How I make and use propane forges

[corinkayaker]

Some people get into making forges through blacksmith and bladesmithing... I went the other way. Working full time in the Gas industry I got into blacksmithing and bladesmithing from working on forges and talking to their owners.

There are as many ways to make and use forges as I have had hot dinners, but I have a few preferences. Obviously I sell burners and related equipment because thats my day job, but I also help folks make forges at every opportunity.... not to make money but just cause I like making forges.

Anyhow there is a lot of miss information on the net concerning combustion and forges, and while I know far from everything I work on around 1 forge per fortnight, for farriers, blacksmiths and bladesmiths. I have seen a lot of designs and helped a lot of owners sort out the issues with them. Always looking to learn more so if there is something you can share with me I would love to hear it.

I have a quick and easy way I make my forges, based on a pretty old model that has been around a good long while (because it does work well)

Anyhow, I am making a few videos on how they work and how to build and use, hopefully it will be of use to some of you.

I have made a few changes to the burner design I have been supplying unchanged for many years.... Look forward to my testing videos on that burner.... I am hoping it will significantly improve scale formation during heat treat. Experiments so far have shown most scale wipes off after heat treat leaving gray metal. Exciting stuff if you like that sort of thing.

Anyhow here are a few videos to kick this off.

[video=youtube_share;EFKoGZkUQt4]http://youtu.be/EFKoGZkUQt4[/video]

[video=youtube_share;v4AuZTyEo2o]http://youtu.be/v4AuZTyEo2o[/video]

 

[Rick Marchand]

I like the forge... Great craftsmanship. I would prefer the through-hole on the back be an upright slot as that's how I pump blades through. I rarely lay anything on its side.

I'm not quite sure about your heat treat method but to each, his own. A few questions if you don't mind...
Your as-quenched hardness is 59-60 HRC? What type of steel? see edit
How are you sure you are not getting decarb? Decarburization goes further than just the scale. Your hardness makes me wonder.see edit
Have you ever tried a muffle pipe set up?

Thanks for sharing.

EDIT:
Sorry I just caught that you are using cable damascus. Pretty tough to make any judgements on hardness.

 

[pap11y]

I found the lack of scale on blades after heat treating very exciting

Looks like a pleasant day in the videos. You can't really tell it was the hottest day in about 50 years...

Good work mate..

 

[Turborocket]

Tagged

 

[corinkayaker]

I like the forge... Great craftsmanship. I would prefer the through-hole on the back be an upright slot as that's how I pump blades through. I rarely lay anything on its side.

I'm not quite sure about your heat treat method but to each, his own. A few questions if you don't mind...
Your as-quenched hardness is 59-60 HRC? What type of steel? see edit
How are you sure you are not getting decarb? Decarburization goes further than just the scale. Your hardness makes me wonder.see edit
Have you ever tried a muffle pipe set up?

Thanks for sharing.

EDIT:
Sorry I just caught that you are using cable damascus. Pretty tough to make any judgements on hardness.

Its like this mate...
If things are not going to go according to plan its going to happen when your making a you tube video...

I have heat treated countless blades in my forge, with all kinds of known and unknown steels. I pretty much always get a hardness that the 65 rc file skims right over. For whatever reason it did not happen when I did this video. You suggest it may be cause it is cable Damascus, but I heat treated a blade I made from cable Damascus (same cable) a few days later and it was + 65 so I am uncertain. most of my steal comes out very very well and lots of people can testify to that, but yeah in the video there is both more scale and less hardness than I normally ever get.

I have not tried the muffler tube method, I am guessing that is what you do? I will do some experimenting with this, I was concerned (probably needlessly) about the free oxygen creating excess scale.

How do I know I am not decarburizing.... Well unless someone wants to pay to have a sample tested I don't really.

HOWEVER...


It is however a fact that Carbon Monoxide is used to Carburize steel and carbon dioxide to decarburize.

(For those that don't know Carbon Monioxide is a toxic deadly gas and any experimenting with it should be conducted in controlled conditions in extremely well ventilated areas.)

References: page 67-68 http://books.google.com.au/books?id...ce=gbs_ge_summary_r&cad=0#v=onepage&q&f=false
http://en.wikipedia.org/wiki/Carburizing

Anyhow, the way I am running my burner, using a carbon monoxide meter I have measured the huge amount of carbon monoxide it is producing with the flame adjusted as I have done in the video. In may case as many have seen first hand, steel will come out of the quench a grey colour with nowhere near as much scale as in this video. Normally what scale there is is only on the burner side.

The theory is good (I think) even if I have no real method available to me to prove it. Like the title says, it is what I am aiming for....

 

[Rick Marchand]

Thanks for the reply. 65HRC is good. I hear you on the Youtube/Murphy's Law thing... but you could see my concern. You may want to do another video with everything working in your favour. When you checked that blade, it had me scratching my head.

Please don't think that I am attacking your method. This is Shop Talk, so I'm just bouncing some ideas off of you for interesting conversation.

I would suggest a larger quench tank that will hold a higher volume of oil. What type of oil are you using?
Have you ever experimented with fully quenching your blades? The reason I ask is that agitation is a very important factor in heat transfer. You need to break up that vapour jacket so the oil can do its job. If you feel that edge quenching is how you want to go about it, then I would make a limiter plate/cage in your tank. This way you can keep your desired quench depth and agitate without the fear of dipping too low.

I don't use the muffle pipe as much, anymore(I have an electric kiln now) but it can be a great way to even out heat and reduce decarb if you set them up right. Your forges run very well. I like the amount temperature control you are able get with them. What psi range do they run in? I also like your etching video.... keep up the great work.

 

[corinkayaker]

Please don't think that I am attacking your method. This is Shop Talk, so I'm just bouncing some ideas off of you for interesting conversation.

Haha no worries mate, you are questioning my method and that can only be a good thing!

I would suggest a larger quench tank that will hold a higher volume of oil. What type of oil are you using?
Have you ever experimented with fully quenching your blades? The reason I ask is that agitation is a very important factor in heat transfer. You need to break up that vapour jacket so the oil can do its job. If you feel that edge quenching is how you want to go about it, then I would make a limiter plate/cage in your tank. This way you can keep your desired quench depth and agitate without the fear of dipping too low.

Funny you should say that, I just bought some deep metal tanks that hold a couple of gallons and have well fitting metal lids (baine marie servery dishes from a catering supply company) The little dish I was using was OK for one knife at a time, but these days we do three or four per batch and it was getting way too hot for a good quench. We are using Canola oil, However I have some quench oil coming.

I have been meaning to make a limiter plate for ages... currently I just have a lump of steel bar at the depth I want at the tip, then just drop it to the desired height on the blade. We quench full depth to depending on the knife and the steel and the intended application.

What psi range do they run in?

I run them at between 1 and 40 PSI normally, at higher than that bad things start to happen.... burnt and melted steel is quite common. Here is the post thread on the Australian Blade forum site that lead to m making the video if your interested...
http://www.australianbladeforums.co...and-Digital-Thermometer-to-Heat-Treat-at-Home

Thanks for the comments and questions by all means ask more...

 

[DamienC]

great vids corin thanks for posting them

 

[Sam Salvati]

I use my NC tool forge the same way, turn the PSI way down after the forge is warmed up, choke down the intakes on the burners and let it soak, INCREDIBLY even heat inside not too hot not too cold, no overheated tip or edge.