Plating vs. Painting Model A Parts

To plate or not to plate, that is the question. Every restoration requires that choices be made.  Do you save money and paint that originally plated part, or should you spend for a repro?  Or you could really spend and have that original part plated?  Hey!  It’s your car.  This article hopefully will give you some insights on where you might be able to make your car look better and not spend a lot of dollars getting there. 

There are nine types of plating used on the Model A Fords.  From worst to best, these are plain, Raven, cadmium, terne, lead, nickel, Butler, chrome, and Allegheny Rustless Steel (stainless).  If you want to make your car look its best, nothing beats plating.  It adds incredible detailing.  But unless someone is going to compare your car against one that has the correct plating, paint works on many items.  However, neither paint nor plating will make a bad car drive well. 

I was once told that Henry put the cars together to look good all the way to the showroom but not much longer.  The type of plating tends to support that opinion.  The parts that would rust quickest were neither plated nor painted.  Parts were delivered to the assembly line covered in oil.  As the oil wore off, so did the rust protection.  The lower part of the spark rod and the bumper support bracket nuts are good examples of un-plated or un-painted parts.  It is acceptable by all Model A clubs to paint these parts black for preservation.  The paint sheen is not specified and is left to the restorer.  I suggest that once you decide, you stick with the same sheen (flat, satin, or gloss) all the way through the restoration.  Eastwood markets an Under the Hood Black that works well for plain parts as well as the generator and starter.  One problem that you will have with paint on fasteners is the paint chips or scraps off when tighten with a wrench.  For this reason I suggest a light coat of paint.  I do not recommend spraying the plain metal with clear lacquer paint.  The parts will still rust.  Eastwood is now selling a paint that resembles plain steel.  You might try it.  

There are four exceptions to the black paint rule.  One is the bolt holding the carburetor together. Another is the glass-bowl gas-filter fixture.  Its pot metal.  You can clean it.  But, do not paint or plate either of these parts.  The exhaust manifold was originally unfinished.  Gray or black heat resistant paint is acceptable.  The final exception is the muffler.  Black, gray or silver heat resistant paints works.      

The step up from plain steel was Ford’s Raven finish. This finish is now called Black Oxide. Today’s commercial finish is satin black.  The original finish was closer to flat black.  Either is correct.  The technique to create a Raven finish is similar to gun bluing.  Parts are immersed in a chemical for 10 to 20 minutes.  The chemical seeps into the tiny pores of the metal and oxidizes as it dries.  After the part is dried it is given an oil bath.  The Raven finish protects the steel by occupying the pores that could trap and hold moisture.  The finish does not chip or scrap off during assembly.  Raven fasteners give a rich sense of detail.  Surprisingly, it is a fairly effective rust preventative.  A common substitute for Raven finish is a flat or satin black paint. Raven is common to almost all bolts and nuts used on the chassis.  A heavy coat of paint on some fasteners may cause electrical problems, as the electrical circuit can be interrupted.  A good example is the bolt holding the bottom of the headlight bucket.  Here, I suggest buying a replacement bolt rather than painting.

For parts that needed an economical and bright finish, Ford used cadmium (cad) plating.  The cad used by Henry Ford is unavailable today.  The cad plating process produces arsenic gas and is limited by the EPA.  More common is either zinc or zinc chromate plating.  Commercial zinc plating is too bright but it is acceptable for judging.  The original cad was duller with a softer appearance.  Zinc chromate is yellow in color and is not acceptable.  Cad was used for small parts such as grease fittings or hose clamps.  Cad or zinc is economical and effective as a rust preventative.  It protects the base metal by shedding a layer of itself whenever the part gets wet.  Each time you wash the plated part, you are reducing the thickness of the plating.

Cad like all metal plating is applied through electrolysis.  The part to be plated is immersed in a heated solution.  Electricity is passed through the part and the solution.  The electricity drives the metallic particles in the solution onto the base metal.  Parts can be buffed to the desired shine and the finish will not chip off with use.

Most cad parts are available through the Model A vendors if you want to avoid the plating hassles.  However, Cad (or zinc) is the least expensive plating process.  If the part is in good shape, plating is an option.  Be sure to specify you want the gray or silver finish.  Otherwise your parts will be returned in yellow-cad.  Painting is the third option.  The starter switch for example was originally supplied in either cad or painted black.  Black painted switches are acceptable for judging.  For all other parts, Eastwood sells a paint that resembles cad plating.  Do it lightly over a plain part and you can get satisfactory results.  It’s still paint, but from 3 feet away it looks a lot like the real stuff.  The trick is not to mix real cad and painted cad parts.  The paint is then easy to spot. I suggest avoiding aluminum or chrome paint; it’s just too bright.

