Hi Martin,

Welcome to the forum. If the gasket material is porous it may have had some humidity in it when you mounted the gasket, if you used paper as gasket material some papers are slightly acidic. When I use paper gaskets I always impregnate the gasket with oil.

Thor

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Edited By Thor 🇳🇴 on 26/08/2022 17:45:07

Hello Martin,

As Thor says it may have been humidity but already in the material as you assembled it perhaps?. It certainly does seem strange as all other areas are free from rust so can only have come from the material and/or conditions on assembly I would have thought.

Like him I make all gaskets from thick copier paper (90-100gms) and soak it in (slideway) oil on assembly. Not always absolutely seal proof if running on steam of a decent pressure but perfectly fine for air.

That said I ran my first engine, a Twin Vic, at displays on steam for several years with such gasket material – pressure about 40 psi – without any issues save on the second outing. I had not lubricated the cylinders enough after running at the first display. Getting it out for the next the (gunmetal) pistons were solid, rust having formed in the bore either side of them. It required a complete strip down but fortunately the bores were not damaged. After that my clean down procedure after display was to run Steam Oil through on air until it came out of the exhaust. Never had the problem again and something I still do even though I only display on air these days.

Hope that's helpful

Regards Tug

It's good to put a smear of grease on either side of a paper gasket. Would probably stop this rust problem and also makes disassembly easier in the future.