EH Scott Radio Enthusiasts

The Fine Things are Always Hand Made

Hello all. I hope you all are well. i have been experimenting with one of the Caswell chroming kits and am encouraged by the initial test results. My intention is to re-chrome the horizontal surfaces of the various chrome covers on my AW15 and AW23. 

To that end, does anyone know the base metal and metal layering of those pieces. I suspect it would be something like (base metal, copper, nickel, chrome). It seems like I've seen the answer on the forum, but now I can't find it. 

Thanks Steve

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From Scott literature:

A chromium finish is secured by first plating metal parts
in copper; after which they are buffed, then nickel plated
and again buffed. The metal parts are then chromium
plated after which they are buffed and polished. The finish
is permanent and preserves its beautiful luster without
polishing for many years, and gives you absolute assurance
against rust or corrosion in damp and humid
climates.

Kent

I have peeled the chrome off of a number of tube/coil covers.  None of them had copper base.  They are nickel plated then over plated with chrome.  The tube/coil covers I am aware of have come in a thinner aluminum, and a heavier walled style that I believe to be zinc.  Neither one is easy to replate.  If there is a lot of bubbling, that is caused by the aluminum corroding below the plating. Nickel is cathodic to aluminum and a breach in the plating will lead to rapid corrosion of the aluminum.  The horizontal surfaces get hit the worse because of moisture condensation which is fuel for the corrosion process.  During rechroming these pits left by the corrosion are difficult to fill with copper and properly buff smooth.  The tube covers in particular are the most difficult as the buffing action erodes the holes in top making them larger and disfigured. 

On the 2 steel chassis I have mechanically stripped the chrome on (1 tuner and 1 amp/ps),  there was a very thin flash layer of copper, much thinner than you would put on "show" chrome.  The copper is used as a layer to fill in imperfections and allows the plater to buff the surface smooth as glass.  It also adds another layer of protection for the base metal.  

What plating kit are you using from Caswell?  It would be more difficult to plate only one surface of a cover by traditional plating methods as you would have to mask off other areas that are not to be plated, and you would have a new to old chrome transition that would have to be addressed. 

Kent. So much for the " absolute assurance
against rust or corrosion" part. Thanks

Scott. First of all let me be clear that I am an absolute beginner when it comes to plating. I do have considerable experience with woodworking and polishing and buffing, both with wet/dry abrasive paper and with buffing wheels. Given the obscene costs of commercial plating services, there doesn't' seem like anything here that a reasonably skilled hobbyist couldn't do, given that the entire hobby is one big experiment anyway. 

I bought the "Plug and Plate" system. It seemed like a good place to start. I did read the, rather extensive, Coswell Plating Manual. As a practice piece, I spent considerable time and buffed an old copper pipe fitting to a high shine and was able to plate it with chrome successfully. The small hand anode is easy to control where the chrome goes. It appears that the shine of the chrome is directly tied to the quality of the shine of the underlying metal. 

As to the tube can itself, I first, mechanically removed the pits with abrasives and leveled the entire top down to the underlying metal. I ended up with a top that was extremely flat and smooth, but didn't shine very well. My intent is to add additional layers of copper and nickel buffing between layers and then plate with chrome.  Coswell sells separate metal solutions and anodes that work with their P and P system.   However, my amateur eye is unable to determine what the base metal actually is.  How would you suggest I determine what it is. 

As an aside, I found that using my DC power supply works much better than their supplied walwart, as I can control both voltage and current. Further, I played around a bit with using a larger anode and immersing part of the copper fitting. That worked fairly well, but still needs some tweaking. 

So here's my plan. It will take awhile to get the supplies from Caswell. Once I get the supplies I can begin experimenting on plating with the other metals. The P and P wand method seems fairly straight forward. I think I'll also try and "dip"  just the top of the can in the plating bath and see how that works. 

Any help or advice on proceeding would be greatly appreciated. Especially on the initial plating of the base metal.

Thanks Steve

 

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