What packing compound should I use when working on cylinder seals/gaskets?
Packing Compound
RioGrandeFan
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What packing compound should I use when working on cylinder seals/gaskets?
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Several ways to do this but I've used brown paper shopping bag cut to size, then wiped/soaked with oil. Some people have even used dollar bills. Don't use a 5.
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For a sealing compound I have used Permatex 'Copper' high temperature silicone (up to 300 degree C ?) that I apply very very sparingly with a toothpick but be aware as you tighten the part there may be excess squeezed out that can cause problems, so apply just an opaque whisper.
I also use paper money but here in Australia they have gone to 'plastic' type money so the old paper money is best for gaskets
. But of course you can get proper gasket paper that is really thin and that's best.
I also use paper money but here in Australia they have gone to 'plastic' type money so the old paper money is best for gaskets
. But of course you can get proper gasket paper that is really thin and that's best.
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I make cylinder gaskets with punches and scissors using ordinary paper. I just draw the cylinder head on the paper by using it as a template. I punch out the cylinder hole with a big punch. Then I punch the small screw holes with a small hand punch used for leather working. I then cut away around the gasket.
To make it water tight I use sylicone and put a few dabs on it (on both sides); then by pressing it between thumb and finger lightly, while turning the gasket I spread it all around on both surfaces of the gasket. Keep turning it between your fingers and doing this for a minute or two and it spreads a thin coat of sylicone all around with no excess. Then fit cylinder head, with its gasket, normally.
To make it water tight I use sylicone and put a few dabs on it (on both sides); then by pressing it between thumb and finger lightly, while turning the gasket I spread it all around on both surfaces of the gasket. Keep turning it between your fingers and doing this for a minute or two and it spreads a thin coat of sylicone all around with no excess. Then fit cylinder head, with its gasket, normally.
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Thanks!
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My method as well Simon. Hasn't failed yet!
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thanks everyone for the replies and help. I am building my first locomotive kit and I am at the point of assembling the cylinders and it’s calling for packing compound on the gaskets. Now I know this packing compound is simply silicone.
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I think that the stuff provided by Aster is high temperature sylicone, bathroom sylicone might not be as good. Unfortunatly it goes dry inside the tube after a while... Does any knowledgeable person have any info on this?
By the way that isn't packing but gasket work. Packing is done with graphited yarn in the gland box ; and is different from cylinder rings also. Here in France I have been able to obtain in an industrial steam supply firm in Saint Denis, a teflon graphited yarn wich when you separate each strand (easely) is about 1MM in diameter and is very good for both packing and replacing cylinder rings inside old Asters. It should be easier to get in the USA as there are many more users of steam in America than in France, which has lost a great deal of industry. Here is a photo of the good stuff :
![Image]()
Cheers,
By the way that isn't packing but gasket work. Packing is done with graphited yarn in the gland box ; and is different from cylinder rings also. Here in France I have been able to obtain in an industrial steam supply firm in Saint Denis, a teflon graphited yarn wich when you separate each strand (easely) is about 1MM in diameter and is very good for both packing and replacing cylinder rings inside old Asters. It should be easier to get in the USA as there are many more users of steam in America than in France, which has lost a great deal of industry. Here is a photo of the good stuff :
Cheers,
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While technically speaking one could apply oven grade silicone capable of withstanding 1200 degrees Celsius standard silicone (230 degrees C) is perfectly sufficient. Heat stabilised silicone can add 30+ degrees (260+C). There is hardly any reason to go higher as teflon can only withstand temperatures up to 260 degrees C while Rulon used by Aster for cylinder and piston valve sealing rings withstands 288 degrees Celsius. Ordinary and heat stabilised silicone are perfectly stable in constant high temperatures up to 200 degrees. Systematic studies of heat ageing have been done - I requested the manuscript from the authors. Most of the silicone sealants advertised as high-temperature resistant can only withstand intermittent exposure to extreme heat. Other than burner and superheater no part of the live steam loco should become hotter than 150 degrees Celsius - if it does this means you are frying your locomotive and silicone will be the least of your problems... Zubi
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I also talked to Cliff at accucraft and he told me it’s white silicone used in bathrooms and this is what was supposed be included in my kit. They are sending me a tube.
![Image]()
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I still use hi-temp Permatex. The idea of sealing a precision model with bathroom silicone makes me cringe.
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That stuff is regularly available at any decent plumbing supply or large hardware store here in the States.
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I agree with Simon..... DO NOT USE Bathroom grade silicone.
-- As I do not like using Silicone Sealer on small steam cylinder gaskets, I simply use a good grade of Steam Cylinder Oil either soaked in or wiped on.
-- As for the Piston Rod "Glands", as Simon says Teflon Graphited Yard unwrapped to @ 1 mm strings is best. Many small steamers in our Gauge One realms these days have installed small O-Rings which is a different animal to install.....
