What soldering gun wattage is needed for metal chassis soldering/desoldering?

[JCFitz]

I haven't done too much old tv restoration and I'm running into a problem. I don't have anything heavy enough to unsolder the filter caps from the chassis for restuffing. My old weller 100/140 watt gun won't cut the mustard. I bought a gun I thought would do it from Sears a Craftsman 400/150 watt that heats the tip up with 400 and maintains at 150 watt.I'm taking it back. It won't cut the mustard either.

They have a dual wattage one with 250 watt when held in the 2nd position. Looks just like the Weller version. Is that enough?Or do I need to find a butane torch or one of those huge old soldering irons they don't make anymore for this job?...lol.

They must have had something pretty heavy back when they made these sets with metal chassis. The Admiral Super Cascode I'm working on has all 4 twist leads of the caps directly soldered to the chassis also all the terminal strips

[bob91343]

A very cheap and effective iron is a propane torch with a soldering iron tip. I have one and it works beautifully. I also have an assortment of soldering guns (I hate those!) and various irons, up to an old ESICO 100 W that works great.

The secret is to have a tip with large thermal mass so it doesn't immediately cool on laying it to the work. The power rating is secondary, as you don't expect transfer from electrical power to the work directly. Let the tip get hot for ten minutes and, if it's big enough, it will do the job.

[bandersen]

I have a Weller 200/260 watt gun and it's just barely adequate for those twist lock lugs. One of these days I hope to pick up a hefty iron like an American Beauty.

[miniman82]

I forget what mine is, probably a 150/200 watt. Got it free at a garage sale, complete with tip. Works well on those cans, provided you pump new solder into the joint. Seems like that old crap always has a higher melting point, for some reason.

[droptop]

For soldering or de-soldering a chassis I use an 80 watt Weller SPG 80 iron bought at the local Lowe’s home center. I do quite a bit of work on antique radios and it has more than enough heat for chassis work. I recently had a Majestic model 90 battle ship chassis in for repairs and it does the job when removing the metal bypass capacitor cans riveted and soldered to the main chassis as well as twist lock tabs.

[fifties]

Originally Posted by miniman82

Works well on those cans, provided you pump new solder into the joint.

Exactly! The old adage about fighting fire with fire was never more true, lol.

I use a Rat Shack 230/150 -two position trigger- gun, and adding solder when I am trying to unsolder a chassis joint makes the job much faster and easier.

[jeyurkon]

Originally Posted by miniman82

I forget what mine is, probably a 150/200 watt. Got it free at a garage sale, complete with tip. Works well on those cans, provided you pump new solder into the joint. Seems like that old crap always has a higher melting point, for some reason.

Looks like many of have noticed the same thing about the solder.

Originally Posted by droptop

For soldering or de-soldering a chassis I use an 80 watt Weller SPG 80 iron bought at the local Lowe’s home center. I do quite a bit of work on antique radios and it has more than enough heat for chassis work. I recently had a Majestic model 90 battle ship chassis in for repairs and it does the job when removing the metal bypass capacitor cans riveted and soldered to the main chassis as well as twist lock tabs.

The iron works best for me too. It has plenty of thermal mass.

[Findm-Keepm]

Most (Sn/Pb) solder today is Eutectic - lower melting temps than the ol' standard 60/40 stuff used in days of yore. I got a bunch off eBay - 63/37 multicore, in two diameters. Works great for chassis soldering/desoldering. A Weller 8200 works for most folks, and the Weller D550 or D650 is recommended if you need more wattage. Tips are WIDELY available, and Weller is pretty much the last guy standing, thanks to Cooper Industries buying up Ungar and other soldering equipment brands.


Cheers,

[bob91343]

The trick isn't adding solder. It's adding flux.

[Findm-Keepm]

Originally Posted by bob91343

The trick isn't adding solder. It's adding flux.

Adding eutectic solder that lowers the melting point does wonders for desoldering and soldering. Unlike non-eutectic solders, it has only one melt point. 60/40 has a W-I-D-E range of melt temps.

Yes, flux adds a catalyst that removes the oxides from the soldering operation (Lead oxide, tin oxide, cadium oxide, etc.) But for desoldering, flux does little.

Good ol' 63/37 has the lowest melting point (361 degrees F) of all Pb/Sn solders. It's the only alloy used in military electronic apps, for that reason and one other - it remains "plastic" for a far shorter period, reducing "cold" or brittle solder joints. The Navy's Micro-miniature repair school, AKA Soldering school, teaches that adding fresh solder to the joint to be desoldered helps in the removal of solder. We're not talking blobs, but adding 30% more solder or less to the solder to be removed. Works wonders, especially on circuit boards. Chassis? Likely no effect, or very little, due to the heat sinking of the chassis material. With chassis soldering operations, more heat/wattage helps most.

Cheers,

[timmy]

got an old weller 240-325 watts can solder anything together, even at about 30 years old.

[dieseljeep]

Originally Posted by timmy

got an old weller 240-325 watts can solder anything together, even at about 30 years old.

The best Weller guns are the ones that use the tip nuts. The newer ones that use the set screws always need tightening and cleaning. Every time I see one at a garage sale I buy if the price is right.

[timmy]

yes this one has the nuts.

[miniman82]

That's how you know it's a MAN'S solder gun. lol

[Reece]

What you need is a lot of heat fast. Watts aren't necessarily the answer. I have a dual heat Weller and other irons but the one I call on for heavy work, not that often, is an American Beauty soldering iron that I got for a buck at a flea market. I think it's 150 watt. The thing is to plug it in for several minutes and let it heat up all that mass of steel and the big copper slug of a tip that extends deep into the heater. Then when you're ready to solder, all of that stored-up heat, much more than 150 watts, is available to pour out into the work. There's a bigger contact area with the iron and stored heat, more than just the instantaneous electrical rating of a gun.