Trouble Maintaining Seal - Defective Glacier Tank Spool?

[Scalawag]

Hey Guys,

I posted this thread last week about my DIY Passive System.

I came to the fast conclusion that Eagle Stainless Steel bottle is probably not safe above more than 15 PSI, so I built up a recovery tank out of other spools from glacier tank. Long story short, I just got around to testing everything.

The recovery tank: Reaches a vac fast and holds it indefinitely. (Slight loss over time...)

The column (isolated from the collection pot): Reaches a vac fast and holds it indefinitely.

The collection pot: Will get down to -28hg, but not beyond - as soon as I kill the pump, even with the valve closed, the vac is lost. The only two gaskets are the concentric reducer I'm pulling the vac from, connected to a 1.5" ferrule on the lid of the 6" spool. Tri-clamp the lid to the spool. Viton gasket on the reducer, PTFE gasket on the spool.

Everything is clamped down hard - anymore so would be clearly over tightening.

Check this out:

I just noticed the lid has a warped spot. The gasket still sits in the groove pretty well and when it's all clamped down, I wouldn't think it would make a difference, but something is. Still, this lid clearly has a defect.

Any thoughts?

 

[Scalawag]

 

[IlDeuceIV]

have you tried it with brand new 6" gaskets? The PTFE gaskets require high pressure clamps if I am not mistaken, and I use VITON exclusively myself without issues.

 

[Rickys bong]

Your picture is at an odd angle, but I'd guess it's a problem with the flatness of either the lid or the flanges on the spool.

Get a piece of glass or a piece of flat stone tile to serve as a surface plate. If you have a granite counter, that will work too. Put the spool on the flat surface and check for gaps between the flange and the flat surface.

While holding the spool on a flat surface, take a piece of a business card and probe the edge of the flange (ferrule) around the periphery. If it slips in, see how much of a gap is there. You shouldn't see a gap much thicker than the thickness of two business cards...

The lid should be flat since it's machined from solid and not welded at the outside. It may be a manufacturing defect.
Welded 6" sanitary ferrules are quite prone to warpage and Chinese quality control isn't great.

Try the assembly with viton or buna seals as well.

RB

 

[Gray Wolf]

What RB said on using a straight edge or surface plate to determine flatness.

If you are using PTFE gaskets, I recommend that you switch to high pressure clamps at that location.

PTFE gaskets require 50 inch pounds of torque on the high pressure clamps, vis a vis 44 inch pounds with a Viton gasket. Hard to get a reliable seal with a hinged clamp and PTFE seals that size.

 

[Scalawag]

Better shot...

Definitely a defect. Sorry I called it a spool - I meant lid. Picking up an HP clamp just to troubleshoot.

 

[Scalawag]

Sorry about double posting. I wish I could edit!

As you can see below, the lid clearly warps in one section, while it sits perfectly flush the rest of the way around.

Would it be more likely that *this* is the cause for my lack of seal, rather than not exerting enough weight on the clamp?

 

[pharmco]

You need high pressure clamps for PTFE, has always been my experience.

 

[prune]

LOL - that lid is not warped, it is mis-machined and will not seal. That pic should enable the refund feature on your supplier app...

 

[HighStateToke]

Not unheard of, Glacier just sent out some replacement spools for two which had uneven faces. They seemed so surprised at the defect. Make them fix it.

 

[flatslabs]

I have had a few 6" spools from them (Glacier) where the inside was either not machined smoothly, or the welding of the ferrule warped it, making the sides nearly impossible to scrape with a flat tool.

 

[Scalawag]

Glacier will send out a replacement for me Priority - that was no problem.

To address the issue of probably needing a high pressure clamp anyway, I ordered a Dixon one on Amazon. Granted the lid still has that defect, but it sat perfectly round with the 6" spool.

But look at this... this is as far as the high pressure clamp will slide onto the lid and spool. On each side. It's like it's too small. I'm stumped. The single pin tri-clamp seems to fit fine! They're both "600" (6 inch) size, 6" spool, 6" lid...

 

[Scalawag]

I think the lid makes it not fit. See how easily it goes around the spool. Why would this be? The end cap reducer is supposed to be connected by a 6" clamp...

 

[prune]

I referenced back to your first photo and it appears that your lid is a "bit" too thick. You can check with a tape measure that the thickness of the outer edge of the cap is the same as the flange on the spool.

Thinking through the process it is amusing how many hands must have touched that piece without ever noticing even one of it's many unique qualities...

 

[desert fox]

I would say that lid is defective. Tri clamps wouldn't work if it were not for even pressure around the lid and base to make even pressure on the gasket. it relies on the bevel and the flat surface(where yours is defective) to apply pressure the gasket.

 

[Gray Wolf]

You need a new lid. It was made from a defective casting.

 

[Scalawag]

Got my replacement lid.

Weirdest thing though, the high pressure clamp still does not fit. It's like it wasn't thick enough to accommodate the thickness of the lid, gasket, and spool lip - so it wouldn't slide on.

The 6" single pin tri-clamp fits fine, however.

I used the 6" clamp with a PTFE gasket and the new lid, and the system got pulled down to -29+hg within seconds. Closed the valve and it held! Woohoo!

I let it sit overnight, and by morning (8+ hours later) I had lost a fair bit of vacuum.

I vac'ed out my recovery tank and left it as well, and by morning it had barely lost some vac, but still dropped a little.

Does this mean there's a leak? Every thread is heavily and neatly PTFE taped and each connection was wrenched into place, so I'm wondering what to do.

 

[flatslabs]

Those PTFE gaskets are sometimes hard to get tightened down with regular clamps over 1.5". If you have ever seen the Buna-N or Viton gaskets, they are much more pliable than the PTFE ones which are almost like hard plastic.

If I had to guess, your system is leaking on the 6" tri-clamp. Pressurize it up to 60 or 100psi and stick in some water look for bubbles

 

[Scalawag]

Yeah luckily I picked up a 6" Viton gasket with the new lid. I will try that tonight.

As for pressurizing the system... I don't have an air compressor, but I think I have an electric pump. Or shit, even a bike pump. Any way to adapt a pump to a 1/4" NPT connection? I have an extra male quick connect I could use on the end of a pump hose.

 

[Scalawag]

In an effort to keep updating since I know people lurk these threads...

Turns out I do have an air compressor - in the form of an electric inflator pump. So I went schraeder > 1/4" NPT and screwed an extra quick connect on the end to inject into the system. Put about 50 PSI in and did the soapy water test.

*Good News:* 6" Tri-clamp leak seems to be solved. New lid fits great.

*Bad News:* I discovered several leaks at threaded connections! And a leak at a high-pressure clamp connection which I didn't even think was possible.

This was surprising because I took great patience in neatly wrapping each connection, 6+ times in white PTFE tape. Then wrenched everything together with a lot of torque.

So I took apart all the leaky connections. Removed the white PTFE tape. I picked up heavy-duty black/gray PTFE tape from Home Depot that is SIGNIFICANTLY thicker and doesn't shred as easily.

Am I missing some essential thread taping technique? Obviously, always wrap clockwise, skip the bottom thread, etc. Did I need way more wraps with the white? How many should I be doing for the thicker tape?

In the end, it's likely going to be a taping issue vs. a wrenching issue right?