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Re: Re: MicroWave: Re: Indium solder question from KA0RYT (EN34DW - MINN.)




I'm not sure it's what you need exactly. If I can find a tube of it around I
can send you the specs, but Mouser has a silver epoxy that works
quite well with very low resistance. I have used it on solar panels here
instead of the solder and have found it to work well on UHF connections
as well.


At 06:02 PM 09/19/2000 -0700, Clifford Buttschardt wrote:
>Oh my Paul you have hit a nerve that is only hours old.  I asked for some
>Indium/Silver solder as we have a number of solar cells awaiting 
>construction in a satellite project.  Unfortunately even with the
>suggestion of a manufacturer, we distroyed the cells with 60/40 solder.
>      We need an answer!  Not only is the connections between the cells
>important but we need to know what Epoxy---non gassing type--- that will
>work.  So far, only the Indium solder has been suggested and nothing
>regarding the "glue" need to fasten the cells to a satellite face been
>suggested.  The world has all kinds of suggestions but nothing specific
>that we can tell students BUILDING a CUBESAT what to do!  Cliff K7RR
>
>
>On Tue, 19 Sep 2000, Paul Wade W1GHZ (N1BWT) & Beth Wade N1SAI wrote:
>
>> I had lots of experience years ago with indium solder, ALL BAD!
>> when I worked at Microwave Semiconductor, they used indium solder
>> to assemble microwave amplifiers; they ended up replacing every one 
>> of them when the joints failed.  they would come back with alumina 
>> (ceramic) circuit boards rattling around in the case.
>> 
>> as I recall, there were two major problems: 
>> 
>> 1. gold and indium form an amalgam that is very brittle and perhaps 
>>    somewhat porous.
>> 
>> 2. the indium solder required a very active flux (read: ACID).  since
>>    flux is never completely removed, any moisture that seeped in later
>>    would spread the acid around and finish off the joint.  
>> 
>> I recall reading a posting recently looking for a flux-free indium 
>> solder used for photocells.  this would eliminate the second problem.
>> 
>> however, the first problem is not so easy, and probably occurs with 
>> silver as well.  I learned a lot about metallurgy and ceramics the 
>> hard way, and education is always expensive.
>> 
>> so I'd recommend staying away from indium.  ordinary solder works
>> very well with copper, and silver solders are available with higher
>> and lower melting points if you are trying to have more than one
>> soldering temp.
>> 
>> 73
>> paul
>> 
>> 
>> At 09:26 PM 9/18/00 EDT, you wrote:
>> >Hello !! My name is Ron and I was directed to ask you for some info on
your  
>> >experiences with the indium solder that W2DRZ was discussing on the VHF 
>> >reflector ....... I am considering trying with this solder for
experimental 
>> >soldering on some 432 cavity input preamps . I have been constructing 432
>> and 
>> >144 cavity input preamps for several years (please take a look at the
>> Central 
>> >States noise figure results to see my "work") . I am curious if there are
>> any 
>> >bad effects from using this type of solder on the copper pipe type
cavitys 
>> >that I produce here ?? Any info would be appreciated - I am planning to 
>> >silver plate these too ........ 73 and tnx again , Ron Bergantzel KA0RYT 
>> >
>> >
>> 
>> 
>
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>
Reid Bristor
Bristor Associates
URL:	www.bristor-assoc.com
Phone:	(407) 254-1265
FAX:	(407) 253-1162

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