Chrome and Rubber Degradation

Date: Sun, 25 Apr 2004 19:08:19 -0000
From: "Himawari"
Subject: Re: Rechroming Transformers?

Sorry, have to make this brief (no time on my hands currently), there are many types of "chroming" some terms are used very general. The application that is used on plastic items or items which cannot carry a current would be a form of metal deposition. This is what is used for toys and this is the process that I used to chrome some stuff as well while I was living in Japan. There is a company in California that offers a service to take small orders and "chrome" them. Usually this type of service isn't available to the general public because they would require a high volume order. It is not a technique one could perform in their basement or garage either. The machine used would be a large chanber where it could be closed and a very strong vacuum applied. From there, the metal that is to be deposited on the surface of the item to be coated is placed on coil filements where a large DC current passes through to evaporate it under vacuum. The objects in the chamber must be turning since the vapour travels in a straight line. There is also the treating of the parts before they enter the vacuum chamber as well, and would require a proper set up for airbrushing and proper waste control.

I must also add, that if a person wanted to get something "re-chromed", they would have to totally strip all the crome off of the part. This could be difficult without harming the polystyrene resin, or even ABS resin. A person could use a kitchen cleanser (one that said do not use on aluminum) and prepare a bath. Soak the part in it, and all the deposited aluminum will eventually flake off. the next task would be to strip the "glue" that was used for the aluminum to stick to. I remember a product that worked in Japan, but I'm not sure what it's equivalent would be here. I'd want to check on it before I mention what I "think" it would be since I wouldn't want anyone to try something that would not work.

As for rechroming, if a person wanted to go about another way to do it, they could try brush plating. This type of material is available on the commercial market and could be bought in some hobby stores if not on the internet. Basically it is a form of electroplating, where the peice being chromed acts as a cathode (negative pole/charge from a battery) and a paintbrush that has a wire embedded in it is connected to the positive pole and acts as an anode. The electrode (paintbrush) is then dipped into the electrolyte (solution) and painted onto the surface. The only set back to this is, you would have to coat the part (since it is non conductive) with a conductive material on the surface to plate it. In the industry this process may be used, but on metals (for obvious reasons) to repair chipped or dammaged plating and for small parts. I know this is how they would plate baby shoes. They would spray paint the shoes with a conductive copper solution, and then plate them. You could probably do the same with toys. I have yet to try it though, and I can bet this is the method Delta would have used. It is quite easy, and little waste cleanup. True chroming, like car bumpers etc, isn't even related to what is done in the toy industry, so I won't even get into that long expensive process.

Wow, this turned out longer than I thought. Hope it makes sense though.



Date: Sun, 25 Apr 2004 19:48:57 -0000
From: "Himawari"
Subject: Re: Rubber on Transformers?

question...i have noticed even though i take care of all my g1 tf's, their rubber tires, and shockwave's wire, have started to crack...

This is from degradation due to oxidization. basically any exposure to the atmosphere, heat, UV, overworking ie stretching or other forms of plastic deformation will contribute to this.

can you use any type of silicone gel or what not to keep this from happening, or is the rubber made so cheaply that it will just break apart if i do this?

I don't think cost is an issue. Basically the rubber is probably a thermoset. Once it begins to degrade, there is nothing you can do to restore it. There are two types of plastics, thermoplastics (think of butter) and thermosets (think of bread). Thermoplastics can be remelted and reused, whereas thermosets cannot be remelted or reformed, just ground up. Once you make bread, that's it, you can't make bread again. This causes the problem with let's say rubber that is a thermoset, once the bonds begin to break, there is nothing that can be done to join them back together. If you tried to heat a thermoset, it would simply further degrade or burn. As for adding something on the surface to prevent exposure to the outside environment, this may work, but I doubt you'd want your toy wheels or shockwave wires covered with goop. And, it would only do good if done before any degradation started. Oxidization is plastic's cancer. Once it starts, there is no reverse effects that can be done on it to "heal it". If the rubber were a thermoplastic, you could try heating the cracked area only and used force to get the sides that were cracked to stick together, or find a solvent that would "melt" the two sides together similar to what acetone would due to styrene.

Sorry I couldn't have been any further help.



(See Also: Chrome and Rubber Issues)

(See Also: Plastic Degradation Due to UV Light)

(See Also: Plastics Used in Making Testshots and Other TF Toys)