First Try At Hot Bluing

Ok, I went the wrong direction, But the stuff is still not good for you. I did get some on me, Went right through my jeans onto my knee. Did not take much and I felt it.
For some reason I think it turned more black than the normal bluing. Maybe I cooked it a little to long or something. Oh, Also my first job of doing small threads on my small lath.

Apparently I got confused! KVT, your bluing looks Great!

Cactus Farmer said:

This is not an acid. Caustic is sodium hydroxide. Lye!11 Very basic. Ph around 11. Acids are Ph lower than 7. Battery acid, sulfuric acid is Ph 1. Acids burn the surface of your skin. Lye goes right to the core. If you get this mixture (bluing salts) on your skin wash it with vinegar, a very mild acid to neutralize the lye.

Click to expand...

What Cactus Farmer said! If you do get the solution on your skin, flood immediately with cold water, followed by an mild acid rinse. If the skin feels slippery, you have not completely neutralized it. The "slippery" is your skin dissolving. After the acid rinse, you can neutralize any remaining acid with baking soda.
Do not store caustic solutions in glass. They eat glass! It is a slow process but over long term storage it will contaminate your solution and could weaken the glass. I store caustic in polyethylene bottles. Used bottles from bleach, laundry detergent, etc. work well. I also use the gallon jugs from OJ. Wash and rinse thoroughly before use, especially the bleach as bleach has a nasty reaction with caustic.
Potassium nitrate is a strong oxidizer and can burn skin as well.

I think those came out very nice!

Here is a interesting video on blackening using dirty motor oil: Very fastidious gentleman.
Blackening starts @ ~24Minutes

In the heating and AC business, we use an alkaline cleaner to clean the outdoor coils of AC and HP units... it is strong enough, if you get it on your hands it feels slimy.
As noted above, that is the alkaline melting your skin... When I do a lot of coil cleans, even diluted 10:1 with water (10 parts water), after a few days of about 1/2 dozen exposures a day... my hands hurt for a few days. Better IMO to get the proper PPE and use it!
BTW: I got some rubber gloves at HF, they are great for cleaning AC coils... never do it without them anymore.

[QUOTE
For some reason I think it turned more black than the normal bluing. Maybe I cooked it a little to long or something. Oh, Also my first job of doing small threads on my small lath.[/QUOTE]

If you cook it too long it will be oxblood red. Get a thermometer and watch the temperature. 300 degrees to blue hard metal means your salts are getting used up.
Nice threads, by the way. My first threads weren't so pretty, although they worked and we never to be seen again. They were weld sealed after assembly.

I think it's time for some safety precautions when handling lye (sodium hydroxide). This stuff is nasty and very corrosive and it EATS SKIN, and other organics like leather and cotton (jeans). It is particularly nasty when mixed with water and heated. Proper protective clothing/equipment is an absolute must. Wear gloves, apron, and/or clothing made of butyl rubber, nitrile rubber, and/or polyethylene. Wear chemical splash goggles and face shield.

The following is a few excerpts from a Material Safety Data Sheet.

EMERGENCY OVERVIEW
Appearance: white. Danger! Corrosive. Ph 14. Causes eye and skin burns. Hygroscopic. May cause severe respiratory tract irritation with possible burns. May cause severe digestive tract irritation with possible burns.
Target Organs: Eyes, skin, mucous membranes.

Potential Health Effects
Eye: Causes eye burns. May cause chemical conjunctivitis and corneal damage.
Skin: Causes skin burns. May cause deep, penetrating ulcers of the skin. May cause skin rash (in milder cases), and cold and clammy skin with cyanosis or pale color.
Ingestion: May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns. May cause perforation of the digestive tract. Causes severe pain, nausea, vomiting, diarrhea, and shock. May cause corrosion and permanent tissue destruction of the esophagus and digestive tract. May cause systemic effects.
Inhalation: Irritation may lead to chemical pneumonitis and pulmonary edema. Causes severe irritation of upper respiratory tract with coughing, burns, breathing difficulty, and possible coma. Causes chemical burns to the respiratory tract.
Chronic: Prolonged or repeated skin contact may cause dermatitis. Effects may be delayed.

Personal Protective Equipment
Eyes: Wear chemical splash goggles and face shield.
Skin: Wear gloves, apron, and/or clothing made of butyl rubber, nitrile rubber, and/or polyethylene.
Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirator: A respiratory protection program that meets OSHA's 29 CFR 1910.134

Chemical Stability: Stable at room temperature in closed containers under normal storage and handling conditions.
Conditions to Avoid: Moisture, contact with water, exposure to moist air or water, prolonged exposure to air.
Incompatibilities with Other Materials: Acids, water, flammable liquids, organic halogens, metals, aluminum, zinc, tin, leather, wool, nitromethane. (reacts violently with aluminum, evolves highly flammable hydrogen gas)
Hazardous Decomposition Products: Toxic fumes of sodium oxide.

I worked as an analytical chemist for a major battery manufacturer back in the seventies and one of the routine tasks was making up 25% potassium hydroxide solutions (potassium hydroxide is an analog of sodium hydroxide and has very similar properties). A great deal of heat is generated when mixing either of these two chemicals with water. enough to cause boiling of the solution. We always mixed with the vessel in a bath of running cold water to control the temperature. UNDER NO CIRCUMSTANCES SHOULD WATER BE ADDED TO SODIUM HYDROXIDE! Splattering of liquid or soaked granules is highly likely with potentially serious consequences. Mix bu slowly pouring the granules into water with constant stirring. If boiling is evident, allow the solution to cool before adding more granules.
Sodium hydroxide also reacts violently with aluminum. Hydrogen is generated in the process causing a potentially explosive atmosphere and sodium hydroxide is made airborne as an aerosol riding the hydrogen which can cause skin burns or respiratory problems.

I will emphasize the warning not to mix this solution in aluminum, aluminum alloy, pot metal or magnesium alloy containers. And always remember to add add the acid or base to water (like an otter), not the other way around. I had a student get a very bad chemical burn not following this adage.

those pieces turned out excellent op. every time i see one of these threads i start reading with great interest, but by the time im done reading i figure i should just use the store bought blueing for safety reasons.