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Post by mervberry on May 2, 2006 10:06:06 GMT
on
the drawings of my three inch scale little samson taction engine it specifies .025 inch gasket between the cylinder and boiler could someone advise me what to use thank you in anticipation
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Post by Nigel Bennett on May 2, 2006 12:09:13 GMT
Various ME suppliers (Blackgates, Reeves, et al) will supply various gasket materials such as Hallite, Walkerite, Klingerite, etc. (Try a Google search on those) They are available in various thicknesses. You will need something better than oiled brown paper, I guess, which I have often used for things like cylinder covers, slide valve steam chests, and the like.
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wayne
Seasoned Member
Posts: 137
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Post by wayne on May 2, 2006 22:02:50 GMT
My first question is how old are the drawings? On a recent visit to one of the suppliers named above we discussed the properties of the new gasket materials from flexitalic, and the supplier quoted they are not as good as they used to be. The main problem is due to the lack of asbestos in current gasket material making them harder, therefore harder to compress and key to the joint surfaces. The aforementioned problem causes the gasket to blow when the unit sealed has warmed up and cooled several times. Hydrovane compressors had a real problem with this in the mid eighties, with blowing gaskets for this reason. In relation to your question, quotes on gasket specks 20 years ago can be meaning less now. whatever material you decide on rough the faces of both mating surfaces up grease the gasket 24 hrs before assembly to soften it up a bit if you are not using a jointing paste The flexitalic graphite impregnated gasket paper used to be first class and a very suitable material for steam however it was very expensive. but would still be my first choice every time and needs no jointing compounds whatsoever, also I would go for the same thickness as a starting point, but if possible cut a grove 3 to 5 thow deep all the way round the mating face of the block outside and inside of the mounting holes to help the gasket key. To give you a good idea of the forces involved with the gasket selection on the real thing! have a look at the following link and check out the boiler section of the document www.flexitallic.com/documents/Design_Criteria.pdf |
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