Hot bluing line with results?

Fred.Rowe · Jul 4, 2013

My son and I set up an aluminum anodizing line in May then started work on this hot bluing system.

A good friend had kept the entire bluing system, covered with tarps in his back yard. He gave the system to me with my promise of getting it up and running. "I got it set up Dave"

The system consist of a Dio-clean hot water bath, left side. A boiling water bath, left side. Straight ahead are two cold water rinse tanks, one running into the other and then out the overflow. The bluing salts is on the right side directly opposite the twin exhaust fans.

The 4" sch. 40 pvc pipe holds the water displacing oil.

The two damascus blades were our first run.

theHobbyist · Jul 4, 2013

Very nice results!

And now for the "imma newb" question: Does bluing give a better/more durable finish than acid when it comes to damascus?

Fred.Rowe · Jul 4, 2013

theHobbyist said:
Very nice results!

And now for the "imma newb" question: Does bluing give a better/more durable finish than acid when it comes to damascus?

These

Yes I believe it is. The acid is just a discoloration where as the bluing is the product of the reaction between the bluing salts and the surface of the steel. Both of these blades have been sanded using 1200 grit paper after the bluing was completed. This, as is shown, gives the blade a black background with a silver overlay.
Both of these blades will be done with frame handles with snake wood slabs. Lots of black.

Varga Knives · Jul 4, 2013

That is fantastic looking Damascus, Fred. Nice setup.

Bob Katilus · Jul 5, 2013

Those turned out nice, Fred. Can you explain your process, step by step? I know some guys just use a 3 step process, where Brownell's recommends something like 7 steps. Yours looks like somewhere in between, with great results. I am looking to set something up too, just unsure of the exact set up I should go with.

Fred.Rowe · Jul 5, 2013

Bob,

The process runs like this: 20 minutes in the Dio-clean cleansing tank which is at 180 fh. The parts being blued are held in a black iron basket the length of the tanks. It goes from the cleaning tank to the cold water rinse, where it is lightly scrubbed with a soft brush, the basket is lifted from the cold water rinse and into the hot bluing salts tank, which is held at a temp of 292 degrees fh. Depending on how blue or black you wish the part to be, the item being blued is in the bluing salts tank for from 15 to 30 minutes, 30 minutes giving you black. The parts filled basket then goes into the cold water rinse where all traces of the bluing salts are removed. The bluing is fairly fragile at this stage and must be treated with care. Once the parts are rinsed clean they go into the boiling hot water tank where the steel comes to 212 degrees fh. Once the part is heated to temp it goes directly to the water displacing oil, where it sets for 2 hours. After the oil soak the part is hung to dry. The salts are very caustic and a face mask, rubber gloves and respirator are recommended.

Fred

David Stifle · Jul 5, 2013

Wow, Fred! Those blades look great! Congrats on a great little setup.

theHobbyist · Jul 5, 2013

Aloha Fred,

Thanks for the explanation, it's much appreciated, even though I'm no where near the level I need to be to start working the Damascus, I don't think it's too early to start learning about it -=)

Again, awesome work!!

Bob Katilus · Jul 6, 2013

Fred.Rowe said:
Bob,

The process runs like this: 20 minutes in the Dio-clean cleansing tank which is at 180 fh. The parts being blued are held in a black iron basket the length of the tanks. It goes from the cleaning tank to the cold water rinse, where it is lightly scrubbed with a soft brush, the basket is lifted from the cold water rinse and into the hot bluing salts tank, which is held at a temp of 292 degrees fh. Depending on how blue or black you wish the part to be, the item being blued is in the bluing salts tank for from 15 to 30 minutes, 30 minutes giving you black. The parts filled basket then goes into the cold water rinse where all traces of the bluing salts are removed. The bluing is fairly fragile at this stage and must be treated with care. Once the parts are rinsed clean they go into the boiling hot water tank where the steel comes to 212 degrees fh. Once the part is heated to temp it goes directly to the water displacing oil, where it sets for 2 hours. After the oil soak the part is hung to dry. The salts are very caustic and a face mask, rubber gloves and respirator are recommended.

Fred

That is really helpful. Thanks for sharing your process, Fred.