So I bought my first old cast iron pan on eBay, and it looks great except it's not perfectly flat edge to edge. Check out the first photo below (click to make bigger). I'd say the central 65% of the cooking surface is very flat (there is a very slight depression in the center 15%), but outside of that it starts tapering down, and it becomes abruptly deeper at around 85%. The effect is there is a little trough in a circle around the pan where it looks like oil will pool.
The trough appears to be about 1mm to 2mm deep. I find it annoying to look at (admittedly I haven't tried cooking with it yet), but I'm not sure how common it is, or what is to be expected (I've only looked at a few other old skillets in person). I visited someone from Craigslist who had 5 or 6 on hand (unmarked Lodge, Wagner, etc.) for $20~$25, and I noticed none of them were perfectly flat either (had different issues... one of them spun nicely). Please let me know what your thoughts are on this skillet, and what your expectations are for flatness of these classics. I'm guessing a really flat skillet is a rarity, and would perhaps be fairly valuable... although I don't see any photos on ebay with a straight edge where you could really see the flatness profile. Are some brands (i.e. Griswold) better than others in this respect?
Also, any guess as to whether it was cast like this, or if this is heat damage? It was advertised as "sits flat with no warp."
Below are a couple more photos, showing the condition as received from the seller. Notice there is some built up crud in that trough (also extending up the sides):
And these are after I cleaned all the crud off of it (using computer power supply electrolysis, some credit cards, and 0000 steel wool):
The trough appears to be about 1mm to 2mm deep. I find it annoying to look at (admittedly I haven't tried cooking with it yet), but I'm not sure how common it is, or what is to be expected (I've only looked at a few other old skillets in person). I visited someone from Craigslist who had 5 or 6 on hand (unmarked Lodge, Wagner, etc.) for $20~$25, and I noticed none of them were perfectly flat either (had different issues... one of them spun nicely). Please let me know what your thoughts are on this skillet, and what your expectations are for flatness of these classics. I'm guessing a really flat skillet is a rarity, and would perhaps be fairly valuable... although I don't see any photos on ebay with a straight edge where you could really see the flatness profile. Are some brands (i.e. Griswold) better than others in this respect?
Also, any guess as to whether it was cast like this, or if this is heat damage? It was advertised as "sits flat with no warp."
Below are a couple more photos, showing the condition as received from the seller. Notice there is some built up crud in that trough (also extending up the sides):
And these are after I cleaned all the crud off of it (using computer power supply electrolysis, some credit cards, and 0000 steel wool):