Black Phosphate Etching

ABQTBird · Post by **ABQTBird** » Thu Feb 23, 2012 8:46 pm

This is a new thread based on this thread:http://www.vintagethunderbirdclub.net/p ... php?t=7107

I have put together a web page showing my attempt at recreating "black phosphate" etched parts, as described by Jim Wulf.

Take a look here:http://www.southsandia.com/forum/blackphosphate/

I hope you find it interesting.

60fore · Post by **60fore** » Thu Feb 23, 2012 9:16 pm

Cool stuff Tom! The bolts turned out great and the finish looks identical to original to me anyway.

Alan H. Tast · Post by **Alan H. Tast** » Thu Feb 23, 2012 10:06 pm

We need to get this into the Scoop!

Beach Bum · Post by **Beach Bum** » Fri Feb 24, 2012 1:30 am

Tom,

Great stuff! And the write-up on your process is very clean and complete. Nice to see a way to do some restoration that only costs a few bucks for a change.

novanutcase · Post by **novanutcase** » Fri Feb 24, 2012 12:31 pm

Hi Tom,

Great stuff!! Just curious but is this process anything like in the silver jewelry market where they use liver of sulfur to "age" the silver?

John

ABQTBird · Post by **ABQTBird** » Fri Feb 24, 2012 1:13 pm

Yes, Liver of Sulfur (what a weird name, must come from the alchemy days) http://en.wikipedia.org/wiki/Liver_of_sulfur is a tarishing agent that contains various chemicals, most notably, sulfides. Silver reacts with with sulfide compounds to form silver sulfide, or tarnish. Sulfides can also be used to remove tarnish. Tarn-X is a good example. It contains thiourea http://en.wikipedia.org/wiki/Tarn-x another sulfide compound. So when you apply Tarn-X, you are creating a soluble sulfide layer that is easily wiped off. If you leave silver in Tarn-X too long, you will damage the surface beyond repair, as I have done while cleaning some silver coins. You will also notice when using Tarn-X that you get a rotten egg smell. That is hydrogen sulfide, a product of the reaction.

By the way, I love your black paint with the chrome wheels. My 62 is Corinthian White, and I hate it. When it comes time to repaint, I am either going to go bright white, or perhaps chestnut metallic to match the interior. My 14 year-old son want to drive it. So, we are just going to make a driver out of it an make a few changable mods to make it look cool for him.

novanutcase · Post by **novanutcase** » Fri Feb 24, 2012 1:39 pm

This interests me...

I have a few questions from the page you set up to describe the process. I hope you don't mind that I've taken quotes from your site.

"When phosphoric acid, or H3PO4, reacts with iron, the phosphate group precipitates onto the surface of the iron forming Fe3(PO4)2, or iron phosphate, and releases hydrogen gas."

Is the hydrogen gas released at all flammable and is there enough gas produced that it could possibly combust?

The iron phosphate is black in color but being only several microns thick, offers only some corrosion resistance and is commonly oiled to provide additional corrosion resistance. Since the oil will eventually dry out, it can instead be clear coated with a flat or satin clear coat for lasting protection. This process should not be confused with the "black oxide" process which uses chemical bases at elevated temperatures to grow a hard layer of Fe3O4 (magnatite) on the surface."

What would be the outcome if you elevated the temperature in the chemical makeup you used for the phosphorous process? Would you be able to use these same chemicals to get a "black oxide" finish? Would this finish not be desirable to the phosphorous process as it would have a harder outer shell to resist marring it's finish, correct stock finish not being the priority here?

One of the reasons I ask is so that I can apply this process on other projects. I'd like to have different finish options that I could play with to get the desired effect.

I guess I should have payed more attention in chemistry class!!!

ABQTBird wrote:By the way, I love your black paint with the chrome wheels. My 62 is Corinthian White, and I hate it. When it comes time to repaint, I am either going to go bright white, or perhaps chestnut metallic to match the interior. My 14 year-old son want to drive it. So, we are just going to make a driver out of it an make a few changable mods to make it look cool for him.

