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Last Updated: Sep 19, 2007 - 11:39:30 AM |
So why do we collect cars? Many of us
are helpless car nuts that just love the automobile. Some collect all makes and
models whereas others collect specific marques or cars from a certain era.
Collecting gives us personal satisfaction. Our little cars may remind us of a
time when life was simpler or of a special event in our lives. The bottom line
is that we collect because we love to. OK, so we now have a small fortune invested
in a collection of little cars. We never miss an opportunity to proudly show
off our collection of cars to friends and relatives. So how do YOU take care of
them? In my experience, I’ve seen the gamut of display and care techniques.
Cars displayed in dust free, climate controlled environments to the dusty
office of a body shop. I’ve seen people who buy a model and then never touch it
once they put it up in their garage workshop. Then there is the guy who pulls
the model off the shelf once a month just to sit down and admire the details
and workmanship. Sometimes, getting lost in the mystique of the car that the
model represents it what collecting is all about. With a little bit of care and
some responsible display techniques, these models can last a long time. In this
article I hope to cover most of the topics that people have asked me in
letters, phone calls, emails and in person. Topics to be covered will include:
identifying paint problems, basic and advanced care, minor repairs, cosmetic
touch up and display options.
So are our cars made of? Zamak, PVC and ABS. What is Zamak? Zamak consists approximately of 96% Zinc, 4% aluminum and 0.04% Magnesium. When you hear claims of, “Your model was made from the actual piston from the winning car!”, know that a hunk of piston was thrown in the vat when they were cooking the metal for that 10,000 car run. The one thing that we need to be aware of is that certain chemicals in cleaners, solvents or even our water, will react with these metals. So you always want to be aware of the things you use to clean your models with. First thing is first, READ YOUR CARE AND HANDLING MANUALS! There is basic info contained in those little manuals that will help you not only to care for your models correctly but will also give you historical tid-bits about the real car.
So now you have your models and you start seeing problems. What are they?
Paint Blistering – The number one concern among collectors. I have heard that some collectors are selling collections to avoid this malady. Unfortunately this will be their loss as this is not an unusual problem. I've read with great interest on many Forums, the comments regarding Zamak. I should also point out that Zamak 3 is common in the diecast industry. Zamak 2 may have been used early on but it is high in copper which is not only expensive but it is reactive over time. The metals actually react with each other and the Zamak literally can crumble in your hands. This being said, a bad batch of Zamak 3 can do the same if the percentages of the compounds are not within acceptable amounts. A manufacturer has no way of knowing this when the cars are produced.
I found the following on the Internet that is of interest:
ZAMAK alloys were first developed during the 1920's by The New Jersey Zinc Company. The name ZAMAK draws upon the basic metallurgy of the alloy group: Z-Zinc, A-Aluminum, MA-Magnesium, and K-Kopper (e.g., German). In the United States, ZAMAK 3 is the most common alloy for hot chamber die casting. With a combination of superior mechanical properties and low melting/manufacturing costs, it fulfills the needs for most die casting applications. Other ZAMAK alloys include ZAMAK 2, ZAMAK 5, and ZAMAK 7. Common to each alloy is a consistent Aluminum content range, however, the alloys differ in specification by varying amounts of copper, magnesium, and nickel - resulting in different mechanical and physical properties. No. 3 alloy is usually the first choice when considering zinc die casting. Its excellent balance of desirable physical and mechanical properties, superb castability and long-term dimensional stability are the reasons why over 70% of all North American zinc die castings are in No. 3 alloy. It is, therefore, the most widely available alloy from die casting sources. ZAMAK No. 3 also offers excellent finishing characteristics for plating, painting and chromate treatments. It is the "standard" by which other zinc alloys are rated in terms of die casting. No. 2 is the only ZAMAK alloy which is used for gravity casting; mainly for metal forming dies or plastic injection tools. This alloy is sometimes referred to as Kirksite. For die casting, No. 2 offers the highest strength and hardness of the ZAMAK family. However, its high copper content (3%) results in property changes upon long term aging. These changes include slight dimensional growth (0.0014 in/in/after 20 yrs.), lower elongation and reduced impact performance (to levels similar to aluminum alloys) for die cast products.
I do want to point out that Zamak is in a lot of products we use from faucets to door handles. Proper plating, acid avoidance (like acid rain) and salts is essential to protect the metal. Our models are painted but take a look at them under a jeweler's loupe. The surface may be irregular. Heat and cold will expand and contract the metal and crack the paint barrier. Acids in the air, your hands etc will settle on the model and contribute to the issue. Where you store and display your models is also a factor. Humidity is brutal on a model. I’ll discuss these issues in detail.
The white powder is aluminum oxide. Yes, it is harmful but you need to read MSDS sheets on this and it's toxicity. Just do search on the NET and you'll come up with some good info. The amounts we see should not be harmful. Obviously you don't want inhale large quantities or introduce it into an open wound, but neither would you do so with other compounds.
Zinc is a compound that we even injest when we have a cold. Zinc oxide is something that is given off when Zamak is melted. This you do not want to inhale as it is a toxin. As with anything, with prolonged exposure, it can and is harmful. It is the same stuff given off as if you were to weld galvanized steel. I don't suspect many of you will be melting your cars.
