Wagner using Erie 2nd series skillets as patterns

This is a just a one to one test.

I have a Wagner arc #9 nickel plated skillet and a Erie 2nd series #9. I was curious about the claims that Wagner (and I guess many other foundries) used the Erie's as starting molds.

When I placed the Wagner upside down on the Eire it matched the shape but was 1/8" less in diameter. This also was the approximate difference placed heat ring to heat ring:

Wagner weighed 4#2.3oz, Erie 4#1.7oz

Wagner .056-.101 mid wall thickness, Erie .070-.092 mid wall thickness

Very rough bottom thickness measurement only around the perimeter inside the ring:
Wagner .098-.108, .104-.121

The heights match.

Everything points to the use of the Erie #9 as a mold which probably isn't news to most.

I did the same test with same results for a second series Erie branded no. 11 and an early Wagner.

I have not played much with size and thickness measurements, but found weight measurements to be extremely unreliable in trying to make decisions about cast iron.

Hilditch

I'll invoke Steve Stephens here and point out that Erie skillets were used as patterns (not molds) by others. The telling point is that the copies, all other characteristics being the same, are about 1/8" smaller in diameter. Cast iron shrinks as it cools, by a factor of 1/8" per foot (the height difference would therefore be so small as to likely be unnoticeable). For that reason, actual working patterns are always purposely made larger than the desired dimensions of the cast piece in order to account for the shrinkage.