View Full Version : Help..Silver Solder or not???(Newbie)
02-21-2005, 07:19 PM
OK, I ma making progress on getting my ATLAS 10x24 operating . I had a mitre gear with a broken key that went into the lead screw to power the cross drive. So I secured a replacement mitre with a keyway already cut in the metal (common problem apparently) and I milled, from keyway stock a new key (1/8"Wx3/16"H which was my first milling attempt and it went great). Now HOW do I affix the key in the gear? I have read tons of material on soldering, can I use plumbing solder? If not silver solder and the big question is what constitutes silver solder? I have silver bearing solder? or should I buy silver solder rods? The mitre gear will be driven by the ATLAS lead screw. I am unable thus far to find a product called silver solder other than silver solder rods. Is plumbers solder ok??? Or metal non-electrical solder? I have a mapp torch is that too hot? Questions, questions.. answers are the tough part.. I appreciate any assistance that you can muster up!!! Ron
02-21-2005, 07:49 PM
Have not had a lot of experience with the either -or but seems to me you could use regular solder. Fred
02-21-2005, 09:13 PM
Regular solder will be fairly soft, silver bearing solder will be a little harder, but is basically the same. Both melt at lower temperatures than real silver solder. That will need something near dull red heat to make it melt and flow. It can be purchased from metal shops as wire, and is usually either .030 or .062 or close thereabouts. My local shop has easy-flo 45 in the smaller gauge, and they charge by the gram for it.
But as far as securing the key, I would be highly tempted to JB weld it in place, if it absolutely must be held somehow. I think regular soldering is going to fool you into thinking that it's holding, when it's actually going to be too soft to take it, and will let you down. The heat required for silver soldering might de-temper the parts and maybe cause a warping, which you don't want either.
02-21-2005, 09:38 PM
Brownells has quite a few "low temp high strength" solders. I use mostly the Hi-Force 44, sometimes need the Hi-Temp Hi-Force 44. Each one uses its own special flux.
About half as strong as brazing, but only half as much heat input to your part.
[This message has been edited by precisionworks (edited 02-21-2005).]
02-21-2005, 09:46 PM
My question would be "Why solder the key?". I believe it should be a light press fit in the shaft and a tight but sliding fit in the gear. If the keyway in the shaft is worn then it should be milled wider and then use a two width key or broach the gear to a larger size to fit. Soft solder will just pound out of the keyway and it will take an oxy/acet torch to hard solder it.
02-21-2005, 10:20 PM
Silver Solder IS any silver bearing solder. From 0 % to about 40%. The good stuff has more than 15%. It only takes heat. Enought heat only takes time. A Mapp torch will work. Go to a welding supply and acquire a bit of the solder wire and some BLACK flux - not the common white stuff. White flux is used on copper and brass. Black steels and Stainless steels REQUIRE black flux for predictable success. Get rid of any Cadmium plating on the key and flux only the area you want solder to flow into. If you are sloppy with the flux, the solder will go there too and is reqlly difficult to grind or file out. I sandblast as much as possible of Silver Solder projects B4 and after to remove excess flux and solder. Your little gear will solder fine if you are patient. Apply heat in a local area to melt off a BB of solder in a corner. Back away and heat the entire area until the solder flows. It will follow the heat and you will want to add enough solder to fill the joint and radius the cracks. Remember you are NOT welding with the solder wire. You do not want to melt the gear or the key, just solder them into one useable part. If the steel becomes overheated, the solder will not "take" or flow. This is a sign of lack of flux or too quick of heating that incinerated the flux in the joint. Try on scrap to prove I am right. I silver solder many parts in my every day repairs of stainless steel molds used in munitiions packaging production. Get the black flux. It is water soluble, (thin with water when it gets dried out in the can.)
02-21-2005, 10:34 PM
Dunno what or why you’re doing whatever …… however I do know about soldering and brazing (apples and oranges). Soldering is below 800 degrees and brazing is above. There are many filler metal alloys for brazing such as; copper and zinc alloys (brass), copper, nickel and chromium, copper and phosphorus, SILVER, copper and gold, aluminum and silicon and magnesium. The silver brazing alloys all have a high melting temperature (around 1100*F to 1500*). I’ve used quite a bit of Easy-Flo, which is 45% Si, 15% Cu, 16% Zn and 24% Ca. alloy (got’a have much’o ventilation with the cadmium).
