My terpenator just exploed under about 73 PSI
- Thread starter pictureguy
- Start date
Another brass nut stripped.
20 ft lbs is bullshit...clearly FAR beyond my normal hand tightening that almost never had a seal issue.
Torque wrench set to 10 ft lbs and taking nuts out like nobody's business.
Gonna have to start at 50 in lbs and fill with compressed air and go from there I guess.
20 ft lbs is bullshit...clearly FAR beyond my normal hand tightening that almost never had a seal issue.
Torque wrench set to 10 ft lbs and taking nuts out like nobody's business.
Gonna have to start at 50 in lbs and fill with compressed air and go from there I guess.
Last edited:
Gray Wolf "They should be Silicone Bronze bolts, not brass. Silicone Bronze has a higher tensile than the stainless itself, and is self lubricating, but do wear out and require regular replacement."
https://www.icmag.com/ic/showpost.php?p=6928802&postcount=244
I do understand, but that does not solve the issue of the fact that bronze nuts are claimed to be torqued to 20 ft lbs by every manufacturer's standards. Brass, not bronze. Why make brass nuts if brass nuts aren't supposed to clamp down on a washer and bolt?
My question is not, "does bronze have greater tensile strength than brass?"
The only info I have found regarding brass vs bronze is GW's word frrom his mouth, and nothing else. While I'm aware of the general validity of his information, he is no all-knowing deity, and I haven't been able to find any information to explicate why brass is not acceptable, when manufacturers sell brass nuts with 20 ft lb torquing specification.
I also realized that I was missing the "click." It can be surprisingly subtle, and was overcasted by the sound of my nuts squeeking. Half of them went to 20 ft lbs OK, and half of them are squeeking and want to stop with my torque wrench set to 15 ft lbs, and I hadn't even reached a noticeable "click" in the wrench.
Maybe I missed it, but I read through more than a few threads, including the extensive discussion inthe CLS Failures thread. I came to no conclusion other than that "nuts to 20 ft lbs, PTFE to 50 in lbs, and Viton to 44 in lbs."
Have manufacturers just not been made fully aware that 20 ft lbs is shredding their brass nuts? Or they know, and expect you to just blow through them. Seems a bit ridiculous considering I stripped 3 brand new nuts out of the first 10.
My question is not, "does bronze have greater tensile strength than brass?"
The only info I have found regarding brass vs bronze is GW's word frrom his mouth, and nothing else. While I'm aware of the general validity of his information, he is no all-knowing deity, and I haven't been able to find any information to explicate why brass is not acceptable, when manufacturers sell brass nuts with 20 ft lb torquing specification.
I also realized that I was missing the "click." It can be surprisingly subtle, and was overcasted by the sound of my nuts squeeking. Half of them went to 20 ft lbs OK, and half of them are squeeking and want to stop with my torque wrench set to 15 ft lbs, and I hadn't even reached a noticeable "click" in the wrench.
Maybe I missed it, but I read through more than a few threads, including the extensive discussion inthe CLS Failures thread. I came to no conclusion other than that "nuts to 20 ft lbs, PTFE to 50 in lbs, and Viton to 44 in lbs."
Have manufacturers just not been made fully aware that 20 ft lbs is shredding their brass nuts? Or they know, and expect you to just blow through them. Seems a bit ridiculous considering I stripped 3 brand new nuts out of the first 10.
I use:
40 - 50inch pound for viton under 12"
50-60inch pound for viton 12"
I only use PTFE on my 4" material spool and have to torque it to 70inch pound or else it will leak.
I inject -30c to -40c solvent into room temp material and have had no issues with the viton.
I use double bolted high pressure clamps and the standard brass nuts, but plan on upgrading asap to the silicone bronze.
Anything over 10ft pound with a brass nut is asking for trouble imo. The amount of shavings after loosening at 70inch pound is concerning enough, let alone 15 - 20ft lbs.
