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Black/Galv pipe for hydraulics...

Started by Ljohnsaw, April 12, 2015, 01:20:54 PM

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Ljohnsaw

I'm working on my Davis Little Monster backhoe (adding the thumb) and doing some plumbing for the hydraulics.  I was planning on putting a couple of 3/8" street els on the ram to help route the flex hoses.  Went to Ace Hardware and noticed that on all the fittings, they are rated for only 300 psi :o  Back at the ranch, my old Case tractor had lots of "plumbing" fittings with no problems.  Any reason not to use normal pipe fittings for 3,000 psi hydraulics?  Any difference (issues) using galvi vs. black?

I noticed on Arnold113's sawmill he had what looks like normal plumbing fittings.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Papa1stuff

I have a small grader that has a couple black pipe fittings,I was told black is better for hydraulics!
1987 PB Grader with forks added to bucket
2--2008 455 Rancher Husky
WM CBN Sharpener & Setter

Den-Den

"Ordinary" plumbing pipe is schedule 40 and will not hold 3000 psi (at least not for many cycles).  Fixing the split piping and fittings (not to mention getting sprayed with hydraulic fluid) will be a PITA if you use hardware store fittings.
You may think that you can or may think you can't; either way, you are right.

InterMechanico

Den-Den is correct. You must use seamless tubing, wall thickness dependent on pressure and diameter of tubing.

http://www.hydraulic-supply.com/html/productline/prodcat/hydraulic-tubing.htm
Approaching every job with a mind for completing it :)

Stihl MS290 , MS661 C-M , Glanberg Alaskan MkIII Mill , Home Made Edging Jig , All the safety gear

pineywoods

Ignorance is bliss..I have added hydraulics to 3 manual sawmills and not knowing any better, I used black iron pipe and fittings on all 3. Not a problem after several years. Two of those mills are run by hired hands who tend to break stuff..Points to consider...Stay away from chineese fittings.. Avoid galvanized fittings..flakes of zink will mess up o-rings and seals. Install a good filter.That 300psi rating is working pressure, not burst pressure. Mine is an open center system, closed center system would likely be a different situation.
1995 Wood Mizer LT 40, Liquid cooled kawasaki,homebuilt hydraulics. Homebuilt solar dry kiln.  Woodmaster 718 planner, Kubota M4700 with homemade forks and winch, stihl  028, 029, Ms390
100k bd ft club.Charter member of The Grumpy old Men

InterMechanico

With respect, I disagree with you, Piney. If the working pressure is 300 psi, the burst pressure will be somewhere near 900 psi, which is considered low pressure. Open center systems do not limit system pressure by design. They are capable of up to 6000 psi depending on application. A closed center  system is used to increase the efficiency of the system by stopping oil flow when there is no demand for actuator movement.

IF you were considering the use of grey iron pipe and fittings in the return circuit, between the control valve and the reservoir, that would probably be okay. However, every circuit between the hydraulic pump and the control valve, including the circuits to all actuators, must be considered to be subject to the highest possible system pressure; in other words, the pressure at which your relief valve opens.

Hydraulic tubing is not expensive, but usually needs to be welded together.

Lastly, for the benefit of your health, I should tell you that oil injected under the skin (over 1000 psi, sometimes lower) causes immediate necrosis of tissue, and requires the removal of all affected tissue, often resulting in amputation.

Gross, I know, but everyone should know this.

Julian
Approaching every job with a mind for completing it :)

Stihl MS290 , MS661 C-M , Glanberg Alaskan MkIII Mill , Home Made Edging Jig , All the safety gear

stihltoomany

Lots of hydraulics are run in sch 40 pipe and fittings. That is not supposed to work. I have seen factory stuff that way. It is not rated for hyd pressures. Sch 80 pipe and fittings is the minimum that is needed. But you will find fittings that are designed for hyd pressures as cheap or cheaper than pipe fittings. Hyd hoses are not a bad way to go, not as pretty or professional looking but fully functional. Most farm and home type stores and equipment dealers carry some of these hyd fittings. Hyd tubing has to be flared, silver brazed or welded so that is not always a simple solution. Special fittings are available that don't require this but they are very pricey.  So even though you see pipe hyd systems, they are not recommended. In the industrial world they are totally unacceptable. Make your own choice. Good luck!!

