. THe vinyl hose from the keg's gas out turns white in the water (CO2 bubbling through no doubt making it acidic). But it also returns to clear when dried.

 

[DuncB]

@dmnota
THe flares shouldn't be overtightened, definitely increases failure rate. Something about hand tight and then another quarter turn is only needed, think that was on a kegland or home brew network video.
@Ayzala That collar shows dried out starsan which will be a much lower pH than straight out of the bottle and the video suggest that is the issue, David Heath video I think.

Their is likely to be a chemical reaction between the phosphoric acid and the silicone in the tube to turn it into a more rigid form. I'll look up the chemical formula for some clues.

Maybe a quick dunk of the connectors with Ethyl alchohol is the answer to sanitise them, after all the outside doesn't need to be sterile at all and similarly dip the tube end before inserting in alchohol.

 

[dmnota]

THe flares shouldn't be overtightened, definitely increases failure rate. Something about hand tight and then another quarter turn is only needed, think that was on a kegland or home brew network video.

These failures are unrelated to over-tightening. The checkvalves don't have that as an option and the flares' failures are inside the collar, not on the screw fittings.
No doubt a different cleaning/sanitizing method than I used seems to be in order, though!

 

[DuncB]

I thought the first picture was of a flare fitting as I can see the flat parts for tightening. Agree the check valves and other connectors aren't tightened on.