Advice on design and shopping list

[Darkfader]

Hello, new guy here from West Virginia. As if I needed a new hobby, I want to make some knives. I started down the rabbit hole known as YouTube and luckily I found this forum before wasting a lot of time and money. I'm interested in constructing a small and simple forge that will allow me to, at the least, heat treat 1080 when making some stock removal knives. I already have a regular kitchen range in the garage I use for powder coating that should allow me to temper after the heat treat. Perhaps at a later time, I will want to do some actual forging, but for the time being, heat treating flat stock that I've cut and shaped is all I'm really after. 

I've read through the burners 101 and forges 101 threads along with countless "critique my forge threads". For a while, my head was spinning with information overload, but I think I may have a solid plan but I'd greatly appreciate some confirmation on a few specific questions that I have.

The tentative plan: a small forge using a 9kg propane cylinder. I also have a small air tank laying around, but I don't recall it's dimensions and I'm not home right now to check that out. it seems the propane cylinder is a popular shell and seems like a good size for my uses, but my questions will apply equally to both shells.

I believe I have the basics down for the interior, please let me know if I'm wrong:

2 individual layers of 1" kaowool, rigidizing each layer.

1/2" layer of kast-o-lyte 30 over the entire interior surface, with plistex applied over this.

The burner will be the 3/4" Frosty T design and I have already ordered the materials for the burner, but still need all connections from the burner to the fuel source.

These are the specific questions I have so far:

1. Should I plan a front and rear opening with the same dimensions? in my mind I visualize openings the size of a fire brick with a shelf and angle welded to the shell for the brick to slide across the opening to control exhaust. Do I use the K26 bricks for this, or the hard fire bricks found at tractor supply? Do I coat this brick with something such as the plistex?

2. Is one 3/4" Frosty T burner sufficient for this setup or should I plan a second burner? It appears the propane cylinder is roughly 12" in diameter and roughly 12" deep, so subtracting 4" for the wool alone gets me about 402 cu.in. subtract more for castable refractory and even more for flattening the floor, creating more a D shape, I think one burner will be fine but please confirm.

3. Can the Kast-o-lyte 30 be used for the floor, and if so, do I just build it up level to the bottom of the openings and make it as smooth as possible with the bondo squeegee? and then the entire interior gets plistex applied? Can anyone provide an estimate of KOL30 needed to make this happen? If I use the KOL30 for the floor, do I apply it thicker in that area, or do I build the floor up with kaowool or fire brick first?

4. Is the plistex painted on? or is this something thicker that is troweled or squeegeed on? 

Overall, I definitely have a vision in my head of how it should "look", but I absolutely would love to hear opinions of the expertise here on the site. I prefer to do things right the first time, or at least as close to right as I can. I realize homemade designs can always be improved upon and that's part of the fun, but I'd like to have a functional tool rather than a complete mistake. I will order my supplies from Glenn once I am satisfied with the shopping list.

Thanks in advance for any advice or tips. I greatly look forward to the discussion, and as always, I will continue my research. 

[Latticino]

Sounds like you are on track for success.  A couple of notes:

1. I just relined my forge with around 3/4" of Kastolite and it took about a half bag. Mine is a little larger than you project, so that should do you.
2. I'm a fan of casting doors of Kastolite as well, inside angle iron frames. 2" thick doors with material that overlaps the forge opening and frame works well. Soft fire bricks crack with use and hard bricks don't insulate well.
3. I recommend a front door of at least 4" height by an inch or so under the width of your forge.  With good doors you can use that very effectively. Rear opening based on anticipated forging (mine is 2 x 2).

[Darkfader]

Thank you sir for your reply. 

Just to clarify, what size bag of Kastolite did you use? And the rear door is more for allowing longer materials to pass through rather than controlling exhaust?

[Latticino]

Sorry, the standard 55# bag.  Yes, I use the rear door for longer materials, not exhaust, but each to his own there.  I use a forced air burner, so I have less issues with back pressure problems and tuning than a NA burner.

I also recommend having a removable high alumina floor if you plan on welding with flux on a regular basis.  While Kastolite is flux resistant the glassy byproducts of the flux and scale will still build up over time and you will want to be able to replace the floor or your stock will either stick to it or get contaminated.  I plan to use high alumina half-bricks, originally marketed as Crystallite I believe (though I got them over 20 years ago, so you may have to search).  Others use high alumina kiln shelves.