Looking for advice on soldering to the amp chassis

[coreysan]

I just bought a nice 200 watt iron with a 1/2 inch chisel tip. But when I tried to really heat up the
chassis and solder some ground wires to it, the solder still balls up on me.

Are there any secrets to getting the solder to sit down well? I'm working on a vintage Fender kit,
and the chassis is your typical galvanized steel chassis.

Any response would really be so appreciated!

Corey

[sluckey]

Sand the area to be soldered until it is shiny. Use plenty of flux. Heat it up first until your solder flows out flat to tin the area. Then solder your wire.

[coreysan]

I'll give it a try! Thanks!

[supro66]

I never solder to the chassis I use lugs


you can get single or doubles off Doug  Drill a hole in the chassis and use a screw lock washer and a nut
you just wire the lugs together and you have a good solder conection


There are small single lugs

[EL34]

I don't solder to the chassis
I bolt down the grounds with a dedicated bolt


Not a fan of soldering to a metal chassis

[drgonzonm]

The gurus are right as usual. 

With addition of three prong power, the lugs are the way to go.

The problem with soldering old galvanized steel, is that zinc oxide coating giving you the gray oxidized layer.  Some of the rosin fluxes have difficulties converting the zinc oxide back to elemental zinc.  Whats worse, some of steel is actually coated with a zinc-iron alloy, which is difficult to solder.  (Think paintloc steel). 

If you really need to solder to the chassis, try rubbing a pre 1982 penny in the area that you want to solder.  basically you are transferring a copper-zinc  alloy to your chassis point.  It will remain un-oxidized long enough to solder. 

[casssax]

https://youtu.be/GR3rR7tc30Y?t=1h9m53s

I was watching this video of a guy rebuilding a VTVM and he talks at one point about soldering to a chassis with a 250w iron with a #10 wire bridged in the tip.

[EL34]

Solder to a steel chassis is iffy at best
Bolting things down to the chassis is way easier and all you have to do is make sure you bolt the grounds down solid


Use the ring terminals I sell on this page
http://hoffmanamps.com/MyStore/catalog/MiscHardwareMobile.htm


Crimp them and then solder them to the wires