Question about stamping or hallmarking and iron temp by color

Can't help with the first question but the second is answered at

"Professor," quoting: (clip) "metals smiths can tell the approximate temperature of iron by the glow", (clip) ^^^^^^^^^^^^^^^^^ One reason blacksmith shops are usually dark is that that is the proper light for viewing the glow of heated metal. In the sun, a piece may appear dark, while in dim light it can be see to glow brightly. And all stages in between. Which means that to gauge temperature by eye, you really have to know what you're doing. If you were looking at the object inside your furnace, you were seeing, not only its black bady radiation, but also a component of radiation from the furnace walls and heater, reflecting off the surface. This could be very misleading.

Leo:

Yes good point. I should have noted it was in a dark room (garage) and the flame was turned off right before I made my observation. So only the glow from the iron sample was observered. Based on Professor's reply it appears I was at least 1800k or 2780f. Sweet!

Thanks to you and "Professor", second part of my question seems answered now.

Best regards,

- Ben

Depends on your location (Country). The US has never used "hallmarks". You could stamp your pieces "100% Kryptonite" and no-one would care, so long as you didn't use that mark to deceive in trade. (Superman might get a bit cranky, too.)

In the UK, it *used* to be a hanging offence for an individual to hallmark his own goods - now I think its just an "offence".

You can make up your own "maker's mark" anywhere.

I'm guessing you're in the US (roadrunner.com), so go for your life and stamp away to your heart's content. Just don't misrepresent your goods, and don't call the marks "hallmarks" ('cause they're not) unless you have a Guilded association we don't know about.

HTH

-- Jeff R. (100% pure)

Temperature charts come in two flavors: at low temps (from 400F to 630F) steel will get a whole series of faint colors which are oxides forming on the surface. Very useful for tempering steel which is in the same range. At high temps, (1000F and up), the steel acrually emits light, goes through a whole range of red to incandescent white.

If you desicribed it as "red" heat it was probably in the 1200F to 1500F range depending on your definition of "red"

various charts:

Ben wrote:

The first one : Yes, getting people to blind believe it is another story. Buyers might - dealers won't. Not until they have it bonded or such....

Would you take yellow brass looking stuff that is marked 23 ct gold ?

You would test first...

Martin

Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.

Professor wrote:

Yes, thank you. After I posted my previous reply thinking I had a rough estimate of the temp down, I realized I misread the chart. If it were 2500f then I was nearing the point where iron melts and the steel grate it was sitting on would've been melted (right?). I know I wasn't that hot.

I'm guessing now I was in the 1800-2000f range because the iron was distinct red and the steel grate it was sitting on was orange through and approaching yellow. Does that sound about right? And I realize it depends on the type of steel.

I'm shooting for a ~2000F furnace as the material I'm working with (silver .925 to pure .999) melts at ~1600F and ~1750F respectively. To successfully cast I'm told to heat it to melting point + 100F to 150F. So I think my rig is going to work but the darn crucibles aren't here yet! I've got a MAPP/Oxy torch for backup but am hoping to only use that from the time it's pulled from the furnace to pour to keep the heat up.

Links were very useful, thanks again Roy.

- Ben

There are available pellets that you put in the oven to determine what temp it is. The pellets come in all temps. and melt at that temp. They are available from a foundry supply company.

John >

they have remote, hand held infrared thermometers at Frye's for like, thirty dollars once in a while, I'm not sure of the range, though