Author Topic: Gold inlay gold trouble  (Read 4791 times)

Offline rick landes

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Gold inlay gold trouble
« on: August 19, 2011, 04:52:51 PM »
I had a refiner make for me a piece of 24K for lining a flashpan...that I seem never to get to do. Anyway, I heated the piece for annealing it and the small plate had a hidden bubble just under the surface. It is about 20% of the surface. It was assayed properly, just never expected the hidden void to appear on a simple annealing. I am believing the void was created when the piece was rolled to my specified thickness. I am just glad it did not show up after the piece was worked to fit the pan...

FYI it was annealed at about 500 F...I have since learned it could have been done at a lower temp. too.  Another hardknock from my university of life's experiences.
« Last Edit: August 19, 2011, 04:53:27 PM by rick landes »
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Dave Faletti

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Re: Gold inlay gold trouble
« Reply #1 on: August 19, 2011, 08:14:29 PM »
Somebody really goofed to get a bubble rolling it.   Suprised you tried to anneal it.  Pure gold is extremely malleable and ductile.  It doesn't work harden.

Offline Acer Saccharum

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Re: Gold inlay gold trouble
« Reply #2 on: August 19, 2011, 08:36:26 PM »
A jeweler can melt it down, cast an ingot, and run it thru their rolling mill for ya.
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Offline T*O*F

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Re: Gold inlay gold trouble
« Reply #3 on: August 19, 2011, 08:46:26 PM »
If it has room for a bubble, I would speculate that it is too thick for your intended purpose.
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Offline davec2

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Re: Gold inlay gold trouble
« Reply #4 on: August 20, 2011, 05:51:08 AM »
I work a lot of gold.  First, even 24K, while one of the most ductile of all metals, will indeed work harden.  So annealing is a good idea and, in many situations, required.  However, if sheet is cold rolled from scrap that has not been prepared properly, it can have organic inclusions that will cause a bubble upon heating.  The sheet, as Acer points out, should be re-melted and re-rolled.

Along the same lines, if a gold inlay (or pan liner) is installed on a dirty steel surface and the steel is subsesequently heated (as it would be in case hardening), the gas produced by the organic material (i.e.dirt) will bubble or lift the inlay right back off the surface.
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Offline kutter

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Re: Gold inlay gold trouble
« Reply #5 on: August 20, 2011, 11:23:28 PM »
I always annealed 24k before working with it. Even when it comes from the refiner as 'annealed'.
Wire I simply passed through the flame of a gas stove holding one end with a pliers and letting the wire drape accross the trivet. Turn it arround to make sure the other end is done as well. It gets red hot doing it, takes only a few seconds and cools almost as quickly. No need to quench.
Move the tiny dia's quickly or you can melt them in two.
 
Sheet gold I hit quickly either in the same gas stove flame 'cause it's convenient or use a propane torch.
Again it heats to glowing red almost instantly. Grab it by the other end so the area where the pliers was gets heated as well and then let it cool. I toss it on the vise, it's cool to the touch in a few moments.

24k will work harden. You can feel it while working it but it's really not that bad unless you're trying to do tiny inlay work. The lower karets, even just going to 22k are much quicker to work harden and can give you problems if everything isn't right.
Inlaying 14 and 10K  sheet inlays can be tricky they harden so quickly. Holding a couple of the edges in place with small clamps to avoid them wandering about is a real help. They also keep the gold in the undercut instead of curling upwards as work hardened metal wants to do.

I have had wire w/gold solder splices in place. Some refiners will gold solder wire together to splice it together when it breaks while putting up spools of it.
I was unfortunate to have two of these solder splices show up in border wire inlays on gun projects that went through case coloring. The heat was more than enough to melt the gold solder and leave a puddle of 'gold' in the area of the line where the splice had been. A fun clean up job.
It's another reason I started to anneal the wire and sheet once received. It will reveal any such things before I use it.

Since nearly all gold we use is reclaimed from various sources,,there's always a chance of something like that being in the wire or sheet mat'rl.

Remelt the gold you have and either hammer it out to a thickness and shape you need. Or have someone roll it out to a uniform thickness.

What thickness do you use for the pan liner and what method for attachment to the pan?
I've never done a gold pan liner but have an idea of how I'd do it.
Interested to hear the process.

Rasch Chronicles

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Re: Gold inlay gold trouble
« Reply #6 on: August 21, 2011, 08:17:47 AM »
Kutter,

Here is a description w/instructions in the Archives:
http://americanlongrifles.org/old_board/index.php?topic=45.0

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Offline Acer Saccharum

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Re: Gold inlay gold trouble
« Reply #7 on: August 22, 2011, 12:02:32 AM »
To make gold stay in the pan, you have to line it with barbs. These are cut with a graver. The barbs have to all point toward the middle of the pan. If the pan is shallow, it's easy. But if it's a deep pan, you may have to grind a special shape graver to raise the burrs properly.

