If you opened a area to the metal, would the weld displace the chrome while welding, or just make a bubbly mess? I’ve no plan to do this, but during a conversation at work about some OT thing, a guy said he’s done it and all was good. He said he grinded/ground an area, then started there with a Tig. I was thinking maybe, but at a minimum a contaminated weld, maybe compromised? Just had me curious on thoughts is all. Thanks.
Not really good to weld through chrome plating, and it's because of the first copper layer. Normal "triple chrome" is copper on the bare steel, then nickel, then chrome as the final outer. Chrome and nickel will mix into the weld puddle, but the copper does not. Nickel and chromium are both alloying elements used in steel, such as 4340 which is a nicklel/chrome/moly as the main alloying for example.
All those chrome steel wheels are welded through the chrome. They are plated in two pieces and then welded together. Are they ground first, or just don't use copper in their chrome?
The chrome and cadmium coatings should be ground back for welding. The fumes otherwise are unhealthy. Welders have health issues with chromium. The welders on some of our specialty jobs wore masks with filters and fan packs. Spot welding chrome rims together would or should have been done with exhaust air to protect the workers. Our welders welded a lot of stainless steel. I was asked to check the situations for welding stainless for welder safety as there was a corporate request to make sure that welders were not harmed by chromium fumes. There was a real initiative in the last 30 years in our workplace or so to exhaust welding fumes in our shops. I learned that a person should protect themselves spraying zinc chromate primers for same reason.
I just had a set of chrome wheels built, and I was told that they don't copper plate because of the welding issue. The actual welding is done by machine.
Modern chrome dose not use copper. Copper went the way of the dodo in thd 80’s When you see peeling chrome bumpers from the 70’s thats from the first try with no copper but by the 80’s they had it sorted out
You have to grind it back to clean metal. it gas welds easier than electric methods. I used to cut up everone's cast off drag pipes to build exhaust for my old harleys and discovered that gas welding and cleaning grinding the chrome back is the best method.
That's not entirely true. If it's a new part with no surface issues, they'll skip the copper layer. But if restoring a part with surface flaws copper is still used as it's used as 'filler' and is easy to buff to a mirror finish. You also should have copper when plating aluminum as it acts as a 'sealer', preventing corrosion from getting under the plating. A lot of the peeling chrome you used to see was the plater skipping the nickel layer, just chrome straight to steel. Bumper Boyz is/was famous for this.
My point is not all chrome is the same and while one welder has done a good job you dont know if it was copper high nickle blue chrome or flash chrome which makes a huge difference.
Hexavalent chromium is a serious health hazard, we provided special PPE for the welders that welded stainless steel subassemblies!
If the welder ground the plating off of the area, they were just welding steel at that point. Chrome plating doesn't penetrate the base metal all the way through or anything. Or did they grind the plating away in an area and then continue the weld into an area that hadn't been ground? I'm not sure I understand.
Iv'e welded chrome wheels before, used a stainless steel arc rod. Didn't grind anythink back, did a few sets never had a failure.
After I got tired of messing with wheels vintique and waiting months for wheels that were not showing up I cut the centers out of a pair that I bought from summit that were the wrong set back and sent them to Wheelsmith who welded those chrome centers into new chrome hoops. Chrome was undamaged. As for copper, if you walk into the chrome shop where I spend a lot of my time you will find racks of copper plated parts waiting for their shiny coats. If you're dealing with a shop that doesn't copper first, you are dealing with the wrong shop.
yup. If you don't grind the chrome first the chrome will jump off and glom onto your tungsten (tig) and make it impossible to make a decent weld... Wirefeed (mig) sure you can weld over chrome, the wheel people do it all the time
Not optimum but possible. TIG is very intense heat but as Mark stated above it can bloop into the whole gig and make a helluva mess. Copper would contaminate, but unless you're doing some 2000 PSI tested pressure vessel it probably wouldn't fail. Then again I wouldn't want welded chrome plated roll bars either. Pick your spots.
