I feel like I have cracked the magic code and want to share it with everyone here on APUG. I was actually thinking about selling these on eBay, but have decided against it since there are so many sources.
I have found that there are several different brands of tacking irons (or, what we would call tacking irons) available under the name "sealing iron." Here is an example. I purchased one of these from another source and just got it today. Apparently it is for sealing paper or plastic to model airplanes. From looking at it and looking at the one at Fine Art Photo Supply on their site, I believe they are either identical or really close.
I will be happy to report back after using it, but I am very confident that it is going to work just fine. I am sure that it is not as good as an $80 Seal iron, but at $15 plus shipping, it sure doesn't have to be.