Case Hardening with a Charcoal Furnace

[Pete O]

Really enjoyed that video Tom, I can see another use for my oil-fired furnace.
Back when I was 20-something I made an attempt at case-hardening with a similar compound, using an oxy-acetylene torch for heat. Ended up with an empty oxy set and a ruined part.

[TomG]

Thanks Pete.

The secret is to keep oxygen away from the part. These were close to being ruined due to the rupture of the foil. Looking back, I noticed some white smoke coming out of the furnace toward the end and that must have been when the leak started.

Tom

[Mayhem]

Do you think it was the direct air blast that did it? Looking at your video it seemed that the bottom gave way.

The stuff I see on eBay is listed as 0.02mm thick which is about 0.0008". I can't see that holding up to heating up a pie in the oven, let alone heat treating a part...

[TomG]

Maybe. Perhaps it should be double wrapped or set on a plate. Of course there is always the option of putting the parts in a steel box.

Tom

[EdK]

(03-14-2016, 09:53 AM)TomG Wrote: Perhaps it should be double wrapped

That's what I was thinking also.

Ed

[awemawson]

Back in the day, parts would be packed into an iron box with the carbon compounds and a few shavings of wood. The box lid was reasonably tight fitting and retained with a twist of iron wire - the shavings burnt up and exhausted the oxygen from within the box. Knock out was a case of lifting the box from the Furness, knocking the contents out and dunking them.

I too have used the stainless foil and as Tom said, it's razor sharp - mine must be a bit thicker than the stuff Tom was using as it doesn't burn through, but it's the very devil to get the parts out while still hot enough to quench.

I reckon a box is the way forwards.

[Old Minger]

Great video Tom, thanks for the time and effort.



John

[DaveH]

Very nice video Tom    
 
daveH