Thanks! I thought the sportiness of the wheel was a nice contrast to the classic elegance of the lines of the car. The extensive bright work that the car originally came with really helps give definition to the beautiful lines of our generation 'Bird. An aggressive stance just seals the deal!!!:mrgreen:

John

TsNStangs · Post by **TsNStangs** » Fri Feb 24, 2012 1:39 pm

Tom, this is such a great and well-done "How-to", I'm going to move this to the Tech area as an easy reference for all in the future.

Thanks a lot for sharing it with the group -

ABQTBird · Post by **ABQTBird** » Fri Feb 24, 2012 4:25 pm

Is the hydrogen gas released at all flammable and is there enough gas produced that it could possibly combust?

Yes, the hydrogen is flammable but given the amount produced, I don't think it presents a hazard. I will experiment with that. Sounds kind of fun. I would be more worried about the acetone than the hydrogen.

What would be the outcome if you elevated the temperature in the chemical makeup you used for the phosphorous process? Would you be able to use these same chemicals to get a "black oxide" finish? Would this finish not be desirable to the phosphorous process as it would have a harder outer shell to resist marring it's finish, correct stock finish not being the priority here?

The black oxide finish is a different process. It took me awhile to figure out that it was different. It uses bases instead of acids and apprarently is far nastier than the phophate process.http://en.wikipedia.org/wiki/Black_oxide I think black oxide is what you find on the chrome-vanadium impact sockets, some higher end tools, and even dry-wall screws.

Brian Harris · Post by **Brian Harris** » Fri Feb 24, 2012 6:01 pm

First class contribution there Tom... definitely Scoop worthy!

Will try at next opportunity, but initially it seems a bit more process efficient and outcome robust than the Eastwood kit I've used for years, and the pictures suggest a truer texture to original factory/production coating.

Cheers... Brian

ABQTBird · Post by **ABQTBird** » Fri Feb 24, 2012 9:59 pm

Thanks to all who have looked at the technique. After an 8 year hiatus, I am working on my '62 again. The wife said fix it up or get it out. It seems like such a formidable project, but I am back to taking it one step at a time. The car is complete in the sense that everything is there, and I have already done a lot of mechanical work. I even had the transmission rebuilt after it lost drive and would only run in low. That set me back 4 grand. At that point I knew I couldn't sell it or I would take huge loss. I paid $3200 for it in 2001. I will post some pictures of it as soon as I get it out of the garage and cleaned up.

I am working on another how-to that may be old hat to some, but will show an inexpensive technique to convert from road draft tube to PCV that is reversible for the purists out there.

ABQTBird · Post by **ABQTBird** » Fri Feb 24, 2012 10:06 pm

I just thought of something that might be interesting to try. Navel Jelly is nothing more than a suspension of phosphoric acid. I may work slower, but I'll see if it works.

tbird · Post by **tbird** » Fri Feb 24, 2012 10:29 pm

This is my take on original looking bolts with the S-2 finish. The one on the left is done with the old Eastwood kit but not oiled as some times I don't want the oil finish, the centre bolt is a AMK reproduction with their S-2 finish the label has the part info, the right bolt is the Eastwood finish with their oil finish that they use to supply with the kit a number of years ago.

ABQTBird · Post by **ABQTBird** » Sat Feb 25, 2012 12:08 am

For those who have used the Eastwood kit, did it look as perfect and innocuous as this picture? Was there any bubbling?

tbird · Post by **tbird** » Sun Feb 26, 2012 9:05 pm

Tom
Got out my old Eastwood blackening kit today and found that the liquid had a lot of Grey sludge that had settled to the bottom leaving the liquid a light Greenish colour. Took a new lock washer that had been cleaned in a vibratory bowl filled with Walnut shells and dipped it, found that it did not produce any hydrogen bubbles the finish also did not get real Black. The finish looks very thin the chemical may be spent as it is old and has done many fasteners over the years but do not remember it ever fizzing.