Author Topic: Silver Soldering: How to do it? (Read 6934 times)

Claudio Chacon · « **on:** September 01, 2009, 07:31:32 AM »

Hello guys,
I have to solder the flap and stab horns I've made, but I have no previous experience with silver soldering.
What kind of torch would I need? Are those "pencil" type ones OK to do the job?
What kind of flux should I use? And what kind of silver solder?
I know there are two kinds of silver solder: the "hard" one, which contains silver/copper/zinc and the "soft" kind, an alloy of silver/copper/zinc/lead.

Any tips are welcome.
Thanks!
Claudio.

Randy Powell · « **Reply #1 on:** September 01, 2009, 09:06:49 AM »

Claudio,

Were it me, I'd braze them.

Claudio Chacon · « **Reply #2 on:** September 01, 2009, 09:49:36 AM »

Quote from: Randy Powell on September 01, 2009, 09:06:49 AM

Claudio,

Were it me, I'd braze them.

Randy,
Do you think that silver solder is not strong enough?

Randy Powell · « **Reply #3 on:** September 01, 2009, 11:21:22 AM »

Claudio,

If you use real silver solder (not stuff like StayBrite), and can heat it enough, then silver solder is OK. I've used some high silver percentage stuff I got from the welding shop on occasion and it seems to be OK. But I'm paranoid. I'd use a 5000° pen torch and a light brazing rod.

Mark Misegadis · « **Reply #4 on:** September 01, 2009, 11:43:32 AM »

Claudio,

I can help.

First off I want to ask what those horns are made of.

Solder - Stay Brite Silver Solder and the “Acid” flux that it comes with will work great for this. I think that if you braze them you will get too much heat in the part and soften the metal. Stay Brite is 4% Silver and this works out to make it strong but not brittle.

I use typically two major tools to do my silver soldering.

Iron - Weller or Unger 45 or 50 Watt soldering Iron. There are other Irons out there that may even have higher wattage but these work and are of the correct size to go where you need them to go.

Torch - When the part it large enough that I need the heat - I have a Syntax Micro - Butane Torch (I actually have two that are the same but this is the name they are sold under now) These are much cheaper today at around $30 than when I bought my first one years ago at $70 from a store that sells to Jewelers.

This is the supplier I could find quickly on the Web but there are many many more that sell this same torch. The important thing here is that this one has a throttle that works well.
http://www.ottofrei.com/store/product.php?productid=7227&cat=0&page=1#DetImage

Now as far as the soldering goes I could write a novel here on this but if you would prefer it would be easier to chat about this over the phone. I taught a class on this in recent history so I am sure I can get you up to speed.

Here is a link to a sample of where I use these skills.
http://getyourwebsitehere.com/scratchbuilt/gallery/gallery088.html

IF you want them soldered for you I would be more than happy to do so. Just PM me and we can go from there.

Mark

Randy Powell · « **Reply #5 on:** September 01, 2009, 02:28:59 PM »

I think you'll be sorry if you use StayBrite. But that's probably just me. If you get a perfect joint and heat it just right, it would probably hold up alright, but I had one fail with this and won't use it again. The stuff I use is from the welding shop is 60% silver and the rest is Pin-Brass (2-parts copper, 1-part zinc). With a brazing torch, it works really well.

I prefer to buy Tom Morris horns. Making horns can be a pain. But I've done it on several occasions.

Will Hinton · « **Reply #6 on:** September 01, 2009, 02:42:30 PM »

I'm with Randy on the Stay Brite thing - it just won't hold up to several hundred flights every time unless everything is absolutely perfect, and since you're inexperienced, it probably won't be the first many times around.
I use the 45% stuff and a special flux from Harris that I get from Grainger Supply. (Google them)
I use a butane torch and with the special flux the solder only flows to the places where the flux has been applied. This is nearly as strong as brazing and I've never had a joint fail in over 40 years of making my own horns.
As to the thoughts about fear of softening the horns, I only use drill rod instead of piano wire so the horns can be tweaked much easier, but I garuantee you won't see them accidentaly tweaked by bumping the flaps or elevators. Let's be real here, we tend to way over-build these things.

