Repairing ZAMAK Gears???

The ones I have were made by Bernzomatic item #96268, aluminum brazing/welding rods. Have not had a chance to use them however. Instructions say "Ideal for sealing holes in aluminum. Useful in repairing outboard motor castings and most kirksite and zinc base die castings." Working temperature is listed as 700 to 750 f. Think I bought them from Lowe's.
 
Following the thread as I have an Atlas MFB mill with mounting ears on the gear box that were cracked when I bought it. They've since broken off. I figure it's made from Zamak like the gears, handles, etc. Have "visions" of making an aluminum gear box and reuse the Atlas face plate, axles, etc., but a welded repair would be better.

So how do you control the heat to under 700 F so I don't liquify the gear box? I'm guessing heat it in a heat treat over (have one) to 600 - 650 and melt something in the joint? That's what Bill is suggesting above which seems plausible.

Bruce
 
I figure a big rosebud tip and an IR thermometer (or heat crayons) might oughta do it. Always easier to control flame-on heat than it is to control arc heat from welding. 200 degrees should be plenty of range between filler melt temp and base metal melt temp. Besides, that magic aluminum-fixem rod balls up and rolls off when overheated. If that's not a warm fuzzy feeling, you could try the weld with propane. It takes a lot of moving air to get propane up to 700 degrees. 600F is more like it for a propane hand torch.
 
BGHansen said:
Following the thread as I have an Atlas MFB mill with mounting ears on the gear box that were cracked when I bought it. They've since broken off. I figure it's made from Zamak like the gears, handles, etc. Have "visions" of making an aluminum gear box and reuse the Atlas face plate, axles, etc., but a welded repair would be better.
Bruce
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The important point to keep in mind is that the rod isn't a "welding" rod. It does not melt into the parent metal. I think of it as a "hard" solder, between silver soldering and brazing. To use on something like the mill, I would be skeptical of the strength. Prefer to make a replacement part out of Al stock.

There have been a number of "tests" on YouTube as to holding strength. In most of the tests, it holds about as strong as soldering with copper, as in pipe. It will hold for something like I have going, using aluminium angle back to back so the holes are drilled consistant side to side. (3/8x3/8x1/16) Cutting two pieces and soldering back to back, drilling, and heating to release. Solder doesn't take on aluminium, so this is a replacement for that process.

That's why I was asking after folks perceptions about repairing a ZAMAK gear as one would braze an iron gear. Repairing the "gear box", I suppose the first step is to use a magnet on the piece. I have an MF-C and can't picture in my mind what needs repairing. But my machine is mostly iron castings, with ZAMAK gears and knobs. If it's iron, it can be brazed.

.
 
Ulma Doctor said:
i'm no expert in repairing ZAMAK, but i know it is highly unlikely that end result would be favorable, especially on change gears.
you may do better to try to recast, rather than repair.
Zamak was chosen due to its low cost, ease of casting, and lack of post casting machining
it was not chosen due to its ease of repair or superior wear characteristics.


if you are interested in trying an experiment, i could hunt down some 3D objects and 3D print some gears to try
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I know this is a old thread but I have a 12 inch Craftsman and the traverse gear " case' in the apron broke on one corner ( the unit was like that when i got it.. so I used epoxy it lasted a little while, then broke then used this 2 part putty and it worked for a little. Then I saw that piece on ebay in a auction and lost it. ( I should have paid at least half the cost of my lathe) which would have been 200... but now it's broke again. Any ideas or results from ur vesr repair???? I spent lots if time fixing up and cleaning uo this lathe. Folks are basically robbing people for parts. I really need this fixed. What or how is ZAMAK REPaired???? all other metals can be repaired for the most part. Please help

Ken
 
kendion2boston said:
I know this is a old thread but I have a 12 inch Craftsman and the traverse gear " case' in the apron broke on one corner ( the unit was like that when i got it.. so I used epoxy it lasted a little while, then broke then used this 2 part putty and it worked for a little. Then I saw that piece on ebay in a auction and lost it. ( I should have paid at least half the cost of my lathe) which would have been 200... but now it's broke again. Any ideas or results from ur vesr repair???? I spent lots if time fixing up and cleaning uo this lathe. Folks are basically robbing people for parts. I really need this fixed. What or how is ZAMAK REPaired???? all other metals can be repaired for the most part. Please help

Ken
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Re-casting the gear or replacing it with a gear made from brass , bronze or other suitable materials is about all the options i can imagine.
3d printed gears may be an option too.
There may be 3d models in existence, although I have not looked for them.
 
Caswell Plating has a number of specialty products relating to joining low melting temperature materials (I have not tried any of them, but their claims are impressive). They call them Casweld Soldering Rods (various types). If you do try them, let us know the outcome.
 
I tried to repair a broken Ariens mower deck gearbox. I hit a big hidden branch. It broke the gearbox and split the bearing. I had trouble building up the material like I would like, so I bored out the housing, inserted a 6061 bushing and soldered that in place. Have not used it yet. Here is a picture of the 1st repair. After some research I found out there are 2 kinds of Crown alloys repair rod. One turns to liquid, which is the one I have. And the other is capable of being built up, which is what I wish I had. It was doable but VERY close attention to heat control is necessary. It should be stronger than origional as the aluminum should be stronger than the zinc.gearbox weld with Crown alloys.jpg
 
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