I use a digital torque adapter, I think it cost around $50cad from a harbor freight type place, you can set it to beep or just keep an eye on the read out.
I hate to share my settings when they go against mfg recommendations, but it seems like if people where to follow the recommended we will end up with a serious injury from stripped nuts.
Seems odd to have such a big difference between single hinge to double bolt, 44inch lbs to 240inch lbs depending on the clamp?!
40 - 50inch pound for viton under 12"
50-60inch pound for viton 12"
I only use PTFE on my 4" material spool and have to torque it to 70inch pound or else it will leak.
I inject -30c to -40c solvent into room temp material and have had no issues with the viton.
I use double bolted high pressure clamps and the standard brass nuts, but plan on upgrading asap to the silicone bronze.
Anything over 10ft pound with a brass nut is asking for trouble imo. The amount of shavings after loosening at 70inch pound is concerning enough, let alone 15 - 20ft lbs.
I use a digital torque adapter, I think it cost around $50cad from a harbor freight type place, you can set it to beep or just keep an eye on the read out.
I hate to share my settings when they go against mfg recommendations, but it seems like if people where to follow the recommended we will end up with a serious injury from stripped nuts.
Seems odd to have such a big difference between single hinge to double bolt, 44inch lbs to 240inch lbs depending on the clamp?!
Double nuts for safety folks! lol.... I most of the time don't torque my nuts but just watch my viton seal, once it expands a little bit out i go just a tad more tight , like 1 turn, till its got that snug feel, then call it good. I think it helps if you've torqued nuts down a bunch, its easy to guess once you get the feel of that torque. I then Toss my second nut on while its all vacuuming down and then off to the races. Usually when i check the torque while doing this im pretty close to 50 in lbs.
My thoughts exactly.
I'm glad you share your results, as that's the only way we can promote a full understanding rather than something like teacher-handed-me-a-textbook-and-told-me-to-memorize.
I was planning on using only Viton where gasket is not in direct contact with subzero butane.
I was able to do two test runs. No leaks, no issues. I torqued my 6" column clamps till I got squeeking...probably between 10-15 ft lbs.
The 2" clamps (reducer, ball valve) clicked nicely at 20 ft lbs.
My collection pot is dealing with a single hinge and Viton lol.
I'll rock out a fully-loaded run in a couple hours.
I'm well aware haha. I've seen myself bend them through in a week of use. Everywhere else I have backup nuts.
A typical brass has around half the tensile strength of silicon bronze.
It just blows me away that all specs say 20 ft lbs, and half of the nuts don't want anything to with it. No need to belabor the point, I got it. Thanks, guys!
I'll also say that I had no issues using a 2" Viton gasket with mesh and whatman filter paper inserts in between my column reducer and soak valve, so it certainly saw contact with subzero solvent. My hesitation to do so stems from my ability to create a seal with slightly blown gaskets by freezing the Viton for 10 minutes. It definitely shrinks down.
I'll also say that I had no issues using a 2" Viton gasket with mesh and whatman filter paper inserts in between my column reducer and soak valve, so it certainly saw contact with subzero solvent. My hesitation to do so stems from my ability to create a seal with slightly blown gaskets by freezing the Viton for 10 minutes. It definitely shrinks down.
Last edited:
Simple solution, use grade 8 hardware with nylock nuts and do away with the shitty lock washers that aren't good for anything except to shred those POS brass nuts so you have shavings everywhere.
Best practice is to have the shank unthreaded except where you need the nut to go.
Best practice is to have the shank unthreaded except where you need the nut to go.
Time to bring back a thread of reasonable importance, I think.
While I like the nylock nuts xbonger presented, I don't think it addresses the real issue.
First off, what we should be measuring is clamping force, not torque. The clamping force, when the nut is fastened on, creates an opposite/equal force that stretches the bolt. This stretching is what we should be concerned with. Torque just measures the rotationary force applied on the nut.
