I know these two are like oil and water and you end up with either pits or gold hazing in the chrome over where it was mig welded. I'm modifying a '52 Kaiser overrider for my shoebox and did most of the work in mig already and it came out smooth. The chrome shop told me to go over it with silver solder and that should be okay. What I'd like to know is how it was done back in the day and how are the professional shops modifying bumpers and grills before they go to the chrome shop. I'm ***uming most stuff is/was gas welded or brazed? Any input or advice is appreciated. Thanks
If it was me I would have the chrome stripped off at the plater, then do your modification. File it an block it out with sand paper sanding it till the high light runs thru the affected area. I also like to use ****m layout fluid to show the highs and lows ,so you can bump out the dents an file them flat. The better the surface is prepped the better the plating will be so sand it out to at least 400 grit while making sure to remove the scratches from the previous lower grit papers. Depending on how much material needs to be removed I would start at 80 or 150 grit and work you way up. Its a time consuming process but worth it.
If you, and the plater, do it right, you won't see anything. First, good welds with no pinholes, or inclusions. Mig is the worst for this. gas or TIG are better. Sand and polish the welds to be sure it's right (though some platers hate when you do this!) Next, the plater should put a good layer of copper on it, after more polishing. If the plating brings up any pinholes, they can be soldered and filed/sanded to smooth them out. Then re-copper and finish the plating. Simplified, but that's it.
The chrome shop I used to work for uses silver solder as a filler and doesn't have color problems with it, but they also have used MIG welds on steel parts without difficulty. I think the only way you'll have problems is if you didn't have the part electro-stripped by the chrome shop before you started your mods. If you tried to grind the chrome off or welded on a piece that still had chrome on it you might be ****ed. It's not the MIG weld that will screw you, it's the grinding and welding on a part with chrome on it, because it'll cause chrome and nickel impurities in the base metal. So hopefully that is not the case here.
Anything chrome plated will be the color of chrome. Any yellowing will be the absence of chrome showing nickel underneath. Chrome is not transparent, it's reflective, as in reflecting uneveness and pitting. Plating over any steel welds is not a problem at all. The key is to avoid low spots from overgrinding and not having pitting in the welds. The more pitting, the more work for the plater, the more you pay for a nice piece. Simple as that. grinding off old plating will NOT contaminate the base metal. I do it every day at work. However, welding over/through plating is asking for trouble.
You can make a small strip tank for small parts with a plastic container filled with sulphuric aci 75% .add a pint of glycerine to stop pitting,use new lead flashing drapped down 2 sides as the cathode and a bar across the middle to suspend parts on quarter inch copper hooks .hook this puppy up to a couple of truck batteries in parallel .stripping should take about 5 mins .WEAR EYE PROTECTION ,RUBBER APRON RUBBER GLOVES .by now youve used up at least a whole day ,acid cost $$$,leads,lead cost $$$,glycerine cost $$$ PPE cost $$$.what are you trying to achieve , really ,.
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