steam chest joint seal

[steamboat_bruce]

I am currently building steam chests for a couple horizontal steam engines for my steamboat. The material is brass. I have some milled joints that need to withstand 100 psig steam pressure (design). Hopefully, I can get by running with around 20 psig steam. Am I stuck to cut copper or composite gaskets for the joints or is there a sealant like gasket sealant that will withstand the steam pressure/temp?

 

[georgeseal]

Bruce,

I am not recommending the following (I think it is illegal )


A $1.00 bill makes good gasket material due to the silk.

George from Conyers Ga.

 

[Philjoe5]

I've heard about using paper currency as gasket material too. However, due to my tendency to cut outside (or inside) the lines :, I have found Permatex copper gasket sealant to be useful. It flows like very thick caulking, will withstand temps to 500 F. You just smear some on the mating surfaces and fasten them together. I've used it as a gasket material on the hot end of a Stirling that I heat with a propane torch. After a few runs I disassembled the engine to clean it up and I expected to find this gasket material fried but it was still quite serviceable. You can find it in any auto parts store. Hope this helps.

Cheers,
Phil

 

[Bogstandard]

Hi Bruce,

For hi temp thin gaskets I always use the 0.005" ptfe sheet from here.

http://www.smallparts.com/products/descriptions/vt-vte.cfm

Just cut it up with a scalpel and hole punches. It never sticks and is totally reuseable.
I have also used the thicker stuff for head gaskets, never had one blow or leak yet.
Because it is a litle thicker than normal thin paper gasket material, you might have to allow for it, but normally it should be ok.
You should have no trouble keeping within the temp range if using it with high pressure steam or engine head gaskets.

It is wonderful stuff.

Hope this helps.

John

 

[compound driver 2]

Hi
Brown paper soaked it french polish and them smeared with as little silicone as you can put on let it go off slightly so the silicone looses some of its tack and then assemble.
I run a compound at 180psi and its never leaked plus the gaskets can be reused at a push.
Wouldnt recomend PTFE it turns to poridge at any temperature used with steam. There was a guy scalded to death after sealing a mud hole with PTFE.
but yes silk based paper would be good option.

Cheers kevin

 

[compound driver 2]

P/s

forgot to add; If you use silicone on its own it has a way of stringing inside the chest and finding its way onto moving parts. Not noticed it doing any damage but I have a feeling it could hold a valve off its seat.

When assembling let it set or it will extrude out f the joint.

Sorry should have put this in the last post. Old age creeping in

 

[Davyboy]

In the old days, I wanted more compession on my Briggs & Scrapiron go kart engine. I used a head gasket made out of tin foil from Mom's kitchen. smeared with anti sieze to keep it from sticking. You need good flat mating surfaces. Just a thought...oh yeah, the motor ran strong and long.

 

[Bogstandard]

Wouldnt recomend PTFE it turns to poridge at any temperature used with steam.

I personally would query the above statement.

This was posted by a person that advocates Delrin as a piston ring in a steam engine.

http://www.scale-models.co.uk/showthread.php?t=4198

Properties of Delrin

http://www.abbottplastics.com/AcetalDelrinProperties.htm

Properties of PTFE, even the blended versions have nearly twice the constant heat range of Delrin. Even more if you go for the long term useage.

http://www.cowie.com/ptfeprop.htm#Pure



I have been using both materials for over 25 years, including PTFE piston rings, high pressure PTFE steam gaskets, PTFE component spacers in high temp ovens, and I have made all sorts out of Delrin, but because of its low temp range, never in a high temp envelope.

Maybe you should be careful about the information being posted, and make your own decisions as to what to use. We wouldn't want you to get hurt because of bad information.

I DO hope this helps

John

 

[compound driver 2]

Hi

I think you need to look at the uses here and the contexts.

A delrin piston ring failing isnt going to release a scalding jet of steam infact a small engine will run with out a ring look at mamods. A failed gasket can easily release enough steam to hurt some one badly. We must always look to being as safe as we can and safety is the one thing I will not ever compromise on. In all my posts its the first thing I consider . If in doubt about that go back and read my boiler write up that was blocked on here.

I first used Delrin for a piston ring as a stop gap for an engine that wanted a ring and didnt have one the right size It worked and is still working why it works I dont know, id like to know but im happy that I have a ring that works and works very well. i dont doubt there are better plastics to use as rings and at the moment im talking with a chap thats looking at some of the plastics on the market. All i work on is live steam i very occasionaly test with air but more often with a test boiler. I have now 30 plus years with live steam and machining. I DO NOT advocate anything I simply pass on what I find unless its a safety issue. Its up to the person reading it to make there own mind up. As with the idea of using PTFE as a gasket its up to people to way up the options and ideas voiced on this site.

Cheers kevin

 

[compound driver 2]

Hi
I thought id quot from the post I made on the other site John so kindly linked too.

Took the piston out of a TE that had clocked up about 12 hours running yesterday to find the string piston ring all but gone, turned to muck each end of the cylinder.
Not wanting to repeat this I machined a piston ring 11thou over bore from Delrin. Angle split the ring and put it in the packing groove. Put the lot back together and steamed the engine. After 20 mins running the piston runs in the bore better than any ring set up iv ever used! smooth and seals very well.
Dont think it would work for super heated steam but on saturated it seems just fine. Il post an update after 15-20 hours.

I have underlined my reservations about using Delrin with super heated steam. Il point out now and for one time only I am not a bloody fool I take what I do for a hobby as seriously as I do my full time work.

Kevin