Does bronze go bad in time ?

[ramillett]

I have a steering pedestal that needed new chroming . I needed to do some machining and repair work , so I had the chrome removed , it was suggested that I weld the base to the tub so the chroming would be better in that area . I set it up in the lath , and took a clean up cut where the weld would be , and sent it to the welder . When I got it back , I chucked it up , and faced the bottom , and trued the center for a live center . Then I cleaned up the weld . The weld had some bubbles so it went back to the welder . Then I get a call , every time he welds a spot it starts cracking next to the weld . We try heating it up same thing . Now after giving up I started thinking about how it machined . If you look at the chips on the lath you see it's more like dust then chips , like cast iron . And when it cut , it sounded like cutting brass . We have been treating it as bronze , but now i'm wondering if its brass . The copper on the tube is from the plating . The color on the fresh cut base is close to brass . The welder made the comment that he has had problems trying to weld old bronze before ( this would be 59 year old ) , or is this just brass ? If you try to weld cast brass , is cracking normal ? If it was bronze , is it time to start over ? In the 50's would a pedestal be made of brass or bronze ? The builder did use some brass inside the boat . Thanks Bob

[PeterSibley]

A steering pedestal would very likely be brass, it's not submerged and so the high zinc content shouldn't matter .Welding would very likely burn the zinc out though, it oxidizes at quite a low temperature .

[Canoeyawl]

every time he welds a spot it starts cracking next to the weld . We try heating it up same thing

I have had some experience welding brass and have seen this phenomenon or something darn similar. I attributed it to the shrinkage of the metals, the bronze being stronger it would tear the brass. Pre-heating made it worse. If the weld was kept small and cold I had some success but at that point I had to consider it a cosmetic job.
Not science, just an observation

[ramillett]

Here is the pedestal back in 1966



Here it is back a few years



Here it is just before removal

[JimConlin]

Lordy!
There's some beautiful metal work on that boat.
Who was the builder?

Regarding bubbles in the brass bits, can you wipe in some lead and get on with the plating?

[ramillett]

Plymm , The cracks are the problem now , clear through .

[Bob Cleek]

I'm no metalurgist, nor even a good welder, but I do think Peter hit the nail on the head. Maybe your welder knows what he is doing, and maybe not. If you had to "clean up the weld," perhaps not. Brass isn't "welded," but rather "brazed" or "braze soldered." The difference is that in welding, such as with steel, both the metal of work pieces and the rod (or wire, these days) are melted together and harden to one solid piece of metal, leaving a filet, which you were "cleaning up." Both pieces must be heated to melting temperature. With brass, the zinc has a much lower melting temperature than the copper in the brass, so the zinc actually vaporizes and gasses off in the process. (Which, BTW, is very dangerous, as zinc fumes are highly poisonous.) The result is much the same as electrolysis, although the process is different.

Brass is most commonly silver soldered, a process which results in a bond stronger than the brass itself. In this technique, the parts are machined to a very close contact fit to begin with, flux is applied, and silver solder is applied so as to flow into the joint. (Silver solder, unlike lead/tin solder, is NOT "gap filling.") The result is a generally near invisible seam of great strength. In brazing or "silver soldering," unlike welding, the workpiece metal is only heated enough to permit it to "tin," with a thin coating of the solder sticking to the workpiece metal. Silver solder will only stick to clean bare metal and will not flow beyond where the flux has been applied. For this reason, yellow metal is generally "pickled" before soldering, by soaking in a mild acid bath after degreasing, and then dried without touching the surfaces to be joined with your fingers, and the flux painted on. The silver solder ALWAYS has a LOWER melting temperature than the workpiece and it flows into the joint, as contrasted with welding where both the workpiece and the added metal is melted together.

Here's an article from the American Welding Society that explains it much better than I have, I'm sure!

http://www.aws.org/wj/amwelder/9-00/fundamentals.html

[Gold Rock]

I'm also no welder but the guy who owns Pt. Townsend Foundry is. One of his worst nightmares is having to put a torch to brass. And based on the photo's I'd vote for leaving the chrome off. I think it looks wonderful that way.

[PeterSibley]

Plymm , The cracks are the problem now , clear through .

