C.L.S. Mistakes, Failures and Malfunctions...

[Gray Wolf]

Great post GratefulOne.

I'm a mechanic and over tightening is a common problem with new guys in the shop. I can imagine in this application with inexperienced people dealing with flammable things the tendency to wrench on those gaskets is high.

I tried quickly googling for a chart of Tri-clamp sizes/types and torque specs for different gaskets but didn't find one, where did you get the specs?

I bet a lot of people will be very surprised what the actual amount of proper torque feels like. Inch pounds ain't much. I'm surprised the clamps come with brass nuts to hold them together, especially on the larger sizes, but with small torque specs like that there shouldn't be much issue. Each time they're tightened down, even to the proper spec, threads are stretching and wearing a little bit. I'd hate to be doing a propane run with cracked threads on the brass nuts holding 10 or 12 inch tri clamps together. Anything you're tightening and loosing many times like the clamps, nuts, line fittings and all gaskets should be inspected and replaced often. This is a regular part of closed loop maintenance. I'm wagering many of the inexperienced out there are getting into this for the money, use some of it to stay safe.

Krunch, I hope you stay safe man. I have seen shop accidents and they are no joking matter. I would replace your gaskets and clamp hardware and dust off that torque wrench. Good idea on this thread, as it seems even experienced CLS operators can get complacent.

The nuts appear to be bronze and were no doubt chosen because they won't gall the stainless bolts like stainless nuts would. Depending on the bronze alloy, ultimate tensile strength can also be in the neighborhood of 100KSI, with a yield of around that of steel.

The amount of force possible over tightening, can exceed that, and even tightening beyond its ultimate yield, will eventually result in failure through creep.

 

[Gray Wolf]

44-50 inch pounds for viton & ptfe? as per GW on a earlier thread I believe . you can get (inch pounds) torque wrenches on ebay in 1/4 inch .

I did a search last night, looking for my sanitary clamp torque specifications and was not able to find the reference that I used for the 44 inch pounds, though the 50 inch pound number was wide spread for PTFE and I found some 30 inch inch pound specifications for Viton.

I will continue to look, but suspect it was a specific manufacturers specification, and specs between manufacturers seem to vary.

 

[Gray Wolf]

This would work better http://www.sears.com/neiko-03714-1-4-inch-200-inch-1/p-SPM1175669814

50 inch pounds is only 4.17 torque lbs! If I found the right calculator? http://www.kylesconverter.com/torque/inch--pounds-force-to-foot--pounds-force

Are we sure its only 44-50 inch pounds for viton & ptfe? Most torque wrenches only go down to 20lbs

Get an inch pound torque wrench.

 

[BrainChild]

Yeeesh, glad your okay krunch and great thread idea~

What do you think about the rust colored stuff in the tank GW? I've read about a few operators expericing this...it concerns me, as somebody putting together 1st cls. Could it be water in the butane that is rusting the inside of the tank? Have you seen other competents such as mt69 corroding?

 

[Gray Wolf]

Yeeesh, glad your okay krunch and great thread idea~

What do you think about the rust colored stuff in the tank GW? I've read about a few operators expericing this...it concerns me, as somebody putting together 1st cls. Could it be water in the butane that is rusting the inside of the tank? Have you seen other competents such as mt69 corroding?

The tanks are steel and standing water rusts them. It is a good idea to invert the tank and blow out the water daily, if using regularly.

No, my Mt-69 never corroded, but restricted flow and plugged easily with subzero butane.

PS: While distasteful, iron oxide isn't toxic and is insoluble in butane. If the water does reach the dip tube however, it will be injected rust and all into your column and meds, which will affect quality.

 

[Hydrosun]

The tanks are steel and standing water rusts them. It is a good idea to invert the tank and blow out the water daily, if using regularly.

No, my Mt-69 never corroded, but restricted flow and plugged easily with subzero butane.

PS: While distasteful, iron oxide isn't toxic and is insoluble in butane. If the water does reach the dip tube however, it will be injected rust and all into your column and meds, which will affect quality.

