degreasing

[JonnyD]

I was planning to do a little hot bluing on some AKM parts.
I am curious about what methods are being used to degrease parts prior to the hot blue.

I was leaning towards boiling the parts in a solution of sodium carbonate, double rinsing in hot water and then bluing.
I had used that method for metal plating in a chemistry course with great success in the past but wanted to get other opinions on the subject.

I have an abundance of sodium carbonate at my disposal.

Thanks in advance

[sonofeugene]

'Don't know about what' done to prep for bluing, but in the medical device industry we use acetone in an ultrasonic cleaner, then 99% alcohol in the ultrasonic cleaner. That's for metal parts. For plastic, we use Simple Green or Alconox, then deionized water.

For your parts, it wouldn't hurt to use Simple Green, then distilled water, follwed with acetone, then 99% alcohol. That combo should remove just about all contaminants. But remember, once you pull all the oils off the metal surfaces, it start corroding fast. So I wouldn't clean them until you're ready to actually blue them.

[kcstott]

what do you mean "Hot bluing" as in Hot Caustic salts??

If thats the case you should have a complete set of instructions for the bluing process from your chemical supplier.

brownell's has their instructions up on there sight. they use a mild alkaline degreaser and boil the snot out of it.

[JonnyD]

what do you mean "Hot bluing" as in Hot Caustic salts??

If thats the case you should have a complete set of instructions for the bluing process from your chemical supplier.

brownell's has their instructions up on there sight. they use a mild alkaline degreaser and boil the snot out of it.

I do mean hot caustic salts.
I am mixing my own salts as I can get sodium hydroxide and sodium nitrate fairly cheap.

Some notes I have seen said to boil in TSP solution; I saw that some TSP formulations sold at Lowes have sodium carbonate (soda ash) in them and recalled the sodium carb method I used to degrease in the past. I did boil the snot out of it during that experiment.

Sodium carbonate would be alkaline, enough to burn the skin in case of prolonged contact, and has a soapy feel when in solution.

I am mainly curious about whether anyone has used Sodium carb with success in degreasing.


Edit:
After more searching I found that both TSP and Sodium Carbonate (soda ash) work very well as degreasers when used in boiling water.
The TSP is more strongly alkaline than the Soda ash.
Supposedly, they will also remove paint; I am skeptical of that claim but will test and report back.

[kcstott]

Yeah be careful with the TSP
You don't need much to Avalon of water to do the job and the stuff will remove paint. We use it to rebuild machine tools blows the paint right off but you need a container large enough and strong enough to hold you parts . Easier with gun stuffs

[JonnyD]

Yeah be careful with the TSP
You don't need much to Avalon of water to do the job and the stuff will remove paint. We use it to rebuild machine tools blows the paint right off but you need a container large enough and strong enough to hold you parts . Easier with gun stuffs

I have a lot of soda ash so was planning to go that route to degrease the bare metal parts.
I was going to test to see if the soda ash removes paint on a spare part.
Good to know that the TSP will.

excuse any ignorance, but what does the term "Avalon of water" mean? Just another term for a solution of a certain concentration?

Any recommended ratios for either soda ash or TSP?

[Twystd1]

Hot soda ash or caustic soda will definitely strip paint off of anything. (Hot = 120 degree + Fahrenheit)

I suggest you DON'T get any non ferrous metal close to your hot bath. As it may disappear in short order.

-T

[hellayella]

Heat gun or hair dryer or parts in black plastic trash bag to melt cosmoline a d then wipe off

Use brake cleaner and toothbrush and eye protection to scrub and wipe down (clean rubber solvent-proof gloves)

[dune870demon]

Normal engine degreaser or brakekleen

[meno377]

Here's a good video on how to really degrease surfaces. (Milotrain) posted this video in another thread some time ago. The comet with a toothbrush will work very effectively without being too toxic.

https://www.youtube.com/watch?v=HiL6uPNlqRw

[kcstott]

I have a lot of soda ash so was planning to go that route to degrease the bare metal parts.
I was going to test to see if the soda ash removes paint on a spare part.
Good to know that the TSP will.

excuse any ignorance, but what does the term "Avalon of water" mean? Just another term for a solution of a certain concentration?

Any recommended ratios for either soda ash or TSP?

Typo should have read you don need to much to your amount of water.

thing tablespoons to gallons..

[kcstott]

To the rest of you suggesting spray on parts cleaners good luck with that.

This is hot caustic bluing and is very sensitive to oil contamination. if there is a finger print on the steel it will not blue or not blue to the correct color.

It has to be boiled, it has to be boiled for about an hour too.

Like i said brownell's has the blueing process instructions on PDF

[JonnyD]

I did the hot blue Monday.
I went with the TSP as most other guys doing this were using it for their home brew process.
I followed the instructions on the box: 1/4 cup (4 tbsp) per gallon.
I brought it to a rolling boil and submerged my bead blasted parts in the solution for about 20 minutes.
I removed the parts and placed them in a bucket of hot water for 20 min to disperse the TSP.
I removed the parts from the bucket of hot water, sprayed them with the hose and placed them in another bucket of clean water.

I did all of this with gloves on.
All of the parts were hanging on steel wire so I did not even touch them with the gloves.
The parts will rust within minutes of this process so you gotta work fast to get them to the salts.
The parts that did start to rust were quickly wire brushed (fine steel brush, degreased) rinsed and put into the salts.
I did a test on one part where I left the rust on for the hot salt; it made no difference at all. I assume it is because hot salts oxidize the steel, creating the black iron oxide coating; the salts would have just created the conditions to reduce the red iron to black (from Fe2O3 to FeO).

Everything came out really nice.
I will post pics when I post my build process, start to finish.

Thanks to all who contributed advice.