You may be able to repair the cracks with silver solder as Bob mentioned, that is assuming they are just very fine cracks. It would be quite strong, probably as good as the original. If however you decided to replace that section a stepped join machined to a fine fit then joined using the same silver solder would be the way I'd go .

There is also the possibility that a welder might be able to flow phosphor bronze brazing rod into the area but I'm not sure about that one.

[George Ray]

Need to know what the metal is before you can expect a quality repair. It should be fairly easy to figure out if it has a significant amount of zinc (BRASS).
Take some of the machining dust/tailings to local university chemistry department and get them analyzed. Then knowing at least approximately what alloy you have, can begin to think about proper process for welding/brazing/soldering.

A good source of info for welding/brazing/soldering copper alloys is the art community. While you may find some commercial welders that are both experienced and knowledgeable about copper alloy joining/cladding/repair, in the art world it is, I think, more common, think "metal sculpture'.

While it does not sound like the problem you are experiencing, some brass alloys (copper/zinc) can experience dezincification (Dezincification: selective removal of zinc from the alloy, leaving behind a porous, copper-rich structure that has little mechanical strength.) but it typically happens when the material is immersed in an electrolyte such as salt water and for your pedestal, that is not the case. ( A NOTE ON THE DEZINCIFICATION OF BRASS AND THE INHIBITING EFFECT OF ELEMENTAL ADDITIONS => http://www.copper.org/applications/rodbar/pdf/7013.pdf ) For marine applications dezincification is a reason that bronze alloys (copper/tin) are used. Having said that there is much confusion in naming. Naval Brass and Admiralty Brass are alloys that were formulated to avoid the problem of dezincification by adding a small amount of tin (aprox 1%) to the 30%-40% zinc.

http://en.wikipedia.org/wiki/Brass
http://en.wikipedia.org/wiki/Bronze

[Canoeyawl]

As I mentioned earlier occasionally I have welded (not brazed) brass ,
It can be welded, Look here for a welders point of view
http://www.youtube.com/watch?v=Yef3z1a6re8

[MN Dave]

No, I don't think bronze goes bad.

Bob Cleek may not be a metallurgist, but he does seem to know what he's talking about. Brazing is probably your best bet. Never trust a forumite's claim to being ignorant. ...or one's claims not to be ignorant, come to think of it.

Judging from the way the chips break, you probably have a free machining (leaded) bronze. Lead freezes out of the metal as it cools. The little lead inclusions scattered throughout the metal lubricate the cutting tools and break the chips, which is nice for machining, but bad for welding. If you compare the alloy information on a site like anchorbronze, the weldability of similar alloys, say naval brass and leaded naval brass, is worse for the leaded version.

The art bronze advice sounds good too. My first hit on google was a question like yours with similar advice and problems. If I needed to, I would have read a lot more.

I don't know what to say about the idea of trying to flow braze metal into the cracks. They are probably fairly well oxidized inside. I think it would be best to cut out the bad metal and braze in a new piece. I have only seen the picture, and I don't know how bad or where the cracking is.

[PeterSibley]

No, I don't think bronze goes bad.

Bob Cleek may not be a metallurgist, but he does seem to know what he's talking about. Brazing is probably your best bet. Never trust a forumite's claim to being ignorant. ...or one's claims not to be ignorant, come to think of it.

Judging from the way the chips break, you probably have a free machining (leaded) bronze. Lead freezes out of the metal as it cools. The little lead inclusions scattered throughout the metal lubricate the cutting tools and break the chips, which is nice for machining, but bad for welding. If you compare the alloy information on a site like anchorbronze, the weldability of similar alloys, say naval brass and leaded naval brass, is worse for the leaded version.

The art bronze advice sounds good too. My first hit on google was a question like yours with similar advice and problems. If I needed to, I would have read a lot more.

I don't know what to say about the idea of trying to flow braze metal into the cracks. They are probably fairly well oxidized inside. I think it would be best to cut out the bad metal and braze in a new piece. I have only seen the picture, and I don't know how bad or where the cracking is.

I'd say you are completely correct, I thought it might be worth a go with the right flux but it would be an experiment.

