heating Ti to get a colour?

B

Bart student

Joined
Nov 17, 1999
Messages
676
Hello folks,


A while back I tried to heat-colour my Ti bolsters on my Microtech LCC. Since my torch went out, I figured why not use the flame coming out of my gasforge? Then I have a problem..

1. When I hold them there, They are grey, and I see no difference and then suddenly they're red hot. Is that normal?

2. When I got them out, they got a kinda cool battleship greyish colour, which turned out to be a really hard layer (coins in copper, nickel or brass didn't even touch it). What is that?

3. If I want to colour my bolsters say bright blue.. that implies reheating it.. will that hurt the Ti ?

Thanks in advance, Bart.
 
The hard gray that you are seeing is aluminum oxide if the ti is 6AL4V. If it's commercialy pure then the scale is titanium dioxide, I guess. Whatever it is, sand it off and you can recolor. Use a torch and go slow. You'll hit bronze first then purple which quickly turns to a series of blues. You can quench at any time to stop the process.
The temp that the colors occur at is only in the 450-600F range or so, fairly cool compared to your forge. Recolor as many times as you wish.
 
if the hard grey is aluminium oxide, then how do I stop the aluminium from oxidizing because it oxidizes a LOT quicker then Ti. Yes, the bolsters are 6AL4V on the Microtech.

Thanks for the reply Peter

greetz and take care, Bart.
 
Bart, I don't know but Les Halpern tells me that that hard scale is aluminum. All I know is what I said above about the coloring. It has worked for me for years. Now I do anodizing to get more control but the heat colors are actually more colorfast and last longer against wear. I think it's because the oxide layer is deeper.
 
Bart the colors in heated TI (be it CP or 6AL-4V) are oxidation. As long as the piece is in the flame of a torch or forge you will not see the colors. It is when you move it out of the flame that oxygen reaches the piece and the color appears. So move the piece in and out of the flame as it heats up so you can start to see the color come into the piece. As you approach the color you desire go slowly and when the correct color appears quench the part in water to freeze the color. In coloring TImascus we have found the colors from the heat oxidation are much more durable than from anodizing.
 
The temp that the colors occur at is only in the 450-600F range
Click to expand...

Do I can use my kitchen oven to heat the Titanium ?
The temp will be more acurate ?

Alain M-D
 
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