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MG MGB Technical - Metal coating

Working on parts like the wire loom clips in the trunk, and things like the hinges from the rear seat and spair tire cover in my 67 GT.

What would be a good finish to use on these metal parts? Most have 37 years of gunk and some corrosion on them. They clean up well in my tumbler, but they must have had a coating on them when new.

I don't have a plating company close. ANyone have an Over-the-counter product that works?
Bruce Cunha

You could do what I did and Zinc plate them using a home plating kit. I ordered one through Casswell or (Caswell?) plating. The kit was about $100 and works Very Well. I believe that the hindges etc would have had a zinc plating originally to prevent rust. I used it to replate all of the original bolts, clamps, latches etc. you would be surprised how many uses you will find for zinc. With the correct prep it leaves a nice bright finish just like new but it is very labor intensive.
Jim
JCR Royal

JCR,
Can you expound on "labor intensive". I had often considered ordering the same kit. Would love to hear some details.
Frank

Sure,
The kit itself is not labor intensive at all just hook up the zinc plates as an anode and the part as a cathode and plop it into the electrolyte solution and your plating. 15-20 minutes later you usually end up with good looking plates part. The hard part is all the cleaning and degreasing that leads up to that point. you need perfectly clean metal or your wasting your time.
let me know if you want to know more.
Jim
JCR Royal

I will look into this. I took a tip form one of the regulars on the board and have a small rock tumbler that takes a lot of the prep time out of cleaning. Some use units designed to clean rifle shells. You put the parts in, turn it on and come back later (in the case of a small rock tumbler, it mat take overnight) but have very clean parts.
Bruce Cunha

Did some looking on the web. The Caswell system appears to be a good one. Has anyone has used the Eastwood kit? I saw some comments from other car restoration areas, including some from the healy ring, that say the eastwood system works well for small parts also. The eastwood system is about $50 less.
Bruce Cunha

If you are going to zinc plate the part yourself, you have everything to try electrolytic derusting. From what I've read, the process is very effective at removing rust, as well as pretty good at degreasing and cleaning up the parts (the bubbling from the electrolytic process knocks the grease off). You can run a search on the web for more info, but, it is basically the reverse of the zinc plating process - reverse the charge on the anode/cathode and use steel re-bar instead of zinc plate. The rust jumps to the re-bar, and in the process, cleans the metal up.

I've never done it myself, but, from what I've read, it seems effective and several people claim that a side effect is that it is a good degreaser. The one downside is that there will be small pits where the old rust was that would need to be smooted down. I think there was a reference to the process on this board about 6 months ago or so. Not sure how good it would be for a rust free piece of metal or how clean it would actually make it.

As for the zinc plating - really all you need is a battery charger, a zinc source, some electrodes, and a solution (they use washing soda for derusting). Bruce, you could probably save yourself $100 if you already have a battery charger.

Here's a link to derusting:

http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm

J. Lawrence

I agree that you could probably chase down all of the supplies yourself. The thing that talked me into droping a C note at Caswell is that the kit comes with all of the heaters, thermostats, chemicals, brighteners, degreasers and a pretty good manual that covers all types of plating. The manual was worth the read and I was able to produce good results right out of the box. Also they sell a chemical that converts the Zinc coating into a goldish Cadnium (sp?) color as used on many places on our MGBs, They call it Copy cad. As far as the Eastwood kit, I have no experience with it but it looks like it will work well. What made up my mind all of the equipment that Caswell's kit come's with to create consistent results.
J. Lawrence,
As far as derusting parts, I think that what you decribe would work well. You may also want to try an acid pickle. 1 part Muramic (sp?) acid to 2 parts water. This will do a great job on steel.
Bruce,
I have been doing alot of plating lately if you want to see what the finished product looks like drop me an e-mail and I'll plate a sample for you for postage. That should help you make up your mind.

