Hit and Miss With Chrome Plating

[dusty_shelf]

While working on my AMT ‘33 Willys build, I became very frustrated with the parts I de-chromed.  Despite all my best efforts, I could not remove most of the lacquer/varnish applied to the sprue before plating.  The leaf springs in particular are unusable.  This undercoating obscures the details.  I would question of the adhesion of the paint to it.

Fortunately, I have a second parts kit and had complete success removing the chrome.  Took it right down to the original plastic color.  No cleanup necessary.

Upon seeing the results, I compared the racks of chromed parts from the two kits.  What is evident is there was too much undercoating applied for one batch.  It is particularly noticeable on the intake manifold, blower pulley assembly, and the engine block front.  Fine detail is lost and some shapes indistinct.  Also, when handling the bad chrome, little flakes come off like glitter.  I sure wish the manufacturers wouldn’t plate parts never meant to be plated.

[Bainford]

What did you use to try to remove the lacquer undercoat?

That can be some stubborn stuff. Strippers that remove lacquer should take it off eventually. Isopropyl alcohol of at least 91% should work, as should brake fluid, and probably some of the bespoke hobby strippers such as Testors ELO (though I have no experience with this stuff myself). Some people have had good luck with Castrol Super Clean, but in many cases I found it wouldn't remove all of the undercoat.

Some people seem happy with just removing the plating, which supports paint adhesion, but when stripping chrome, I want the detail-hiding lacquer undercoat off as well. It is the most common reason I strip chrome.

[Fantom]

Easy off oven cleaner has worked for me. Sometimes it takes multiple applications and some scrubbing with a tooth brush but eventually the undercoats some off

[StevenGuthmiller]

12 minutes ago, Fantom said:

Easy off oven cleaner has worked for me. Sometimes it takes multiple applications and some scrubbing with a tooth brush but eventually the undercoats some off

One of the things that I like about using Super Clean over oven cleaner, (there are several reasons) is the fact that it can soak for as long as is required to remove stubborn things such as this.

With oven cleaner, what I've found is that the majority of the activity is early in the process, (maybe the first half hour to an hour), and then it begins to loose it's potency.

Not due to the fact that it's ineffective, but just due to the much lower volume of the solution used.

If you spray a couple of tablespoons onto your parts in a plastic bag, there's much less of the active ingredient, (lye) contacting the parts, than the half a gallon of Super Clean that they're floating in, which maintains it's potency for months.

The parts can be left to soak for a week or two if need be.

With oven cleaner, it will require a number of reapplications, and I could very well be wrong, but back when I was using oven cleaner, it seemed as if the huge bulk of it's effectiveness ended after the first application.

I remember vividly trying to strip paint from bodies, and having it look like it was working quite well after the first dunking, but subsequent applications seemed to do very little.

It was almost like it went so far, and that was it, regardless of how many times I re-applied.

 

Just my observations from my personal experience.

 

 

 

 

 

Steve

[dusty_shelf]

My go-to for chrome removal is LA's Totally Awesome Cleaner.  In some instances you can see the chrome come off in real time.  Otherwise, a soak for a couple of hours is usually sufficient. 
 

I had the bad parts submersed for the better part of two days with no noticeable difference.  I did see some removal of the lacquer using non-acetate nail polish remover.  However, because of the potential to soften the plastic, I didn’t want to expose it too long.

[stitchdup]

I find oven cleaner removes the chrome plate but unless its an enamel primer it wont touch the undercoat. la's totaly awesome cleaner removes both but its mild enough to leave resin parts in too and works on enamel and acrylics and even removes black primer if you leave it a while, but its not a fast stripper. bleach removes chrome but not undercoat. after any of these a q tip and alcohol removes the rest.

[peteski]

For the thick stubborn layer the parts need to soak for extended time and often scrubbed multiple times.  Purple Stuff should work, or any other Lye-based product (LA Totally Awesome I believe is Lye-based). It is caustic stuff - wear rubber gloves.  Also what helps is to keep the stripping solution warm. Not hot, but room temperature (80-90 deg. F). The warmth increases the potency of the chemical.

