12-17-2010, 10:14 PM
I looked up the expansion rate of metals. Nickel silver wasn't listed, but the nickel silver track we use is actually a type of stainless steel, there isn't any silver in it at all. All of the stainless steels, and all of the nickel alloy metals had an expansion rate near .000008 inch per inch of material per dereee F of temp rise.
So, if we had 36 inches of track at a normal room temp, say 68 degrees, and the temp had risen 10 degrees, we would calculate .000008 x 36 x 10 and we would arrive at .00288 inches, round to .003 inch. That's 3 thousandths of an inch. If any rail gaps at all were left every so often, I don't see that this would be enough to cause buckling of the track. It is much more likely that the wood shrank as the moisture content went down, and this is what caused the buckling.
So my question about the rail gaps was off base. Rail gaps wouldn't protect against the benchwork wood shrinking. I'm thinking that using ripped plywood instead of dimensional lumber is a good idea.
So, if we had 36 inches of track at a normal room temp, say 68 degrees, and the temp had risen 10 degrees, we would calculate .000008 x 36 x 10 and we would arrive at .00288 inches, round to .003 inch. That's 3 thousandths of an inch. If any rail gaps at all were left every so often, I don't see that this would be enough to cause buckling of the track. It is much more likely that the wood shrank as the moisture content went down, and this is what caused the buckling.
So my question about the rail gaps was off base. Rail gaps wouldn't protect against the benchwork wood shrinking. I'm thinking that using ripped plywood instead of dimensional lumber is a good idea.