I have no connection to Caswell but I have been please with the products.
Jim
JCR Royal

The plating kit was in Enjoying MG a couple of years back . It was shown in the restoration of a twincam A coupe. It worked well. The whole restoration was impressive .You may remeber it , the car was called Ratty to honour it's previuos occupants
S Best

Just my 2cents on rust removal. A gallon of muriatic acid (costs around $1) mixed with 2 gallons of hot water will remove the rust and paint from any steel parts. Adding a small fish tank heater to keep the solution warm speeds the process. Placing an old wire wheel in a plastic bucket with this mixture will result in a clean rust free wheel in a few hours. Of course it will work on dozens of smaller parts as well, and it does an ok job of removing grease too.
Jeff Schlemmer

I tried the electrolysis rust removal. Got to say this is FANTASTIC. I have a 55 gal tank of sodium hydroxide that I use for paint stripping. It sets up on bricks. I attached some rusted parts on a copper wire and suspended them from a pvc pipe into the solution. Used a 4 amp battery charger on 6 volt with the positive lead clipped to the steel drum and the negative to the copper wire. It strips rust better than anything I have seen. (although I have not tried the muratic acid yet.)
It would be very easy to set this up on a smaller scale. Most parts are clean in 30 minutes. i did leave one part in for 3 hours and it totally removed all rust (you do have to wash the part. I used a green scrubbing pad and it removes all traces of the black material that is on the part when it comes out of the bath.
Bruce Cunha

Some notes. First, "muriatic acid" is a specific blend of hydrocloric acid often used in swiming pools. Even mixed with water, it is a strong acid and, if you have not had chemistry class, be careful about mixing it. (Do not remember, from freshman chemistry whether you pour the acid into the water or vice versa.) One thing to consider is stress bearing parts. Hardened steel parts, plunged into hydrocloric acid, become hydrogen embrittled. My experience, in the firearms field, is that these parts become brittle an tend to crack under stress. I have had this happen with slide stops and barrel bushings on the Colt 1911 pistol. I have also heard of it happening in fasteners used, in automotive work, in a stressed condition.

The original "tumblers" were made for polishing rocks and pieces of rocks. There are now vibrating cleaners which, depending on the media used for cleaning and the various polishing compounds used, can clean up rusted or oxidized parts. My experience is that bead blasting does a better job and is much faster. A small, "bench top" bead blaster is a rather inexpensive item from either Harbor Freight or any of the various machine tool supply companies (I have dealt with Rutland Tool extensively). They do need a compressor, but a home compressor is a great thing to have allowing you to top up the tire pressure (did that today before my daughter drove her car back to Tucson) and use various air tools. Life is much more pleasant with air tools, especially things like air ratchets, die grinders and pneumatic cut off wheels.

As to finishes, the various plating processess are of moderate to poor quality. Even the best are not as good as a commercial plating process because of the cost of the equipment required to do a top quality job. A minor set up for the industrial black oxide (blueing/bluing in firearms terms)process would cost about $1K US. Then, you have the problem of disposal of "hazzardous waste products".

I have used Gun Kote, a process that was originally developed to coat the main gun on battle tanks, and has been adapted for automotive and small shop use, for a number of years. The coating requires that the parts be blasted, cleaned, then sprayed with Gun Kote. Gun Kote resists most organic solvent, including brake fluid. I used it on the clutch master cylinder of my daughter's car several years ago when the plated finish became rusted. The clutch master cylinder, today, looked like new. The parts need to be baked at 300 deg. F for one hour after they have dryed to "set" the finish. For small parts, I use a toaster oven with good results. For larger parts, I picked up an old kitchen range from a neighbor for free. I have tried both high temperature paint and Gun Kote on rear brake drums. After five years, the drums coated with Gun Kote look new and the ones coated with paint need to be refinished. There are also some allied finishes associated with the Gun Kote process made for industrial and automotive use. These might be worth considering depending on the application. A "Google" search for "Gun Kote" should turn up some interesting information which might be of use.

Les
Les Bengtson

Les,

Always pour acid in to water in order to dilute (slowly, and keep an eye on the temp of the water). Other way can lead to more extreme exotherm and spitting of the acid and it heats up very quickly.

Iain
I D Cameron

Iain. Thanks. I somewhat remembered there being a specfic procedure. The heat generated when the two are mixed or the possibility of splashing were the two reasons I remembered having explained as to why it was important to do the thing properly. But, freshman chemistry was something over 35 years ago now and high school chemistry even further back into pre-history. Thanks for giving out the correct info. Les
Les Bengtson

As my highschool chemistry teacher drilled into us

"DO AS YOU OTTER - ADDD ACID TO WATER"
Bruce Cunha

This thread was discussed between 07/04/2005 and 12/04/2005

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