[StevenGuthmiller]

31 minutes ago, peteski said:

For the thick stubborn layer the parts need to soak for extended time and often scrubbed multiple times.  Purple Stuff should work, or any other Lye-based product (LA Totally Awesome I believe is Lye-based). It is caustic stuff - wear rubber gloves.  Also what helps is to keep the stripping solution warm. Not hot, but room temperature (80-90 deg. F). The warmth increases the potency of the chemical.

Sodium Hydroxide, (lye) is what almost all of these cleaners have in common, and is the ingredient that is most responsible for its effectiveness.

The concentration of the sodium hydroxide in the solution is the key to the extent of that effectiveness.

I feel as if I’m constantly trying to make people in the Facebook groups understand that virtually all of these cleaners/degreasers, (Super Clean, Purple Power, Easy Off, Totally Awesome, Simple Green, etc,etc) all have comparable ingredients, and their effectiveness is directly related to the concentration of the “active ingredient” and the circumstances of the job that they’re expected to perform.

Your success or failure is much more likely to pivot on what materials you’re trying to remove and how they were applied than the product itself.

There seem to be a lot of guys that for some reason have the impression that their product of choice is made of fairy dust and unicorn farts and is the “only” one that works, which is absolute BS, but there are some that will work better than others on some of the tougher jobs.

If you’re just stripping basic chrome or simple enamel paint, one is as good as the other.

The lacquer under chrome or lacquer paints can require a little extra oomph!

 

 

 

 

Steve

[Fantom]

I agree with everything said above … I don’t think oven cleaner is the necessarily the best at all, but I use it because it’s convenient for me to buy. I have had success with super clean etc, but I can get oven cleaner at the grocery store 😀

[StevenGuthmiller]

29 minutes ago, Fantom said:

I agree with everything said above … I don’t think oven cleaner is the necessarily the best at all, but I use it because it’s convenient for me to buy. I have had success with super clean etc, but I can get oven cleaner at the grocery store 😀

I get that.

That’s pretty much the same reason that I used it for a number of years.

The biggest reasons that I stopped using it were, A... the caustic fumes that it pumped into the air every time I used it, (really nasty stuff) and B... when I discovered that Super Clean was actually much more economical due to the fact that it can be used over and over again, (I’m still using the same gallon that I bought probably more than 4 years ago)

It’s just much more user friendly in my opinion.

No muss, no fuss. 😉

 

 

 

 

Steve

[bobss396]

I just de chromed a '40 Ford front axle using Purple Power. It left some of the lacquer, I was able to pick at the stubborn spots. The next time I will use oven cleaner. Which is not available in the two dollar stores I went to. 

[Bills72sj]

I have never used oven cleaner. I use Westley's Bleach White for chrome. (I have a car with Raised White Letters) Super Clean lasts for years and will do MULTIPLE bodies. I actually left one body in for 5 months with NO harm. I also use brake fluid when Super Clean is having a struggle. Sometimes back and forth between the two.

[dusty_shelf]

I think I have found the right combination.  I will continue to strip using the LA’s Awesome.  It works super fast and removes paint as well.

At the suggestion of Bainford, I immersed the bad parts in 91% alcohol for 24 hours.  All of the lacquer flaked off using a fine wire brush.  No damage to detail.

Thanks to all who commented.

[robdebie]

I believe that you can increase the effectiveness of any stripping medium by putting it in an ultrasonic bath. The vacuum bubble implosions have a hammering effect that actively removes the coatings. Here are my experiences:

https://robdebie.home.xs4all.nl/models/ultrasonic.htm

Rob

[ColonelKrypton]

Good evening all.

I posted this elsewhere when the topic of model "chrome" stripper came up. 

I did a lot of searching online and found many suggestions and in turn tried most. After a lot of testing I came up with method that works reliably for me every time.

"chrome" plating on plastic model parts is actually a very thin vapour deposited aluminum. 