How does inverting the tank help? Am I to open the Vapor valve while upside down? This would shoot out high pressure liquid, and if the water is present it should be at the bottom of all liquid because water has specific gravity of 1.0 and butane .6. I understand this in theory, but opening a valve to have liquid rush out then quickly closing it, scares me.

I will test the potentially corroded MT69 today. The stainless IC69 is now and has always been rust free.

Another common failure I've experienced is thumb clamps that even when tightened 100% don't hold under pressure, thus oozing sticky oil out and effectively sealing small leaks (gluing them shut with product).

 

[Gray Wolf]

How does inverting the tank help? Am I to open the Vapor valve while upside down? This would shoot out high pressure liquid, and if the water is present it should be at the bottom of all liquid because water has specific gravity of 1.0 and butane .6. I understand this in theory, but opening a valve to have liquid rush out then quickly closing it, scares me.

Try it with a hose hooked to it and pointed somewhere you find more comfortable. You don't have to open the valve wide open, just crack it enough to vent any water present

I will test the potentially corroded MT69 today. The stainless IC69 is now and has always been rust free.

Another common failure I've experienced is thumb clamps that even when tightened 100% don't hold under pressure, thus oozing sticky oil out and effectively sealing small leaks (gluing them shut with product).

Yeah, and the problem is harder to contain as the size of the clamp increases. They usually leak about where the hinge pin(s) are.

 

[SkyHighLer]

The threads of the bolt in the pic that Krunch posted look like they have been run over by a bulldozer a few times. Typical Chinese quality control.

The two bolt clamps are sold with brass nuts to prevent galling. This happens with stainless nuts on stainless bolts where the nut will cold weld itself to the bolt. The problem is worse with poor quality fasteners. Unfortunately the fasteners sold with these clamps are usually crap...

Inspect your fasteners, if the nuts are a sloppy fit on the bolt replace them with new ones. Make sure there is a bit of lube on them.

Stainless bolts really are not needed in this application since the environment is dry and not subject to caustic washdown. Take the Chinese bolts and throw them in the nearest dumpster.
Buy some new plated steel bolts and nuts from your local industrial supplier. Grade 5 or better.

Lube them with grease or never-seize and you'll never need to worry about flying nuts again.

Also inspect the flanges (ferrules) on each connection. Place them on a flat surface and check that the gasket surface is flat. This issue gets worse with larger diameter parts as it is harder to keep larger ferrules from warping during welding. A lot of this stuff has little quality control so you need to be wary...

If the mating surfaces are warped you'll need more torque on the bolts to get a good seal.

RB

That is the correct answer imo, replace with high grade steel nuts and bolts. A little lube and they should last a long time.

 

[Kcar]

I wasn't there when it happened but I walked in and my buddies face was ashen,
the wall was covered with green sludge and, there was a 3 foot wide hole in the ceiling.
The grooves in the bolt had worn down from repeated use and the top of the column exploded off.

Are you guys dumping cold butane in a closed column and then
letting it warm up? Sounds like a good way to make a bomb...

 

[krunchbubble]

Threads backing out of another nut, inspect EVERYTHING....

 

[A6 Grower]

^^^ Thats crazy!! You've got some arms on you lol. I use a power drill set at 20(IDK what that is) that makes them squeak a little when they get tight and non of my 6 months old nuts look like this. They get removed and put back on at least 4 times a day 6 days a week. I wounder how tight your tightening them?

 

[Gray Wolf]

Threads backing out of another nut, inspect EVERYTHING....

https://www.icmag.com/ic/picture.php?albumid=52882&pictureid=1364523View Image

You are exceeding the yield of the material at about 60,200 psi and experiencing creep. Note the 13% elongation before reaching ultimate tensile.

http://elginfasteners.com/resources...icon-bronze-655-material-property-data-sheet/

I would replace all your nuts and start over with a torque wrench.

