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topic 30736

Aluminum Brite Dip Chemical Composition / Effective Polishing Techniques

brite dip  automatic anodizing banner

A discussion started in 2004 but continuing through 2018

2004

Q. In regards to Type II Anodizing, I have read about a process called Brite Dipping in which the part(s) are brought to a high shine utilizing a solution of this so called Brite Dip. I have done much looking on this subject and have been unable to determine what the chemical composition of this Brite Dip solution is. Is it possibly/advisable to mix my own Brite Dip solution? Secondly, at what temperature does this Brite Dip solution operate at?

I am also looking for an effective mechanical way to polish several parts at once on a processing line environment. Currently I am buffing my parts manually utilizing a variety of polishes. What would you suggest a person use in order to increase production without losing any of the quality. Would a simple bead blast followed by a Brite Dip be sufficient?

Thanks so much for your time. Cheers!

daniel degueldre
Daniel DeGueldre
   anodizing shop entrepreneur
Ste. Anne, Manitoba, Canada


2004

Q. I am quite surprised that nobody has offered any input to this post over the past 1-1/2 weeks. Perhaps this Bright Dip solution is an old family recipe and not meant for prying eyes. Perhaps there are several recipes utilized in order to mix an aluminum Bright Dip solution. None-the-less, I have found myself stumped.

I think I have narrowed down the most important chemicals required in order to mix a Bright Dip. So far I have, Phosphoric Acid (H3O4P) and Nitric Acid (HNO3). I have done a lot of reading of the past weeks in regards to this question, yet I'm still stumped. I think I have the two major chemicals correct, however, the actual solution formula still proves impossible to nail down.

If you know what your Bright Dip solution is composed of or if you are mixing your own Bright Dip solution in your shop, please post your recipe here. I am also curious as to what temperature your Bright Dip operates at. Thanks so much in advance.

Cheers!

daniel degueldre
Daniel DeGueldre
   anodizing shop entrepreneur
Ste. Anne, Manitoba, Canada


2004

"Surface Treatment & Finishing of Aluminium and Its Alloys"
by Wernick, Pinner & Sheasby

from Abe Books
or
info on Amazon

A. Hi Daniel. Wernick, Pinner & Sheasby has a 94-page chapter on chemical and electrochemical brightening of aluminum that will explain everything you could imagine. Generic bright dip is composed of nitric acid & phosphoric acid and operates at 190-210 °F. A typical formula is 80% by volume nitric acid & 3.5% nitric acid.

People probably don't say much about brite dipping chemistry for a number of reasons.
First, very few anodizers do brite dipping, which limits the amount of response we can expect.
Second, there are a number of proprietary suppliers, and people may not be sure if a composition they know of is generic knowledge or is actually a proprietary trade secret they can get in trouble for publishing.
Third -- and most important -- those who are familiar with it realize this is a really, really, nasty solution that requires specially designed garage-door type fume containment (not conventional lip exhaust or push-pull exhaust), special unconventional fume scrubbers to deal with the wild NOx fuming and high solubility of nitric acid that conventional fume scrubbers can't handle, and very well engineered secondary containment because it is extremely aggressive even to expensive construction materials. This stuff running on the floor after eating through a 316L stainless tank is a major concern.

Speaking for myself, while I'll cheerfully give anyone a few minutes of my time, when we get into aluminum bright dipping, it's just so chock full of "Why in the name of hell didn't you warn me about THAT?!" issues that it's a topic that can't be quickly dispatched. I, and maybe others, tend to not want to be pulled into a discussion when I see such a long rocky road in front of me. Are you willing to invest in a totally enclosed ventilation system, special double fume scrubbing, and double-walled 316L stainless steel process and rinse tanks? If not, I really don't want you working with this chemistry :-)

This is perhaps a good area to start with a proprietary solution from a vendor who will give you some hands-on help. I believe Albright & Wilson may be one; search for their Phosbrite.

Good luck.

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


2004

A. Well...For those who care to contribute or simply for those who wish to experiment, I have learned of the following formula for a Bright Dip bath :

94% Phosphoric Acid & 6% Nitric Acid operated at a temperature of 180-185 °F.

If this seems crazy, please correct me. I'm simply relaying information which has come across my desk.

It should be noted that this solution requires extreme caution when handling. Use in a properly ventilated area and dispose of the waste accordingly!

daniel degueldre
Daniel DeGueldre
   anodizing shop entrepreneur
Ste. Anne, Manitoba, Canada

2004

A. Typical home-made solution is as follows:
Phosphoric Acid 73-83% (vol)
Nitric Acid 2-5% (vol)
DI Water 14-23% (vol)

Heated to a temp of 200-210 F.

Like Ted said: extremely nasty stuff, and use with caution. This bath works well on wrought alloys, not castings (or alloys with high silicon content). Nitric acid content must be kept stable, or you'll have undesirable results. Also heed his advice on finding a supplier of pre-made brite dips. They are much easier to work with, but if you're intent on making your own, the above recipe works well. Use double walled 316L tanks to contain your solution (I would even coat the inside with a fluoropolymer coating).

Marc Green
Marc Green
anodizer - Idaho


2004

A. Bright dip for aluminum:
phosphoric acid(d=1,75) 65%
nitric acid(d=1,5) 25%
acetic acid 10%
30-60 sec, 80-110 °C temp.

