20 replies to this topic

[Red Car Driver]

Quick question: Do you folks use the flux that comes with the Stay-Brite solder?? If not, what acid flux is best? The Stay-Brite stuff seems to encourage some bubbling and I've seen some brown residue that looks like rosin.

[BWA]

The bubbling is the solder itself, many low temp silver solders just do not flow as well as regular 60/40.

The only one I have found is that sold by Slick 7. It is the best-flowing low temp silver solder I have ever used.

[tonyp]

The Stay-Brite flux works very well. That is what I use. At work we found it to be the best for silver-soldering commutator tabs on our R/C motors.

[team burrito]

Stay-Brite acid flux is the best; the last bottle I bought is 12 or 16 ounces off of eBay. All the other stuff is crap, although Lucky Bob's works okay. I use Stay-Brite to start the solder joint; to reflow the solder, I use acid paste flux. It seems to make a nicer solder joint. I also use a torch, the higher heat helps purge out any air bubbles.

[GT40]

I think you mean Stay-Clean flux; Stay-Brite is the associated solder from the same manufacturer.

I agree, it works much better than a couple of other acid fluxes I've used.

[Tex]

I also use a torch, the higher heat helps purge out any air bubbles.

Speaking of torches, I hope to invest in one "someday". My local track has one for sale but I don't know what brands/models are recommended(?). The one they have is priced at $49; is that reasonable? What do you recommend?

[JimF]

Rustle has been using torches far longer than I have but so far a $24.99 Ronson torch has worked for me.

[yomama]

Where is the Stay-Brite acid flux sold?

[team burrito]

Here's where I got mine:



Click here for the link to eBay.

Rustle has been using torches far longer than I have but so far a $24.99 Ronson torch has worked for me.

Hey, Jimmy, what about this one?



Think it will do the job?

[Red Car Driver]

Thanx, guys.

I'll try the Stay-Clean flux. I also have an old Radio Schlok oxy-butane torch that I'll try with the little solder wedge trick. I'm only doing HO scale so it's often tight quarters.

[Rick]

Stay-Brite is the best out there, it is almost 6% silver, nothing else even comes close; most are 2% and some are 4%.

Stay-Clean is the flux. The bubbling is a good thing, means it is working. Silver solder seems to wet out at about 450 degrees and most 60/40 will wet out at a lower temp. If the joint is smooth, it was enough heat; if it's lumpy or rough-looking, not enough heat.

I used to buy the flux by the case in gallons and repack in small containers for slot use...

I don't think a torch is necessary except for guide tongues but the board guys like them.

[Bill from NH]

The regular Stay-Brite solder has a 4% silver content, they also make Stay-Brite 8 that is 6%. I've only seen a 2% silver bearing solder being sold at Rat Shack though it must be available at other places.

[Tex]

I don't think a torch is necassary except for guide tongues...

That's EXACTLY what I want to use it for; I solder a 1/16" brass guide tongue on top of a 1/16" brass plate.

[Jim]

Tex,

I have found that if I tin both pieces and use a very hot iron, I can easily solder them together. Mike Steube demonstrated a technique using lots of Stay-Clean flux and an Inland 100 watt iron which worked very well. He actually put solder on the top of the two pieces as well as mating surfaces to get the solder to flow evenly everywhere. After the joint was finished, he just cleaned the excess solder off with sandpaper and Scotchbrite pads.

I would also add that I have done more than a little inadvertent damage to my bench while using a torch. For that reason I have just tried to use the hottest iron available. At this point, that is the Inland unit that I bought at Buena Park Raceway.

If I am having problems getting a good solder joint, it's almost always either not clean enough or not hot enough.

Hope that helps.

[MSwiss]

That's EXACTLY what I want to use it for; I solder a 1/16" brass guide tongue on top of a 1/16" brass plate.

I'm not much of a "fire" guy. Along with the flame, I'm always a bit afraid of getting things too hot and have them lose their temper. I go with two irons when soldering to 1/16" brass. (BTW, isn't 1/16" for the tongue a bit overkill?)

Back to flux, for those who will attend the Sano and are flying/can't bring liquids, I'll have some real killer flux at the raceway they can try. I've never had Stay-Clean in the big bottle, but the stuff I have, IMHO, is a bit stronger/better than the Stay-Clean flux you get when you buy the combo with the silver solder. If you get the flux on your skin, it makes your skin tingle to the point that you find yourself walking fast to the faucet to neutralize it.

[GT40]

Nothing like the "skin test" for rating fluxes... kind of like the tongue test with 9 volt batteries

I have found that an 80 watt Weller iron, nominally sold for stained glass work, is plenty of heat for soldering even to chassis that are one big slab of brass. Much preferable to torches, in my opinion.

As Jim mentioned, Steube points out in his chassis building video that heat transfers from the iron tip to the work much more effectively if you tin the contact point, even when you are sweating two pieces together. This has been helpful for me.

Our local track owner Steve Foster will place a large piece of metal on a hot plate to warm it up before soldering. It is surprising how much of a difference it makes just warming the piece, even if it's not heated to the melting point of the solder.

[Cheater]

Our local track owner Steve Foster will place a large piece of metal on a hot plate to warm it up before soldering. It is surprising how much of a difference it makes just warming the piece, even if it's not heated to the melting point of the solder.

Steve, when I was 11 or 12 years old, I had a Weller 100/140 gun that didn't work really well for soldering thick brass.

What I did was place my chassis on the bare concrete floor in the laundry room, douse it with lighter fluid, and light it. After the flames had died down, the brass was preheated enough that the Weller soldered just fine...

I'm real glad my parents never discovered me using that trick!

The Stay-Brite flux works very well... At work we found it to be the best for silver-soldering commutator tabs on our R/C motors.

Uh, Tony, every reference I've seen says not to use acid flux on electrical connections. Is that not a problem for you guys?

[team burrito]

Mike Steube demonstrated a technique using lots of Stay-Clean flux and an Inland 100 watt iron which worked very well. He actually put solder on the top of the two pieces as well as mating surfaces to get the solder to flow evenly everywhere. After the joint was finished, he just cleaned the excess solder off with sandpaper and Scotchbrite pads.

If you tin both parts and hit it with the torch, you don't have to clean off the excess solder. And the solder get in every little crack and crevasse. Looky here:

[tonyp]

Greg,

We clean them really well. The high temp silver solder we use really won't flow any other way. On multiple winds at the last /first pole it's really important to make sure all the wires make good contact.

[GT40]

Cheater,

The phrase, "After the flames had died down..." always get my attention... particularly working at a place where they launch large rockets.