Jump to content
I Forge Iron

Copper fill/inlay?


RogueRugger

Recommended Posts

Attached are two pictures of the same small bowl.  5 in diameter, 0.75" deep, 14g mild steel. I have intentionally put a 'crack' in the side of the bowl and would like to fill the opening with copper (or brass).  My first attempt at annealing a piece of copper wire and beating it to submission into the crack was unsuccessful.  The next steps will be to fire up the ox-ace torch and simply melt/solder the copper wire into the opening.  Probably assisted by some flux. Obviously there will be considerable cleanup afterward. (FWIW - I kinda like the way it looks now and I'll likely make a new one to experiment on.) 

 

Any suggestions about how to tackle this would be greatly appreciated! 

Dave Robinson

 

 

 

 

CrackedBowl_1.jpg

CrackedBowl_2.jpg

Link to comment
Share on other sites

Before I saw the pictures I thought this was to be an inlay problem, it is most definately a fill!

Brazing would be the obvious solution, as you have a gas torch. Copper is also possible, gun smiths use copper as a solder to fix the sights to gun barrels using pine resin as flux.

I see the biggest problem will be stopping the fill falling out before you finish, maybe wedge copper in and then braze it, should make an interesting feature after cleaning up. Best of Luck and we want to see the pics of the finished item.

Link to comment
Share on other sites

Thanks Smoggy, here's a quick look at the initial results.  

 

Figures 1 and 2 are the bowl and the backing plate I made. I put both in a hollow of a stump I used for making bowls. Lesson learned: wet the stump down before. Stupid... Figure 3 and 4 are the initial results of just melting some copper wire and letting it be drawn into crack. Pretty ugly, but as I expected. Figures 5 and 6 are after tackling the area with an old flap disk.  Lesson: too much copper and had to be more aggressive than I liked to get the excess off.  I thought the flap disk was at the end of its useful life, but it still had some bite to it.

I was reasonably happy and thought it looked pretty good.  Not real happy with the voids in the copper.  Tried a few times to get the copper to re-flow and smooth out; also tried some flux.  Finally gave up and thought that the voids would blend in after retexturing the area.  Unfortunately, during retexturing, the  copper pulled away from the sides of the crack.  Figure 7 is what happens when I tried to re-flow the copper again.  Burned. Through. #@$!*$@$@#$%@ etc.

The retexturing had thinned out the metal around the crack.  Sigh....  

Any thoughts on what I might do different would be greatly appreciated!  Meanwhile, I'm gonna go make something that I can beat up on the anvil ... 

Dave 

Copper_1.jpg

Copper_2.jpg

Copper_3.jpg

Copper_4.jpg

Copper_5.jpg

Copper_6.jpg

Copper_7.jpg

Link to comment
Share on other sites

Greetings Dave,

TIG is the optimum but if that is not available . You might try a super clean surface using some silver solder flux and adjust your torch ( small tip or mini set up like a jeweler) with a oxygen lean mix. I would also pre- heat the surrounding area. Stainless works well for a backup or a graphite block.  I wish you success. 

Forge on and make beautiful things 

Jim

 

Also after the copper sets keep the area warm so that it cools at a slow rate.  A propane torch would work well. 

Link to comment
Share on other sites

Do you want the filling flush, or can it be proud?  As to having it proud, I would think that you could fit a piece then peen it along the edges, and let it clamp the steel.

Even peening after flowing it in may help. With the differences in expansion coefficients peening will spread it out and help keep it against the steel. 

Link to comment
Share on other sites

Jim: forgot to add that I was already using a silver flux. The stainless steel worked like a champ.  

BigGunDoc: I'd rather have it flush. I'm trying to mimic the look of  Kintsugi the Japanese method of repairing pottery. 

Smoggy: Thanks for the encouragement.  I'm going to start from scratch and use what i've learned so far and take advantage of the great suggestions.  

So far I've only tried melting the copper wire - any thoughts on the advantage of brazing with a bronze stick?  

 

Unfortunately, it was a pretty cool looking bowl.  For now, I have turned the recent experiment into a very nice spatula for my cooking disco .

