Leyland was a British manufacturer of trucks (lorries) and buses that is sadly no more.
A regular customer in the UK specializes in supplying gaskets for industrial marques that have long gone by the wayside, with spares difficult if not impossible to find. After sending an image of an old Leyland gasket along with dimensions and thickness for a quotation he was happy with the quoted price and sent a copy of a used gasket to use as a pattern.
This type of gasket is known as a copper sandwich gasket, also referred to as a copandas gasket in the UK, and consists of an inner material sandwiched by sheets of copper. Originally these contained asbestos inner material, but asbestos is now banned in Europe, Australia, NZ, and most other countries, with the exception of the USA and a few others. Instead of asbestos we have been using a non-asbestos material very similar in appearance to the original white asbestos. This material is supplied by Interface Solutions (USA) and known as HT5050. Alternatively, and expecially for thicker gaskets, we use a metal mesh reinforced composite head gasket material from Interface Solutions. In this case the customer opted for the latter option.
This gasket was sealed around the outside, which means the copper is crimped over to seal the inner material. I am not sure if that really makes any difference, but some of the older gaskets came that way and in order to make these as authentic as possible the customer wanted that. All the holes except for the bolt holes were bushed as well, so this was a fairly labor-intensive gasket to make. The results are below, with the old pattern gasket on top and one of the 3 replacement gaskets we made below:
If you recognize that Leyland gasket and need one let me know and I will put you in touch with my customer.
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Scan of original Armstrong style metal sandwich exhaust gaskets
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