Lots of guys have Colwood Cubs.
I have a Detailmaster Sabre (Woodcraft brand.....think you have one of those stores local, and the local owner will probably give you a discount for it being for education)
My recent purchase is a Razertip. The reason I got it is because of the feather former tips. The same pen that holds the feather former tips also accept custom nichrome wire tips you can make for yourself. No doubt these custom tips would be the most economical for your class. They can be made with any of the burners I have mentioned I am sure with the right pen, but I know the Razertip has them for sure because I have done it, and done it easily.
You can buy the wire by the foot on Ebay. Research sizes that would be useful. I don't remember what I have off hand.
Razertip also has an awesome writing tip set. It gets WAY finer than anything I have seen from Detailmaster.
The cheapest American place to buy Razertip tools from is Greg Dorrance. Awesome customer service too. They could very well honor an educator discount too.
She Walters shows as cheaper by a few bucks, but if you dig, you will find the company is in Australia, so shipping takes a WHILE and I don't want to find out about customer returns on something like that. My buddy says they have been great to deal with at the same time.