Here is where the issue lies.
You could have a series of identically manufactured bolts. The same torque applied on all of them would not necessarily create the same clamping force (or cause the bolt shaft to stretch under the same tension).
I saw a video demonstration of this, using identical steel bolts/nuts used on many construction job sites. The only variable was the condition of the hardware. The first bolt - lubricated; the second bolt - dry (no lubricant); and the third - rusted after several days of being exposed to the on-site elements.
All three groups saw the same torquing, while a target clamping force of 3900 kips was sought after.
To my surprise, simply by having dry bolts/nuts, the torquing specs rendered almost as useless as using completely rusty bolts. I don't believe the dry bolts exceeded a true clamping force of 2300 kips, and the rusty bolts saw as low as 1200 kips, but the difference was relatively insignificant, considering both were wayyy under proper clamping force created. And I believe just 2 of the 3 lubricated bolts measured above the minimum clamping force (4100 kips required for a good seal if 3900 is the minimum).
On that note, perhaps using something like Direct Torque Indicator bolts or washers could help us determine proper clamping force.
Food fo' thot
So I say regardless of nut material (brass, silicone bronze, stainless steel).....lubricate that shit!! Otherwise, your torque wrench is fighting your coefficient of friction where the threads are at, and probably clicking a little too early.
While I like the nylock nuts xbonger presented, I don't think it addresses the real issue.
First off, what we should be measuring is clamping force, not torque. The clamping force, when the nut is fastened on, creates an opposite/equal force that stretches the bolt. This stretching is what we should be concerned with. Torque just measures the rotationary force applied on the nut.
Here is where the issue lies.
You could have a series of identically manufactured bolts. The same torque applied on all of them would not necessarily create the same clamping force (or cause the bolt shaft to stretch under the same tension).
I saw a video demonstration of this, using identical steel bolts/nuts used on many construction job sites. The only variable was the condition of the hardware. The first bolt - lubricated; the second bolt - dry (no lubricant); and the third - rusted after several days of being exposed to the on-site elements.
All three groups saw the same torquing, while a target clamping force of 3900 kips was sought after.
To my surprise, simply by having dry bolts/nuts, the torquing specs rendered almost as useless as using completely rusty bolts. I don't believe the dry bolts exceeded a true clamping force of 2300 kips, and the rusty bolts saw as low as 1200 kips, but the difference was relatively insignificant, considering both were wayyy under proper clamping force created. And I believe just 2 of the 3 lubricated bolts measured above the minimum clamping force (4100 kips required for a good seal if 3900 is the minimum).
On that note, perhaps using something like Direct Torque Indicator bolts or washers could help us determine proper clamping force.
Food fo' thot
So I say regardless of nut material (brass, silicone bronze, stainless steel).....lubricate that shit!! Otherwise, your torque wrench is fighting your coefficient of friction where the threads are at, and probably clicking a little too early.
Measuring bolt stretch is applicable to bolted metal to metal joints where the members being fastened are solid and the bolt can actually undergo elastic deformation.
That isn't the case here. The bolts won't get enough torque on them to undergo any measureable stretch.
Another variable in using bolt torque to determine gasket compression is the tapered surfaces on the ferrules and clamps. These are rarely lubricated and there is a massive variation in surface finish quality on the ferrules and clamps when comparing high quality Tri-Clover clamps and cheap shit clamps.
The bolts compress the gasket through a wedge mechanism that has a huge amount of variation in it is what I'm getting at.
Using a torque wrench to determine if a joint is sealed properly is ok for plumbing carrying milk but I don't think it's reliable enough for flammable liquids...
Ideally what you want to measure is clamping force on the gasket. You don't get an accurate indication of that from bolt torque.
If... If all ferrules had standard surface finish and the clamps were made with accurate matching tapers torque figures could give reliable results but that ain't the case.
