Silver Solder vs. Loctite Retaining Compound

[tghsmith]

for small stuff mapp will work fine,, a ceramic soldering base helps greatly as it insulates the work and allows the parts to heat evenly..working in a darkened space helps to see the glow of the pieces better..

 

[rjs44032]

I would use their clearance spec. Remember the parts will expand during the brazing. The silver braze will fill that gap fine.

Best Regards,
Bob

 

[JRaut]

Sounds like a plan. Thanks again for all the quick help.

 

[tghsmith]

for small work I get my solder from a jeweler's supply,, fine wire 22ga much easier to control placement and amounts..

 

[francist]

Some cursory online research says that a MAPP torch w/o oxygen will get hot enough, particularly for these small parts. Anyone agree/disagree?

Propane will get you there on small parts, especially if you block up a very simple soldering corner of fire brick to refract the heat. Like this..

There was a good thread on this topic not long ago here..

Tooling up for silver soldering

I did a lot of soft soldering on brass plate in the 60s during the slot car craze. Very simple and cheap - a 75 watt soldering iron, some paste, and some solder. that's all.... Soft soldered joints where you can't engineer a wide contact area can be fragile. The more stress it takes, the...

www.hobby-machinist.com

-frank

 

[pontiac428]

The point of some projects is to learn some of the old methods. If you don't know how to silver solder, here's a good opportunity to learn. It is not hard to do and is easily picked up. Hard solder and silver-bearing soft solders wick and flow like a dream. Most of the time, if you really mess up the process is reversible. It's not expensive. It is useful on a number of things. Give it a try!

 

[pontiac428]

Some cursory online research says that a MAPP torch w/o oxygen will get hot enough, particularly for these small parts. Anyone agree/disagree?

I disagree. Silver bearing soft solder will work with propane, but to do the same work with hard solder will take MAPP gas and a refractory enclosure like @francist set up in the photo above. I built a refractory furnace in a gallon paint can with refractory cement, it gets hot enough on MAPP for hard solder eventually, but I would say in general that propane is just shy of the temps needed to work productively.

 

[machPete99]

I would suggest putting a generous chamfer on the ID of the outer faces of the gears and use that to direct the solder between its ID and the sleeve.
You can silver solder from each side separately.
I would not attempt to apply solder between the gears, that will likely result in a mess.

 

[hman]

I'm definitely out of practice (what little I ever had) with regard to silver soldering and/or brazing. But one technique I like to use with soft solder and, when possible, soft silver-bearing solder like StayBrite, is to make a pre-form. In the case of something like that gear set, I would form a small single loop of thin wire solder around the sleeve, insert it between the gears, flux well, then heat. When the solder melts, the gears should pull together by surface tension.

I know this would work with soft solder. I'd love to hear what those in the know think of the idea - especially given for the 22 ga. wire that tghsmith mentioned - for hard/silver solder. Thanks!

 

[mikey]

You got some really good advice here and I have little to add other than another vote for Stay-Brite soft solder for this application. It works really well with Stay-Clean flux and a Mapp gas torch. I've used it on multiple small projects and it is much easier to use than hard silver solder. Stay-Brite only needs about 450 deg. F to melt so Mapp works for me on small parts like this.

As noted, clean is critical, as is applying the flux only where you want it to go. I've found that as you heat the flux it will dry, then turn liquid again. When that happens you can apply the solder. I found that heating everything up evenly is important (move your torch around) but when applying the solder, hold the flame on one side and apply the solder to the other side at the joint. The solder will wick and follow the heat. As soon as the solder begins to flow, remove the torch. You do not want to keep applying solder once it starts to wick or you'll have excess solder in and around the joint and a big mess to clean up.

Let the parts cool a little and drop it in warm water as suggested to get the flux off.