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Vintage threads from the first ten years

Old Fender amp soldering Q...

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8/9/2004 8:10 AM
Mike Z	Old Fender amp soldering Q... How do I unsolder the leads that go to the brass grouning strip? I have tried my regular soldering iron and it cant melt them. I tried a 140W soldering gun and still no luck. What do you guys use to melt these joints? Is there a trick? I figure the whole strip is acting as a very effective heat sink... Thanks... Mike

8/9/2004 4:07 PM

You're right, it is a very effective heat sink!

What I do (If I'm afraid to use a torch!) is to pull on the lead with needle nose pliers while heating the lead with my gun just before the lead hits the solder on the brass. If the lead gets hot it will slowly lift away from the solder as the solder immediately around the lead melts.

It's important to have the lead pulling at an angle rather than a straight pull so that the lead will be encouraged to slowly lift away from the solder blob.

Good luck!

---Wild Bill

8/11/2004 6:06 PM
mark h	Perhaps the trick is in the mass of the iron and not the wattage. I use a 50watt ungar element in my solder iron and it melts those blobs on the ground plate and chassis like butter. The iron has a broad tip so I can have a large contact patch on the area being heated. Good luck..M

8/11/2004 7:24 PM

It is the mass that matters.. btw, the approved technical term for these tools is "BFI".

I've been on a couple of BBS's where folks who didn't fall asleep in physics like I did were able to explain the mass thing to me..

Anyhow, go to a hobby shop that has stuff for stained glass windows. There is an 80W Weller model with a big chisel tip those folks use(heavy mutha!) that's what I use to weld, err, solder to the chassis and the brass bar and the backs of pots. Some local hardware stores *might* also have one around. Get a tube of flux from your local rat shack. Get one of those little tins of tip cleaner/tinning stuff as well.. keeping the tip clean and shiny makes thing go a lot smoother. Scuff up the brass with emery paper or steel wool. Put a glob of flux on it and heat her up.. soldering should not be a problem any more. Same proceedure for soldering to the chassis. You can clean the flux off afterwards with various solvents and a q-tip.. It still takes skill and patience, but at least it's possible with the right iron!

8/19/2004 11:05 AM

quote:
"I tried a 140W soldering gun and still no luck. "

You might be able to use the gun if you remove the tip and replace it with a couple pieces of heavy gage wire to act as electrodes. This converts it into a nifty "resistance" soldering iron. The iron will force current through the metal between the electrodes and the resistance of the metal will create heat. I haven't tried this with a soldering gun but it makes sense. Now I wish I hadn't thrown away those "useless" soldering guns years ago...

RE

8/21/2004 10:29 PM
Mike	Thanks for the replies guys - a larger solder tip did the trick. I do want to try the resistance soldering idea... Mike

10/21/2004 3:10 PM
anoinimois	Blow torch.

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