Poor mans itc 100?

[Nick alvorez]

First time on here been reading some of these posts for a while now but never signed up, figured i would.  So ive recently decided to make a new forge the one im currently using is a Hells forge double venturi burner.  It works great and gets to forging temp rather fast..  but its to small.  I dont know the exact measurements off the top of my head but a rough guess id say its 20in long 4in hight and 6in wide oval shaped.  With 1in thick blanket with 2 4x6 fire brick as a base. Needless to say i can light my ciggarette off the side of it after its been running for 30 mins. The one im in the making is 20in long 11in hight and 11in wide. A box esentially.  With 2in blanket all around. With bricks lined the bottom.  Still in the works tho.  I need to rigidize it and still coat refractory about 1in maybe a half in then i want to do a itc 100 but its out of my price range.  I have 5lbs of alumina oxcide 5lbs of zerconium 3lbs of silica sand  2lbs of kaolin clay  and a big xxx bag of cat litter with the sodium hydroxide to go with it. Ive heard it can be done with the keolin and zerconium.  im guessing the zirconium could work due to its high heat gloss for clays but i dont want to put it on just yet im not sure if its a good idea or not.  If anyone could throw me a bone on your thoughts it would be mutch appreciated

[Mikey98118]

Zirconium silicate and bentonite makes a much better choice than ITC 100.

[Latticino]

Couple of suggestions, though some you may be addressing as the forge is still in process:

1. Make sure that you put the full 2" of refractory blanket under the split hard fire brick floor, otherwise that will be a huge heat sink and thermal path to losing heat.
2. Door design is one of the trickiest parts of making a good forge, plan for this in advance.
3. It is very important to have your blown style burner piping correctly sealed downstream of the gas inlet.  Use gas rated pipe tape or pipe dope to seal joints
4. Be careful to use quick connects rated for gas service, the standard air compressor fittings are not safe for this application
5. I'm not sure why you are using a TEE fitting for your blower connection.  Do you expect to have too much pressure and are planning on a waste gate?
6. What are you using for a refractory coating?  If an insulating castable you may be able to get away with using it for your floor, but you will need a lot more thickness than the blanket.
7. I would certainly go for at least 3/4" thickness on your castable refractory.  With the roof configuration you have you will likely have trouble with the top falling down after a bunch of use.  Anything you can do to improve this will certainly help down the road.  You may want to consider wiring the blanket up to the metal box with nichrome wire under the refractory coating (especially if it is an insulating castable like Kastolite 30)

[Irondragon Forge ClayWorks]

Welcome to IFI... Lots of good info here. I always suggest reading this to get the best out of the forum. https://www.iforgeiron.com/topic/53873-read-this-first/

 

[Nick alvorez]

Thanks mikey for that.  

I am gonna be pulling those bricks out and adding another layer of blanket due to the heat loss as of now it does reach a bright orange.  I have put a door on sence this photo was taken i have a simple sliding brick door took 3 tries to get it right without the metal warping and the door is lined with keowool(aside the brick) the TEE was used at first cuz my gas air ratio was off.  I was using a .030 mig tip and the jet hole was way to small so i bored it out to 5/16 and seems to be working fine. Mind you this is my first blower forge.  So the t has been blocked off for now im just using it because im using a hair dryer and the width of the pipe is close to the with of the opening of the hair dryer as the refractory im not sure yet im still playing around with that.  The ceiling falling was a consern wireing it up sounds like a good idea.im gonna post a few photos when i get home tonight.

Thanks irondragon ill read that as soon as i get a chance look forward to the information on here

 

[Latticino]

24 minutes ago, Nick alvorez said:

I was using a .030 mig tip and the jet hole was way to small so i bored it out to 5/16 and seems to be working fine

Nick,

For a blown burner you don't need an orifice of a specific size, necessarily, though for safety I wouldn't exceed a 1/4" dia. outlet by much.  What you should have is a variable pressure regulator, with a gauge.  On a serious budget you can get by with a gas rated needle valve.  In combination with some way to modulate your airflow this allows you the key benefit of a forced air burner:  the ability to adjust gas and airflow independently.  

