Gasket Discussion, Comparison PTFE vs Viton vs Polysteel vs Solid PTFE or Envelope ?

[AtomiCronic]

So what would the recommended ft. lbs. of torque for envelope gaskets be?
also when torquing down on my current setup with ptfe gaskets im not able to get even close to 50 ft. lbs. without starting to bend the bolts or the clamp. Is there something im doing wrong? i dont have any leaks currently with them but i know it's recommended to go to 50 ft. lbs.

 

[GratefulOne]

So what would the recommended ft. lbs. of torque for envelope gaskets be?
also when torquing down on my current setup with ptfe gaskets im not able to get even close to 50 ft. lbs. without starting to bend the bolts or the clamp. Is there something im doing wrong? i dont have any leaks currently with them but i know it's recommended to go to 50 ft. lbs.

For two bolt clamps:
"13MHP HIGH PRESSURE CLAMP

Note: Pressure ratings are based on the following parameters:
Nominal wall thickness (.065 1.5"-3", .083 4"), use of elastomer
type gasket*, weld ferrules, properly aligned and assembled
joints (nuts torqued to 20 ft. lb.) and the absence of water
hammer or shock loads."

http://gfistainless.com/GFI CATALOG/WCB SANITARY FITTINGS & CLAMPS.pdf

This also means no straight PTFE gaskets with two bolt clamps according to the manufacturers. PTFE cold flows and will start to leak without checking torque often. People have success running a cls with pure PTFE gaskets by checking torque right before each run. Officially though use elastomer gaskets Check out envelope gaskets.

Also note some clamp specs are INCH POUNDS and some are FOOT POUNDS. Some are 20 in lbs and some 20 ft lbs. Check the details! Good luck! Be safe!

 

[edwok]

Flanged or Unflanged for PTFE Envelope Gaskets? About to order some from here :http://www.austenitex.com/shop_by_category/Tri-Clamp-Gaskets-Envelope

 

[APK47]

Unflanged

 

[leftkidney]

hey guys I just read most of the posts and I have a few questions about the gaskets used and the torque pressure you use


1. I need to know the pressure to torque these clamps down to, do I need some sorta oil between the clamp and the body of the device to prevent the squeaking when its tightening?

2. how do I know the torque setting is correct on both sides do I need 2 wrenches at the same time and how do I know that the clamp being tight against the metal squeaking isnt just an artificial torque reading and when the thermal changes happen will the clamp loosen?

3. how do I know of the clamps and gaskets need replacing if they dont show any signs of wear are they still safe to use?


I have the sweet leaf 3-in-1 extractor I just picked up and I have 2 different gaskets with it, I asked them about this and they said it was just a mistake they changed over from PTFE to polysteel and a few PTFE got in the mix so they sent me new ones

I need 2 6 inch gaskets for the 2 large tanks and I want to get the best ones I can get however the 1 tank will probably not be opened much as it will have only butane in it and not needing to be cleaned so I was thinking about some sorta "crusher gasket" for that one, one that you crush as its tightened and you throw it away after that

the other ones I need some that have the metal screens in them for 2 places in my setup, I want those to be the best they can be

thanks for your help

 

[pictureguy]

From my minimal reading, I determined I needed to upgrade my single pin clamps to high pressure clamps in order to use ptfe gaskets. I can't even get single pins to torque proper when using ptfe gaskets. I always torque so hard my bolts bend slightly, I never go light, what's the point? I actually just upgraded to tuf - steel which seems so work amazing, I haven't had a single issue.

I have used epdm insert ptfe gaskets, I torqued them so hard they mashed to garbage. I should post the pic lol.

I always use my air compressor to blast my machine to 100 PSI to check for leaks before running with flammable gas. I only once had a leak from not to equine hard enough the first time, and that's when I noticed the epdm gasket was mashed, so I over torqued.