Thanks again to all...

Dave

 

 

 

Link to comment
Share on other sites

I figured that was the look you were going for, but with a less costly option than gold.

Pottery clay can work as a backer. Look for cone 10, or wood fired clay bodies for the best heat resistance. It is cheap, easy to use, nonstick, and will take the heat of brazing.

C173/C175 will give you the look of gold at $20 a pound, but you need to take precautions when polishing BeCu alloys. I made some crucifixion spikes out of some, and when they came out of the acid bath at work they looked like polished gold. It literally only takes seconds to polish it that way, and I had that available to me at the time. These alloys are hot short, so they cannot be hot forged, only annealed and cold worked. Wear proper PPE, and I would polish by hand either outside, or do it wet inside. Filing makes big enough chips, but sanding or polishing can create the hazardous dust. These alloys are limited to 2% Be, and the MSDS called out hazards from chronic exposure to dust and fumes, not incidental. So, I have never been scared to use them for items I make since most are machined, and not creating dust. We literally ran tons of these alloys through the screwmachines where I worked at making electrical contacts. 

Link to comment
Share on other sites

Smoggy: i actually tried that after the burn through.  Actually, I layered the bowl, copper sheet, and then a stainless steel sheet.  I filled the burn hole, but as soon as I started cleaning up, the copper just peeled off the steel. it's likely a combination of some other issue, but i decided to just start fresh. 

 

BigGunDoc: Interesting thought about the pottery clay. I'm heading to Albuquerque in a week or so and can check out what Rio Grande Jewelry has to offer.  Regarding the BeCu - I've never worked with it but have heard many horror stories.  I suppose the usual advice of being smart about handling would prevail.  Thanks for the heads up. However, are you suggesting that they be used more as 'inlays' in the cracks rather than brazing?  

 

Any thoughts on the possibility of using one of the metal epoxy powders?  I've never seen it used on metals before.  

 

Thanks to both for the suggestions, Dave

 

Link to comment
Share on other sites

Either way, but an inlay would probably be the easiest method. 

It may have peeled off of the steel due to an oxide layer/poor flux, or the copper shrunk father than the steel thus tearing the edge. That is why I suggested peening the copper as it cools to spread it out and keep the bond at the edges tight. It is the same thing you have to do with cast iron welds. The weld bead cools and shrinks much faster than the cast iron does, the peening prevents that tearing away at the edges.

Link to comment
Share on other sites

3 minutes ago, BIGGUNDOCTOR said:

Either way, but an inlay would probably be the easiest method. 

It may have peeled off of the steel due to an oxide layer/poor flux, or the copper shrunk father than the steel thus tearing the edge. That is why I suggested peening the copper as it cools to spread it out and keep the bond at the edges tight. It is the same thing you have to do with cast iron welds. The weld bead cools and shrinks much faster than the cast iron does, the peening prevents that tearing away at the edges.

It could easily have been either oxide layer or poor flux.  I did peen the copper as it cooled, but it was mostly out of frustration as I watched it separate; obviously I need to peen sooner.  Thanks again for the suggestions. (Thanks also for the additional info about the cast iron welds ... new to me, but makes sense.) Dave

 

Link to comment
Share on other sites

1 hour ago, RogueRugger said:

Smoggy: i actually tried that after the burn through.  Actually, I layered the bowl, copper sheet, and then a stainless steel sheet.  I filled the burn hole, but as soon as I started cleaning up, the copper just peeled off the steel.

I was intending backing the crack with copper simply to act as a support and fill the crack with braze, which should have taken to the bowl edge, and the copper backing. the copper need not be attached to bowl, but I would expect it to take to the braze. I envisaged you would then only need to grind off the copper outside and any high spots of braze inside. leaving you with a brass filled crack.

But.....keep at it......sooner or later you'll sort it.....