[Nick alvorez]

I have a 20psi regulator as of now but no guage im gonna try picking one of those us sooner than later and a needle valve as well right now there is a ball valve on it it works but not ideal.  Just got back from the hardware store on lunch.  Grabbed 1ft of all thread and washers to hold up the keowool and a rubber fitting for the blower.  I looked for the valve and the regulator and they didnt have either in stock unfortunately and thanks for the info been a great help that wire u mentioned nichrome.  Wcould that be found at a regular hardware store ive never heard of it

[Frosty]

Welcome aboard Nick, glad to have you. On what part of the planet do you cast a shadow? I'd guess the USA, you're not making the kinds of grammatical mistakes made by translation software. However we have members living in one of the 150 countries represented here who speak better American English than a lot of us. 

Lose the fire brick. Securing the roof is a good idea, that much flatness could easily sag and or fall off. I used SS screws through the top of the shell stopping maybe 34 of the way through the inside ply of Kaowool and it's holding up nicely. That forge has a roof approximately 18" x 6" and flat as a fritter.

If you must mess with making your own kiln wash (ITC-100 being a very expensive and inappropriate one for a forge) use as few ingredients as possible. So far the best home brew I've seen is approx 3% bentonite clay and 97% Zircopax. 

Whatever you end up using, the kiln wash is the last thing in the liner  in direct contact with the flame, steel and whatever fluxes you use if you wish to weld. It's got to be mechanically tough to take being banged and gouged by cold steel while the liner is at high yellow. It needs to withstand the extremely caustic conditions any borax based welding flux lays on it at welding temps.

The last and least significant is as an IR re-radiator It's not insignificant, just not top of the goodness list.

Once the Kaowool has been installed, rigidized, dried and heat cured a layer of a: 3,000 f., water setting, high alumina, castable refractory 1/2" thick all round is usually good for final high temp. armor. With that much room you shouldn't be banging things into it so you shouldn't need a thick hard inner liner. Mine has approx 1/2" of Kastolite 30 all around but one of my more ham handed friends has managed to knock some loose on the ceiling near the door if you believe that.  I guess it's easy to hook odd shapes there if you're always in a hurry.

So this how I line a forge. Cut the Kaowool, use proper PPE, prolonged or heavy exposure is a serious breathing hazard, check out Mesothelioma for example. I wet it down before cutting but I'll probably die from all the . . . stuff I've done to my longs if another tree doesn't get me, before ceramic fiber dusts can get me. No need for you or anybody to take chances they don't need to.

Cut the blanket a little large so its a compression fit, it'll help keep it in place. For a big flat ceiling I cut the roof first so the side walls butt against it and help hold it up. I cut the walls to rest on the shell, once rigidized they're under the least stress.

Butter the blanket, this is spritzing it with water so the rigidizer doesn't dry on contact, ask any mason what happens if you don't butter before applying mortar, same effect. The rigidizer that's becoming the consensus better product is a home brew of "Fumed Silica" as found at fiberglass suppliers, paint and plastics suppliers. They use it to thicken resins and paint, it's REALLY  inexpensive as opposed to buying a purpose made rigidizer from a HVAC supply. Just mix it with clean fresh water as thick as will still spray through a spray bottle like Windex comes in. A couple few drops of food coloring is a good idea it lets you see when it's coated evenly.

Butter the blanket and spritz the rigidizer until well coated. Allow it to dry then heat cure it a Bernzomatic butane torch works fine or you can fire up your burner for a LITTLE while, no need to get it red hot but red's okay if you do.

Cut and apply the next layer of blanket, rigidize, dry and heat cure. If you haven't already cut the burner port(s) at least 1" larger diameter, you'll want to armor them with hard refractory.

Mix whatever hard refractory you get. NO, refractory cement or mortar will NOT WORK! Cements and mortars are designed to be sticky NOT take direct contact with crazy hot flame and the extremely aggressive high temp chemistry in a propane forge. High alumina refractory is very resistant to the caustic chemistry of borax at temp, silicon oxides are not, they tend to dissolve quickly. Hard fire brick lasts as long as it does because of a high % of iron oxide clay in the mix.

If you can find mixing directions for hard refractories they are for maximum temperature and structural strength and it generally far exceeds what we need, we're not lining a furnace fed by the rail car load. Don't get crazy but add enough water to trowel on without too much work or cast reasonably easily. This WILL be wetter than recommended by the manufacturers but. . . see above.

Again, butter the blanket BEFORE applying the hard refractory to prevent contact drying, this is IMPORTANT. Water set refractories do NOT dry, they set up by absorbing moisture molecularly, if they come into contact with a dry surface the moisture is absorbed by the surface and can not set properly. This allows the refractory to separate at the contact surface. Applied to a buttered surface the moisture causes the . . . stuff to liquefy slightly and is absorbed into the surface before setting up making for as strong a bond as possible. Make sense? This is why you see masons brushing the wall with water and dipping bricks in the water bucket before applying mortar and setting the brick. 