Andrew Tinsley · « **Reply #7 on:** September 01, 2009, 04:48:29 PM »

Hi Claudio,
I am from the UK so I can't quote suppliers and materials that you can get in the US. For the metals you are using, a high percentage silver solder (at least 50% Ag) and the appropriate flux is what I would go for. Brazing is fine if you go to a higher temp. The fluxing needs a bit more skill than silver soldering in my experience. But either method will give a very strong bond.
The thought of something the other guys call Staybrite at 4% silver,, fills me with horror as does talk of electric soldering irons. This sort of thing will not get the job done! Those folk that recommend it, must have been very lucky to get away with it. Don't even think of going there. High temperature brazing and real silver soldering are fool proof, if done properly.

Good torching,

Andrew.

Claudio Chacon · « **Reply #8 on:** September 01, 2009, 05:20:09 PM »

Hello Gentlemen,

Mark:
Many thanks for your advice and your offering about soldering the horns for me, but I live in Argentina.
I'm sure that the "Stay Bright" stuff may have worked for you in this kind of application but if I solder my horns with it, I'm afraid I will never be able to sleep for the rest of my life. You know...
Thanks again!

Randy, Will, Andrew:
Of course, Stay Brite was absolutely out of the question from the beginning . Great stuff but certainly NOT for this use.
I've been doing a little "research" and found that there are not two but five grades of silver solder:

- Extra Hard: 80% silver - 16% copper - 4% zinc (fusion point 809ºC - 1488ºF)
- Hard: 76% silver - 21% copper - 3% zinc (fusion point 773ºC - 1423ºF)
- Medium: 70% silver - 20% copper - 10% zinc (fusion point 747ºC - 1376ºF)
- Soft: 60% silver - 25% copper - 15% zinc (fusion point 711ºC - 1312ºF)
- Extra Soft: 50% silver - 15% copper - 15% zinc - 20% cadmium (fusion point 681ºC - 1258ºF)

Following your advice, I think I can stick with the "soft" grade.
I'll do a couple of soldering tests first -not with the actual horns- and see how it goes.
I'll keep you posted!

Thanks a lot to everyone,
Claudio.

Mark Misegadis · « **Reply #9 on:** September 02, 2009, 08:41:57 PM »

Good Luck Claudio,

You have done some good research.

Please post photos of how it works out for you. Right now these horns are very nice looking.

I have not yet soldored any horns for aircraft yet. What I do use it on is slot car racing. When we mess up we hit the wall and expect all the soldor joint to stay so that they car can be resloted and continue racing. I will admit that something may get bent but we expect the solder work to survive.
I still think this is much more stress than you will see.

If you guys will allow me to post some of my fabrication as an example. Please see attached.

Mark

Dan McEntee · « **Reply #10 on:** September 03, 2009, 12:37:55 AM »

StayBrite should work perfectly well for this. You have all of the basics for a good silver solder job already, nice, tight fitting parts and everything antiseptically clean. That is the main critical aspect for me to get good results on any kind of solder joint whether it is soft solder or silver solder of any percentage. If you had problems with StayBrite failing, you probably didn't have a good fityting joint, or it wasn't clean or something caused insufficient flow of the material. Sometimes, it only takes a very small void to allow a joint to fail, and I'm speaking from personal experience here
In the horns as you have them pictured, I would follow this procedure; First, solder up the horn to the wire first, just enough to do the job. Next, I would solder the re-enforcement washer on either side, one at a time making sure everything is properly fluxed first. And I would do it all with a clean, well tinned 40 to 50 watt soldering iron with a broad tip. A torch can be used, but the other way that you can cause a silver solder joint to fail is to overheat the joint and cause oxidation, something you can't see. It's very very difficult to over heat a joint with a soldering iron.
And the best way to get proficient at all of this is to practice, practice, practice! It's the only way to Carnegie Hall! Make your mistakes on the practice pieces, and try testing them to destruction so you can see exactly what kind and how much stress they will take.
Good luck with it!
Type at you later,
Dan McEntee

George · « **Reply #11 on:** September 03, 2009, 07:41:43 AM »

Just another opinion, but doesn't a lot depend on the TYPE of construction.

For those of us who use a short piece of brass tubing over the wire to provide more area, and then a thick piece of brass soldered to the tubing, Stay Brite seems to work.

Note that Claudio's setup seems to be thin sheet steel over the wire (or rod) with washers for area. For this, I don't think Stay Brite would hack it.

Also, a piped .60 will induce a LOT more stress on the joint than a Fox .35, so what strength do you need?

And besides, if Claudio uses the good stuff, he knows he's done his best...and can sleep better.

George

Mark Misegadis · « **Reply #12 on:** September 03, 2009, 01:33:04 PM »

ITs very true that Design and Execution are equally important. No matter what the material choices are Dans comments on cleanliness will be something that is consistant. The proper heat for a "complete" flow is also critical.