Goran Budija
- Zagreb, Croatia


sidebar







sidebar
December 11, 2008

A. DEAR SIR I HAVE A RADIATOR SHOP AND USED BRIGHT DIP FOR 48 YEARS, AND YOU DON'T NEED ANY HEAT. USE COLD. I USED A PLASTIC BOTTLE LAY ON IT TAKE KNIFE CUT 10 INCH HOLE IN IT PUT THE BRIGHT DIP IN ABOUT 2 INCH AND PUT THE PART INSIDE, LOOK AT IN 20 MIN. IF CLEAN, WASH IT WITH WATER , IF IT'S REAL BAD YOU LEAVE IT IN LONGER, OK? BRIGHT DIP IS AN ACID don't LEAVE THE PART HALF WAY OUT OF THE BRIGHT DIP, IT WILL CUT THE PART. OK, HOPE THIS HELP YOU.

DOUG BROWN
- MAXWELL, TEXAS


November 23, 2010

A. I used chromic acid to brite dip aluminum parts for years at our chrome plating shop. It works immediately and is used at about 120 °F.

Jack Hamor
- Hesperia California


November 24, 2010

thumbs up signHi, folks.

To an infantryman, a tank is an armored fighting vehicle, while to an oil delivery man, it's a vessel for holding fuel. Similarly, aluminum 'brite dip' or 'bright dip' is slang that's applied to more than one process or situation.

The bright dip that a radiator shop or truck-wash uses might be room temperature hydrofluoric acid ...
The bright dip that a plating shop uses might be a Chromic acid based desmutter for removing dark smuts from aluminum ...
... but the other posters here were referring to solutions which dissolve the aluminum to make it optically smooth and chemically polish it. Perhaps the phrase "chemical polishing" would be better than "bright dipping". The chemical polishing or bright dipping that we are talking about here is what is used before anodizing to make reflectors for outdoor lighting, doctors' and dentists' lights, etc., and it always involves noxious, near boiling, solutions -- usually of nitric and phosphoric acid.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E.
finishing.com
Pine Beach, New Jersey


December 14, 2008

A. I know of 2 basic formulas for bright dipping aluminum.
The typical R5 process consists of 80% phosphoric acid, water, and HNO3. specific gravity should be around 1.65
You need 1000 ppm of copper (as copper sulphate) and diammonium phosphate or urea (2%) as a fume suppressant.
The nitric acid concentration is the 3 to 4%, water should be about 10%, the balance is the phosphoric acid. Make sure you use 80% phosphoric acid.

The second formula, similar to the phosbrite 174, is a mixture of phosphoric acid and sulphuric acid. the specific gravity should be about 1.70. Also use copper and the fume suppressant. Same concentrations as before : Nitric 2 to 4 %, about 10% water, 15 to 20% sulphuric, the balance is 80% phosphoric acid.

Operating temperature should be over 212 °F, as the b/d generates water. With the heat you control the specific gravity of the solution (also by adding water when necessary).
The immersion time should be from 1 to 3 minutes (depending on the alloy).

To formulate a B/D bath is pretty simple - I provided you with the "secret" ingredients. The real deal is to know how to operate it in a production line.

The operating parameters are very tight, if you don't keep accurate controls, you are bound for disaster.

Martiroz Avoyan
- No. Hollywood, California


February 25, 2016

thumbs up signDaniel. This is a good topic. Bright dip anodize is what they used on aluminum car parts. I restore them and send my parts out to get bright dip anodized. I would like to do my own and this here has given me a lot of information. Thank you all for commenting.

Francisco salas
Chrome world - azusa california usa



Room Temperature Acid Brightener for Aluminum

September 13, 2018

Q. Hi all, let me introduce myself, My name is Alfredo, I just opened a small workshop for aluminum products (anodizing and powder coating).
Right now I have a project to brighten aluminum. My question is:
1. Are there any Acid Based chemical for aluminum brightener that works on room temperature (do not need any heating procedures)? I don't have such facility in my workshop.
2. If there are any, can I make my own solution? I want to make the solution myself since there's no chemical supplier that provides such chemicals here.

I've read some articles using Phosphoric Acid and Nitric Acid, but none of them work (maybe it's because I have the wrong percentage of it)

I'd be really grateful for any suggestion from experts here.

Thanks before!!

Regards,
Alfredo

Alfredo Antoni
- Indonesia


October 2018

A. Hi Alfredo. The nitric-phosphoric acid bright dip requires high temperature; moreover, it's a very dangerous mix.

What is the alloy? Are the products castings with silicon, which would require fluoride chemicals? Are you sure it's not more practical to mechanically polish the products?

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"


October 12, 2018

Q. Thank you Ted for your reply, really appreciate it.
The alloy is an aluminum-magnesium 5xxx series, I assume it is the 5005 aluminum series (the same aluminum for extrusion/door partition, etc). I don't know about the silicon castings of the aluminum, but I have a friend that used to work in an anodizing plant and he said that he used an acid based chemical to brighten the aluminum without any heating procedures, unfortunately the chemical is imported and he's not working there anymore.

Thanks,
Regards,

Alfredo

ALFREDO ANTONI [returning]
- Jakarta, DKI Jakarta, Indonesia



Burner Clener

October 7, 2018

Q. Hi, I just want to find out how to clean my gas stove buyers and now I am back in my biology class at school which I hated. Is there any simple way to clean/brighten the gas burners?

Basie Van Wyk
- Stellenbosch South Africa


October 2018

A. Hi Basie. Can we assume that your gas stove burners are made of aluminum? For a win-win, you might ask your biology teacher if she is familiar with any grease eating bacteria or other organisms that might help clean the burners.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"



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