12 replies to this topic

[leepol83]

Hi all anyone painted plastic with chrome spray paint,what's the best stuff for a really high shine. If anyone's got pictures that would be awesome thanks guys

[silve1999]

http://www.sprayonch...com/index2.html

[tiger99]

I fear that you may be disappointed with the results. You will not get the shine of chrome on polished metal, unfortunately. For that, you would need the plastic to be plasma sprayed with suitable metal and then polished to a very good finish before chrome plating. The plasma spraying is not as hot as you might think, and many plastics will survive, but polishing will generate lots of heat so I don't think it is practicable.

 

If the plastic is very smooth it may be possible to electroplate the usual copper, nickel, chromium on to a layer of graphite or silver paint, but I am not sure about the adhesion. Or, and I have experience of this, you can use the conductive paint just as a base for plating a heavy copper layer, which is then highly polished (it will be very rough) and overplated with nickel and chrome, the plastic being removed to leave a metal shell, which of course will be slightly larger than the original part.

 

If all else fails, the plastic part could be used as the former to make a mould for a brass casting, which of course can be polished and plated easily. If the expense is woth it, of course....

[1984mini25]

Try looking for chrome spray for rc car bodies...

 

[Dusky]

Maybe just using a plastic primer + chrome spray works?

[iTomKart]

I fear that you may be disappointed with the results. You will not get the shine of chrome on polished metal, unfortunately. For that, you would need the plastic to be plasma sprayed with suitable metal and then polished to a very good finish before chrome plating. The plasma spraying is not as hot as you might think, and many plastics will survive, but polishing will generate lots of heat so I don't think it is practicable.
 
If the plastic is very smooth it may be possible to electroplate the usual copper, nickel, chromium on to a layer of graphite or silver paint, but I am not sure about the adhesion. Or, and I have experience of this, you can use the conductive paint just as a base for plating a heavy copper layer, which is then highly polished (it will be very rough) and overplated with nickel and chrome, the plastic being removed to leave a metal shell, which of course will be slightly larger than the original part.
 
If all else fails, the plastic part could be used as the former to make a mould for a brass casting, which of course can be polished and plated easily. If the expense is woth it, of course....

Not true, chrome paint jobs on helmets in motorsport are a big thing now, with the helmets being made of fibreglass (essentially the same as plastic when it comes to paint reactions). It starts with some coats of primer, then loads of layers of black, then even more layers of the chrome paint on top, then loads of coats of lacquer. When the lacquer is flatted back and polished enough, it gives a complete mirror finish


by iTomMini, on Flickr

[tiger99]

Well, maybe a lot better nowadays, but there is no getting away from the fact that the "chrome", which may actually be a different metal, is applied as a series of discrete particles, not a continuous metallic film. However, I am willing to be suitably impressed if you can show a picture of real chrome, of good quality, side by side with the painted type.

 

I should add that vacuum deposition of aluminium is a simple process, if the vacuum tank is large enough to take the item, and if the plastic is highly polished, the surface will be very shiny indeed, but will need protection by laquer. That is how the mirrors in astronomical telescopes are coated, and re-coated often, the ali just dissolves in something like an acid, or caustic soda. I think they are usually coated with magnesium fluoride, vacuum deposited, for protection, but you would need conventional laquer on a car. Ali is more reflective than chrome.

 

 

You can't realistically chrome plate a complete car, unless you can bake it using a properly controlled process to avoid hydrogen embrittlement, but given a large enough tank, you most certainly could apply aluminium, as it is a cold and fairly harmless process. Now there is an idea. Would a shiny car be illegal, I wonder?

 

I am just thinking of the size of tank and vacuum pumps needed to do a Mini.......

[iTomKart]

Proper chrome spray paint onto plastic parts (not rattle cans):

 

[midridge2]

Only tiger99 can make a simple question into a chemistry lecture.

[tiger99]

Actually it was more of a physics lecture. I am a physicist by training, and many years ago, in my very first job, we had the facility to do vacuum deposition on small items. Someone did "recondition" a pair of headlight reflectors.

 

Just remembered one thing that we had done outside, chromium on glass. It was REALLY smooth and shiny. The company that did it was called Graticules Ltd, I think. Where that might be useful on a Mini would be on the windscreen, to mask the adhesive and protect it from UV light, if you weld in extra metal to create an overlap and use adhesive bonding to form a more reliable seal than the usual leaky rubber thing. I think that a chromed surround on the glass would look very smart.

[Dusky]

Proper chrome spray paint onto plastic parts (not rattle cans):

 

Nice imagine spraying this on a car..

[iTomKart]

 

Proper chrome spray paint onto plastic parts (not rattle cans):

 

Nice imagine spraying this on a car..

 

 

Touching up chips and scratches would be a nightmare!

[pdaykin]

I have tried a few rattle can varieties and have always been disappointed.

However, it is clearly possible as many plastic items are chrome (type) finished from car trim to buttons on games consoles.

Try looking on a few other modelling forums/sites.

I'd check durability too - I hate putting all the effort/money in to things for them not to last