Everything in the photos I posted is all done with an Ungar iron.

As far as execution goes take a good look at the V shaped motor brace and how it picks up the inside of the motor bracket while resting on the bearing tubes. Design and exection. That little .030 wire does alot of work.

Even though this is a different application it is one where the environment its expected to perform can be severe. I borrow ideas from everywhere so this is just another example of that. At some point there will be a Jewelry class to gain further experiece in working with varoius melting points of solder on the same piece.

Mark

john e. holliday · « **Reply #13 on:** September 04, 2009, 08:07:44 AM »

Mark, that is some nice work. Where do you run slot cars? Here in KC it is a dead event as far as I can tell. At one time there were at least a dozen slot car tracks in the area. Now I can't find even one. DOC Holliday

Mark Misegadis · « **Reply #14 on:** September 04, 2009, 08:25:21 AM »

Thanks Doc,

We run in Loveland Colorado. There is a series that runs Vintage style slot cars that I run at the facility once a month for Can Am cars and Vintage Stock cars. Its something I have always been involved in that is now popular again. Scratchbuilding was voodoo and there were a couple of us that knew of each other in 07. Now its back really big. I had my own commercial track open in 2008 but it is tough to keep the interest in the summer time. I still have the track and am looking for space. During my time open I taught a scratchbuilding class and it went very well. This is a particular area where I have some skills to offer and I thought I should do that considering all the questions I have asked of everyone here.

As of last summer I got back into 1/2a control line again as a neighbor had a bunch of stuff hung in his house stored for a friend. I found out some of the kits of these same planes were available and we were off. We have had a blast with it.

We just recently found out about a big event in Denver this weekend for Control line and plan on going up to spectate that. It should be a blast!

Mark

Derek Moran · « **Reply #15 on:** September 04, 2009, 09:34:13 AM »

Claudio,
I wrote a construction article on the Stuka Stunt Foum that may interest you:
http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=331672&mesg_id=331672&listing_type=search
Derek

Claudio Chacon · « **Reply #16 on:** September 04, 2009, 12:13:01 PM »

Dear all:

Mark,
Ahh, the slot cars...
Your pictures reminds me my childhood. I remember that Christmas (I was

when I received from my father that "Scalextric" slot racing track...and that special "scent" of the plastic cars with the "Mabuchi" engines. Good old days, gone but not forgotten...
By the way, very good soldering job you did in those chassis.
Yes, I'll post some pics as soon as I can get the horns soldered.

George,
Yes, the horns are made out of sheet steel and 1/8" K&S piano wire, and the planes will carry Saito .72s.
Shake it baby...!

Dan,
Thank you for taking the time to post your tips, but I'd rather stay away from Stay Brite for this specific job.
There would be a high risk involved that I can't afford...

Derek,
What a GREAT tutorial you have there. Very enlightening! No doubt that is a professional job. AWESOME jig!
I don't have the tooling required to do something like that, but I've made a much more modest horn jig to hold the parts steady in place while soldering. Hope it serves me to get the job done.
Many thanks for your input.

See you later guys

!

Mark Misegadis · « **Reply #17 on:** September 04, 2009, 02:06:28 PM »

Claudio,

Nice Jig. The only thing you might consider when you are using it would be that the arm at the top holding the horn could act as a heat sync. See what happens first as it might be just fine. Something to keep in mind.

Pretty stuff!

Mark

Claudio Chacon · « **Reply #18 on:** September 05, 2009, 01:23:22 PM »

Well guys, here are my soldered horns.
I think they came out really well, may be not as Derek's job

, but I'm quite satisfied. The silver solder just ran through the joints by capillary action as soon as I touched the heated parts with the silver rod, pretty much as the thin CA does.
Very interesting first time experience for me. I'm happy

!

Thanks to everyone who took the time to post their tips!
Cheers,
Claudio

Derek Moran · « **Reply #19 on:** September 05, 2009, 07:02:34 PM »

Beautiful work, Claudio!
What is the thickness of the horn material you are using? I used .063 inch (1.6mm) which makes a good brazed joint, but otherwise it is unnecessarily strong and heavy.
Derek

Claudio Chacon · « **Reply #20 on:** September 06, 2009, 09:10:49 AM »

Quote from: Derek Moran on September 05, 2009, 07:02:34 PM

Beautiful work, Claudio!
What is the thickness of the horn material you are using? I used .063 inch (1.6mm) which makes a good brazed joint, but otherwise it is unnecessarily strong and heavy.
Derek

Thanks Derek!
The sheet steel I use is #20 (0,89 mm. - 0,035"). There's no way we can bend that horns even under the worst flying conditions, and those washers I added provide that extra thickness and soldering area at the joint.
Yes, I agree: you can save some grams by reducing the thickness of the sheet steel you use for the horns. But on the other hand, they won't look so NICE!