Just personal opinion, but if you are wanting a consistent gasket seal measuring gasket compression would be a much better indicator.
Your gasket will have a fairly reliable spring constant.
By that I mean it will compress a given amount for a given load whether it is new or used (within reason)
Taking a caliper measurement with a uncompressed gasket (bolts just snug) and compressed would give a direct indication of how much force has been applied to the seal you are concerned with.
RB
That isn't the case here. The bolts won't get enough torque on them to undergo any measureable stretch.
Another variable in using bolt torque to determine gasket compression is the tapered surfaces on the ferrules and clamps. These are rarely lubricated and there is a massive variation in surface finish quality on the ferrules and clamps when comparing high quality Tri-Clover clamps and cheap shit clamps.
The bolts compress the gasket through a wedge mechanism that has a huge amount of variation in it is what I'm getting at.
Using a torque wrench to determine if a joint is sealed properly is ok for plumbing carrying milk but I don't think it's reliable enough for flammable liquids...
Ideally what you want to measure is clamping force on the gasket. You don't get an accurate indication of that from bolt torque.
If... If all ferrules had standard surface finish and the clamps were made with accurate matching tapers torque figures could give reliable results but that ain't the case.
Just personal opinion, but if you are wanting a consistent gasket seal measuring gasket compression would be a much better indicator.
Your gasket will have a fairly reliable spring constant.
By that I mean it will compress a given amount for a given load whether it is new or used (within reason)
Taking a caliper measurement with a uncompressed gasket (bolts just snug) and compressed would give a direct indication of how much force has been applied to the seal you are concerned with.
RB
I actually haven't torqued my nuts down for a while now. I dont recommend it, unless you get very familiar with how tight proper torque is. I just got the feel of about the correct torque and just guess and mainly just watch my seal. Once it starts to bulge out a little i stop. Ive never had a leak when doing this. Ive had a leak on my bottom seal of the collection pot by using torque alone. Messy mistake, now i just keep and seals and triclamp end nice and clean so like RB said, my seals will provide a consistent "spring" or bulge as i call it lol. I replace my seals ever 3 months also.
RckyMtRdnk
Active member
Thanks to everybody here for caring and sharing about being safe with our tools.
Much appreciated
Much appreciated
Yeah, each individual gasket should be checked and yes, I can tell when my gaskets are nearing the end of their lives, and need replacement, especially PTFE.
I still use the torque wrench for a quick and general tightening, but agree that experience and hands-on trial and testing with the machine is of much greater use than any manufacturer's specs.
I do want to emphasize the affect of corrosion or non-lubricated hardware. I'll admit, I've been using and replacing frequent brass nuts, and ordered some silicone bronze. But silicone bronze will still corrode against stainless steel, so would still need replacing over time, even though they show greater tensile strength.
Check out this table:
For harsh environments (salt water, high humidity), I believe a voltage difference of less than 0.1V is ideal. For a controlled environment, I believe 0.25V difference is a maximum recommendation.
Materials attack from the bottom of the list, up. Silicone bronze is borderline for reasonably harsh environments, so I'd say it's a great choice for indoor use, but would go all stainless if I were by the beach.
I still use the torque wrench for a quick and general tightening, but agree that experience and hands-on trial and testing with the machine is of much greater use than any manufacturer's specs.
I do want to emphasize the affect of corrosion or non-lubricated hardware. I'll admit, I've been using and replacing frequent brass nuts, and ordered some silicone bronze. But silicone bronze will still corrode against stainless steel, so would still need replacing over time, even though they show greater tensile strength.
Check out this table:
For harsh environments (salt water, high humidity), I believe a voltage difference of less than 0.1V is ideal. For a controlled environment, I believe 0.25V difference is a maximum recommendation.
Materials attack from the bottom of the list, up. Silicone bronze is borderline for reasonably harsh environments, so I'd say it's a great choice for indoor use, but would go all stainless if I were by the beach.
Attachments
