Joseph M Gwinn skrev: > [email protected] wrote on 01/20/2009 04:32:15 PM: > >> Bruce Griffiths skrev: >>> The relatively low thermal conductivity of the steel can will help >>> considerably in avoiding thermal damage if the heat is >> applied to the joint. >>> If the can were copper it would be much more difficult to avoid > thermal >>> damage. >> When I needed to have a McCoy oscillator can opened my trusty good old >> friend Sten did the usual trick of pre-heating the can and then when >> applying heat to the solder the thermal difference is lower and hence > the >> heat-flow away from the joint. Didn't take much time and I think the >> oscillator is 100% intact. >> >> Pre-heating and hot air are his main tools for tricky soldering jobs. He > >> has low fatality rate on problems like that. This is why we let him do >> that kind of stuff at work. > > I imagine that Sten works *very* fast. I've found that when soldering > thermally sensitive things like small coil bobbins made of nylon that a > high temperature and relatively large iron is best - the terminals come up > to temperature almost instantly, and it's all over before the heat can > spread and melt the bobbin. > > Hot air has the advantage over a flame that overtemperature is less likely > with hot air.
Actually, the pre-heating takes a bit of time... but then it doesn't take much effort to push the solder over to melting and it took relatively little time. The pre-heating doesn't go all the way up there, so melting of plastics isn't really a problem. The pre-heating trick actually makes the big soldering iron rest most of the time... We have boards with so much ground/power grids that it is really a headache to do without pre-heating, which is similar to the iron case soldering problem. So, doing it this way makes it go fast. Cheers, Magnus _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
