Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: G._Hoffman on February 22, 2010, 05:06:37 pm
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So, I'm reading the NASA soldering standards in the references thread, (which appears to have disappeared between yesterday and today, but HERE IT IS (http://web.archive.org/web/20080616150909/http://web.archive.org/web/20080616150909/http://workmanship.nasa.gov/lib/insp/2+books/links/sections/graphics/613/613-41.gif) on the Internet Archive), and I noticed they say that components should be glued to the board surface - makes sense for a vehicle that will be seeing a 5+G liftoff - and I'm just wondering, what adhesive would you use for that? Certainly, nothing we use for woodworking, although I suppose Duco might work...
I'm not actually planning on doing anything like that - I don't suspect anything I make will ever be included in a launch vehicle - but I am curious.
Gabriel
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I bond electrolytic caps to the preamp board with high temp silicone. If you look inside a Carr amp, there is tons of it for all kinds of components.
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I use Isaberg Rapid Eco T hot glue with a Rapid gun.
Easy to apply despite a tendency to form strings, holds very well large components, surprisingly easy to remove - leaves everything clean when peeled off.
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For caps I tend to use double-sided foam tape; or if clearance is an issue, flat double-sided tape. For resistors, slicone glue; but it has a long set time. I also like to use terminal strips so the components are suspended.
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> silicone glue; but it has a long set time.
And do NOT apply power until completely set. It's full of water and acid, great conductor until the reaction is totally done. I discovered this 30+ years ago and still remember the arcs, flame, and stench.
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> silicone glue; but it has a long set time.
And do NOT apply power until completely set. It's full of water and acid, great conductor until the reaction is totally done. I discovered this 30+ years ago and still remember the arcs, flame, and stench.
that reminds me of the first time i tried etching my own PCB circa 1975 - ferrichloride + aluminum pan = lots of nasty smoke and heat... :embarrassed:
i used to work for a HV hybrid component mfgr. - we used cyanoacrylate based adhesives (crazy glue) for the chips, caps, and some of the dice. the finished components were then hermetically sealed with silicon rubber and epoxy.
if you use silicone based adhesives or epoxies, you can accelerate the cure time to just a few hours if you place the part(s) in a temp. controlled oven ~~125deg. F
warning! your SO may not like the stench + your neighbors may think you're running a meth lab... but then again, i'm the kind of guy that dis-assembled a pair of 428CJ heads on the kitchen table and used the hotplate as a re-flow to repair SIMMs. :angel