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Author Topic: dumb soldering question of the day  (Read 669 times)

Offline IQ_imbalance

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dumb soldering question of the day
« on: June 22, 2020, 1958 UTC »
Any tips on soldering female F-connectors, esp. to the body?  I'm spitballing a RF filter circuit before i start cutting on my last mint tin.....
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Offline redhat

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Re: dumb soldering question of the day
« Reply #1 on: June 23, 2020, 0025 UTC »
Use a big (60W or better) iron.  Smaller pencil irons don't have enough heat to adequately solder larger metal parts.  Cheaper connectors with non-ptfe dielectric will melt if you use too much heat for too long.

The only stupid questions are the ones not asked :)

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Offline syfr

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Re: dumb soldering question of the day
« Reply #2 on: June 23, 2020, 1220 UTC »
I'll second the recommendation to get a big soldering iron.

I have picked up two--- the first is a 500+ watt monster which was probably used for duct work. I paid a dollar for it at a garage sale. This thing (after 5 min of warm up) solders even big connectors like PL259's like a boss, with little damage to the cable.  I can reflow solder on a PL259 in 10 seconds or so.

Likewise, I got a 300 watt American Beauty for a couple bucks at a hamfest. Same same.

With all cable connectors (unless you've purchased REAL silver plated stuff from Amphenol, etc), file off the plating in the area you're about to solder.  The junk plating put on most cheap connectors is tough to get solder to flow to.

Also: Cheap connectors have cheap dielectrics which melt easily.
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Offline Stretchyman

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Re: dumb soldering question of the day
« Reply #3 on: June 23, 2020, 1506 UTC »
Those irons sound awful, maybe ok for plumbing pipes and such but no use in any electronic environment!

METCAL, the one and only. Yes there were probably over $1000 new but you're going to buy a second hand one anyway.

They pop up on eBay quite often, just get one, you won't regret it.

Str.
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Offline IQ_imbalance

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Re: dumb soldering question of the day
« Reply #4 on: June 23, 2020, 1510 UTC »
Thanks!  Now that I've got a VNA i'm putting a toe into the 'brew your own RF filter' water.  On the plus side...i've gotten good with some of the simulation software, and the filter i cobbled together works after a fashion.  On the minus side....the simulations and real life frequency cutoffs are very different, i suspect due to my half-ass attempt at making coils.  Still...progress!
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Offline ChrisSmolinski

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Re: dumb soldering question of the day
« Reply #5 on: June 23, 2020, 1626 UTC »
I just picked up a nanoVNA 2.0, and am also having great fun with it, checking out several filters I built in the past. A very useful tool.
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Offline redhat

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Re: dumb soldering question of the day
« Reply #6 on: June 23, 2020, 1626 UTC »
60-100W is really all you need.  I have an older Hakko 60W I bought on closeout from a large electronics retailer years ago and use it routinely for connector replacement on commercial equipment, and also in situations where I need more heat.  FWIW I used a metcal tweezer for many years, until the probes started leaking and blowing up components.  I then switched to a Hakko base and tweezer to compliment the rest of the bench setup.  Metcal was always way overpriced in my book, even used.

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Offline Stretchyman

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Re: dumb soldering question of the day
« Reply #7 on: June 23, 2020, 1719 UTC »
Every company I've worked for use METCAL. I suppose cost is no object. Still I wouldn't use anything else.

Coil wise, stick to toroids and get a pair of measuring tweezers, not sure what you call them but have an LCD display and brass tweezers for measuring SMT components. Very nifty.

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Offline redhat

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Re: dumb soldering question of the day
« Reply #8 on: June 23, 2020, 1857 UTC »
Over here, I've seen a mixed bag.  Development places working with R&D or grant money see more metcal (where cost IS no object).  The rework folks like myself seem to lean more toward Hakko, Weller, Ungar, and a lot of the cheap Chinese stuff.  I just got a Quick hot air rework station, mainly for doing SMT rework and small run proto's.

Above 50 MHz, SMT inductors can be had in values close enough to suit your needs, and the repeatability will be better.  Not sure I'd use torroids at 300 MHz...

+-RH
« Last Edit: June 23, 2020, 1858 UTC by redhat »
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Offline syfr

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Re: dumb soldering question of the day
« Reply #9 on: June 25, 2020, 1240 UTC »
I have a Metcal with 20+ tips for electronics that I use daily (and have for 20+ yrs)

For CONNECTORS, there's no substitute for thermal mass.  The Metcal is not nearly as effective on large connectors as a large iron.  I can get on and off a large connector in a few seconds, and quench it before  affecting any of the dielectric.   




Those irons sound awful, maybe ok for plumbing pipes and such but no use in any electronic environment!

METCAL, the one and only. Yes there were probably over $1000 new but you're going to buy a second hand one anyway.

They pop up on eBay quite often, just get one, you won't regret it.

Str.
NRD525/TenTec Paragon lotsa wires and some beams

Offline Azimuth Coordinator

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Re: dumb soldering question of the day
« Reply #10 on: June 25, 2020, 2224 UTC »
I've been using a Weller WTCPN as my go to for the last 40 Years..  Oh Wow.. I'm getting old.. never had any issue soldering anything.. I also have two PACE MBT Rework Stations for desoldering and hot work they have a 35 watt iron as well.

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Offline Charlie_Dont_Surf

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Re: dumb soldering question of the day
« Reply #11 on: June 27, 2020, 2138 UTC »
Recognize that if you are soldering to a metal case, that case is a heatsink and will draw away the heat from your soldering iron, etc. As others have said, you need a large source and this is where I would use an air source.

I would also recommend pre-heating with a hot plate on the other side of the enclosure, if that is at all practical. The pre-heater is not not to heat things up enough that it solders on its own, rather just to reduce the amount of additional heat that your pencil or gun needs to provide to flow the solder. I use pre-heaters for SMD assembly and rework (all the good techs do this) but I used it for some connectors recently and it helped. Just don't make it too hot because you will melt the PTFE or whatever they use as the dielectric between the center and the shield side.

I also recommend using flux if you are using leadfree solder.
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