Some parts that were originally cad plated are now being manufactured in stainless steel. Stainless steel can be made to look like cad by bead blasting.  Examples are lug nuts or the rivets that hold the headlight bucket to the mounting bracket. 

What is terne plating?  It’s an often-asked question.  The only part I know that was terne plated is the cutout switch.  Cutout switches today are likely to be cad plated, stainless, or painted black by the restorer. Cad switches are acceptable for judging in Penn-Ohio or the touring class for the national clubs.  But originally the finish was dull gray metallic plating. Using a soldering iron and a high lead solder best duplicates terne at home.

Another uncommon plating was lead.  It was used one place, the battery-grounding strap.  Today’s repro parts are copper straps.  The originals were similar but lead coated.  This can be duplicated using body solder available from auto body stores.  Or, mail order plating companies sell a brush-on lead coating that works extremely well when heated with a propane torch.  Considering that this strap is impossible to see, very few restorers will worry about getting it right. 

Starting with the 1928 models, Ford used nickel-plating inside and out for all bright trim parts.  Nickel can be buffed to a very bright, almost chrome-like shine.  The problem is that it oxidizes and turns dull quickly.  On the plus side, nickel is non-porous.  Water cannot penetrate nickel. The low-buck alternative to plating is buying new repro parts that are nickel-plated. Painting nickel-plated parts seriously detracts from quality of the restoration and should be avoided if you are having your car judged.

Mid-way through production Henry started using a Butler-nickel finish for interior plated parts on deluxe cars.  Butler finish is a satin finish.  It makes the interior look richer.  In fact, I bet you think that’s why Ford did it.  Wrong!  It saved labor.  To achieve a bright nickel finish both the copper coat and the finish nickel plating had to be buffed.  There is no buffing done to a butler-plated part.  The Butler portion was lightly scratched using a Butler wheel on a bench grinder.  Butler parts were not chrome plated.  There is no cheap way to duplicate Butler-nickel finish.  The least expensive route that will keep your restoration looking sharp is to use repro nickel-plated parts or to find good used parts.  You will lose only marginal points in judging for using bright nickel in place of Butler.

Some of the hardest pieces to nickel plate are pot metal parts.  The plating used as the base coat is either copper or nickel.  Both are high in acid content.  Pot metal is very susceptible to acid.  Old pot metal tends to develop cracks that allow the acid to penetrate the metal.  Once this happens, the piece begins to dissolve in the plating solution.  To solve this problem platers use a different non-acid copper solution as the first coat.

Repro parts generally do not have a copper base coat.  They receive a “flash” coat of nickel over the base metal to provide a bright finish.  The flash coat is very thin.  Underlying scratches or imperfections will show through.          

Bumpers were manufactured in chrome from the start of production.  The plus side to chrome is that is not affected by air and does not oxidize.  The downside is that chrome is porous.  Water can penetrate chrome and rust the base metal if not protected by a coating of nickel.  Chrome is also expensive.  Original chrome parts should be retained and re-plated if possible.  Original bumpers are heavier and made from spring steel.  Reproduction bumpers are not.

By late 1929, Henry began experimenting with chrome radiators and cowl bands on the town cars.  However the extra cost to chrome plate made it impractical for the bright work on the Model A’s.  In 1930, the switch was made to a relatively new product, Allegheny Rustless Steel.  Today we know this product as stainless.  Stainless items should not need to be replaced.  Stainless can be re-buffed to a high shine. 

In general, nickel, Butler, chrome, and stainless parts should not be painted.  These items are all very visible on your car.  You are better off spending the dollars here on restoring the original parts or finding good used parts with little wear.  The low dollar alternative is to buy reproduction parts.

Perhaps this is more information than you wanted regarding Model A plating.  In short, if you are showing your car locally or at Penn-Ohio, I recommend the following.

Plain steel – the general rule is to paint it black.

Raven – paint satin or flat black.

Cad plating – buy a new reproduction part.

Terne –the only part terne plated was the generator cutout.  If you still run a generator, buy a new reproduction part in cad. 

Lead – the only part lead plated was the battery grounding strap.  You don’t see it so use what you have.

Nickel – buy a new reproduction part.

Butler – substitute a new nickel-plated reproduction part and take the loss of points.

Chrome – substitute a new chrome plated part.

Stainless steel – rebuff to original shine.

The quick and simple recommendation is that the best compromise between plating and painting is to buy reproduction parts.  You can get away with painting a few parts that were either not plated or available either painted or plated.  But, every time you paint a plated part, you will lose detail and devalue your restoration.  If you plan to show the car for MARC or MAFCA, plate the original part.

This tech tip was originally provided by Bob Hudec and printed in the August 2001 “A” Quail Call.