I contacted my good friend in Hong Kong, Herrick Koo, who was a lead engineer at Franklin Mint. He also worked on the engineering staff for the company that makes models for GMP. Herrick and I recognized the problem when I was still at FM and he did a lot of research into this malady. The number one cause for the blistering paint effect is the diecast itself. If the parts are molded with porosity or bad cold flow marks, it’s almost certain that you’ll see blisters over time. It may be caused by tiny air bubbles trapped inside the diecast part and are released over time. This is probably the most severe case and hard to solve. You can fine tune a mold and polish it so much that you may not “see” the problem on a molded part.
The second and most common reason is cleaning. If the cleaning process is not performed properly, before applying paint, you may have an issue later. Sometimes you can see the blister form as a fingerprint pattern. At FM’s China plant, they have a process of cleaning that involves ultra sound degreasing plus phosphating. Phosphating is a process that forms a layer of zinc phosphate on top of a diecast part to enhance adhesion with paint. Both processes really help in preventing paint blistering.
The final reason is oxidation. From experience, a model in a humid environment will have a higher incidence of blistering than a model displayed in a climate-controlled environment. Moisture leaches into the paint through open pores and reacts with the metal’s components. Similar to older aluminum wheels on newer cars today. You can see oxidation blistering under the wheel’s clearcoat.
These three reasons are compounded if the wrong Zamak is used or there are impurities in the raw Zamak itself.
The paint itself is not the problem. In fact, surprisingly, metallic paints have a lower incidence of blistering, probably due to the fact that the metallic in the paint acts as a physical barrier. The suspended metallic particles have a “leaf layering” barrier effect and seal the surface well.
So what can be done to prevent blistering? Store your cars in a controlled environment. Cars stored in hot attics or cold garages will suffer the greatest damage. Keep your cars out of the EPS or poly foam containers. If you have to store them, let them breathe once in a while and see the light of day. It would not hurt to carefully wrap them in a cotton cover so as to minimize surface contact with the EPS shell. Even strips cut to fit the tops and sides of the model will work. Body shop supply houses carry cotton polishing cloths that look like disposable paper napkins. These are perfect and inexpensive. If you do have the unfortunate happen with the EPS sticking to your paint, it can be removed by wetting a cotton swab with water and gently working the “stuck” EPS from the model. It should come off easily. If you have a paint imperfection due to outgassing of the EPS, the defect can be polished out using products mentioned.
If you have minor blisters, they can be polished out using waxes or mild abrasive polish. I will caution you, if you’ve never done this before go easy – especially using any kind of abrasive! If your blisters are extensive, the model may have to be repaired professionally. Novus #3, followed by #2 and then #1 will work to get minor blisters out of your paint. Be sure to then follow this with #26 Meguiar’s so as to protect your model from further damage. Remember to work gently with the abrasive.
Orange Peel – As the name implies the surface looks like the skin of an orange. Short of vigorous polishing and surface sanding, there is no much you can do about this. On a new model, this defect is worthy of sending back to the manufacturer or dealer.
Dirt – Dirt in the paint sometimes can be removed with a super-fine wet grit sanding film, patience and some liquid polishing. The problem is determining where the dust or dirt is in the layer. If the speck is close to the surface, you are in good shape. Simply place your sanding film (I use 12000 grit wet for this procedure) over the dust speck and put you finger over both. Pull the strip away from the model. The dirt or dust will be removed. The area will have a slight haze to it from the sanding medium. Use your glaze to buff it out to a nice shine and then wax.
Chips – Again, if this is a new model, it should go back. If you have a rare model or an older discontinued issue, you can repair the chip easily. Hobby shops carry minute, disposable touch up brushes and a wide assortment of hobby paints. These are good for small jobs. It also gives you a chance to play with color mixing. I have successfully repaired many models, even for customers, with the repair not being evident.
Fish Eyes – This is a problem caused by silicone or other impurities on the surface before painting. This is a serious problem and the model should be returned.
Edge Pooling – Most commonly seen with light colored metallic paints. Let’s face it our models are not made individually. They are assembly-lined through paint booths and incur problems associated with mass production. Bodies are hung and transported through the booth. The paint is applied and the heavy metallic settles out on the edges either by capillary action or gravity – it’s a painting fact of life. To avoid this, the paint would have to be applied in multiple light mist coats, but I don’t think many of us would pay $2000 per model. You can repair this if you have patience and a light hand. Using a medium cut polish you can gently buff down the high paint spots and level the metallic. One word of caution: you will cut to the metal if you are too aggressive with the buffing medium.
Surface scratches – These vary from the light haze you find on a black car to deep scratches found when your wife’s friend with all the diamonds handles your models. The light haze type defects can be buffed out with a glaze and wax application. You must be sure to use a soft cotton cloth and light pressure. Soft paint will and a heavy hand will only add surface scratches. An excellent low-tech method of testing paint reflection is to hold the paint under a light bulb. If you can read the writing on the bulb in the paint, you have an outstanding shine on your model.
Deep scratches can be touched up with paint and blended in with polish, glaze and wax. You will need to carefully color match the paint and level it with the polish. You can attempt to repair some scratches with Meguiar’s Scratch-X. I have successfully removed some deep scratches and the typical package scuffing with Scratch-X. It also helps with models that are just starting to show surface irregularities.
Basic cleaning and waxing using a Care Kit
Part 2
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