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57BLITZ Samba Member
Joined: June 12, 2012 Posts: 2385 Location: DEEK - U.S.A.
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Posted: Mon Apr 18, 2016 4:16 pm Post subject: Re: restoring semi-decent chrome hubcaps |
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Maybe try this so that your chrome plating will remain intact . . . http://bmxmuseum.com/forums/viewtopic.php?id=351132 _________________ Jesucristo es mi Seņor y Salvador! |
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mcdonaldneal Samba Member
Joined: June 13, 2013 Posts: 2639 Location: Gullane, Scotland
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kman Samba Member
Joined: November 04, 2005 Posts: 739 Location: Michigan
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Posted: Tue Apr 19, 2016 4:30 am Post subject: Re: restoring semi-decent chrome hubcaps |
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raygreenwood wrote: |
The commercial name for it us hydrochloric acid.
Let me warn you explicitly. .....
work outdoors with it.
Put a fan to the side and behind you blowing across the work away from you.
Keep a 5lb box of baking soda close by for spills plus a garden hose turned on with a hand sprayer.
Mix up a bucket of 1 gallon water with 1 lb baking soda for neutralizing and for emergencies.
You MUST/SHOULD wear a reapirator with acid/VOC cartridges.....most tool stores can sell you one for about $30 that will serve you for years. You can get away without one IF you are careful and have cross vemtilation so you dont breathe the smoke and vapor that comes off the acid.
Wear splash proof goggles. Nitrile gloves are fine.
NEVER add water to the acid. You can pour acid into some water if you want to dilute it. About 70/30 acid to water is good for working slow.
Easiest, safest way is to pour about 2-3 ounces at a time into a ceramic or glass dish and use a cheap china bristle brush with the bristles cut down to about 3/4" long.
Dip the brush and work into the rust. It will fizz up as it eats rust. When it quits fizzing add more.
It wont hurt the chrome unless it has pinholes through the plating or you leave it on for long periods. On rust like that hubcap I use acid straight.
When you get all the rust dissolved......pour the spent acid into a plastic container snd then dip the hubcap into the bucket of baking soda and water. It will fizz hard.
Then rinse. When you arr done....take the plastic container of spent acid and the ceramic bowl....and drop them into the bucket of baking soda and water. They will fizz violently for a while. Then take the hose and dilute that gallon of water with 5-10 gallons of fresh water and run it down the drain or gutter its safe at that point. Ray |
Ray is a smart guy. I only have a couple things to add. The muratic acid around here is about 32% Hydrochloric acid. 100% is crazy dangerous. Also not only are the fumes bad enough to knock you out (hence the respirator) but the fumes are also highly corrosive to any bare metal you might have nearby. Everything nearby will flash rust. I only use it for small piles of bolts. About 10 minutes in acid, a baking soda/water rinse. A heavy water rinse. Then a short bath in some metal ready.
alternatively you can do a long bath in 1 part feed grade molasses and 5-7 parts water. A gallon around here is less than 10 bucks. Soak for 2-3 weeks. All the rust will disappear. Won't hurt any metal. Rinse and scrub heavily then treat with metal ready before it flash rusts(which is immediately) it slowly dissolves the rust through a process known as chelation.
Oh yeah, this smells pretty bad.. A sealed 5 gallon bucket helps. If you put your hands in it, you will smell bad for days, but it's safe. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Tue Apr 19, 2016 7:03 am Post subject: Re: restoring semi-decent chrome hubcaps |
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Yes.....just like any high solution strength acid.....muriatic/hydrochloric acid has a habit of....like any vapor actually....of condensing on the coolest/coldest objects around.
This is why is common.....to find nearby metals corroded. If the temp of the metal is above the room dewpoint and the vapors dont condense......its not really a problem. Its not like the acid has any particular affinity to metals.
This is also why I was explicit to use it outdoors with cross ventilation.
Ray |
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dnielsen Samba Member
Joined: June 19, 2005 Posts: 80 Location: Phoenix, AZ
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Posted: Fri Apr 29, 2016 1:45 pm Post subject: Re: restoring semi-decent chrome hubcaps |
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This is the best way I have found. The oxalic acid is sold as Wood Bleach at the hardware store.
