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 Post subject: Soft packings-
PostPosted: Thu Aug 04, 2011 2:49 pm 

Joined: Sun Aug 22, 2004 11:06 am
Posts: 508
Location: NE PA
What are you using to pack your valves, air compressors, stokers, water pumps and other appliances with. How often do you need to renew your packings? Do you use the Chevron(V style) or square style off the roll and cut your own? Which is a better value? What materials are your packings made from? What are your packings lubricated (graphite, teflon, etc.) with from the factory? Can you recommend your supplier, does he carry stock? Are your reciprocating rods chromed? Just an informal survey, maybe some of us can learn from others without having to go a more expensive(trial & error) way.
Thanks for your input.
Mike Tillger


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 4:00 pm 

Joined: Sun Aug 22, 2004 8:35 pm
Posts: 374
Mike,

If you would like to contact us off line, we have the packing material in stock. We use a graphite rope type material that is as close to the original material as one can get. Yes, there are many who have hard chrome piston rods but, keep in mind, there is a MAJOR difference between decorative chrome and HARD CHROME. I would be happy to explain further.

I can be contacted at:

info@wrrc.us

Thank you,

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John E. Rimmasch
Wasatch Railroad Contractors


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 4:08 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5934
Location: southeastern USA
I've had good experience with Garlock braided graphited teflon rope packings with a square cross section - the gray stuff. I cut the packing to make one complete ring each, and dip it in the appripriate oil (steam oil, air oil, etc) before installing and repeating, staggering joints, as necessary until the gland is full.

On worn or rough rods, I've made it last longer by making a die to form it in oil in a press under medium light pressure into a ring to fit the rod. each ring is then already round before installing, makes it take up immediately and need less compression soon after installing.

Others probably have great ideas about what tricks and products worked for them.

dave

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Corollary: "He who does is doomed to watch those who don't repeat it anyway."


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 4:23 pm 

Joined: Sun Aug 22, 2004 11:06 am
Posts: 508
Location: NE PA
John,
I started this thread with the intent of educating myself and others about what works and what doen't work. Perhaps you would care to elaborate on this forum about the differences in chromes used in plating so everyone can learn at the same time. I will list what we use very successfully when I get back to the shop next week. I for one would not object to anyone listing the products they sell on the forum, to me that would be a whole lot more useful than the multitude of railfan posts. I come to this forum for useful information to share and use in preservation.

All
Perhaps as Dave pointed out, we can add techniques used to fit up packing as part of the discussion.

Thanks John & Dave for your replies.
Mike Tillger


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 6:21 pm 

Joined: Sun Aug 22, 2004 8:35 pm
Posts: 374
Mike,

Sure thing;

Decorative chroming is normally done by a dip process. Say you have a bumper for your car and you need it chromed. You take it the chrome shop, they will either strip it by use of a chemical or they will sand blast it, in order to clean it. Then, (and please keep in mind technology changes as do process, this is just a fast over view of the basics...right?) The chrome shop may or may not "pickle" the item. Pickling has to do with applying an agent that will adhere to the base metal and also allow the chrome to stick. Once that is done, the item is dipped in a solution and the chrome is applied. Decorative chrome is actually just a very thin layer of metal applied to the surface for looks.

Hard Chrome on the other hand is designed to add a layer of hard material that will withstand pressure and will not flake off. As I understand things, the process of applying hard chrome is not identical to that of decorative chrome. Hard chroming shops are few and far between. We have a hard chrome shop that we use if you need more information.

Hard Chroming has been done by a number of operations as it aids in keeping items that sit in packings from pitting. You will notice that many old and un-rebuilt air compressors have pitted piston rods as a result of sitting behind the packing submerged in water and oil. Hard Chroming has been found to prevent this. Hydrolic pistons are Hard Chromed.

You asked about installation practices on packing. There are as many process as there are people who have done it. In short, here are the two most used processes.

With small items, such as smaller pistons and or valve stems, you will see people cut one band of packing as a single ring and install rings of packing, usually three or four deep (depending on how deep the gland is) and then putting the gland nut, or ring on and then tightening from there.

On bigger items, it is not uncommon to see people install one continuous piece of packing and wrapping it around the piston rod multiple times and then running down the packing nut from there. The trick is: How much space do you have, what is easiest, what will last longest and how big is the packing.

NOTE: Most big steam locomotives do NOT have a rope type packing in the valve or the main piston of the drive train. This is generally a Paxton-Mitchell or other type of segmented packing unit held together with springs and other keepers so that it is allowed to move with the piston rod. If you are trying to pack a large locomotive piston rod with rope packing.....I say, best of luck. Though we do it on small locomotives, it does not prove well on large locomotives.

