How to silver solder?

[Paul Arsenault]

I did some searching and found a post from 2005 by pastimes suggesting silver solder to repair a wheel that has "whizzed" on its arbor. Can anyone suggest where to find "how to" for this process? I have soldered electronics components, stained glass but never attempted silver solder. Would Tix solder or Stay-Brite #8 be strong enough to hole the 1st wheel? Stay-Brite #8 has a tinsis strength of 10,600 psi. and a very low melting point. Any help would be appreciated. Paul

[Robert M.]

I did some searching and found a post from 2005 by pastimes suggesting silver solder to repair a wheel that has "whizzed" on its arbor. Can anyone suggest where to find "how to" for this process? I have soldered electronics components, stained glass but never attempted silver solder. Would Tix solder or Stay-Brite #8 be strong enough to hole the 1st wheel? Stay-Brite #8 has a tinsis strength of 10,600 psi. and a very low melting point. Any help would be appreciated. Paul

Rather than soldering you may want to try a dab of Loc-Tite #620 Paul.This product is made specifically for cylindrical slip type connections as opposed to the thread gripping Loc-Tite most of us are familiar with.I use it when I re-pivot an arbor and for wheels that tend to slip on their arbors.It only requires one little drop to do the job.The only thing I would tell you is that the mating area has to be absolutely clean and devoid of any grease or oil.The best thing about using this product is that if you want to break the connection down the road just heat the joint with a small butane torch and it'll break the bond.
I just thought I'd pass this process on to you as an alternative to soldering.
Bob Fullerton

[EmmaR]

there are other ways. I wonder if the collet has moved or the wheel on the collet? if the wheel is loose on the collet, then you should think about re-riveting it. solder here looks awful no matter what type. I believe this is not a good repair.

if the collet is loose, the locktite is pretty good, or the old fashioned way with emery dust and a little oil in a paste to make it tight.

soft (lead) solder has one problem to reattach a collet to an arbor, and that is that it wont wick inside the joint, you will only get a ring around each end. If you can get the solder inside, then thats great, but if you cant, then you have a joint that really wont stand much stress.

silver I dont like, for this job, because it is a repair that cant be reversed. thats not so good from a conservation point of view.
silver solder will wick into the actual pores of the steel and brass as the metal expands, this is what gives it its strength.
but if you insist, here is a kinda how-to with silver solder.
silver solder is available with lots of different compositions, mostly silver,tin and or lead.
this is mostly to give different melting points and cappillary flow rates. (gosh i sound like a scientist) actually, I grew up in my dad's welding workshop.. might explain some useless facts I know.. )
you probably should get one with a high level of silver, and some tin, and not much, if any lead.
you need a flame that will melt the solder, and get the item you are soldering hot enough so the solder sucks into the pores.
you need a flux, probably a liquid silver solder flux would be best, its pink and some kind of acid, I think. maybe someone knows?(the label is missing )

so you get everything spotlessly clean, drip some flux around the joint, and warm the whole lot up till it it gets hot enough to melt the solder when u touch it on the joint. it should all run round it nicely then and thru the middle, leaving a neat Little seam either end. only takes a minute.

I dont like this repair,for this application, and I would hesitate to use it to repair a customers clock. there are other ways.


but everyone should learn how to silver solder.

*EM*

[Paul Arsenault]

Bob & EM: Thanks for the reply. I have added a picture of the problem wheel. It is the 1st wheel that takes the full power from the mainspring barrell. There is no slop or excessive movement, just age has caused this problem. Thanks..Paul

[Robert M.]

Paul,have you tried staking the hub in 3 or 4 spots so it can expand into the wheel.Just take your wheel assembly,place it on a steel block,hub up and take a center punch and put 4 prick punches along the outside perimeter of the hub.Those prick punches if done properly will expand into the wheel and lock it in place.
Bob Fullerton

[shutterbug]

I agree with Bob's advise. This would be the best way to repair this wheel. If you do solder, Em gave you some great details, but I'll add that you want to heat the arbor. The rest will heat up with no problem. Don't use much solder! As Em says, just a little ring will do it.

[kirxklox]

WHY? If this wheel was splined in the hub, you will not get a good joint using Silver Solder without overheating the Shaft and causing more problems. If it is a common wheel, replace it Check with Horolovar for replacement parts. If it is a rare movement part, you may need to chuck it up to a lathe and cut the lip of the hub to disassemble it and then tighten the Wheel by peening it. Then you can reset the Wheel onto the hub and then reseat the wheel.

Sounds to me as the clock had a broken mainspring to cause this. Wonder it did not top the escape wheel.

[bangster]

I'm in on this discussion late, and the problem's probly already fixed, but I still have some comments to make.

To tighten a loose arbor, others have recommended, first, knurl the appropriate part of the arbor by laying on a flat surface and rolling it with a file, bearing down. Will raise little ridges.

THEN to tighten it further, punch it as Bob suggests. I think that's more or less the way wheels are tightened on arbors at the factory.

If you want further security, Loctite 620 is a good bet since it's formulated for that very purpose.

If you nevertheless want to use solder, I recommend TIX...high strength and low melting point. And I disagree with Emma about wickability. If the target metal is hot enough to make the solder flow freely, the solder will creep right down into the crack...if there's any crack to creep into. But it has to be the metal melting the solder, not the heat source (torch or whatever).

bangster

[Robert M.]

I agree with Bang.The trick to getting solder to flow in a crack or joint is to thoroughly clean the inside perimeter of the wheel or whatever and also the matching sleeve.Then apply your flux to that same area.Actually a quality solder joint will have very little exposed solder.A good bond dictates that the solder bond to the walls of the joint not the exposed area such as a fillet weld on the exposed metallic joint.Excessive solder is wasted solder.It certainly doesn't have much strength without a thorough bonding to the inner wall.
Bob Fullerton

[Paul Arsenault]

Thanks to all who commented. The repair has been successfully completed. I ended up using Stay-Brite #8. This has a tinsil strength of 10,600 psi and a very low melting point. If I remember correctly the silver content is 5-6 %. Using a 100 watt iron it flowed very well into the joint. Bang i love the idea of knurling with a file. I have a metal lathe and never would have given a thought to repairing it by knurling. This is a learning process for sure. Again thanks to all...Paul

[Paul Arsenault]

I really wanted to buy a Little Torch (tm) but could not justify the cost..Paul