Like a shark's array of teeth, all points go toward the gullet, easy trip to the stomach, but never escape. So, too, the points in the pan will let the gold get tapped down, but never lift out.

Many older pans were lined by gold wires laid side-by-side, then burnished. This works, but I've also seen wires blown out by the vent gasses. So a sheet liner is more secure.

You can make a punch that is pan shaped to push the liner in place.
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Offline kutter

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Re: Gold inlay gold trouble
« Reply #8 on: August 22, 2011, 01:10:49 AM »
Thanks for the link..
That was the idea I had of getting the gold overlay in place. I put the vast majority of inlays in place with that method but with a little difference in technique.
The idea is the same,,just a bit of different technique. This comes from inlaying hundreds of gold and silver figures into firearms parts that have been color case hardened, hot blued, rust blued, nitre blued and abused.

I start with polished, clean metal. No scale, old blue, case color, etc.
Instead of a graver, I use a chisel point punch. It looks the same as the one I use to detail the gold figures once they are in place and polished off. I've caught myself using the same tool for both at times.

Very accute angle,,very sharp, A width that is convenient to the work surface. If you have a lot of area to cover,,go wide. To get into narrow areas, make a narrow point.

Lay it back at a slight angle just as with the graver method and strike it into the surface. It drives up a burr as wide as the edge of the chisel. Now without lifting it from the work surface, walk it along while tapping it,,making a continuous line of burr from one end of the area to be scarred to the other.
With a narrow enough tool, you should be able to go right accross even a deep pan w/o stopping no matter the direction.
It's fairly fast work once you master the rhythm of the tool & hammer and your hand/finger pressure on the tool. Tipping the tool ever to slightly in the direction you want it to travel helps it get going.
Same technique is used in dovetailing line cuts for inlay with a punch.

Go back and leave a tiny space behind that first line and run another line the length of the inlay area. When you've finished, you have a series of somewhat parallel lines, each a continuous burr.

Now  you want to do the same thing again to the surface ,,2 more times.
Making a total of three sets of parallel lines/burrs. Each set at approx. 120 degrees from next.
This will cut each line of burr into multi hundreds if not thousands of triangular teeth. Each row pointing up at a slight angle and at 120degrees from the other line(s).

Three lines is enough. If you over do it, you'll start to chop the teeth off with the next additional rows you try to add. Too finely spaced and you will have the same problem. It takes a bit of practice but better too much space between parallel rows than placing them too close.

For an additional anchor at the edges, you can cut a line just barely in from your edge and under cut it with the same punch. Creates a dovetail and is the standard method of holding line inlay. It will make a nice tidy, clean edge to your sheet inlay as well when the final polish is done.

Make sure the surface is clean, clean before applying the gold. I brush with acetone usually.

Anneal the gold. As I said in the previous post, I heat it to red. Cool it and use it. Make sure the gold is clean too. Keep even finger prints off of it.

Look over your area again for any burrs that may be too high. Cut them off with a graver. You don't want them poking through the sheet gold.
Use a thickness you deem necessary for the job. This attachment method will hold any thickness to the steel. Extra is just that and will end up as expensive filing. Collect it for the gunmakers/engravers retirement fund jar.

The annealed gold with snag easily onto the steel teeth. The teeth being 3 directional won't let it move if you've done everything right. Extra thick gold sheet will 'flow' as it's hammered into place, so don't mistake that for the whole piece moving about.

I would probably shape the gold sheet out a bit first to be able to set it into the bottom of the pan and stake it into place. Then working up the sides and back staking it down into place till you reach the top edges.
A brass, steel or even a hard wood tool shaped appropriately for the job tapped carefully with a hammer is all that's necessary to stake it into place.
Work up to those edges and pay particular attention at that point to make sure they are secured. Then trim the excess that has swaged and flowed it's way out with a flat graver (trimming go into the Engravers retirement fund jar).

Then burnish and/or carefully plannish the pan area smooth and polish. Polish the upper edges to reveal the gold to steel abutment where you undercut it earlier.

You can also do the area with gold wire using the same cross hatched teeth attachment technique. You have to be carefull when laying the new wire against a previously attached piece to make sure a square joint is formed. If overlap occurs, thin pieces will curl off in the final polishing and reveal part of the technique. If done correctly, none of the cold formed joints will show and it will be attached as firmly as a one piece inlay.

A continuous piece of wire can be used somewhat like coiling a rope on the ground if you're careful. The gold flattens as swaged into place and you can guide it somewhat into small odd shapes if they exist. A full piece around the edge is good to start then continue inwards.

Most of my inlays & overlays were done with wire. Much quicker than cutting out small pieces of critters with a jewelers saw from tabs of sheet stock.


Offline JTR

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Re: Gold inlay gold trouble
« Reply #9 on: August 22, 2011, 04:11:17 PM »
Kutter,
Thanks for all your good advise! Your first hand experience is much appreciated!
John
John Robbins