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NazareneCarpenter (Structural) (OP)
13 Feb 06 23:42
Gentlemen (& Ladies)

I just stumbled across this site and found it informative for what I need.

I am restoring an old American car, on a very tight budget I might add, and there is a few chromed plastic parts that I can't seem to find anywhere except once in a blue moon on Ebay for "get-rich-quick" prices.

My questions are: What would be the best mold/repro process I can use as a "diy-er"? What would be the best material for the chrome parts? Should I worry about copyrights if I were to decide to somehow market them in the future even if these parts are obsolete and haven't been made for over 40 years?
Do forgive me for my lack of knowledge in this area but any help or guidance is greatly appreciated.

Thanks in advance.

Abe
ozchevy (Mechanical)
20 Feb 06 5:42
What make of motor vehicle are we talking about?

Classic Industries sell remanufactured parts for many models of classic cars at very good prices.

I'm in Australia, and own a 79 model Chevy Camaro, which is not a common vehicle down-under, Classic Industries have been a vital part of my restoration project.
NazareneCarpenter (Structural) (OP)
20 Feb 06 12:08
Thanks ozchevy for your reply. I am well aware of most if not all chevy parts catalogs (I am trying to restore a chevy truck) here in US, but the parts I need and can't seem to find have to do with the A/C venting. The vents are some kind of plastic that have been chromed but did not come on any other car so that I could use those. These style are original to this model. I do have an original vent that I can use for a mold but I'm wondering as to the reproduction possibilities seeing that these are obosolete and not produced in the aftermarket.
THanks
patprimmer (Publican)
20 Feb 06 18:35
If it is to be chrome plated anyway, I would be inclined to get a local foundry to cast it in aluminium. They can use the original part as a pattern if the part is simple, or if it is a bit more complex, maybe cut the pattern in half so that each part can be pressed into a sand box, and withdrawn without distorting the impression left in the sand. If it is necessary to do 2 parts, they can be welded together before plating.

Regards

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MikeHalloran (Mechanical)
20 Feb 06 21:32
You could fabricate one or two from styrene or ABS sheet, or carve negatives in wax and cast the parts in acrylic or epoxy.

Then paint the result with simulated chrome paint.  I have not seen it that I know of, but I have been told the stuff from Eastwood looks pretty decent.

Mike Halloran
Pembroke Pines, FL, USA

ozchevy (Mechanical)
21 Feb 06 23:40
This sounds as though it's a part that could be easily made in a fabricated steel mould and Rotary Moulded. Only thing is it would have to be moulded in Polyethelene, which I'm not sure of for Chrome plating. Maybe using a cross-link additive to the powder would work mixed with cadium.

A steel fabricated mould would cost very little to manufacture. Abe, can you email me a drawing and we can go from there. I work for a Rotary moulding company as a Toolmaker.  
NazareneCarpenter (Structural) (OP)
22 Feb 06 0:29
Thanks again for your comments...I'm reading them and trying to digest as much info as possible on this subject. I do also like the thought of casting it in aluminum or some other metal and giving it a high polished look. I also just found a website where a guy is making his own sand castings for old/obsolete motorcycle parts. It might work for me. I'll keep ya'll posted.
Thanks a bunch.
Abe
patprimmer (Publican)
22 Feb 06 10:19
PE would be about the hardest material there is to plate.

The naturally greasy and inert surface makes it difficult to get either a chemical or a physical bond.

Special grades of ABS or PC/ABS can be easily plated, but not rotomoulded. Also rotomoulding gives poor surface detail.

Nylon and Acetal can also be plated but not so easily or successfully as ABS or PC/ABS. They also cannot be rotomoulded.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

ozchevy (Mechanical)
23 Feb 06 5:40
Pat,

I hear you, re: greasy surface PE - but tend to dissagree on poor surface finish. Really depends on what effort is made in the finish of the tooling, I could manufacture a mould that leaves a surface finish to the product, equal to an injected moulded die finish. Depends on what the client wants and how much he/she is willing to spend. Mostly rotomould tooling is a sand or bead blast finish, sometimes vacuum honing leaves a really nice surface texture, and then on aluminium moulds a mirror finish is required on some products.
Also on the subject of PE in rotomoulding and greasy surface, a lot can be said on over use of mould release.
NazareneCarpenter (Structural) (OP)
24 Jul 06 17:05
Thanks to all for your replies...I know it's been awhile since I've posted to this thread. In the meantime I have looked into a mold website called Freemansupply.com and they seem to have everything I would need. I spoke to the tech rep. and told him what I intended on Doing (reproduce obsolete plastic A/C vent part then electro-plate it) but he said that their products were mainly for prototypes and probably not able to withstand the use/abuse of and a/c vent. I'm not looking for anything fancy, just something I could reproduce myself without having to shell out the thousands for one little part. My question now is...what is the genereal consensus here as to the best plastic material to be used for eventual chrome plating? Also, could one of you guys check out the website for me and decipher for materials they got that would work best for my application?

I appreciate any and every help possible.

Abe
patprimmer (Publican)
25 Jul 06 1:53
I still go with the sand cast aluminium with a lot of hand finishing then plating.

It will be the easiest way to make an original looking, durable, functional part.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

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