Gaskets for small surfaces

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flavinny
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Joined: Sun Jun 29, 2014 2:47 pm

Gaskets for small surfaces

Post by flavinny » Sun Jan 16, 2022 9:05 am

Making progress on installing a new boiler on my Allen engine but looking for suggestions on "how to".
Before starting the boiler replacement project, I had a problem with the stem on the blowdown valves leaking. I removed the valve and replaced a dried o-ring and reassembled and reinstalled the valve. It now leaked between the two halves of the valve body. The original valve had no gasket, so I initially tried some RTV rubber which did not work. The problem is that the surfaces are so narrow a traditional gasket does not seem to work, the gasket material just gets pushed out. Next option seems to be to try to lap the parts together, but I see the possibility of making things worse. I also considered using Loctite has anyone had experience trying this any other suggestions?

hoppercar
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Re: Gaskets for small surfaces

Post by hoppercar » Sun Jan 16, 2022 9:30 am

I use number 2 permatex on everything

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cbrew
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Re: Gaskets for small surfaces

Post by cbrew » Sun Jan 16, 2022 9:37 am

take a THICK piece of glass and some 2000 grid wet sand paper (used to auto painting)
using a water, likely lap the mating surfaces. use bluing to so you can see the surfaces are true.
then reassembly
If it is not live steam. its not worth it.

John Hasler
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Re: Gaskets for small surfaces

Post by John Hasler » Sun Jan 16, 2022 10:09 am

Use a very thin, stiff gasket material such as printer paper. Leave a lot of overhang on the outside and trim it off after assembly.

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NP317
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Re: Gaskets for small surfaces

Post by NP317 » Sun Jan 16, 2022 11:56 am

What CBrew suggested.
I always lap the blowdown valve halves on a flat plate when servicing them. It is easy to see when the surfaces are shiny flat.
They always seal perfectly that way.
RussN

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Bill Shields
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Re: Gaskets for small surfaces

Post by Bill Shields » Sun Jan 16, 2022 2:32 pm

Are you sure that there was not a thin copper ring on the inside?
Too many things going on to bother listing them.

RET
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Re: Gaskets for small surfaces

Post by RET » Sun Jan 16, 2022 5:34 pm

Hi,

CBrew is right, but instead of sandpaper, use polishing paper because it is thinner. I use 400 grit, but while it works, something finer would be better and I use it on a surface plate (because I have one). If you don't, glass is a good substitute. While it may be obvious to most, make sure the abrasive side is up.
I don't use gaskets, I use the lapping method instead and it always works. It doesn't take very long either and when you are done, you will have a mirror surface on the part.

Richard Trounce.

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cbrew
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Re: Gaskets for small surfaces

Post by cbrew » Sun Jan 16, 2022 6:46 pm

RET wrote:
Sun Jan 16, 2022 5:34 pm
Hi,

CBrew is right, but instead of sandpaper, use polishing paper because it is thinner. I use 400 grit, but while it works, something finer would be better and I use it on a surface plate (because I have one). If you don't, glass is a good substitute. While it may be obvious to most, make sure the abrasive side is up.
I don't use gaskets, I use the lapping method instead and it always works. It doesn't take very long either and when you are done, you will have a mirror surface on the part.

Richard Trounce.
likely just used the wrong term, i use four stages when i lapped my valves surfaces, started with 400, 800, 1500 and 2000 grit.
If it is not live steam. its not worth it.

Santafescotty60
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Joined: Wed Dec 27, 2017 11:00 pm

Re: Gaskets for small surfaces

Post by Santafescotty60 » Mon Jan 24, 2022 10:31 am

Hello Good People ,I have used glass plate, comet and diesel fuel. That is what we lapped fuel injectors on older Mercedes diesels

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