A cleaner which contains sodium hydroxide removes the "chrome" by actually reacting with the aluminum producing a tiny bit of hydrogen as a by product ( the tiny bubbles you may see.  The remaining yellow or whatever coating that remains is ( as far as I can find out ) a conductive lacquer. 

the best thing I have found to remove not only the "chrome" and the underlying lacquer is Tamiya lacquer thinner ( which is mostly isopropyl alcohol ) or Tamiya paint remover either each alone or what I find even better is a 50:50 mix of the two.  In fact, if you read the label on Tamiya Paint Remover it also states that it can be used to remove metallic coatings ( i.e. model "chrome" )

These products remove the "chrome" by dissolving the underlaying lacquer layer and the "chrome" comes off as little bits. A typical part will can be stripped of "chrome" and lacquer in about a half hour or so. Some "chrome" can be a bit stubborn so I generally let parts soak overnight.

I have left parts in my 50:50 mix for many days with no ill effects on the plastic. A toothbrush will remove any stubborn bits and not damage the plastic. Follow up with a wash in warm soapy water.

The Tamiya products are not as inexpensive as household cleaners but can be reused many many times.  I have a jar of my 50:50 mix that I have been using for over a year and has been used to de-chrome many parts.

Be careful with general lacquer thinners. Lacquer thinner is a generic term and not all lacquer thinners are the same.  Hardware store lacquer thinner is more likely closer in composition to  model plastic cement and often contains acetone and MEK. For example, Mr Color levelling thinner contains something which will attack polystyrene plastic as does AK Real Colors High Compatibility Thinner. Solveable brand Lacquer which I buy locally contains toluene, acetone, and methyl ethyl ketone which is definitely not polystyrene friendly other than being useful as a plastic cement but is nevertheless sold as "lacquer thinner".

Strippers, and household and industrial cleansers may all contain many similar chemicals each having a different purpose. In general they all contain an active ingredient ( i.e. sodium hydroxide or some sort of solvent ), surfactants which enhances their wetting and spreading properties ( better "sticks" and coats the object being cleaned or stripped ), emulsifiers which help keep everything mixed, and likely some form of stabilizer and ph adjuster to optimize the products performance.

Do Test Test Test anything new you use. 

Experiment with other brands and products at your discretion but I have not yet found anything that works better than the two Tamiya products I noted above.

Tamiya product numbers:

Tamiya Lacquer Thinner 250 ml 87077  ( yellow cap )

Tamiya Paint Remover 250ml 87183

From their safety data sheets, 

Tamiya lacquer thinner yellow cap product number 87077 contains

Propan-2-ol                     CAS no.  67-63-0 also known as isopropyl alcohol content > 50%
4-methylpentan-2-one  CAS no. 108-10-1 also known as isobutyl methyl ketone (not MEK) < 30%
2-butoxyethanol             CAS no. 111-76-2 content 5 - <10%

CAS - Chemical Abstracts Service assigns a unique registry number to specific chemicals. Many chemicals have numerous names but regardless of name will have the same CAS number.

Tamiya Paint Remover product number 87183 contains:

Benzylalkohol                                 CAS-Nr.  100-51-6   70 - < 80 %
Butyl diglykol                                  CAS-Nr.  112-34-5   10 - < 15 %
Dipropylene Glycol Methyl Ether   CAS-Nr. 34590-94-8   5 - < 10 %

 

cheers, Graham
 

Edited January 13 by ColonelKrypton
tinger frouble

[ColonelKrypton]

12 hours ago, robdebie said:

ultrasonic bath.

That will help as will warming the stripping medium. Chemical reactions increase with temperature and most if not all ultrasonic cleaners also have built in heaters/warmers.

cheers, Graham

 

[stavanzer]

Thank, Graham.

[iBorg]

Question on the Totally Awesome. My local dollar store has several varieties from a yellow to a purple. Which one do you use?

[deuces wild]

Is Castrol Super Clean or LA AWESOME flammable????....