[ramillett]

Well , it's not brass , but the leaded does make sense . Well , the boat comes out of the water next Tuesday , so my focus is going to be on some new ribs and maybe a new horn timber . The pedestal is going to be shoved in the corner for the next 3 or 4 weeks . How this next job goes well determine how energetic I well be on making a new pedestal

[Bob Cleek]

I'd say you are completely correct, I thought it might be worth a go with the right flux but it would be an experiment.

In order to get brazing metal to flow into the cracks and hold, I'd think you'd definitely have to pickle the piece really well beforehand. "Pickling" in an acid bath removes all surface patina. Unless this step is performed, there is no way the brazing metal will bond to the piece. The problems many experience when first attempting "silver soldering" are almost always the result of 1) failure to prepare and hold the pieces to be joined in perfect contact with each other (Unlike lead based solder or "welding," silver solder is NOT gap-filling) and 2) failure to properly thoroughly clean the surfaces to be joined, either by sanding with emery paper or "pickling" in acid.

[Nicholas Carey]

No, I don't think bronze goes bad.

Correct!

Holding up pretty good after c. 2,600 years...



A GREEK BRONZE HELMET OF ILLYRIAN TYPE
ARCHAIC PERIOD, CIRCA 600-550 B.C.

Lot Description
A GREEK BRONZE HELMET OF ILLYRIAN TYPE
ARCHAIC PERIOD, CIRCA 600-550 B.C.

Of hammered sheet, with a flaring neck-guard, two parallel double ridges running across the crown front to back, a perforation between the ridges at the front, one on each ridge at the crown, and two at the back, all for attachment of a crest, a raised horizontal ridge above the brow, the perimeter with evenly-spaced gilt-bronze rivets, the proper left cheek-guard with a perforation at the forward tip
11 in. (27.9 cm.) high

[Mad Scientist]

Another unique 'hat' for Thorne!

Tom

[ramillett]

Anyone out there ever see wood or wood covered steering pedestal ? Bob

[Stiletto]

In the faded depths of my memory I recall seeing one in an early Wooden Boat magazine I think. It was hexagonal or octagonal and had a compass mounted on top in the normal way. It looked great, I remember that.

[ramillett]

If you run across , pictures would be helpful thanks Bob

[Ian McColgin]

Bob hit it dead center. Your "welder" ruined the piece. It's really that simple. Every now and then one manages, even with the best of intentions, to give the job to the wrong person. There's a reason that was not welded in the first place and I really can't heap enough scorn on the "welder" who did not realize this. Whatever you do, don't let that fool anywhere near anything that takes a load, like turnbuckles, chain plates or a stem head. You may or may not exact a terrible revenge on the jerk, but you are looking at a new pedestal unless you can find a super genius who knows how to go backwards from over-torching.

Sorry for your loss.

[Ian McColgin]

There are lots of wooden steering pedestals. They tend to be a bit heftier than what would fit your cockpit - too much visual mass. Whether rectangular shaped (most common) or round, all the wooden pedestals I have seen are pretty much right sided from top to bottom. The metal pedestals give both visual and leg room relief by being, whatever, say 3-1/2" on the stem and 8" at the compass. It makes a huge difference in yacht cockpits which is why such wooden pedestals are mostly found on flush decked schooners.

Marmalade came with a wooden pedestal for her compass but that was a turned leg about 2" diameter and solid, not suitable at all to also hold the chain for a wheel. Also, it never looked right and I replaced it with the old bronze pedestal (again compass only) that I had saved from Goblin. I used Goblin's compass as well as it was one of the original run of Danforth-White's marked in 5 degree increments.

[SchoonerRat]

The Privateer 35 I delivered a couple of years ago had a wood pedestal. It was big and rectangular. Not particularly attractive, but solid and functional. The one thing I really remember is it had excellent access to the guts. I'm not sure this one is worth any trouble to obtain a pic, but if you would really like one I could probably get the owner to send me a couple.

[MN Dave]

More often than not, I find that Google image search brings me right back to the post than made me look in the first place. This time it was close, but no cigar. -Gartside-Yawl-Construction I'll bet you could do a nice job with birdsmouth mast construction if you want to go with a round one.