02-21-2005, 10:42 PM
If all you are wanting to do is stick the key in the gear there are other methods.
I have in the past drilled through the hub into the key and fixed it with a small roll pin.I also have did the same with small screws,like 4-40
I also have used Loctite 271 bearing locker,properly used it will work fine.
[This message has been edited by wierdscience (edited 02-21-2005).]
02-21-2005, 11:37 PM
Many Thanks to all I will sift throough all of these suggestions VERY carefully... Thanks for your time and effort... Ron
02-22-2005, 12:20 AM
Ron, no one has touched on the fact that being an Atlas the gear is kind of a pot metal called Zamak. Having never tried it, I don't know if silver solder will stick. I think it contains a large amount of zinc. Might be something to t hink about. James
P.S. just reread your post, if the repacement is steel silver solder should work fine.
[This message has been edited by J. Randall (edited 02-21-2005).]
02-22-2005, 08:43 AM
if the gear is Zamak - DO NOT try to silver solder it. Silver solder melts AFTER the Zamak is a puddle on the floor !
02-22-2005, 09:06 AM
DITTO, Do not heat this thing.
Why are you soldering this anyway? it wasnt to begin with, If you feel you must afix it some way, JB weld it, though I will catch some flack or saying so here.
The process usually called "Silver soldering" is -- as Smokedaddy points out -- more properly called "silver brazing" as the material used typically melts around 1100-1300 degrees F. This can be done, on small pieces, with a propane torch. Larger pieces may require MAPP, or a Really Big propane torch.
There is also "soft" silver solder, like regular soft solder with a small precentage of silver, but that's not what is usually meant in model engineering literature when the turm "silver solder" is used.
Brownell's www.brownells.com (http://www.brownells.com) and Small Parts www.smallparts.com (http://www.smallparts.com) sell both the high- and low-temp silver solder.
But, keys typically just sit there and are NOT secured in place by anything except a close fit. If you feel compelled for some reason to fasten the key in place, I think the idea of epoxy is probably the most reasonable.
Your Old Dog
07-07-2005, 06:51 PM
One more go on this thread please!
I'm reading all this wondering if this is the kind of silver soldering they talk about when soldering bandsaw blades? I happen to have some left over "germain silver" rods in various diameteres from my knife making days. Is this the same as silver solder? I was told it was also called "white brass"
I was going to try to MIG weld some bandsaw blades and now think I might be more confident brazing them. What say you?
BTW, on the epoxy for application in question on this thread. I have to agree. I've used "5 min epoxy" with fantastic results. It'w worked everywhere a brittle joined is not needed. Holding a key in place to keep it from working it's way out would be a piece of cake!
07-07-2005, 09:37 PM
YOD I think German silver is different.Seems it is composed of copper and nickle and doesn't have any zinc or cadnium to make it flow.
You can silver solder bandsaw blades pretty easily,cut them to length+1/2 and then file a scarf joint back 1/4" on each side,line the ends up in a jig flux and solder,then file off the excess solder minding the teeth.
I have TIGed blades before,but it is tricky.
BTW,if any of those rods you have are bigger than 3/8" keep them someplace special,from what I have been told they are hard to find.
[This message has been edited by wierdscience (edited 07-07-2005).]
07-07-2005, 09:39 PM
[This message has been edited by wierdscience (edited 07-07-2005).]
Your Old Dog
07-07-2005, 10:27 PM
When you say "silver solder" are you talking actual low temp solder with some silver in it or are you referring to something like white or silver brazing rod? Can I use ordinary brazing rod to braze bandsaw blades? I have a quantity of that in 1/16th as I used to use it for homemade rivets.
If you know what I have to ask for at the welding store please let me know.
07-07-2005, 10:47 PM
Almost any of the silver brazing alloys will work,Harris is the most popular,get the .062" wire,the bigger rectangular stuff is too big,unless you are doing 1" or bigger blades.Local welding shop carries it in 2oz. rolls,bout $6.00 for the stuff I get,don't remember what alloy it is,but the other alloy they carry is $17.00 for the same quanity,I get the cheap stuff http://bbs.homeshopmachinist.net//biggrin.gif
07-07-2005, 10:59 PM
I ran into the same problem on my Atlas 10x36. My fix was to bore out the bevel gear and make a brass bush with keyway. I installed a small screw to keep the key from sliding out of the bevel gear in the leadscrew keyway. As was posted above the casting will not take silver-solder temp. It has been in use for several years now and is in great shape.