Way too many saws, mostly STIHL
Bobcat S650, Bobcat 331 excavator Bobcat A770
and other dirt toys
Looking for hyd bandsaw mill, Timberking used maybe? NOT anymore!
WoodMizer LT40 super

Den-Den

For my own use, I would be comfortable with schedule 80 pipe and forged fittings.  The cast fittings fail at unpredictable pressures.  Many hydraulic systems will never see 3000 psi but why take the chance.
You may think that you can or may think you can't; either way, you are right.

dean herring

Don't use galvanized or sch. 40
Use sch.80 pipe seamless and at least 2000# fittings
Failure is not an option  3D Lumber

Ljohnsaw

Thanks for all the comments!  I was sort of thinking that galvi would be bad (flaking).  I have a small ram (2") that I will be using to make a thumb on my backhoe.  I wanted a sharp turn on the ram to route the hoses back tight with the hoe arms.  The ram has 3/8" fitting and wouldn't you know, the big box and small hardware stores don't sell 3/8" black street els  >:(  Also, I was planning on putting a 10" extension on the "bottom" fitting to bring the plumbing back up even with the "top" fitting.  I bought 108" hoses to go from the ram all the way back to the valve rather than have two sets of short hoses and a set of hard lines.  Yeah, it won't look as professional, but it was really cheap and this is a prototype of sorts.

My backhoe has four relief valves: 2000# on the main bank to protect everything, 3000# each on the main boom and dipper stick and 2000# on the swing cylinders (actually two in there - for each direction).

I have to wait for some grade 8 all-thread to come in so I guess I'll be visiting my local hydraulic store or ordering off of Amazon or eBay.
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

21incher

I have had good luck ordering my hydraulic fittings from Surplus Center online, they have a great selection. I also like to use the permatex thread compound that is rated for hydraulics.
Hudson HFE-21 on a custom trailer, Deere 4100, Kubota BX 2360, Echo CS590 & CS310, home built wood splitter, home built log arch, a logrite cant hook and a bread machine. And a Kubota Sidekick with a Defective Subaru motor.

03westernstar

We have 14 Tandem axle Freightliner snow plow trucks that push and spread the central VA Richmond area and running Pto Pumps off the transmission with 14' salt spreader boxes they all have Hardware store galvanized ''plumbing pipe'' fittings $43 worth of fittings on each truck and haven't had a minuets trouble out of any of them in two years and they run an average of 2700PSI for 6-48hrs straight while pushing snow and spreading salt.

Not saying that the ''plumbing pipe'' fittings will work for everyone just saying we have had very good luck with them.But none of these fittings are near an operator/driver so if one were to bust/break no one should be injured

InterMechanico

Quote from: ljohnsaw on April 13, 2015, 12:29:53 AM
Thanks for all the comments!  I was sort of thinking that galvi would be bad (flaking).  I have a small ram (2") that I will be using to make a thumb on my backhoe.  I wanted a sharp turn on the ram to route the hoses back tight with the hoe arms.  The ram has 3/8" fitting and wouldn't you know, the big box and small hardware stores don't sell 3/8" black street els  >:(  Also, I was planning on putting a 10" extension on the "bottom" fitting to bring the plumbing back up even with the "top" fitting.  I bought 108" hoses to go from the ram all the way back to the valve rather than have two sets of short hoses and a set of hard lines.  Yeah, it won't look as professional, but it was really cheap and this is a prototype of sorts.

My backhoe has four relief valves: 2000# on the main bank to protect everything, 3000# each on the main boom and dipper stick and 2000# on the swing cylinders (actually two in there - for each direction).

