Convert a 110V device to 220V
Step-down transformers for this purpose are quite common. Check under "expats" on Google. I had several of these during my couple of European assignments.  Smaller transformers are sold as razor adapters and larger transformers are sold in areas where there are US military bases as they will convert the voltages for TV's and other higher current appliances. If the base has a local sale/swap board, you will find them there as people move back to the US and want to unload them. I obtained several 1 kW versions for free with this method. In fact I still have them thanks to the company paying my moving expenses but unfortunately shipping one to you wouldn't be cost effective.

You may also have some success with a lamp dimmer. Connect the dimmer to the mains and adjust the output voltage for 110 Volts. Continue to monitor its output voltage and plug in and briefly turn on your soldering station. Don't use this solution however, if your soldering station has a motor for a vacuum pump as the motor won't be happy with the chopped sine wave.