This deluxe iron has a mains 117V power cord with the heat control knob on the handle. Is it ok to power it from a variac, adjustable transformer reducing the mains voltage to dial down the heat?

I did that for a while and it seems to have thrown off the calibration of the on board temp dial. I find the small knob on the handle to be awkward. I would prefer to adjust it with this Variac. It's an actual transformer not a solid state lamp dimmer.

I don't need calibrated temps just a way to pause the heat between jobs and I don't want to damage this Hakko.

I know the variac is fine for old school irons but what about this Ceramic heater?

 

First - to answer your question intelligently - I don't know the answer. However, I would suspect that when you set a heat and then reduce the incoming power the Hakko will attempt to maintain the original heat setting. You may damage it.

Would suggest getting an iron without heat control and hook that up to your Variac. Cheaper, and less likely to be damaged.