This time it was close, but no cigar. -Gartside-Yawl-Construction
And one more:

[ramillett]

Bob hit it dead center. Your "welder" ruined the piece. It's really that simple. Every now and then one manages, even with the best of intentions, to give the job to the wrong person. There's a reason that was not welded in the first place and I really can't heap enough scorn on the "welder" who did not realize this. Whatever you do, don't let that fool anywhere near anything that takes a load, like turnbuckles, chain plates or a stem head. You may or may not exact a terrible revenge on the jerk, but you are looking at a new pedestal unless you can find a super genius who knows how to go backwards from over-torching.

Sorry for your loss.

Ian my welder has done great work on all my bronze and stainless work , never a problem , thats why this one left me baffled . The castings have not worked like any bronze I've used before , and it did not leave any of the white residue that zinc leaves when you burn brass . Bob

[Ian McColgin]

Well, perhaps I judged too harshly, perhaps he did something differently, or perhaps you were just lucky. Bronze can respond to high heat differently depending on how it was manufactured and worked, but I'm not aware of bronze being just welded like with an arc weld. Only seen it brazed or welded by forgeing with a hammer, which then requires some further work to ensure that the resulting metal has not dealloyed - so to speak - itself. But I'm not a metalurgist and there are certainly gaps in my understanding.

[Thad Van Gilder]

Ian,
Down here we weld bronze either Tig or with the stick welder.

Brass will weld with an silicon bronze stick, but the results are not usually clean.

-Thad

[Ian McColgin]

Time for a metalurgist to instruct me. Like Mark might well know.

In my lay notion, welding as with ferrous metals and even (different temp) aluminum involves melting the mateing edges. So there's a bead from the rod but the real strength is a fusion of the metal pieces. Brazing is more like soldering where two nicely fitting and clean edges are brought together and the rod is flowed - some capilary action here - in the nearly invisible gap. Brazing is more like gluing, in other words.

I'd thought but could well be wrong that you can forge weld bronze like we do with an iron wagon wheel tyre where the edges are beveled, heated past cherry, and pounded together.

Again, a metalurgist can help here but I always thought that most bronze alloys somehow unalloyed themselves if heated too much in the wrong way.

Here's hoping that my level of misunderstanding will cause someone who knows to make a lucid correction.

[Garret]

My rudder supports are welded (tig) to the rudder shaft. While brazing or silver soldering is often done, welding - done properly - works just fine & is stronger.

I can't help but wonder if the base is brass. If the builder did use brass places, then the base is a logical place for it.

[Ed Burnett]

On the subject of pedestals, this pic shows what we came up with for an 83' schooner launched earlier this year in Turkey:



It is built around a standard (jefa in this case) steering pedestal, octagonal timber clad for the most part with a pretty simple stainless fabricated top cage and standard Ritchie binacle compass on top.

Came out pretty well.

[TR]

This is perhaps a bit more elaborate that the one Ed posted above. Obviously you'll want something smaller and lighter looking, the steering box is the determining factor.

Aboard Maria Cattiva.......

[Canoeyawl]

I have worked on (and remachined) enough old Merriman brothers stuff over the years to know that a mix of materials was common practice (from examination of the machining process and the chips, hardly scientific, but similar to identifying a wood species without seeing the tree). In the era that the part was built, red brass pipe was a common item and often used in conjunction with bronze castings.
(I suspect that some variation of gun metal was the preferred casting material based on the patina and the ductility of those old parts).

Brazing is more like soldering where two nicely fitting and clean edges are brought together and the rod is flowed - some capilary action here - in the nearly invisible gap. Brazing is more like gluing, in other words.
.

A note about brazing...
For any brazing job a minimum gap is required to achieve flow and fill, usually about .003" to .005". If you don't have this it will be a poor job with voids.
Now .003" (three thousandths of an inch) may seem like an invisible gap but it is about the size of a hair or a little larger, and you would surely see that in your pasta. The best brazing is done in a furnace with a controlled temperature and the gap pre-determined. Sometimes this gap can be created by placing the filler metal under the two parts to be joined and just letting the parts settle together when the filler metal melts, this often requires a fixture to align the parts.
The surfaces must be clean and accurate, sand blasting the joints before assembly is a good (and preferred) method for preparation.

