Steam Dome Gaskets

Frisco1522 · **Posted:** Sun Oct 04, 2015 9:16 pm

We used the same method as Kelly mentioned on 1522's gasket. Every time we had the lid off, I would take the gasket to work and have it annealed by our heat treat dept.
Never had a moment's problem with it or the one we made to replace it when it got too thin.

David H. Hamley · **Joined:** Tue Aug 24, 2004 3:07 pm **Posts:** 705

If you want to try a flat gasket, try Industrial Gasket & Shim Co. at Meadow Lands, PA. They can make anything you can draw out of anything you can dream of.

I have no connection with the firm, but have used their help a number of times in connection with Pennsylvania Trolley Museum restoration projects.

Paul Boschan · **Joined:** Mon Mar 14, 2011 6:45 pm **Posts:** 89

Mike Tillger wrote:

I don't believe it is wise to be substituting other materials for your gasket than what is used in your dome lid factor of safety calculations, as the compressive force per square inch needed for some of the gasket materials commercially available (flexotallic, etc) can be 8 to 10 times higher than that of a properly sized and annealed copper gasket and can lead to the conditions discussed above about bent studs and misshaped dome lids. This was actually discussed at the ASME Locomotive subgroup meeting, another good reason for attending these meetings if one has the chance.

my 2 cents,
Mike Tillger

The results of the discussions at the ASME Section I Subgroup on Locomotive Boilers meetings has now been published in the 2015 Edition of the ASME Code. Paragraph PL-21.4.1 specifically addresses the bolted, gasketed joint between a flanged dome top and a flat cover.

J.David · **Posted:** Mon Oct 05, 2015 1:21 pm

Greetings:
At Valley Railroad, we use 3/8" square copper bar stock, rolled to the proper diameter, a step joint filed on the ends and then silver soldered.
These last for decades without much attention as long as you are careful not to overheat the joint when annealing every year.
The point in re-over tightening dome cap nuts and consequently bending the studs is well taken.
One of our guys (who is an ME) calculated that if we torqued the dome cap nuts to 160 foot pounds, we would have sufficient pressure on the cap to seal AND not over stress the studs. Note: we use "traditional" dished dome caps.
J.David

Lincoln Penn · **Joined:** Wed Feb 02, 2011 9:40 pm **Posts:** 841

Another thing to mention is to tighten them in a cris-cross pattern, to keep from bending or overstressing the studs or the lid.

M Austin · **Joined:** Sat Feb 05, 2005 1:05 am **Posts:** 488

These are the calcs for the Granite Rock #10's gasket. This assumes a 0.100" flat squish on a 1/4" round copper ring. It requires 113 ft-lbs of torque for proper loading.
I personally prefer to forge weld the copper ring. A little flux and 5 minutes with a torch and hammer. Maybe 5 minutes with a file and no one can find the joint.

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Lincoln Penn wrote:

Another thing to mention is to tighten them in a cris-cross pattern, to keep from bending or overstressing the studs or the lid.

If this has to be told, the apprentices should not be bolting the dome lid on unattended.