Heat Treating at Home, Preventing Scale, Overheat and Decarburization

[Corin]

Hi Guys,

about time I made another contribution on here so here goes.

This method works extremely well for me both for knives and anything that needs heat treating where scale and decarburization will cause problems. The purpose of this thread is not to discuss the properties of various types of steel, but simply how a gas forge can be best utilized.

OK first up, the Setup I use... Here is a simple sketch...



This sums it up pretty simply.

Here is how the thermocouple is mounted...

Drill a hole in the side of the forge, make a hole in the refractory, I think I just poked a nail through but whatever works for you..



Next take your thermocouple and stick it into the hole (very difficult this forge business)



The tip of the thermocouple is very delicate once it has been heated a few times it will be very brittle and easy to damage. So don't. The tip is the only bit that needs to get hot. so don't poke it in too far.



The knife slides in here... When heat treating is underway monitor that the knife and thermocouple are at the same colour. Note all the black stuff? thats steel that has melted to my floor... moral of the story, melting things in your forge is fun but quickly stops it looking real pretty.



And here is how it looks like with the door in place note the thermocouple coming in the right hand side.



Now there is way more to it than that, but a simple system like this will get you going.... Here is a video that shows the process I use.

Obviously this method produces a lot of carbon monoxide as well as carbon and soot, so a well ventilated space is essential.

[Corin]

This has been moved, which is fine, but this process works equally well for any item you want to heat treat and particularly well for items that have been finished to a high tolerance. I use this process for making precision punch sets where I cannot afford to loose anything to scale...

Mod Note: Your Video was about knives so most sensable people would look for that here. rather than in general or gas forges.