Once the refractory is applied you MUST give it set and cure time! It may appear dry the next day but give it a couple more to be sure. Putting an old pair of wet blue jeans in the chamber and wrapping the whole unit in a plastic garbage bag for a couple days is NOT over kill, maybe not a must depending on the refractory but it'll sure make it happier.

Once the refractory is set and cured go ahead, fire it up to almost red heat, shut it off and let it cool. This isn't so important for modern refractories though some of the older ones require heat curing. For modern refractories it's as much to let you find problems before they're bad ones. Look the inside surface over for cracking or worse spalling. If flakes have fallen or blown off it wasn't set or cured long enough. If it's a home brew refractory then it needed a much  more gradual hat cure and probably longer dry/set time.

Once the hard inner liner is set and cured butter it again and apply the kiln wash. I find a kiln wash about the consistency of latex paint works well, it's thin enough to penetrate the refractory but thick enough to stick and not run. If it wants to run anyway kiln wash one side at a time so it's in the down flat position. Buttering first is even more important for kiln washes. Same reason just much more important.

Once the kiln wash is dry you're ready to rock and roll.

Last word. Do NOT get in a hurry! The only thing rushing does reliably is make mistakes permanent more quickly.  Do some reading, forges 101 here and the ceramics boards have a LOT of good info Re. kilns, liners, etc. 

Asking us questions is a good idea, just do some home work first please. We appreciate good questions by folk who read first so they know enough to ask good ones and understand our answers. Then take our advice into consideration, try it out maybe and get back with results and your next series of questions. 

Frosty The Lucky.

[ThomasPowers]

Is that regulator adjustable?  On my blown burner I don't use a gauge or needle valve. I tune by eye and ear: eye---when the flame impingement is brightest then the burn is balanced, ear: when it's loudest then the burn is balanced. So if I need more heat I turn up the gas using the regulator and then adjust my air to get a balanced burn. (For bladesmithing I often de-balance it on the rich side to have less scale and decarb---but greater CO production.)

[Nick alvorez]

Thanks for the information frosty you just ansered all the questions i was gonna ask all in one post.  Im fairly new to all this amd dont know to mutch about the casts and washes.  Tho i have been on here reading alot religiously.  Everynight befor bed lol.  Thanks a bunch.  I will be posting to this after i maje the new adjustments im gonna be taking it apart when i get out of work.oh and i am from the us massachusettes

Thomas.

   It is an ajustable one.  Ive been doing the same thing playing by eye and ear

[JHCC]

5 hours ago, Nick alvorez said:

i am from the us massachusettes

Please add that information to your profile settings; none of us will remember that five minutes from now.

If you haven't yet, please READ THIS FIRST!!!

[Nick alvorez]

So its been a while from when i said id ost pics.  Been busy havent had to mutch time to tinker but ended up making the refractory from scratch.  I used 60 alumina 40 zirconium and 10 bentonite.  Let cure for 3 days then finished curing by firing the burner( the original one i had put on in the previous photo) then i did the ceramic coating the zirconium and bentonite let cure for 3 days then fired and it poped in the botton of the forge i dont think i let it cure long enought.  Still not finished taking longer than id hope but i only get an hour or two a day to tinker.  But one question maybe one of you gents could answer or have a knowledgeable opinion.  So bentonite is sugested to make a good ceramic coating with zirconium now what about veegum t or hectorite all of wich are smectites.  I dont know if one or the other would make to mutch of a difference because of the low % but there all plasticizers and very similar in charactaristics.  Anyhoo heres wonderwall...... jk let the show commence!!! 

[Mikey98118]

8 minutes ago, Nick alvorez said:

 So bentonite is sugested to make a good ceramic coating with zirconium now what about veegum t or hectorite all of wich are smectites.  I dont know if one or the other would make to mutch of a difference because of the low % but there all plasticizers and very similar in charactaristics.

The formula that uses those smectites call for zirconium silicate. We wouldn't want readers to confuse that with zirconium oxide, which won't work as a substitute. That formula also calls for Veegum T. Various guys here have substituted bentonite because it is cheaper and more easily available.

BUT, we are always happy to hear from people who are experimenting with other versions of the original recipe. It sounds like you are doing well with it.