How to strip Trumpeter chrome?

[kensar]

This may have been covered somewhere before, but I can't find the topic.

What will take the chrome plating off of Trumpeter's sprues?

I have tried Easy Off oven cleaner, bleach, Super Clean, and Floquil Easy Lift Off.  None of these have cleaned the chrome off.  I have used all of these before and each one has worked on chrome plating from other manufacturers.

Any other ideas?

[kensar]

Moderator - how many more posts must I put up before they don't need to be reviewed?  The forum information says six, but I have posted far more than that.

[iamsuperdan]

25 minutes ago, kensar said:

Moderator - how many more posts must I put up before they don't need to be reviewed?  The forum information says six, but I have posted far more than that.

It's actually 25 posts before the auto-moderation is removed.

 

 

[peteski]

For some reason Trumpeter instead of the typical vacuum metalizing using aluminum (like most model manufacturers), actually used electroplating process to cover the plastic with relatively thick layer of metal. I don't think it is actual chrome but it will be very though to remove.  There have been threads here about this in the past.  Just have to find one.

EDIT: I looked and no luck. Looks like nobody found any simple or easy way to remove it.

Edited March 22, 2024 by peteski

[stitchdup]

your best bet if nothing is stripping the chrome is to just sand it with 800+ grit, prime it and paint over it.

[stavanzer]

IIRC, when Scale Auto did a review of the Trumpy kit they noted that the chrome had a copper undercoating, just like 'real' chrome.

It may be almost impossible to strip the chrome plating with out ruining the plastic,

I'd spray the parts with a good primer (Tamiya, maybe?) and then paint to suit.

Also, what colour are you planning on painting the de-chromed parts? If it is a different shade of chrome, I might try different clear flat paints to see what finish I could get.

[kelson]

I'm working on the Trumpeter 63'nova and tried to strip the chrome as well and nothing worked! like Stitchdup said just sand it off.

[kensar]

Well, after an extensive internet search, the only method of stripping aluminum coatings I found were to use bleach (7% sodium hypochlorite) or lye (sodium hydroxide).  The bleach did not do an adequate job, even after soaking overnight.  I went to a hardware store and got 100% lye, used for clearing out stopped up drains, and mixed up a strong batch of about 40% - 50% NaOH.  Soaking the parts for 2-3 hours removed the plating (but not the clear yellow coating that makes the surfaces smooth).  So this is what I will do to strip the chrome from the parts.  I guess the aluminum coating is thicker on Trumpeter parts than parts from other manufacturers.

 

[Ace-Garageguy]

DELETED. The answer is out there but it's too potentially dangerous for me to recommend.

Edited March 25, 2024 by Ace-Garageguy

[TonyK]

Sounds like the same problem dealing with Salvino's chrome. I've tried using a metal file on some parts and that barely scratches the surface. Very frustrating!

[peteski]

On 3/24/2024 at 3:03 PM, kensar said:

Well, after an extensive internet search, the only method of stripping aluminum coatings I found were to use bleach (7% sodium hypochlorite) or lye (c).  The bleach did not do an adequate job, even after soaking overnight.  I went to a hardware store and got 100% lye, used for clearing out stopped up drains, and mixed up a strong batch of about 40% - 50% NaOH.  Soaking the parts for 2-3 hours removed the plating (but not the clear yellow coating that makes the surfaces smooth).  So this is what I will do to strip the chrome from the parts.  I guess the aluminum coating is thicker on Trumpeter parts than parts from other manufacturers.

 

Ken, Trumpeter "chrome" is *NOT* a typical aluminum coating used in other kits. It is some different metal electroplated (much thicker layer) onto the plastic. But I'm glad that whatever you came up with worked for you.  Be very careful with such strong solution of sodium hydroxide.  Best to use glass container.

BTW, most household bleach contains a blend of both, chlorine (sodium hypochlorite) and lye (sodium hydroxide).

[Ace-Garageguy]

4 hours ago, peteski said:

BTW, most household bleach contains a blend of both, chlorine (sodium hypochlorite) and lye (sodium hydroxide).

Ummm...no. Chlorine is NOT sodium hypochlorite, which is a chemical compound made up of sodium, oxygen, and chlorine, NaOCl.

Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature.

Accuracy in science matters.