I don't think there will be success with brazing in this application because the cracks are too small and impossible to clean and flux. Cutting the assembly apart and preparing it properly for brazing might work, but that binnacle is liable to have a dynamic stress of several hundred pounds hanging from it, and if it fails is there a likely hood of injury or even worse. (you wouldn't want the steering wheel on your car brazed on..)
If it were mine, I would be thinking about a new casting for the base that would be shouldered, fitted and assembled then brazed or even threaded perhaps onto the column.

[shade of knucklehead]

One tip I have found only recently, if you want to know exactly what alloy you have, take the part to a good junkyard. The one we take scraps to has a machine they use that tells them what the metal is. If you have a good relationship with them, or offer them a bit they will check it out for you.

[MN Dave]

There isn't much to add to Bob, Ian and Canoeyawl's comments, but why let that stop me? Welding is joining by melting the base metal, any base metal. With brazing and soldering only the filler metal melts, not the base metal. The filler metal melts at a low temp for solder and high temp for a braze.

Pretty much as Ian said, when you melt an alloy, some of the components can segregate out as it cools, and that can be a problem, especially if one of the components is lead. Sometimes it helps to have a braze metal with a wide temperature range between all solid and all liquid when you need a mushy stage to fill gaps. Not big gaps maybe, but some fillers are more tolerant of gaps.

As long as the bad area is round, I'm not convinced that it would be that difficult to turn a ring on your lathe to replace the cracked weld area for a braze repair. Brazed joints can be as strong as the base metal. A little extra metal on the inside to reinforce the joint and line up the parts wouldn't hurt. If the welder knew it was leaded (assuming my guess is right), he probably would have suggested a braze instead.

You can test for lead in bronze with a lead paint test kt from the hardware store. Home Despot has a kit, and must have a store near Newport Beach. They might take a few days to order the kit. There are a number of similar kits available from hardware stores for paint testing that should work. http://hazcat.com/ has all kinds of chemical tests, but unless you need to do a lot more tests and like chemistry, I'd stick with the lead paint kits.

[ramillett]

Today I made some bronze washers , after doing some milling , then some drilling , I'm almost convinced that the base is red brass . The bronze I cut today would leave a nice long chip , no sign of that rippy sound that brass gives , and my pedestal made . I think in the next few days I'm going to chuck that monster back up and try to remove the weld , and try to get it apart , reface the joint , then retry , as brass with TIG again . If no luck , I'll get some 1/4'' silica bronze plate , and roll my own pipe with material I can trust . I appreciate the info , before this problem , I always thought brass and bronze could be welded in the same way . Bob

And Thanks guys for those pictures of steering pedestals , that got my design juices going

[Ian McColgin]

Just an aside, ramillett. You have some lovely pix of a wonderful boat. One day you must make a site that gives us a virtual tour inside and out, including close ups of your meticulously maintained systems and ever so well varnished surfaces.

[SV Papillon]

If you are going to build a new one, seamless copper nickel pipe and tubing are readily avail and weld very well to bronze. Not sure if it will take chroming though.

[Canoeyawl]

Standard copper water pipe is available, it will weld nicely with silicon bronze rod or wire.
(I made a 3" dia. rudder stock that way).

[MN Dave]

Try welding and brazing on the section you cut off. If it gives you any trouble, the big piece is doomed. I really think the weld is a bad idea, but there is promise for the braze.

The lead test will tell you that you are out of luck, but for entertainment, pink chemicals are no match for weld spatter.

[ramillett]

Just an aside, ramillett. You have some lovely pix of a wonderful boat. One day you must make a site that gives us a virtual tour inside and out, including close ups of your meticulously maintained systems and ever so well varnished surfaces.

Someday it would be fun , maybe after I get her back sailing again , or better yet come and go sailing

[MN Dave]

A note about brazing...
For any brazing job a minimum gap is required to achieve flow and fill, usually about .003" to .005".

I know that's true. Seen it many times, but I got thinking about my cracked manifold back a few decades, and... www.youtube.com/watch?v=ZojIpKCo4TQ

[CJ]

Bronze can definitely go bad in time...

[MN Dave]

Ouch.

Hey, bronze can get bronze disease.

http://www.classicalcoins.com/bronze_disease.html

[landlocked sailor]

CJ, that is truly disturbing. True, but disturbing nonetheless. Rick