chrome removal

[Lizard Racing]

I've been using oven cleaner to strip chrome plating from detail parts.

Sometimes there is a brown residue which has to be scraped off.

Does anybody know what it is, and more important, how to get rid of it?  Should I use something else?

Thanks in advance.

[Ace-Garageguy]

The brown residue is most likely a combination of the clear undercoat that's under a lot of kit chrome, and residual soapy scum from the oven cleaner.

I use the real smelly EasyOff stuff, let the parts soak in a sealed plastic bag for a couple hours...which always seems to loosen EVERYTHING...and then rinse and SCRUB with HOT water, Comet, and a toothbrush.

Results?  These are 1/8 scale parts that had thick chrome and undercoat...

WARNING WARNING DANGER DANGER: WEAR EYE AND HAND PROTECTION. OVEN CLEANER WILL BURN HANDS AND EYES.

Edited October 31, 2016 by Ace-Garageguy

[PARTSMARTY]

I've had good luck with Westleys bleche white whitewall cleaner.Now it's black magic whiewall cleaner-same exactly looking bottle.

 

[Casey]

[Art Anderson]

I realize that this link is very informative, but it's also a very long thread, so I'll cut to the chase here:   Vacuum-metalizing (which is what model car kit "chorme" really is, consists of three steps:   1) A precoating of non-penetrating lacquer (today, almost universally clear--but years ago, it tended to be light transparent yellow, even light brown in shade), which both makes for a very shiny aurface and gives adhesion to the very thin layer of aluminum which is the "chrome" you see on model parts. 

2)  The trees of parts to be plated are then loaded into a large vacuum chamber, which has all air pumped out of it, to a mechanically perfect vacuum, after which thin strips of pure aluminum are instantly vaporized by a charge of high-voltage electricity--which vaporized aluminum adheres almost instantly to everything inside of the vacuum chamber.

3)   Upon removal from the vacuum chamber, the trees of parts are coated once again with a very thin clear non-penetrating lacquer, which seals the aluminum coating (which is only a few molecules thick) which prevents the aluminum from simply oxidizing away, or even being worn away by being touched.

Most paint strippers found in hardware/paint/home improvement stores contain sodium hydroxide, which dissolves aluminum rapidly, but also contain other solvents which will destroy styrene plastic almost instantaneously as well.  Sodium Hydroxide is a water-soluble chemical also commonly known as lye. While lye is no longer commonly available in crystal or powdered form due to it's status as a chemical hazard, particularly to human skin and mucus membranes, it's still available in common household products such as Easy-Off Oven Cleaner in the can with the yellow cap, as well as in most drain openers.  Concentrated lye solutions will soften and strip the lacquer coating over the aluminum plating, dissolve the aluminum quite rapidly, and given sufficient time, will soften virtually every type of pre-coating ever used on model car parts, in my experience, although it may take some persuasion, as Bill and others have noted, with say, a stiff toothbrush.

PPE, or Personal Protective Equipment is essential when using Easy-Off or lye based drain cleaners, by that I mean protective gloves--such as the nitrile gloves which can be found in just about every pharmacy, and protective eyewear, as even the tiniest droplet of lye solution can and will damage your eyes irreversibly.  The leftover lye can simply be flushed down your toilet, or poured down the sink drain (just follow with running water for a minute or so, which will weaken the lye solution to the point of making it harmless to brass or copper drain pipes.

I've stripped far more plated model car parts than I can count over my decades of building model cars, and can attest to the effectiveness of lye solutions.

Art

 

 

[Bullitt]

I found that Windex does a great job at removing chrome from parts.

[Snake45]

If all you want to do is remove the "chrome," pure ammonia will do it so fast you can almost watch it happen.

If you want to take everything right down to bare plastic, Easy-Off, as Art recommends, will do it. I only find this necessary if there is some flaw in the clearcoat--runs, dust, and so forth.

I've also done a LOT of painting right over kit chrome over the years. Unless there's masking (as with tape) involved, this usually isn't a problem.

[hedotwo]

I'll agree with the problems of getting rid of the yellow (usually heavy) undercoat.  Many solutions for the chrome plating, but the undercoat can be a bugger.  And, unfortunately, that's where the part detail can get covered up.  Depending on what I'm removing the plating from, I'll spend alot, or a little, time with the undercoating.  Easy Off appears to be the only way to minimize the work in getting rid of it, but even then there are times when even that's not enough.