Edited March 27, 2024 by Ace-Garageguy

[Bugatti Fan]

One has to ask the question, why is it  necessary to remove the Trumpeter chrome in the first place?

If it is simply too bright and unrealistic looking my method of getting over this is using Tamiya Translucent Smoke to tone it down for a more realistic appearance.

Some of the chemicals mentioned in this thread are a bit evil to use without due caution for anyone's own safety!

 

Edited March 27, 2024 by Bugatti Fan

[peteski]

11 hours ago, Ace-Garageguy said:

Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature.

You are correct of course.  My goal was to point out that in the household bleach it is lye (sodium hydroxide) that reacts with aluminum in the "chromed" plastic parts.  The chlorine (in the form of sodium hypochlorite) does the actual bleaching of laundered fabrics. At least that is how I understand this.

[Ace-Garageguy]

6 hours ago, Bugatti Fan said:

One has to ask the question, why is it  necessary to remove the Trumpeter chrome in the first place?

If it is simply too bright and unrealistic looking my method of getting over this is using Tamiya Translucent Smoke to tone it down for a more realistic appearance.

Some of the chemicals mentioned in this thread are a bit evil to use without due caution for anyone's own safety!

 

The potential safety issues are why I withdrew my recommendations above.

ONE possible (probable) reason for removing chrome is that there MIGHT be mold-lines present under the chrome.

Manufacturers NEVER remove these lines, and they usually appear on the ends of plastic model car bumpers in highly visible locations.

And while it is usually possible to design injection molded parts without any surface-visible mold parting-lines, it's not going to happen in most kits due to additional costs and the desire to put the bumper on a conventional sprue with many other parts.

[Bugatti Fan]

I agree Bill that the mould lines are generally the biggest bugbear on such components. Generally just a pain in the butt  having to remove them.

[kensar]

I wanted to remove the chrome because it is the wrong finish for the parts I am working with.  Removing the mold lines is also another reason to remove the chrome, but for some parts, they would need to be re-chromed.

I am unfamiliar with the process to electroplate an unconductive material, such as polystyrene.  Can you explain more about this?  I am a Chemical Engineer and I have never heard of this.

As far as working with this highly corrosive material (NaOH), I am familiar with the hazards.  I am not advocating that anyone else use this method just because some clown on the internet did.  Every person should familiarize themselves with the hazards associated with whatever materials or processes they are using!

[Curt]

Copper conductive paint can be applied to make non-conductive items such as plastics or resins conductive so they can be electroplated.

[Ace-Garageguy]

6 hours ago, kensar said:

I am unfamiliar with the process to electroplate an unconductive material, such as polystyrene.  Can you explain more about this?  I am a Chemical Engineer and I have never heard of this.

Quoting from the web page linked below: "Unfortunately, plastic chrome plating is not as simple as applying a coat of chrome to the part. Typically, we will first coat the part with a layer of copper or nickel through a process called electro-less plating. This means that we do not use an electric current to apply the plating. Applying this coating makes the part conducive, which makes it possible to apply the chrome plating later on."

Whole process here (this is NOT vacuum metalizing):    https://www.vacuum-metalizing.com/plastic-chrome-plating/

EDIT: Electro-less nickel plating, including on non-conductive materials...   https://hcsplating.com/resources/nickel-plating-guide/electroless-vs-electrolytic-nickel-plating/

EDIT 2: After the electro-less plating is applied, either copper or nickel (apparently copper in Trumpeter's case), plastic parts can be electroplated with actual chrome in the usual way.

Edited March 28, 2024 by Ace-Garageguy

[stavanzer]

8 hours ago, kensar said:

I wanted to remove the chrome because it is the wrong finish for the parts I am working with.

Man, Just paint them with a good Primer, and re-paint in whatever colour you want. Or Use the Tamiya Smoke or some other flat clear.

Frankly what you mention seems to be swatting flies with a sledge hammer. Any Chrome but Trumpeter, I get you. But Trumpy Chrome, Just forget it.

[kensar]

Thanks Curt and Ace-Garageguy for the explanation regarding the electroplating.  It makes more sense to me now.

I would prefer to strip the chrome and paint with solvent based paints for better paint adhesion to the plastic.  Poor adhesion to the plastic is why I don't use aqueous based paints.

Thank you everyone for the discussion.