Small Gas Forge: Build vs Buy (Which Type)

[Hawk45]

Hi all,
Want to try out some heat treating of 1080 with a small forge. My knifemaking is just for hobby and getting tired of sending blades off for HT post grinding. Kills the creative process.
No ready to go all in on HT oven yet, and since I work mostly with high carbon steels, was thinking going non-magnetic then into oil, then tempering in oven should be good enough for the hobby.
My issue on going DIY is time.. finding all the parts, ordering, waiting, getting, assemblying, building burners, etc. I see lots of smaller forges for sale from $200 to $500 and thinking of just putting up the cost of buying one to play with and get going. If I go DIY I know it will be a long time before I get built opposed to pulling out of a box and hooking up a gas tank.

So with that in mind, what's the best VALUE in a gas forge? I'm sure some on Amazon are junk and don't mind paying a little more for known good quality, but a Chili Forge is way out of what I want to pay at this time. I do blades up to 3" wide and 18" long, so would need to get those size pieces up to proper temp.

Thanks much!

 

[Ken H>]

My first choice for purchasing a forge for bladesmithing (HT'ing) would be: http://www.atlasknife.com/product/graham-forge/ for $400. It's a blown forge with the burner angled slightly upward and rearward which provides an excellent swirling action to the flame so there are no (well, almost none) hotspots inside. I expect a 12" billet will glow evenly from end to end. Just doesn't happen with the normal vertical burners. This being a blown burner you'll be able to better control the temperature for HT'ing. For HT'ing you'll also need a temperature probe, and the one Atlas has for $45 isn't bad price. I'm not sure how well the TC will hold up, but for inserting to check temp, then removing it should be just fine.

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Building a forge isn't near as daunting a task as it seems. My first forge I purchased and it was crap for blade smithing, just fine for blacksmithing. It had two vertical burners (just like FiF's 3 burner forges) that gave two big hotspots requiring constantly moving billet around trying to heat evenly.

For HT'ing a muffler pipe is good to protect the blade from direct contact with the flame. In a small size forge as linked above I'd flatten the muffler pipe so it would fit in the lower half of the opening and have the TC probe inside the muffler tube with the blade to get temp stabilized.

While a blown forge can be PID controlled for good temp control, you can do it with manual control also, just have to watch forge the whole time the blade is in forge.

 

[Storm W]

Atlas forges are made by a knife maker for knife makers. His little forge sips fuel and gets up to welding heat unlike many horseshoeing forges and some blacksmithing forges.

His little knife making anvils are cool as heck as well and you gets tons of performance for the price.

I got mine so that I could do my own HT. I feel like for a beginner I had a better than average understanding of metal after a 20 year welding correer but unless you have someone who knows what they are doing to help train you you forge HT isn't going to be as good as sending your pieces out. I have knives I did and they are pretty good but they are a lot less than a real oven and quench oil HT even on very easy steels.

 

[HSC ///]

3" x 18" ? that's like a lawnmower blade....
I regularly HT in a forge and have previously used a weed burner successfully in the past for well over a hundred blades
but if I was to do that large of a blade I would do it in a furnace, or send it out for HT.
I wouldn't advise a best value forge for that size blade,

 

[Londinium Armoury]

I find building them fun, and the good thing about building them is it's cheap and you can customize the perfect size for your own knives.
I have built about 6-7 forges, some coal some gas, some huge some tiny. My favourite is my little mini heat treating forge with open back. It's just a simple empty can with the bottom cut out filled with refractory heat resistant cement. It allows me to really control the colour changes in the steel when quenching in the evening time. I've been practicing quenching by eye for probably over 4 years now in the evening darkness. I found this little forge with the open back is perfect because you can stop the tip over heating or any grain growth if you are attentative. Learn to keep the blade cherry red or dull orange and once it is that colour keep moving it in and out and don't be afraid to let it all come out into the air to bring the temp down, most important thing I found is not over heating steel, you can produce very good small grain refinement and good temp control with practice and playing around with forge size, blade length type of gas used. I prefer Mapp gas as it gets nice and hot. It is possible to hold 10+ minute soak times by eye in a gas forge, I can hold 7-9 mins a time no issue, just stay alert and make sure it's dark and you know what colour your steel turns at the temp it needs for the quench, some steels need higher or lower than cherry red slightly.
You will hear that you cannot get excellent controlled results with a forge compared to an oven for quenching, but with a lot of practice and good evening darkness you actually can. I've seen worse grain refinement from production knives than my own batches I test. You can get very small refined cross section samples when you break your knives to check your work.
I say make your own, they are pretty easy to make only take about 1 hour if that.

 

[Atlas Knife Company]

The Graham forge would be ideal for the blade size you are building. It gets really hot, and heats very evenly. It's also got a 4" x 2" rear opening for longer blades.

 

[Travis Fry]

I'm liking the Atlas + I picked up at Blade this year, so +1 for Atlas Knife Company . I think it was $325 or $350ish, and has a little bigger opening than the original Atlas. Not sure about welding heat (haven't tried) but for that you should really have a separate welding forge. But if you're really doing blades as big as you mention, the Graham would be the thing for you.