Again, this is the general and short answer, we could go even deeper if you wish, we shall see where this takes us.

Kindly yours,

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John E. Rimmasch
Wasatch Railroad Contractors


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 8:04 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5934
Location: southeastern USA
Inspection of rods for cracking may be difficult if chromed. Theoretically the chrome sticks so well the crack will also crack the chrome, but..........not critical on a compressor rod or valve rod, but I'd be careful about chroming or coating a piston rod with anything opaque.

dave

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Santayana: "He who does not remember the past is condemned to repeat it."
Corollary: "He who does is doomed to watch those who don't repeat it anyway."


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 10:35 pm 

Joined: Sun Aug 22, 2004 8:28 am
Posts: 2555
Location: Salt Lake City, Utah
What can be done to remediate pitting on piston rods in an air compressor, where the pitting has come from age and/or neglect? Can you build it up with welding, and then have it hard chromed? How well does the hard chrome adhere to the new filler material?

With regard to rods and plating, I thought the N&W used a plating on some of their locomotive's rods, but can't remember the material, though I know it wasn't chrome.

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David M. Wilkins
Terrible Railfan
Salt Lake City, Utah


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 11:06 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5934
Location: southeastern USA
Depends. You can take a skim off the rod and reduce the diameter a bit, but not too much. You will then need to make some gland alterations to capture the packing such that it won't extrude with the rod into the bores. A new rod will be necessary if the pits are deep, but some people have managed to get by with metallizing the old one and remachining it. Maybe if you are having fun around the yard a few days a year, but for scheduled service..........I like reliability.

dave

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Santayana: "He who does not remember the past is condemned to repeat it."
Corollary: "He who does is doomed to watch those who don't repeat it anyway."


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 11:07 pm 

Joined: Sun Aug 22, 2004 10:56 am
Posts: 1330
Location: Roanoke Va.
Speak to this Mr. Sobczynski, we were talking about it while looking at 611, 1118 ,1151 & 1218 on Sunday

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Gary


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 Post subject: Re: Soft packings-
PostPosted: Thu Aug 04, 2011 11:28 pm 

Joined: Sun Aug 22, 2004 8:28 am
Posts: 2555
Location: Salt Lake City, Utah
Dave wrote:
Depends. You can take a skim off the rod and reduce the diameter a bit, but not too much. You will then need to make some gland alterations to capture the packing such that it won't extrude with the rod into the bores. A new rod will be necessary if the pits are deep, but some people have managed to get by with metallizing the old one and remachining it. Maybe if you are having fun around the yard a few days a year, but for scheduled service..........I like reliability.

dave


Thanks. This whole thread reminded me of the fact that when I was with KRM we ran into a similar issue with L&N 152s air compressor. I think we re-metalized the rod on the low pressure side of the pump, and it lasted for only a little while. I believe we eventually went with a new rod. Of course, I was a lowly grunt and was just observing, between helping take the pump apart, needle chipping various parts of the locomotive, etc.

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David M. Wilkins
Terrible Railfan
Salt Lake City, Utah


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 Post subject: hard chrome?
PostPosted: Fri Aug 05, 2011 12:56 am 

Joined: Mon Aug 23, 2004 2:09 pm
Posts: 386
Location: Los Angeles
The process of decorative chrome and hard chrome deposition is almost identicle. Both are applied using an electric current, DC if I remember correctly, and both are done in a chemical bath. The major difference though would be the material to be plated and this is supplied by an annode. In decorative chrome plating the annode is just hung in the bath as well as the bumper or other decorative piece. In hard chrome the annode is most likely shaped to fit the shape of the recieving piece. In hard chrome this is a more exacting process. In either process any dipping in baths is for cleaning and pickling. No metal is added or deposited at this time. One caveat though. Plastics can be plated by using an electroless copper which is just a chemical dip. Then the next metal, chrome, copper or whatever is electrically plated. Decorative chrome deposition is a relatively fast process as the layer of copper and then chrome is fairly thin. In hard chrome the plating process deposits around .001 an hour. So therefore if you are adding .040 to your work piece then that is 40 hours. There will be some grinding and polishing to finish as well. Now someone mentioned that another process was used other than hard chrome. I don't know specifically what that particular company did however most of the pump repair shops in Los Angeles recommend for reciprocating rods tungsten carbide. Reason is that the TC coating will hold lubrication where HC does not. The TC coating is longer wearing as well.