 

[krunchbubble]

You are exceeding the yield of the material at about 60,200 psi and experiencing creep. Note the 13% elongation before reaching ultimate tensile.

http://elginfasteners.com/resources...icon-bronze-655-material-property-data-sheet/

I would replace all your nuts and start over with a torque wrench.

Yes, all NEW nuts, gaskets and torque wrench next next....

 

[Roji]

Yes, hello. Roji here. I'll just pop into the lab for a quick extraction and take the rest of Sunday off. It'll be great, I said...

So I'm tearing down the system after recovery and what's this? A broken screen under the column? Odd... wait... wheres my filters?

OH SHIIIIIII-

NOOOOOOOOOOO!!!!!

That'll be a complete rebuild. Who needs days off anyways. Ill run the recovered weed/live resin goop pile tomorrow in my little column.
GOSH!

 

[Kcar]

Yes, all NEW nuts, gaskets and torque wrench next next....

We all know how you like to overdo everything, Krunch!
Quit over tightening! You won't believe it when that torque wrench
clicks!

 

[EpicExtracts]

Lube them with grease or never-seize and you'll never need to worry about flying nuts again.

A little lube and they should last a long time.

Another mechanic/engineering student here. Just my 2 cents, I prefer to clean the threads of my fasteners with Brakleen and make sure there is no lube on them. There is a difference between wet and dry torque specs.

 

[krunchbubble]

Another mechanic/engineering student here. Just my 2 cents, I prefer to clean the threads of my fasteners with Brakleen and make sure there is no lube on them. There is a difference between wet and dry torque specs.

Can you elaborate a bit? I was ready to go to home Depot and buy some never-seize...

 

[GratefulOne]

Anti-seize is a pain in the butt if you don't have to use it. It is great in a dirty environment but in a super clean workspace it will get on everything. It never dries and transfers to everything you touch. I would look for other solution if it were me.

The bronze nuts have a good built in ability to lube. You could switch out the stainless bolts to grade 5 or 8 carbon steel. That might help the nut last longer. Bronze is very touchy about over torquing. If you use a torque wrench it will last a good amount of time.

The other option I see is switch the nut and bolt to carbon steel and apply a tiny bit of grease to the threads. Wipe the grease off so only residue is left. This should work and stay fairly clean. You will need to apply new grease every few weeks depending on how much you use them.

 

[GratefulOne]

Remember the proper torque is very little force. The bronze nuts should last a decent number of uses. Most people using a large socket wrench will get around 50 foot pounds of torque when it "feels" tight.

We are talking 50 inch pound and a possible of 20 foot pounds for a max.

50 in lbs = 4.1 foot pounds. This is a TINY amount of force.

1 Foot pound = 1 pound of force applied 12 inches out from the center of the bolt or 2 lbs applied at 6”

When buying a torque wrench it is a really good idea to buy one with your working range in the middle of the wrenches ability. The ends of the wrenches range are not very accurate. This is especially true on the low end and low torques. Ex: if you need a 15 to 30 foot pound working range- buy a wrench with at least a 10 foot pound min setting (5 would be better).

 

[GratefulOne]

Now the other topic in this thread: the rusty tanks.

Stainless tanks would be a great option. The only ones I have found are very pricey. If we can find stainless options it seems it would be best.

Idea for discussion:
Painting the inside of the carbon steel tanks everyone is using now.

1: Take a new tank or properly cleaned and prepared used tank (assuming the tanks are bare steel inside). If the tank is not bare steel inside consult a paint or machine shop about acid or solvent cleaning the inside to bare metal.
2: Prep with solvent rinse.
3: Pour in paint and roll tank to thoroughly coat the inside.
4: Pour out extra paint and leave tank upside down while paint cures.
5: Clean threads and install valve.

Paint: My thought is to use two part epoxy which does not need air to cure. A coating which can handle hydrocarbons and be food grade should be fairly easy to spec. I can help with this and sourcing if anyone feels like trying it.

Ideas? Thoughts? Suggestions?