graymachine

Beautiful piece of work! What gauge sheeting did you use?

I recently finished putting together a new furnace made from an old keg. The top and bottom are solid 2700F refractory and the walls are 2" kaowool with a refractory shell. My burner is this Venturi. I took the furnace up to my brother-in-law's farm to do its first firing for curing and ran into a problem that I hope someone can help me with; you may be able to hear me mentioning in the videos, but for clarity the furnace runs great while I have the lid off but when I put it on the flame chokes out, spraying nothing but propane. I have to dial my PSI down extremely low in order to sustain a flame inside with the lid on and it isn't a sufficient heat source to get me to melting temp in any sort of practical time frame. I expect that the answer is simply to continue to fiddle with it further until I have it dialed in, but are there any obvious issues? This is something I would ask about over at Alloy Avenue, but I still haven't been approved for an account; their registration process is peculiar. 

I am building a new furnace out of a keg, essentially following Brian Oltrogge's FIRE-KEG build. Instead of making the walls out of castable refractory as he did, I plan to use 2" kaowool and coat it will about 1/2" high temp mortar to shield it (and prevent any nasty health effects from heating the kaowool). I plan on using just a simple furnace mortar, the type that you pick up at a big box store, but I'm unsure how well it will work being only 1/2" thick. Does anyone have any experience with that? I know that Satanite would be the best option, but I would prefer to avoid that if I can since the cost plus shipping would be pushing my budget. Thanks for any insights!

32 minutes ago, Steve Sells said:

for one: I cant imagine a few gallons of oil fitting in a skillet...

Right; I misspoke, as it were. What I was trying to reference was the heating source, namely a portable hot plate like this one; local jargon alternatively refers to it as a skillet top or just skillet. I hadn't considered the dimensions of the vessel yet, but would make sure it was sufficient for complete vertical submersion (not to mention nonflammable.)

8 hours ago, Bo T said:

Don't ruin your Weber. Check the forums on solid fuel forges. Make a side blast out of an old (whatever will hold it and isn't flammable) some sand, and clay. Focus on ones designed for charcoal. If my memory serves there are some threads on these older type of forges.

Thanks! I thought about it some more and realized that it would probably not be worth it and I was just getting eager. 

12 hours ago, Steve Sells said:

52100 and oil warmed in a skillet??? PLEASE read the pinned s heat treat information I already went to a lot of trouble to write before you do anything else.

I see what the issue is now; I was confused on terminology, or at least conflating it. What I meant was that I had planned to normalize the knife after grinding it to profile (probably following the steps for heat treating 52100 I found elsewhere on here) and then harden it later, using a quench in canola oil unless there is an oil you think would be better.

56 minutes ago, ThomasPowers said:

I can get it at my local walmart.  However what they stock is regional so I can't say about yours.  If you get fully charred charcoal there is NO smoke.  So charcal they sell partially charred to flavour stuff cooked on it, just avoid that stuff and you are ok (they generally charge more for it too so the "cheap stuff" is the best stuff for smithing in my experience.

That is not a steel I would have suggested for your first attempt.

I am sorry you don't have access to a yard where a hole in the ground would be very much like forges used for over 2000 years.

Good to know; that covers the fuel issue.

Should I just use found steel to start? I ordered it mostly to have something good on hand when I need it; it seemed to be good for the application (making kitchen knives) but am I wrong?

I have a yard but I don't think digging a hole in it to use as a forge would go over well with my wife.

32 minutes ago, Steve Sells said:

52100 and oil warmed in a skillet??? PLEASE read the pinned s heat treat information I already went to a lot of trouble to write before you do anything else.

I read it and it was informative, but I don't see how it relates to 52100 and warmed oil; it makes no mention of what to quench in outside of noting that thicker steel can be quenched in water and some exotic quenching methods, unless I missed it. I meant a portable electric hot plate, not a skillet. Should I use a different oil? Is that what you mean?

39 minutes ago, ThomasPowers said:

Well I buy it at Walmart and make my own and sift my woodstove ashes for it and recover it from bonfire locations and...

So I can get it at Walmart? Cool. Does it smoke a lot? From the videos I've seen it smokes a good deal at least when starting, which is what inclined me to charcoal briquettes since I want to keep neighbor annoyance to a minimum.

What do you think of the steel I ordered? Is it adequate to the task or do I go overboard?

Also, what do you think about using my Weber for heat treating? It is the best thing I have available for the time being but I'm concerned about ruining it.

27 minutes ago, the iron dwarf said:

proper lumpwood charcoal should not have additives in it but the brickettes and easy light will, you will go through a lot of charcoal.

which part of the world are you in ( it helps to add it to your profile to stop people asking all the time ) because a lot of questions would have different answers depending on where you are.

a lot of things on instructibles are not the best, look here on the forum for ideas that work and ask people who know what they are talking about

I'm in Kentucky. There are several things in the Instructible that were questionable due to other sources of information, but that was the basic plan, i.e. Cut out a blank with a grinder, grind out the blade profile, heat treat and temper, add a handle. I was planning on picking up some maple to use for the handle.

41 minutes ago, ThomasPowers said:

Charcoal is perfect for heat treating; charcoal *briquettes* are horrible; don't use them! Use real chunk charcoal.

What are you using for your "stock"?  $35 for a beginner project seems rather steep and that instructable has some MAJOR mistakes in it; like 

"Depending on the type of steel you have, you will either be using water or oil to quench. The difference is water cools the metal more slowly than oil, and some steels prefer different speeds of cooling for this process. "

Water is a MUCH faster quench than oil; and I would advise warm vegetable oil (around 140 deg F) over random oil at room temp.

If you are close let me know and I will give you a suitable piece of large (foot wide) bandsaw blade to use.

Where would I go about getting chunk? It's what's called cowboy charcoal, right? Can't I find it at a hardware store?

I ordered a 1/8" thick bar of 2"x48" 52100HC steel from New Jersey Steel Baron. 

I knew that quenching in water was a mistake; I was planning on quenching in canola oil warmed on a skillet, although if you think something else would work I'm game. 

As I said to the iron dwarf, I'm planning on using maple for the handle and am considering spalting the wood first.

Hi, I'm new to metal working as a hobby and am just getting started. I have a brake drum that I am planning on making into a forge, but that isn't something I can put together anytime soon; I know it isn't the best thing in the world but I am essentially starting from scratch. For the time being, I was curious if I could use my Weber charcoal grill to heat treat a kitchen knife that I plan to cut out of stock with a grinder, essentially following this Instructable. It seems to me that it should be fine to bring it up to sufficient temperature with a makeshift blower on the bottom to get the steel to 1500F without ruining said grill, but that could just be my inexperience. I think it would certainly be fine if I lined the grill with a refractory material, but I don't want to take that step unless I have to. I plan on using charcoal for the time being; I know that it has unwanted additives in it that could adversely affect the steel, but I would be doing this in my neighborhood so I want to minimize any annoyance to my neighbors. Thanks for any help!