SRC - Ken
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Permatex also makes a "Thread Sealant - High Temperature" which withstands up to 400 degrees F., and allows some parts re-positioning after application. I have used it on small screw threads, and it works well, and it is very thin so applies quite easily..... I have never tried it on Cylinder Gaskets and Steam Chest Gaskets, but it may work well in our smaller scales (??). Anyone else tried this stuff?
SRC - Ken
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Makes me cringe, too-- Pete!
As I replied to a comment above: Permatex and Loctite both also make a "Thread Sealant - High Temperature" which withstands temperatures to 400 degrees F., is pressure resistant, and allows some parts repositioning after application. It is very thin and wipes on easily. I have used it on small screw threads, and it works quite well. I have never used it as a sealer for Gaskets, but it may work quite well on our small scale Cylinder & Steam Chest Gaskets..... any one else tried this stuff as a gasket sealer??
SRC - Ken
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Thanks Zubi for that low down on sylicones. Although they are manufactured near Lyon which is only about a hundred miles from me, I had no notion on what temperatures it was good for. So when my old aster tube goes dry I will buy this instead.
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Hi Zubi !
-- As most of us can deduce, boiler shell temperature is determined by boiler pressure. Data from a Saturated Steam Table indicates at the following pressures, the steam temperatures in Degrees F would be, for example: at 30 PSI = 274 F, at 40 PSI = 287 F, at 60 PSI = 307 F, at 90 PSI = 331 F. It requires those temps to raise Sat Steam to those pressures in a closed vessel. Of course, temperatures at the exposed boiler "backhead", on the firebox shell, and on the smokebox shell & smokebox front, can be expected to be higher; where temps on an insulated jacket of the boiler shell would be noticeably lower.
-- Using a "Handheld Digital Laser/Infrared Thermometer", I checked three of my own Gauge #1 Steam Locomotives' Boiler Shell, Backhead, Firebox, and Smokebox temperatures with a Boiler having a PSI of 50 to 60. The results were quite consistent with the Steam Table data, for example at the: Cab Boiler Fill Plug = 260 to 280 F, Boiler Backhead = 280 to 300 F, Burner Mounting Plate = 325 to 330 F, Smokebox Side, Front & Door = 300 to 380 F, Safety Valve & Exhaust Stack = Inconclusive; Inside the Smokebox (Door Open) temps were typically 400 to 600 F, depending on the exposure to the Single Flue.
-- As I mentioned in a couple of my other comments in this Topic String, RE: "Gasket Sealers & Packing" on the Steam Cylinders, etc., I prefer to wipe the Gasket thoroughly with Steam Cylinder Oil, and have only tried Thread Sealer on the small bolts. However, there are two "High Temperature Thread Sealers" (Permatex and Loctite) which I have used on small bolts, which would quite likely make decent Gasket Sealers (but I have not tried them in that application). Both "HT Thread Sealers" are similar in their chemical ingredients being of teflon/silicon/acrylic (??), are fairly thin and easy to apply, are rated for up to 400 F temperatures, are pressure resistant, and parts can be somewhat repositioned after the application. Their normal use is on High Temp Water, Steam, & Hydraulic "Threaded Fittings"..... however I see no reason both of these HT Thread Sealers cannot be useful as a "Gasket Sealer" on our small Lokey's, but must say I do not have personal experience with the application on Gaskets, except on Safety-Valve threads and some other small plumbing tubing connector fittings..... anybody out there tried these products as Gasket Sealers?? "Permatex High Temperature - Thread Sealant" and "Loctite #592 High Temperature - Thread Sealant".
CHEERS! ;-) SRC - Ken
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I use this stuff with great success on all my water connections including on my sight glass parts.
I've decided to use this on my cylinders and picked up a tube today.
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Hi Ken, pressure point well taken, but steam is generated primarily around the flues. These need to reach the temperature of around 150 degrees Celsius for generating water vapour at pressures between 50-60 psi (3,3-4.1 bar). You are not actually boiling the entire volume of water in the boiler as you may be used to when boiling water in your kettle. Unless you are - check this in your water gauge;-)... As I wrote earlier, the burner becomes much hotter and so does the superheater. But as your measurements indicate, boiler fittings do not reach the temperature of 150 degrees Celsius. Boiler backhead is near that temperature (150 C) simply because burner mounting plate which conducts heat from the much hotter burner is mounted on the backhead. This is of course not a problem since 150 C is a perfectly safe temperature for standard silicone which can even withstand temperatures well above 200 C (392F). So you can safely use standard bathroom silicone for threads mounted directly on your boiler backhead. As for the other measurements you took, you clearly fry your smokebox and smokebox door. This is a common problem with not very efficient burners and poor insulation of both the smokebox and the smokebox doors. As we all know, locomotives with better burners retain their paint colour on smokeboxes and stacks. Some locomotives though would even melt their smokebox and trucks under them. Anyway, I am surprised that you did not provide measurements of the temperature of the cylinders as this is what we are talking about. Cheers, Zubi
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