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 Post subject: Re: Soft packings-
PostPosted: Fri Aug 05, 2011 1:03 am 

Joined: Mon Aug 23, 2004 2:09 pm
Posts: 386
Location: Los Angeles
Dave,
Some type of ultrasonic inspection should always be done prior to plating. Your correct, you can cover the bad stuff with the plating.

[quote="Dave"]Inspection of rods for cracking may be difficult if chromed. Theoretically the chrome sticks so well the crack will also crack the chrome, but..........not critical on a compressor rod or valve rod, but I'd be careful about chroming or coating a piston rod with anything opaque.

dave[/quote]


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 Post subject: Re: Soft packings-
PostPosted: Fri Aug 05, 2011 1:24 am 

Joined: Wed Aug 25, 2004 11:16 am
Posts: 737
The current type used in platting is DC. In the copper refinnery I once worked in we monitored metal concentration in solution, acid levels, horse glue levels (for a smooth surface), and montiored amperage levels as the amperage density per square foot was of particular interest. Dave and BobK is absolutely right that plating can hide defects particularly from surface penitrating defect finders.

Robby Peartree


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 Post subject: Re: Soft packings-
PostPosted: Sat Aug 06, 2011 3:03 pm 

Joined: Tue Aug 24, 2004 10:34 pm
Posts: 811
Back is the mid 1970's I hauled pistons and rods to a plating shop in Appleton, Wi for "spray weld"? The locomotive was Mid Continents former W&0V #1 which is no longer on the property but still in WI. The rods were supposed to be built up and if not mistaken re-ground? I think the loco was by this time sold to Carl Ulrich. It had been dismantled pretty far, the pistons build up by brazing and remachined. The spray process was new to me at the time and may have been fairly new process? The locomotive was apart for a number of years and I never saw the engine run again as I was not around much after that time period. So I do not know if Carl got it up and running or not and not sure if the "spray weld" helped? Later the locomotive was moved to North Lake, Wi. Dave Wantz would remember if this repair worked. He is out east and not sure if he reads this or not. This so called running repair was done almost 40 years ago already and if the engine ran again after re-assembly I do not think it ran for very long so the repair might not of had time to be tested I really don't know. But I do find the subject interesting and thought I would add one more approach to running repairs. Agree the best repair is probably a new rod.

The locomotive is a classic beauty queen and is cosmetically restored displayed in SW Wi. Sorry no link or pics.

The owner of the Polson or Saginaw #2 had the rods hard chromed, but boiler is still off frame, but hopefully soon we will see if this helped or not. In this case the cyl bores were so out of round the rods might of had a "curve" or "bend" in them from the wear coming from cyl being so worn out? Seems to me this locomotive had serious leakage and packing problems. I do think the owner has addressed or has tried to address this problem, under steam and during break in will tell if repairs work or not. The cyl were bored and pistons built up and re-machined. Seems to me he had new packing glands made up? Will have to ask him. Of course both loco's mentioned are smaller shortline type, no super power here.

Cheers, John.


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 Post subject: Re: Soft packings-
PostPosted: Mon Aug 08, 2011 10:31 am 

Joined: Sun Sep 12, 2004 1:41 pm
Posts: 830
Location: Bowling Green, KY
John is right, the best packing out there are those of the graphited teflon type. The most common brands are sepco and palmetto....100% GFO is the way to go! It does not get hard, just add more as it wears/is consumed. Having said that, if the packing is allowed to leak as badly, consistently and for such extended periods as those of all to many engines I have seen then it will become hard with solids from the boiler water. How hard is it to grab a wrench and give an 1/8 to 1/4 turn if a leak develops? Like everything else on these machines people to often overlook simple preventative maintenance.

http://www.sepcousa.com/products/packin ... graph.html

http://palmettopackings.com/Style1389.pdf

The hard chroming of piston rods has worked very well on air compressor piston rods. I can see it doing very well for locomotives such as the #2. Perhaps on larger power....However, given the effects of the acid bath on the surface of the base metal would it be a good idea to utilize this practice on larger power that sees as designed impact loadings? The chroming process, as it has been explained to me, causes surface embrittlement. Not an issue on hydraulic cylinders as there is not really any impact. Maybe a well maintained locomotive doesn't really see any issues with this.
One railroad in the US (atleast one) chromed crosshead guides, this worked VERY well for them.
There was a locomotive some years ago which had all rods chromed plated, before it went into service the chrome had to be stripped off due to the embrittlement issues. As it was explained to me the chroming of the rod was equivalent to planting seeds for cracks.

Jason


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