Regards,
Claudio.

Randy Powell · « **Reply #21 on:** September 06, 2009, 03:02:38 PM »

Very nice work, Claudio. I didn't see, what did you decide on for the silver solder?

Claudio Chacon · « **Reply #22 on:** September 06, 2009, 04:03:31 PM »

Quote from: Randy Powell on September 06, 2009, 03:02:38 PM

Very nice work, Claudio. I didn't see, what did you decide on for the silver solder?

Thanks Randy.
I used the extra soft grade (50% silver) just because that was the only kind I could get in my area.
Everything else may fail in the plane (HEAVEN FORBID!) but not that soldered joints, I can bet on that.

Richard Grogan · « **Reply #23 on:** September 06, 2009, 04:44:09 PM »

Just out of curiousity, what method does Tom Morris(Jim Snelson) use on his/their products?

GGeezer · « **Reply #24 on:** September 06, 2009, 06:36:41 PM »

The phrase "silver solder" is often wrongly used

to describe a welding process that is really called "silver brazing". If the joining process is done below 800 deg. F, it is called "soldering", if above 800 deg. F it is called "brazing" if a filler metal other than the base material is used.
Silver brazing wire or rod is an alloy of silver, copper, zinc and often cadmium and requires an oxygen/gas torch to provide enough heat for most jobs, although for small jobs, a propane torch will work if it can get the base material to a dull red heat.
In many applications, a silver brazed joint is stronger than the base material.

Orv.

Randy Powell · « **Reply #25 on:** September 07, 2009, 01:04:30 AM »

>>Silver brazing wire or rod is an alloy of silver, copper, zinc and often cadmium and requires an oxygen/gas torch to provide enough heat for most jobs, although for small jobs, a propane torch will work if it can get the base material to a dull red heat.
In many applications, a silver brazed joint is stronger than the base material.<<

I usually use MAP gas. I've also used a MAP/Oxy setup, but not usually. MAP generally does the job.

Bob Reeves · « **Reply #26 on:** September 07, 2009, 04:15:15 PM »

Quote from: Richard Grogan on September 06, 2009, 04:44:09 PM

Just out of curiousity, what method does Tom Morris(Jim Snelson) use on his/their products?

Tom's are brazed.

Alan Resinger · « **Reply #27 on:** September 08, 2009, 07:45:13 AM »

There are probably a lot of people out there who would love to have the skills displayed by Claudio in the execution of his horns. I've built a ton of horns over the years and have used Stay Brite and even used standard solder. Before everyone says that my horns are an accident looking for a place to happen, I want to show my method so that anyone can make horns and you don't need anything but a standard soldering iron and common solder. Before I go any farther I want to admit that I didn't invent this system and owe the credit to the late Bob Baron for the methon of horn construction. I've included the drawing for both an elevator and a flap horn showing the uprights and will give a brief explanation.
As can be seen both the uprights have holes for the horn wire plus a small diameter second hole adjacient to it. After thoroughly cleaning the upright and the horn wire but before bending the wire, insert the wire through the hole. Cut a piece of smaller wire the diameter of the second hole about 3/8" long and make sure it has been cleaned and is ready for soldering. Insert into it hole and then wrap a few turns of thin copper wire around the two wires on both sides of the upright and solder. The horn wire is then bent at the proper locations after brass tubing bushings are slipped onto the wire. With a good solder joint the horn upright will never twist around the horn wire. Even common solder will work as I've made test pieces and tested them to really hight twist forces.