[Ace-Garageguy]

 Easy Off appears to be the only way to minimize the work in getting rid of it, but even then there are times when even that's not enough.

I have not yet encountered any plating "undercoating" that failed to be removed by soaking in Easy Off (in a sealed plastic bag...to prevent the Easy Off from drying out...for several hours) and then scrubbing vigorously with an abrasive cleanser, hot water and a toothbrush, as I mentioned above.

Soaking does the work, and the scrub takes only a few minutes.

If I may ask, which kits have you had particularly stubborn chrome undercoating on? I have an extensive collection, and if I have the offending kit in stock, I'd be more than happy to chrome-strip part of it to evaluate the problem further.

[Snake45]

PPE, or Personal Protective Equipment is essential when using Easy-Off or lye based drain cleaners, by that I mean protective gloves--such as the nitrile gloves which can be found in just about every pharmacy, and protective eyewear, as even the tiniest droplet of lye solution can and will damage your eyes irreversibly.  The leftover lye can simply be flushed down your toilet, or poured down the sink drain (just follow with running water for a minute or so, which will weaken the lye solution to the point of making it harmless to brass or copper drain pipes.

 

I ALWAYS ALWAYS use protective glasses when working with Easy-Off. I never wear gloves, though. My normal routine is spray the body or part down, put it in an airtight container for 20-30 minutes, attack it with a toothbrush, rinse under warm running water (still scrubbing with the toothbrush), repeat as necessary. This weekend I sustained a VERY painful chemical burn on the pad of my left ring finger--apparently that spot was constantly in contact with an Easy-Off-covered surface for two or three minutes. It hurts like a B-word!

The contact seems to be an important element. I remember about 20 years ago at a club meeting, a guy had some severe injuries on both arms from oven cleaner stripping (another brand). He'd been resting both forearms on the sink while he worked and that's where it hit him--he looked like the victim of a shark attack.

I might have to start using the gloves....

[Lizard Racing]

The last two to show the undercoat were Revell '67 Corvette and MPC Young American Dragster.

These are older kits.  Would that have something to do with it?

I've heard Easy Off is pretty nasty stuff.  I have been using house brand fumeless oven cleaner.  I will get some Comet for scrubbing.

Brake fluid also works good.

Thanks for all the helpful comments.

[Ace-Garageguy]

 

I've heard Easy Off is pretty nasty stuff.  I have been using house brand fumeless oven cleaner.  

 

There's your problem.  

Seriously, it's the "nasty stuff" that does the job.

If you use it carefully and intelligently, it's not bad at all.    

Edited November 1, 2016 by Ace-Garageguy

[StevenGuthmiller]

Nobody's mentioned Super Clean?

This stuff will strip chrome clean as a whistle in a matter of an hour.

I've never had problems with it taking off the under coat either.

And there are no caustic fumes like with oven cleaner.

It has a very mild, pleasant smell.

I used to use a lot of easy off for stripping chrome & paint but have had just as good or better luck with Super Clean.

Plus, Super Clean is re-usable & is also biodegradable.

You still need to use gloves with it as it will tear up your skin just like oven cleaner.

 

Steve

[peteski]

Yes Super Clean (the Purple Stuff, etc.) has lye (sodium hydroxide) in it (same as in the original formula EasyOff). It is the lye which does most of the stripping (the other chemicals in Super Clean help too).  I was also surprised that Super Clean has not been mentioned yet.  It strips the metallic layer and the clear coat under it..  Keeping it the stripper warm also speeds up the stripping action.  By warm I mean around 90-100 F.

[Art Anderson]

I have not yet encountered any plating "undercoating" that failed to be removed by soaking in Easy Off (in a sealed plastic bag...to prevent the Easy Off from drying out...for several hours) and then scrubbing vigorously with an abrasive cleanser, hot water and a toothbrush, as I mentioned above.

Soaking does the work, and the scrub takes only a few minutes.

If I may ask, which kits have you had particularly stubborn chrome undercoating on? I have an extensive collection, and if I have the offending kit in stock, I'd be more than happy to chrome-strip part of it to evaluate the problem further.

On my ICM 1/24 scale 1913 Model T, the gold-tone plating had to be stripped from the windshield frame, as Ford discontinued brass windshield frames in late 1912. Using Easy-Off (yellow label), the transparent yellow top coat came off, as did the plating itself, but the basecoating (some sort of transparent brown lacquer or varnish) never did soften, even after several days in the Easy-Off--I had to CAREFULLY scrape and peel hat stuff off!

Art