I have been offline for several weeks due to a major computer failure and will now add my two cents worth.
1, the 110v 60hz USA tacking iron will NOT work on the european 220v 50 hz system, it will get extremely hot and fail totally within 20 seconds.

2, The uk system is 230 v but most of the rest of europe is 220v both use 50hz.

3, A soldering iron will not substitute for a tacking iron as the tip temerature on a soldering iron is around 140 / 170 degrees Celsius and mounting tissue melts at 80 to 90 degrees Celsius. (Americans will have to convert to Farenheight , or join the real world?)

4, using a soldering iron to tack the tissue to the back of a print will heat damage the emulsion of the print, I speak from bitter experience.