Hot melt is a bad choice for most things, ultimately. Its quick and easy to use and sets quite quickly but it doesn't last as a glue. Many people use it in electronic assemblies and my universal experience is that it deteriorates in a year or two. If the glue is load bearing the glued object drops off and does whatever the glue was initially meant to stop it doing. (Its excellent for use in products with a one year warranty :-)). A much nicer adhesive which lasts longer than I have been using it (the manufacturer of some versions says it will last 20 years out in the weather) is "Silicon Rubber" (RTV etc). This sets in hours rather than minutes but doesn't let go. Messier, gap filling and slowish setting. You MUST use "neutral cure" versions - MOST versions use acetic acid cure which is potentially corrosive, bad on eyes etc and unnecessary. I use a neutral cure "marine" version which is marvelous for secondary anchoring of components which will be subject to mechanical shock. The glue sets to a "rubber" with excellent adhesion and a some flexibility which stops shock fracturing. Very useful is "household epoxy" (as its called here in NZ) which is epoxy resin with about a 1 minute pot life. Sets to good tack strength in 2 minutes (firm and unworkable - would easily hold an IC socket) and is very very well set in 10 or 15 minutes. Its very probably not as strong as regular epoxies but works superbly for anything that needs strength and speed. Not quite as fast as "superglue", gap fills (so no good on crockery) and is 2 part but still useful. The resistance between probe tips placed as close as I can get them without touching (0.5mm / 0.020"???) is over 30 megohms (standard el cheapo electronic meter, low voltage) whether fully cured (scrap from bin) or just mixed. I've never tried it in a power on situation but it sounds like the glue you want. -----Original Message----- From: Lee Jones To: PICLIST@MITVMA.MIT.EDU Date: Monday, August 31, 1998 7:39 PM Subject: Re: Weldbond - Weird Problem with the 16C64A >> I just found a weird one that you should be aware of: >> >> I am building a circuit with a 16C64A and I am putting a 40 Pin DIP onto a >> Wire Wrap Board. I couldn't find a 40 pin W/W socket, so I made one by >> cutting up two 16 pin and one 8 pin W/W DIP Sockets. > >> glue [sockets] down with "Weldbond". > >> Putting in the 16C64A, I found it wouldn't run. > >> glue, two were straddling these pins and Vdd. I scraped off >> the glue and lo and behold, it started to work > >Very interesting tidbit that I'll have to remember. > >On the subject of resistances of liquids... We were trying to >figure out how some soft drink dispensers stop filling the cups >when they reach the top. Our guess was dispenser measured the >resistance from liquid stream to the metal (always) push bar. >So I measured flowing carbonated soft drinks. Got 10K ohms for >diet and 40-50K for sugar ones. > > >> So, I guess I should be looking for some other glue for this type >> application. Does anybody have any suggestions? > >I've tried hot-melt too. I switched to Devcon 5 minute epoxy. >Been a while since I've done any wire-wrap though I still use >the wire to jumper pins on prototype boards. A couple wraps >holds it nicely while you're soldering. > > Lee Jones > >------------------------------------------------------------------- >Jones Computer Communications lee@frumble.claremont.edu >509 Black Hills Dr, Claremont, CA 91711 voice: 909-621-9008 >------------------------------------------------------------------- >