Steam engine is eating graphite yarn!

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Hi folks!

 

I has copmleted the Stuart Triple steam engine after 2 year's work. Today i ran the steam triple engine and learned out the graphite yarn is disappearing from glands and need retightening too often on gland box until there is no more yarn inside. Deposition of graphite yarn is on the rods. There is enough oil in the steam engine. I am using steam engine cylinder oil.

The graphite yarn is difference from what i had in the Stuart D10 where the graphite yarn is more compact and fringe free. The graphite yarn from the set of Stuart triple steam engine was loose, thin and frayed.

What is caused the graphite yarn is disappearing from cland box?

Edited By Jens Eirik Skogstad on 19/03/2015 11:32:36

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

[andrew winksParticipant @andrewwinks64215]

Too much clearance or the rod has burrs. This would be a guess. Replacing with suitable O Ring could be a good solution.

cheers, Andrew

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

The rod is without burrs and the rod and hole is without clearance (tight but free moving in both ways). Also the steam engine is new. The graphite yarn was well packed in the gland box.

Ok, i can take a test with O-ring instead graphite yarn. Is it common all folks is using O-ring instead graphite yarn?

[andrew winksParticipant @andrewwinks64215]

Jens, O rings are very good but traditional packing yarn works well. With packing, I like to tighten the gland just to the point where no steam leaks are observed, with maybe a wisp, allow to run and bed in and tighten slightly as required.

Can you post a photo of the item of interest, cheers, Andrew

[JasonBModerator @jasonb]

You really need to size the gland cavity to suit an O ring from the start so just shoving one in the hole my mean that it is not being compressed correctly.

I mostly use the traditional graphit yarn and it seems to stay where its put.

Are you using a stock size rod? ground mild steel can be a bit abrasive as can a rod turned down from a larger diameter, run your finger nail along the rod if there is some resistance and it leaves a white line then your rod is like a miniature file. Clean it up by rubbing lengthways with wet & dry.

Edited By JasonB on 19/03/2015 13:13:08

[Neil WyattModerator @neilwyatt]

Try oiling the packing.

Neil

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

The rod is made of stainless steel and the surface is smooth and shiny. The size is selected to nearest size as possible since we has not imperial sized material in Norway, to example: 5/16" rod replaced with 8 mm rod. The hole and rod is in same size. When the clean rod is entering into the gland box and then out of gland box, there is black graphite on rod. Tried to tighten the gland box and later the glandbox is wobbling, retightening and the yarn is reduced. Wobling again. The rods is well oiled. The picture will be added later..

[Bob YouldonParticipant @bobyouldon45599]

Hello Jens,

I suspect the material being used is some form of flax yarn simply impregnated with graphite grease and is breaking up in use or compressing far too much and leaching out the grease, also check the clearances of the glands and stuffing boxes; a quality graphite packing yarn will generally not give up too easily, some of the cheaper yarn is only suitable for limited use and movement, stop valve spindles being an example. Original graphite string gland packing had a considerable amount of free graphite within the body of the packing which was generally an asbestos based material with a certain amount of graphite grease, but sadly some of these so called modern alternatives sometimes do not come up to scratch. I'd advise a good modern alterative, the PTFE packing yarn, carefully fitted it will seal easily and has the advantage of an almost friction free seal; take a look on the popular model engineering suppliers web sites and they will generally have a suitable PTFE alternative available.

Regards,

Bob Youldon

[SaxalbyParticipant @saxalby]

I had exactly the same problem on my Stuart Twin Victoria. As with Jens the rods were polished etc etc., but the graphite packing ended up as a ring of graphite and fibres on the rods.

Do as Bob suggests and use PTFE.

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Exactly what Bob Yuldon and  Saxalby told about the flaking graphite yarn unlike the older graphite yarn who was a hard type with smooth surface as i am using in my Stuart D10 steam engine.  Is Stuart models become poorer quality materials in recent years?  See these photos..

Edited By Jens Eirik Skogstad on 19/03/2015 20:22:21

Edited By Jens Eirik Skogstad on 19/03/2015 20:25:29

[JasonBModerator @jasonb]

That does look nasty stuff. The yarn I have is a much smoother surface, I think it is soaked in tallow or another animal fat judging by the smell and then rolled in graphite. I have had it a long time so can't say where it came from.

 

That looks more like one of the graphite fillament type seals (pilotpack 4010)  rather than the greasy twisted type (pilotsil 8110) which is more like what I use

 

J

Edited By JasonB on 19/03/2015 20:36:04

Edited By JasonB on 19/03/2015 20:41:54

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

Jason B, thanks a lots! I am planning to order the greasy twisted Pilotsil 8110 to replace the useless graphite yarn delivered from Stuart Models.

PS, i must not forget to thank to other who gave tips about PTFE string and O-ring.

Edited By Jens Eirik Skogstad on 19/03/2015 21:10:46

[andrew winksParticipant @andrewwinks64215]

Wow Jens, I would not even use that packing in my worst enemies rusty wheelbarrow! Good to see you have arrived at the cause of the problem. I was quick to suggest workmanship but its the raw materials that failed you. Apologies

Please post a photo of the engine when she is running with the correct packing.

[julian atkinsParticipant @julianatkins58923]

hi Jens,

if you want any of the proper old fashioned packing i'll send you some. as Bob states the 'new' stuff is pretty awful and i wouldnt touch it myself. the old stuff still crops up on ebay.

cheers,

julian

[Jens Eirik Skogstad 1Participant @jenseirikskogstad1]

I has replaced all dirty graphite yarn with a better quality of braided graphite yarn and ran the Stuart triple steam engine on test with air. No trouble with the graphite yarn. Thanks to all folks who gave the tips about the braided graphite yarn.

http://www.youtube.com/watch?v=1xhXqMLKHeQ

 

Edited By Jens Eirik Skogstad on 02/06/2015 21:18:37

Edited By Jens Eirik Skogstad on 02/06/2015 21:19:15

[andrew winksParticipant @andrewwinks64215]

That's nice to hear, Jens.

Now for some steam through her veins!

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