Torque them bolts

 

[pictureguy]

Tried to attach the pic of the gasket

 

[pictureguy]

I lost about 1 psi over the course of 4 hours, so I ran with it cause I needed to finish the job. I figured at 1 psi, the loss was so little so gradual it wouldn't matter. I couldn't even pick up butane on my sensor and the system was clearly leaking, incredibly slow

 

[Pangea]

Your ruining ptfe gaskets each run?! There is such a thing as over torquing the gaskets/clamps.

I run viton in the 40-50in/lb range and PTFE 60-70in/lbs. I use a 40 or 50 buck digital torque wrench adapter from princess auto(harbour freight type place)

You could easily strip your nuts causing a potential failure.

Torque them bolts... to their appropriate levels.

 

[pictureguy]

Nah just the epdm insert ones, I haven't managed to over torque a ptfe gasket. I mashed that gasket after 8 runs, and the 8th run was not a full seal as I said above

 

[pictureguy]

I supposed I could strip my bolts, but it would be obvious and noticeable and they are in nearly perfect condition

 

[Pangea]

I thought that would be expensive if it was the case, phew.

Noticeable amounts of brass shavings and dust come off of brass nuts each use, its a common concern of contamination for a cls.

No reason to guess, get a torque wrench to use the clamps and gaskets correctly as they were designed.

 

[MEMED]

so the epdm envelope gaskets are kosher? Last I checked it was leach city, no bueno? Eww? I gotta 'ford me some a those tuff steal jammers, they look nice.

 

[HG23]

I use the envelopes with viton for the insert, they work great. Too bad they don't have screened versions.

I'm seriously LOLing at that picture, guy.

"Torque them bolts"

lol

 

[BrainChild]

so the epdm envelope gaskets are kosher? Last I checked it was leach city, no bueno? Eww? I gotta 'ford me some a those tuff steal jammers, they look nice.

Whatever material that's inside the envelope (epdm in this case) isn't exposed to the solvent, it's only exposed on the outside. I'm using the PTFE/viton envelopes, they work really well.

 

[leftkidney]

I am only using the 2 bolt high pressure clamps as thats what came with my machine and I want to know the best gasket to use, I can torque the bolts down properly I have the torque wrench I just want to know the proper torque settings for these clamps - is it different for different clamps? should I "grease" the inner part of the clamps to prevent them from squeaking when I tighten them?

the cost isnt really a problem its going to be an expense that someone else will pay for they just want the best ones that will last the longest

currently I am using the polysteal for the 2 - 6" ones and PTFE for the others, but some are polysteal

the 4" with fine mesh is polysteal

the 4" with coarse and fine mesh is PTFE


I have the sweetleaf v3 3-in-1 and it has a few gaskets the ones it needs are

2 - 6"

2 - 4"

1 - 4" with metal mesh, coarse on one side and fine on the other

1 - 4" with fine metal mesh

1 - 3"

1 - 2" - on the clamp it says "Glacier Tanks 2" 13(MHP, or MNP, cant read properly)-200

7 - 1.5" - it says "1-1.5 HT20150521" on the clamp so I assume 1.5" clamp



thanks for your help

 

[Gray Wolf]

Whatever material that's inside the envelope (epdm in this case) isn't exposed to the solvent, it's only exposed on the outside. I'm using the PTFE/viton envelopes, they work really well.

The whole idea of the envelope gasket, is to have a highly chemical resistant outer coating, and a soft resilient inner material, so that the gasket has a lower effective durometer and is easier to seal.

I suggest a Viton or Buna n inner and PTFE outer, for the best of both worlds. Buna n works well for butane, just doesn't stand up to cleaning with alcohol.

 

[Old Gold]

Viton has been scrapped entirely, except for envelope gaskets.

 

[Old Gold]

This cinnamon scented bullshit is endless and hilarious. I thought it was just Viton, but PTFE too!! And this is coming from various sources (Open Source Steel, Xtractor Depot, even Rubberfab directly!) ...and none ever mentioning anything but pure PTFE. Scent should not be involved.

 

[Symbiotic AD]

Just our of curiosity is there any gasket that can withstand -40c temperatures, but still be malleable/flexible enough to work in a CLS... obviously chemically resistant to butane/propane.