How To Clean Magnesium And Aluminum Slot Car Parts
To start with, one strong warning, avoid lemon juice at all cost ! The acid in lemon juice is highly corrosive to magnesium (Cox chassis parts and wheels) and will remove metal from the parts you are trying to restore.
I would recommend glass bead blasting as the optimum method to clean but not risk damage to the metal. One problem with this is the somewhat industrial nature of the blasting cabinets and monstrous and somewhat clumsy gloves that one must wear inside the cabinets. All that stuff does not lend itself to itsy bitsy bits like slot car wheels and chassis parts. It is far too easy to have those parts disappear down the grate inside the blasting cabinet, never to be seen again ... and absolutely silly trying to handle wheels and effectively clean all of the surfaces ...
Sooooooo ... what's a body to do ?? .. first, find a bud that is a serious racer or hobbyist that has one of these monster machines, second, buy the chap a bag of glass beads and a couple cans of his favorite beverage to get on his good side (medium grit recommended), third, put together a handy fixture to make life at least somewhat bearable when you are crouching down over the device with sweat pouring down your snoze.
Some suggestions on handy dandy fixtures follow for the serious hobbyist that wants to give this a try. The first one pictured is very simple to make and has a number of different uses. Picture follows :
The base of this one is made from phenolic plastic, but other materials would also work like MDF (medium density fiberboard), aluminum, steel, etc. This example is 10" long by 2" wide of 1/2" thick plastic. The 5-40 threaded axles used in this are pressed into a slightly undersized hole to save time, but you could thread all of the holes and Loctite the axles in place. Up to 28 parts can be handled at one time with the short & stubby axles at the ends just there to prevent things like drop arms from spinning around. Cox chassis sections, Dynamic parts or other bits can also be mounted on this type of fixture with the only limitation being the length of the axle used must be long enough to allow the parts to be secured by nuts on the top and the part in question must have some suitable hole to allow the axle to pass through and do it's job of retaining the bits in the blast cabinet. Extra material at each end facilitates gripping and handling with the aforementioned gloves.
Another similar variant to this fixture design if shown below :
This one allows much better access to the rear of the wheels.
And finally the piece de resistance (pardon my French PDL) ..... One problem with the prior designs is that they do not allow any work with corrosion inside the wheel threads or taper area for those Cox axles .... The ingenious solution to all that is as follows :
This one uses a 1/16" pc. of piano wire with a threaded thumb screw to retain the piano wire .. this one has been the answer to much experimentation and fumbling about with other ways to solve the problem.
Hope thais is of interest .... at least to some ....
And finally, some bits that were cleaned :
The glass beads will also do wonders for die cast aluminum that was used in Dynamic chassis bits and wheels. After cleaning place the bits in heavy duty Ziploc freezer bags while avoiding touching with fingers and the associated deposition of grimy finger oils. Squeeze the bag a bit to expel excess air & zip tight. If so handled the bits will stay bright for a long time, these were done over a year ago.
To prevent further corrosion ... you can paint the bits right on the fixture in some cases .... silver paint looks great on wheels for example, and there is an Aerospace general goop I use called " Boeshield T-9" .. this stuff comes in a spray can and deposits a waxy coating that is very thin, but very effective in preventing corrosive residue from forming.
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