gasket material

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jeffsmith
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gasket material

Post by jeffsmith »

Has anyone tried using soft copper for gasket making? Anyone ever try it for steam use.

Jeff
Doug_Edwards
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Re: gasket material

Post by Doug_Edwards »

Jeff,

Soft copper works well in steam use. Willamette used it as a gasket between the steam dome and lid.

That being said, I'm not sure in model work if you would be able to apply enough pressure to get it to seal.

Regards,

Doug
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Rwilliams
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Re: gasket material

Post by Rwilliams »

For years Westinghouse air pumps were sealed with thin copper gaskets that seemed to last forever if not abused. The composite gaskets of today are easily destroyed by steam leaks in a short period of time and are not reuseable. This one shot gasket use has to be making the gasket suppliers a handsome income as the older pumps still in use need more maintenance than ever before.

The large 5/8 and 3/4 inch diameter bolts of the compressors supply plenty of crush factor just as to the 1 inch diameter or larger steam dome studs.

Very thin annealed copper gaskets might work in our scale models with enough of the industrial quality fasteners being used. The 12L14 model hex bolts are probably not up to the task of compressing copper for a desired steam tight fit. Elimination of all cutter tool marks from both surfaces would be a good way to begin achieving a good steam tight fit. I stone all surfaces that thread together on steam valve rebuilds with a 1000 grit stone and light oil for a steam tight fit when assembled.
super7b
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Re: gasket material

Post by super7b »

It all depends on what use you put copper sheet to. It works perfectly well as a washer, between 2 screwed components such as a fitting screwed into a boss and secured with a nut. Annealed, thin sheet can be used instead of a conventional sheet material, but it begs the question, why would you want to? If there are errors on the mating faces then using a different jointing material is not really the way to go.
Then as I said, all depends on your use.
jeffsmith
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Re: gasket material

Post by jeffsmith »

I would like to use it for cylinder head gaskets. If they sealed I would think they would last a lot longer.

Jeff
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NP317
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Re: gasket material

Post by NP317 »

For cylinder head gaskets on my Allen Ten Wheeler, I admit to using oil-soaked heavy paper bags!
They remain steam tight 15 years later.
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Greg_Lewis
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Re: gasket material

Post by Greg_Lewis »

jeffsmith wrote: Thu May 28, 2020 3:37 pm I would like to use it for cylinder head gaskets. If they sealed I would think they would last a lot longer.

Jeff

Does this mean you are having problems with more conventional gasket material?
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Sandiapaul
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Re: gasket material

Post by Sandiapaul »

We use it at work in ultra high vacuum seals all the time. Seems worth a try.
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Steggy
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Re: gasket material

Post by Steggy »

How about lapping the mating surfaces?
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rkcarguy
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Re: gasket material

Post by rkcarguy »

I don't think the tiny bolts used in scale models are going to adequately compress a copper gasket.
I'd almost want to entertain cutting an o-ring groove in the head and using some sort of high temp o-ring instead.

Have a look at these, there is a drop down menu with tons of size options. Viton should be good to 400*.

https://www.amazon.com/230-Viton-Ring-D ... ial&sr=1-5
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NP317
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Re: gasket material

Post by NP317 »

When performing annual boiler service on full sized logging locomotives, we would remove the dome cover for internal access.
The gaskets were made from sections of H-shaped copper trolly wire (an interesting story) end-brazed together into a hoop.
Before reinstalling those gaskets we would anneal them with an oxy-acet torch and water quenching.
Then a quick "polishing" with Scotch-Brite and back it went onto the dome top.
The annealed copper easily compressed under bolt-tightening to seal for 200 psi operating pressures.
We could re-use each gasket for several years.
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RET
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Re: gasket material

Post by RET »

Hi,

For what its worth, I use Viton "O" rings a lot for static seals like the steam dome on the Big Boy boiler where the "O" ring sits in a groove on the inside of the dome (cap or cover). The dome "cover" itself extends down inside. This way, the dome comes off easily and goes back on with a leak tight seal no matter how often it is removed and replaced. It takes a little extra time to make, but down the road, that extra time is recovered many times over. Viton "O" rings work OK and are better than the Silicone ones. Viton doesn't take a "set" (a permanent deformation) the way silicone can. I keep a stock of Viton "O" rings in the sizes I often use for two reasons. First, they are handy when I need one, and second when I order some, they come in a bag of ten or more depending on the size I order.
Installing internal piping (7).jpg
I have also found that if you take the time to make sure the mating surfaces are truly flat and smooth, a metal to metal seal works just fine. No gasket or sealant of any kind is needed. The easy way to do this is to put a sheet of abrasive paper (paper not cloth, cloth is too thick) about 400 grit or finer on a surface plate (glass is also OK) and slide the part around on the paper with an even but not heavy pressure. Keep turning the part and apply the pressure as far down on the part as possible to avoid tipping.

Its a simple process and really doesn't take very long. As the process continues, you can see all the tool marks on the surface of the part gradually disappear and the surface will become smooth and shiny. When both parts have been treated, they can be assembled and disassembled as many times as you like without any leaks.

I also use the clear Silicone Seal to seal mating surfaces. It is easy to apply, stands up to smokebox temperatures, is easy to remove and lasts for years.

Just my experience.

Richard Trounce.
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