Steve, decorative chrome is 5 millionths on an inch thick. Not enough to peel. I started in a bumper rechrome shop in 1970, here's my disertation and observations of 50 years in the industry. In the 1920's trim parts were nickel plated in a simple "Watts" bath. A short copper plating was required to promote adhesion. The nickel plating was dull, a mat finish, but buffed easily to a shine. We can see this on the back side of Model A bumpers where the face was shiny and the backs were the natural dull finish because they were not polished before plating or after like the fronts were. Henry started chroming bumpers in 1930. The back side of chrome over the dull nickel looked almost like grey primer. The Model A Club notes a "Butler finish" on the shifter and emergency brake lever. This was a rough polish before plating with only the top part of the em brake handle polished. '28-9 dashes were nickel, 30-31 were chrome. Some interior handles remained nickel. The 1933 Ford grille had only the outer ring polished and the bars remained the dull gray. 1934 had the face of the bars polished, but not the sides. By the late forties nickel plating had advanced to a system of brighteners that no longer required buffing before chrome plating. This was a big savings in labor, but the new nickel was not as durable as the old style. This led to a intoduction of "Duplex" nickel where the parts were plated with the old style "Watts" nickel and then the new bright nickel. Thru the 60's some platers continued copper plating for appearance and durability, most notably Cadillac and Oldsmobile. Ford's plater was experimenting with multiple thinner coatings of copper, brass and what might have been cobalt. It was strange polishing a bumper that had as many as 6 layers of different metals. Like feathering out a paint job that had been repainted many times. During the Korean War there was a nickel shortage and this made some platers flash chrome dirrectly over a polished copper plate. I didn't understand this until at a swap meet I saw a NOS hood ornament that had some shelf wear but the back side was shiny copper and had some clear coat on it. Never saw a bumper that was plated this way, but many grille pieces, mostly Ford and Chevy. For years platers used the example of a paint job to explain the plating process. Copper is like primer, nickel is like the color and chrome is the sealer like clear. This led to many thinking that chrome is clear. In fact chrome has it's own color as the chrome over copper shows. Another instance of chrome being flashed over metal to inhance it's color is stainless trim. Cheaper stainless has a yellow, nickel color and manufacturers would flash chrome over the buffed part to match other chrome trim on the car. Steve, plating aluminum is a whole new set of problems. Like all plating the key is cleaning and preping the surface for the plating bath. All the cleaning and pretreat baths have to be in optimum condition for reject free results. The main cause of rejects is dirt or oxidation on the surface of the plated object. Aluminum oxidizes rapidly, common process is to soak in nitric acid and immediately immerse in a zincate solution. The zincate seals the aluminum and prevents oxidation. One process is to copper plate then proceed to nickel-chrome. Some shops place the aluminum directly in the nickel. The theory is the acid in the nickel tank disolves the zinc and the nickel then plates on the clean oxide free aluminum. P.S. All steel welding rod and wire is copper coated
In the last 40 years every chrome plating failure on aluminum I've had has been where they skipped the copper layer with one exception. The one was a set of OEM aluminum wheels where they didn't fixture to get the plating into recessed areas, and it was very thin or non-existent there. Once corrosion gets under the plating, it's toast...
Doesn't take much grinding to remove everything involved with chrome plating. Unless the metal in my shop was brand new and free of everything, I pretty much hit everything that was going to be within a 1/4" of the weld bead with the grinder to shiny steel. I also ground to shiny steel, a place to hook the ground lead (or vice grips I could hook the ground lead to), always up close to my weld joint. That grinding solved a lot of problems. If the customer didn't want me to grind those areas, they took the welding job someplace else.
I wouldn't try to weld thru chrome or have it anywhere in your weld pool. A specific example that we had to do on stamping dies. The punch in form dies were typically hard chromed for wear - if there was a damaged area, had to grind it out, get a clean edge to the chrome, peen up the edge, fill the weld repair as close to surface as possible with a bit of overfill. Peening the edge raised it and allowed the weld to burn in and hopefully finish out flush. Careful grinding and stoning to old surface without taking out too much chrome. It was all a short term fix, the chromed versus weld area wore differently and created their own problems. Had to be repaired a second time when it could be sent out for rechrome. The weld on the edge that was burning in chrome got very inconsistent, only a few welders could pull it off and not get big piles of shit trying to burn in that chrome edge. He explained it as "burning under the chrome them filling it up" - made sense if you could watch it.
We used to have a lot of problems with aluminum parts on our bikes. That was when you and me were still kids. Most chrome shops advertised triple plating, I was led to believe that meant, copper, nickel and chrome. I have never been a plater nor worked for one. Then someone started advertising electro plating as a cure for the plating not sticking to chrome. Perhaps all chrome was electro plating. Like I said, never worked for a plater. All that said, plated parts have always been problematic when it comes to welding. Best bet is to grind it before welding, no matter how it has been chromed. Choose your poison gas, stick, tig, mig and got for it.
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