Thanks guys, I should have looked up whiting. Oakum/hemp I'm familiar with.
My father in law once brought me a full gallon of raw linseed oil he didn't want any more -- looks like it's from the 50's judging by the label. I've used boiled linseed oil before because it air dries easily, but not raw, so I've had no particular use for it either.
But maybe now, to make up a once a year removable traditional putty it might be just the thing. I'm wondering however -- whiting -- I haven't seen it anywhere in the local hardware stores as such, but we do have something which might be the same thing -- plumbers putty -- oil based chalky and smelling of linseed oil, and also very similar, window glazing compound -- white chalky, linseed oil-ish smelling, and supposedly non drying.
Last night I ordered some of the Gasoila non-teflon pipe compound, since I found it for $5 plus change on Amazon in a small quantity. The specs say good for potable systems, NFS approved, and good to 400F. But, still, whatever is in it is unknown and it's reaction to high temps above that also unknown, while whiting and oakum are very well known ingredients, and non toxic no matter what the temp.
You know Andrew I came across the paint as joint compound recommendation elsewhere in old writings re. model engineering. I was tempted by that, too.
so many choices.......