I have to wait for some grade 8 all-thread to come in so I guess I'll be visiting my local hydraulic store or ordering off of Amazon or eBay.

Good call, ljohnsaw. There's no better feeling than completing a job, and knowing it has been done right and will last a long time.
Approaching every job with a mind for completing it :)

Stihl MS290 , MS661 C-M , Glanberg Alaskan MkIII Mill , Home Made Edging Jig , All the safety gear

InterMechanico

Quote from: 03westernstar on April 13, 2015, 11:00:48 PM
We have 14 Tandem axle Freightliner snow plow trucks that push and spread the central VA Richmond area and running Pto Pumps off the transmission with 14' salt spreader boxes they all have Hardware store galvanized ''plumbing pipe'' fittings $43 worth of fittings on each truck and haven't had a minuets trouble out of any of them in two years and they run an average of 2700PSI for 6-48hrs straight while pushing snow and spreading salt.

Not saying that the ''plumbing pipe'' fittings will work for everyone just saying we have had very good luck with them.But none of these fittings are near an operator/driver so if one were to bust/break no one should be injured

I suspect that the grey iron fittings are located between the reservoir and the pump, operating at less than 1 bar. If they are in a high pressure circuit, then the system was designed or (more likely) built incorrectly and doesn't meet any safety or performance standards whatsoever.

It is certainly possible to build a hydraulic system using grey iron fittings and tubing, just like you can build a roof out of toilet paper; it'll work until it doesn't. I would never do it, but I know better I guess.

Approaching every job with a mind for completing it :)

Stihl MS290 , MS661 C-M , Glanberg Alaskan MkIII Mill , Home Made Edging Jig , All the safety gear

InterMechanico

Sorry, not trying to be mean or condescending, which is how my last post looks.... :-\
Approaching every job with a mind for completing it :)

Stihl MS290 , MS661 C-M , Glanberg Alaskan MkIII Mill , Home Made Edging Jig , All the safety gear

bandmiller2

Common black maliable pipe fittings are not supposed to stand up to hydraulic pressure but no one has told them that. I have had many machines that came that way and I have replaced  and built with pipe fittings. Most of my hydraulics maxed out at 1500 psi. Only one I've seen blow was a brass 1/2" ell. I would recomend anyone building spend a little extra and get the heavy ones. Frank C.
A man armed with common sense is packing a big piece

Ljohnsaw

Had a pleasant surprise.  I was at a plumbing shop and they had black pipe fitting, but no hydraulics.  Black street els the were $4.something each!  Went to a hydraulic shop down the street.  Almost walked out because it looked like a normal office inside - just desks.  Guy came around the cubical walls and asked what I needed.  He said hold on and ran to the back.  Came out with 4 Parker hydraulic street els (3/8").  Totaled it up and all four were $7.58 out the door!  Cheaper than eBay and no shipping, either.  I wanted to run a length of solid pipe up the side of the ram but I guess I'll just need to run the hose and use a big hose clamp to secure it in place.

Pays to do it right (old saying), in this case, it was cheaper, too!
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

jamesamd

All that is gold does not glitter,not all those that wander are lost.....

jamesamd

All that is gold does not glitter,not all those that wander are lost.....

Ljohnsaw

Quote from: jamesamd on April 14, 2015, 09:18:59 PM
You life
??

The attachment is very interesting.  The pressure rating drops off from 2000 to 500 psi with a 350° temperature rise!  Scary!
John Sawicky

Just North-East of Sacramento...

SkyTrak 9038, Ford 545D FEL, Davis Little Monster backhoe, Case 16+4 Trencher, Home Built 42" capacity/36" cut Bandmill up to 54' long - using it all to build a timber frame cabin.

Warped

Had an old hoe and never popped an iron line or fitting, those dang dry rotted hoses popped quite often :o
Good with the rough stuff and rough with the good stuff

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