Link to comment
Share on other sites

I think that this would have been a very beautiful "mu shin" piece if you had succeeded. I admire the idea. At the stage when the copper pulled away from the steel I would have tried to connet it with some kind of solder that has a lower melting point than the copper. preferably with a contrasting colour like some kind of brass or even tin solder. In my view a thin "silver lining" between copper and steel would have been very nice looking

Link to comment
Share on other sites

okay, made a little bit more progress today.  

gote: 'mu shin' - from my perspective, this is a bit of a pun since i'm working with 'no brain' on this ... :) I'm sure you meant it in the more positive sense 

I tried a couple of things today:

-Tried the same size crack as yesterday and just smush the copper into the crack. Was hoping that if this worked I could justify getting a flypress :D. No joy.  

Tried brazing (for the first time). I had a package of flux coated bronze brazing rods (unopened). Seemed like it was working, but I had a hard time controlling the flow of the bronze. However, the dang stuff stuck all over the place so whatever the flux is, it worked great.  I even ran some copper as filler over a few of the bronze voids.  Real interesting color scheme that will be explored later - when I get better at brazing.  Result was something along the lines of what GOTE was suggesting with the copper/solder.

Then decided to start with a smaller crack (shorter and skinnier) and work my way up to something more serious. I crumbled the flux off the brazing rods and laid a short strip of copper wire on top of that. Worked fine, but clean up was tedious.  The flux glass and copper stuck in a few places outside the crack.  If the bowl were destined for a smooth finish, it would have been fine. I think I will get better at controlling the flow of the copper with a bit more practice.  Unfortunately, the dimples on the surface make clean up difficult and then the retexturing brings a lot of stress to the copper. I annealed the copper inlay a few times while I was retexturing and I think that helped avoid some copper/steel separation. 

The figure below is the result.  The right 1" of the crack is through the plate, while the remaining crack on the left is really more of a gouge. The copper wouldn't stick in the gouge.  The flux from the brazing rod seemed to make a big difference.  

Thanks again for all the suggestions ... Dave

 

Q: Can anyone suggest a stand-alone flux that would be similar to what is on the brazing rods?  

Copper_9.jpg

Link to comment
Share on other sites

Looks Like you are making good progress, it may not be perfect but you have achieved what you set out to do. From here it looks like practice, practice, practice..... ok maybe a little process refining......but lots of practice too! :D

Link to comment
Share on other sites

6 minutes ago, gote said:

I ment in the zen meaning of acting on something real - in this case the original crack. Accepting it as it is, discovering the possibilities and going from there.   

 Thanks, that really describes what this was about. Kinda describes a lot of the non-production stuff I like to do. 

 

(I was thinking of it in terms of the translation: 'empty mind' .)

Link to comment
Share on other sites

Yupp! Empty your mind - - - of prejudices. Act on your feelings. Star wars: Luke trying to hit the ball in the air. Seven samurais: Leader testing applicants. On the Mat in the Dojo: You throw the opponent without thinking about it - it just happened.  

Link to comment
Share on other sites

4 hours ago, gote said:

Yupp! Empty your mind - - - of prejudices. Act on your feelings. Star wars: Luke trying to hit the ball in the air. Seven samurais: Leader testing applicants. On the Mat in the Dojo: You throw the opponent without thinking about it - it just happened.  

Excellent! (Ex-AF Judo team so I can relate.) 

 

4 hours ago, ThomasPowers said:

You could also suture the crack using copper wire as a different artistic look.  (My Daughter is a Veterinarian and one of her pieces of furniture from her school days has all the tears in the upholstery neatly sutured...)

I forget what that method is called but working with a wood guy to do this on a cookie of old bristle cone. i have a piece of metal plate where I have tried this; the inlay kept squishing into the crack and the effect was lost. Probably mostly from my inexperience at anticipating where the metal was going to go after a tap. Great idea though. 

Link to comment
Share on other sites

On 1/24/2017 at 7:04 PM, RogueRugger said:

So far I've only tried melting the copper wire - any thoughts on the advantage of brazing with a bronze stick? 

Thanks again to all...

Dave

That was my first thought, ... and a very sensible repair technique.

On 1/24/2017 at 7:04 PM, RogueRugger said:

 

 

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...