Claudio Chacon · « **Reply #28 on:** September 08, 2009, 12:26:43 PM »

Quote from: Alan Resinger on September 08, 2009, 07:45:13 AM

There are probably a lot of people out there who would love to have the skills displayed by Claudio in the execution of his horns. I've built a ton of horns over the years and have used Stay Brite and even used standard solder. Before everyone says that my horns are an accident looking for a place to happen, I want to show my method so that anyone can make horns and you don't need anything but a standard soldering iron and common solder. Before I go any farther I want to admit that I didn't invent this system and owe the credit to the late Bob Baron for the methon of horn construction. I've included the drawing for both an elevator and a flap horn showing the uprights and will give a brief explanation.
As can be seen both the uprights have holes for the horn wire plus a small diameter second hole adjacient to it. After thoroughly cleaning the upright and the horn wire but before bending the wire, insert the wire through the hole. Cut a piece of smaller wire the diameter of the second hole about 3/8" long and make sure it has been cleaned and is ready for soldering. Insert into it hole and then wrap a few turns of thin copper wire around the two wires on both sides of the upright and solder. The horn wire is then bent at the proper locations after brass tubing bushings are slipped onto the wire. With a good solder joint the horn upright will never twist around the horn wire. Even common solder will work as I've made test pieces and tested them to really hight twist forces.

Alan,
That's a very good alternate method. I can see that with the additional small diameter wire, there's no way the horn can twist around the horn wire. I like it!

A bit of off topic history: I'm sure you don't remember me, but I remember you very well. We met each other during the CL World Championships held at Pécs, Hungary in 1986. I was one of the argentine team members. You were flying a BEAUTIFULLY FINISHED "Macchi Castoldi" powered by -if memory serves me well- a ST.60.
Let's see a couple of scanned pics of those days...
1) From L to R: Me (wearing a cap that you may recall) James Casale and Carlos Barrabino, other argentine team member.
2) Standing, the USA team.
3) Your gorgeous Macchi Castoldi.

By the way: I STILL have the cap you gave me!

Hope you enjoyed the pics Alan, good old memories...

See you around

Claudio.

NOTE: The white dots and little stains you see in Alan's plane are not actually finishing flaws. Those are some dirt spots present in my scanner glass. Alan's plane must be seen to be believed!

Randy Powell · « **Reply #29 on:** September 08, 2009, 12:34:36 PM »

Alan,

I've used a lot of alternate methods for horns. The best was using a steel upright piece for the pushrod connection then using two pieces of drill rod, bend them up in the center and lace copper wire through the steel piece and around the upright bend of the drill rod. Regular solder works fine. But doing this is something of a pain and not nearly as pretty as Claudio's work.

After having a control system part fail in my last plane (in the middle of the vertical 8 in high winds), I won't take chances again.

Allan Perret · « **Reply #30 on:** September 14, 2009, 07:38:41 AM »

Quote from: Derek Moran on September 05, 2009, 07:02:34 PM

Beautiful work, Claudio!
What is the thickness of the horn material you are using? I used .063 inch (1.6mm) which makes a good brazed joint, but otherwise it is unnecessarily strong and heavy.
Derek

Instead of steel for the arm, what do you think about using the K&S brass strip or even the rectangular brass tubings. Do you think it would be strong enough. The strip is available in .063" and .094". Also would the same brazing process / materials you used for all steel horns work with a brass / steel junction ?

Randy Powell · « **Reply #31 on:** September 14, 2009, 09:49:50 AM »

Allen,

I would be concerned about fatigue with brass. Perhaps a bronze alloy?

Claudio Chacon · « **Reply #32 on:** September 14, 2009, 07:26:53 PM »

Quote from: Allan Perret on September 14, 2009, 07:38:41 AM

Instead of steel for the arm, what do you think about using the K&S brass strip or even the rectangular brass tubings. Do you think it would be strong enough. The strip is available in .063" and .094". Also would the same brazing process / materials you used for all steel horns work with a brass / steel junction ?

I don't know about the rectangular brass tubings, but I have a solid 1,5 mm. brass horn arm in my "Voodoo" (this one is brazed). More than 400 flights in it (since 2002) with no stress signs of any kind.
However, I think sheet steel is better for three reasons:
1- It's lighter.
2- It's stronger.
3- It's cheaper

Doug Moon · « **Reply #33 on:** September 15, 2009, 07:45:46 PM »

Your work is outstanding as usual.

Be sure to use a wire brush and clean them. Looks like you already did but skipping that step can cause problems later on down the road.

Claudio Chacon · « **Reply #34 on:** September 16, 2009, 07:11:10 AM »

Quote from: Doug Moon on September 15, 2009, 07:45:46 PM

Your work is outstanding as usual.

Be sure to use a wire brush and clean them. Looks like you already did but skipping that step can cause problems later on down the road.

Thanks Doug.
Yes yes, the horns were thoroughly cleaned eliminating all possible flux residue.