Gaffers tape (very important to use real gaffers tape, and NOT duct tape. See link below for the specific brand I use)
Scissors (large and small)
Small metal pin or wire tool (to wrap the valves around)
1) I've had one harp with these valves in it for approximately 3 months now. The adhesive is still going strong. This tape is different from other tapes in that regard. The properties of the adhesive used in gaffers is a very important part of why these valves work as well as they do...
2) In the three or so months since I've been using these type of valves I have had not ONE sticking valve, even after an hour of play (including TB and chording, with a reasonable amount of saliva getting into the harp)
3) The ONLY problem I've had with these valves are from not curling them properly (ie., that one or two valves I made curled up away from the plate). That problem is solved by curling them tightly around a piece of wire (like a paperclip) BEFORE applying them. Rolling them from the adhesive edge outwards produces a better curvature, and largely prevents "curl away".
4) The exact product I'm using is JVCC brand Gaffers tape, available at Amazon for a little more than $12: (http://www.amazon.com/gp/product/B000QDRRIE/ref=oh_details_o02_s00_i01?ie=UTF8&psc=1). I chose this brand based on the results of this survey: (https://www.findtape.com/product321/FindTape-GAFF-TEST-PACK-Gaffers-Tape-Challenge-Pack.aspx#survey-results), and from other comments around the 'net that suggest it a) has a better adhesive than most (doesn't leave residue), and b) has a better cloth like "hand" to the tape material.
5) For tips on how to approach half-valved playing (including intonation, bends, vibrato, and legato playing), please see my other instructable.
Please feel free to PM me with any questions!
If you found this video helpful, consider leaving me a tip! You can do so easily at the following site: http://gotip.it/oneharp