more on strawing
 

Dear Experts


After the parts to be strawed are down to bare metal, should they be polished using oil and bronze wool, or just bronze wool?

Delete the use of bronze wool all together.......polish by buffing wheel or coucous cloth.

Chemical strawing
 

Selenic acid H2SeO4 ----------- 10 parts
Copper (II) sulfate CuSO4 ---- 10 parts
Distilled water ------------------- 1000 parts

After a good pickling of the metal part put the part in the solution described above.
Part will start changing the color from the yellow to the dark blue depending on how long you keep the part in the solution. Just take the part at the desired color and wash it in the distilled water. Worm up and apply olive oil.

There you go, I just revealed more than 300 years old recipe on the net. One of the trade secrets.

The best results I have gotten have involved heating the polished part to be strawed.

Where do you get selenic acid? By pickling do you mean cleaning the parts in phosphoric acid?

It's still used: Add some nitric acid, and you'll have the recipe for modern cold blue.