To protect the inside you could either paint it or use a rust proofing wax / grease like Fluid Film. I use lanolin dissolved in mineral spirits for rust proofing undercarriage parts and various shop tools. |
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raygreenwood Samba Member
Joined: November 24, 2008 Posts: 21474 Location: Oklahoma City
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Posted: Tue May 03, 2016 11:12 am Post subject: Re: restoring semi-decent chrome hubcaps |
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dnielsen wrote: |
This is the best way I have found. The oxalic acid is sold as Wood Bleach at the hardware store.
To protect the inside you could either paint it or use a rust proofing wax / grease like Fluid Film. I use lanolin dissolved in mineral spirits for rust proofing undercarriage parts and various shop tools. |
Doing things the hard way. Oxalic acid is simply an acid...no better or worse than muriatic....and much harder to dial up or down in strength because as a crystal its bound up in a salt with a substance of opposite pH.
The second you get it wet...the salt begins to negate the acid.
Also..eve though that was a nice write up....a few little items are missing and a few not really known about.
Yes....wear gloves. Yes...its an acid....and yes its hard o the skin. Skin absorption is slow as an ingestion method but oxalic acid being the main ingredient in kidney stones...dont take your chances.
Also....a note about rust and chrome.
There is not one single acid or caustic rust remover on this planet that is gentle or safe on chrome....if it has pitting of ANY KIND as that bike frame does in that write up.
In general with solid chrome plating...no pits or chips or flexing cracks.....none of these acids....muriatic, hydrochloric, phosphoric, acetic or oxalic...will have any negative effect on good chrome like that.
Very high solution strength acids like nitric and sulfhuric acid....will attack chrome.
BUT....pits...or very small rust specs, rust blooms, crusty white discolorations (which are impurities in the chrome plating...which are weak spots) or tarnish blooms in chrome....are through holes in the plating...down to the metal underneath....PERIOD.
When you use any kind of acid on chrome with any blemishes like I noted above....the acid WILL dissolve away the rust...down to the base metal.
It will not touch the chrome at all. It MAY attack the copper layer exposed around the edges of the pit from the copper plating layer that is used in some triple chrome plating.....but it will not hurt the chrome......
HOWEVER....it now leaves an open hole THROUGH the chrome and down to base metal. Not only will it rust eventually...that rust will spread laterally.
This is why...pitted chrome...will only look good ONCE...and only for a while...after derusting with any acid or caustic product. Eventually the pits will rust and spread laterally....causing the chrome to start flaking...always.
By the way.....none of the acids mentioned (except for nitric and sulfuric) used at about the 60-70% strength range ....will hurt water slide decals that dont have any cracks or edge peels to attack the adhesive.
However....anything that is caustic/corrosive...like oven cleaner, purple power etc.....will attack the inks that are printed on the water slide decal base (water slide decals are one of the many things I have printed for a living)....actually leaving them bleached out and blank.
By the way...after reading that rather excellent write up on cleaning BMX frames....I feel the need to add the usual note.....quit using so much Simple Green.
Simple Green is one of the biggest "green washed" lies out there. Operationally its a superb degreaser...great product. There is nothing green about it. Its got a dirty little secret.
It adds a cumulative chemical into the watershed that is harmful to fish and fauna.
Use it sparingly...not as a replacement for other purpose used chemicals or because its cheap.
Ray |
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dnielsen Samba Member
Joined: June 19, 2005 Posts: 80 Location: Phoenix, AZ
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Posted: Tue May 03, 2016 5:45 pm Post subject: Re: restoring semi-decent chrome hubcaps |
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That is some good info on the decals. I was not aware they were so sensitive. Also, good point about the pitted rust only looking good once.
From what I understand, the disadvantage of hydrochloric acid (muriatic acid) is that it deposits chloride ions in the steel that will cause more rust to form. Oxalic acid or citric acid (or even better, ammonium citrate) will not deposit chloride ions but they have their own issues (cost, toxicity, slow working, etc). |
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planenut Samba Member
Joined: April 12, 2012 Posts: 334 Location: Georgia
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Posted: Wed May 11, 2016 5:37 pm Post subject: Re: Restoring semi-decent chrome hubcaps |
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Those hubcaps reminded me of the ones my daddy used to feed his coon dogs in! Used to look pretty raunchy inside! |
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