How do you put a date on ceramic insulators

[bottlerocket]

How do you put a date on ceramic insulators?I have 3 different ones here and was wondering when they could have been made.Nothing stamped, etched, or embossed on them.I am guessing they are ceramic. Porcelain? [attachment=insulators.JPG]

 

[cowseatmaize]

How do you put a date on ceramic insulators?

Have you tried a Dremel? []

 

[BillinMo]

Good one, Eric. BR, collectors call these porcelain, which aligns with what the manufacturers called them. Electrical porcelain is completely non-porous. Like glass insulators, we often have to go by evolution of styles and such, especially since most porcelain pieces are unmarked. Being able to identify "dry process" or "wet process" porcelain is one step. The petticoat firing rest was around since the early 1900s but became more common on side-tie styles like these later on, in the 1920s and later. Glaze colors and styles changed over time, too. Earlier insulators tend to have nicely mottled glazes, and later on looked more "industrial" with flat white, chocolate brown, or sky (grayish) glazes. There really isn't a simple answer when it comes to dating these. It's tough to tell from just a photo, but I'd guess the insulator on the left is the oldest just from the shape, maybe 1920s-1930s. The other two are a more squared-off "hat" style, so probably 1930s-1960s. White (or white-ish) glazes and side-tie styles gradually became less common after WW2, but were still around into the 60s.

 

[bottlerocket]

WOW cowseat, I think I will put 1800 on them and proudly display them as OLD insulators LOL! Thanks BillinMo, That makes sense since the 2 whitish ones are from a 20's dump. The off-white one I took from poles I was removing from old RR poles during a construction update. They are not as good looking as glass but unique non the less.