Building a keg furnace. Need advice.

[br5409]

Hello all,

Let me start by saying I am a total newb to all of this, but I have been doing a lot of reading on this forum the last couple of months.

I am building a foundry/furnace out of an old beer keg. My main interest are to melt/cast aluminum and copper to begin with. Brass interest me but from what I have read on here, it is pretty nasty stuff to mess with so maybe later on that.

I have the top cut off the keg and purchased 2" kawool, rigidizer, ITC-100, tongs, clay graphite crucible, and made my burner(waste oil burner). I have purchased welding gloves, face shield, respirator, much of the safety equipment. That is about as far as I hove gotten. My question is do I need to install a hard refractory liner after the kaowool or can I use Satanite or something similar and then coat with the ITC-100? I know Frosty recommends kast-o-lite 30 but there is no place close to me that has it and every place that I have checked wants close to $150 in shipping fees to send me a 55lb $100 bag. The area inside the keg is almost 8 sq ft, so I would need many bags of it too. What are the pros/cons by not installing the hard liner and just using Satanite? Every place close to me just gives me the "deer in the headlight stare" when I ask about any of this stuff.

Also, can anyone give me the coverage area of Satanite? I have emailed back and forth all day to Harbison Walker and they can not even tell me. You would think that the manufacturer would know huh? They say it is a mortar and is for brick laying. They keep recommending me get Mizzou Castable Plus. Again, no where available close to me.

Thanks in advance for any help or suggestions.

[Steve Sells]

Not sure where to get these things in Hawaii, you ARE in Haw right? you didnt say so I took a guess

[Frosty]

Hello back, if you put your general location in the header someone on the forum who knows how to build a melter might live within visiting distance. 

Have you tried reading a casting forum? Iforge is a Blacksmith Forum they're not the same even though there are casters onboard here. 

You have a couple fundamental problems going. First you bought all kinds of stuff BEFORE finding out what you need. Aluminum and Copper are WAY different melts I used to cast aluminum in green sand molds using a campfire as the melter and a steel pot as the crucible. Copper is a different world entirely. 

Another serious problem you have. You asked Harbison Walker what the coverage is for Satanite and they told you it is MORTAR for sticking bricks together. It is NOT a good flame face liner even though lots of people get away with it for a while. You wonder why the people who make Satanite don't have the answer YOU THINK you need. Have you considered the EXPERTS just told you it won't work, that maybe just MAYBE they know what they're talking about?

If you can't cover 8 sq/ft 1/2" thick with Kastolite I can't help you, even then oil flame contact is going to erode it.  A couple few hundred dollars worth of Plistex 900 might do the trick though.

Lastly you want to use a waste oil burner. <sigh> ANY idea what an oil burner does to refractory if the fuel isn't completely consumed BEFORE flame contact? You see lots of claims of how great they are online, it's a common urban myth. They're WAY more hassle than they're worth. Propane is cheaper when you consider how many liners an oil flame is going to go through. IF you can get the burner to work in the first place.

You are WAY out of your depth, so far so, the best I can do for you, your health and physical well being is discourage you from even trying casting outside of a classroom or professional casting studio that gives lessons. Colleges have metal arts courses that involve casting where you will learn to make molds, melt metal and pour SAFELY. ONE pound of molten (low melt) aluminum spilled on a concrete floor WILL splash molten 1,100f aluminum more than 30' if every direction. It WILL light You and the building around or near you on fire, disfigure and cripple you in one of the most horrendously painful ways imaginable. How much is 1lb. of molten aluminum? Think 4oz coffee cupful give or take a LITTLE.

Copper is a high melt and makes molten aluminum look like gargle.

I'm REALLY trying not to be sarcastic or snide. I REALLY don't want you injuring yourself and would rather you hated me for the rest of your life so long as you live a long healthy one. Honest. Do NOT try this without going to school to learn how to do it right. You aren't even close.

Frosty The Lucky.

 

[George N. M.]

Welcoe aboard from 7500' in SE Wyoming. Glad to have you.

I second what Frosty has said but possibly not quite as emphatically.  Casting can get dangerous very fast in a way that blacksmithing does not.  Yes, you can get burnt or injured blacksmithing but a mistake or accident with molten metal can get very, very bad very quickly.

I don't know what experience or training you have had in handling molten metal but if you are a rookie I REALLY recommend that you get some training before you start trying to do it at home.  Also, depending on the melting point of the metal some metals are more dangerous than others.  The hotter the liquid the more hazarous it is.  Some matals get reactive in their liquid state.  Do you know about fluxes to protect the metal from oxidation?

So, approach this VERY cautiously.

Sorry, but I can't help you with your technical questions regarding refactories, etc..

"By hammer and hand all arts do stand." 

[TLeeBlanq]

I wondered how the steam locomotives were able to generate such power and (slow to learn here) through reading finally sorted it out that the conversion of water into steam has a 1700% expansion rate!! That's what makes casting problematic as if you get a tad of water (even a drop of sweat) under the molten surface, your day is going to go downhill quick. Am (too) familiar with the hot chunk of slag in the shoe (bunny hop time), a time or two managing to get a chunk in the ear, and even on my head. The last 2 was from out of position mig welding.. The former was chunk burned through top of leather shoe. Again ,learn slow, but now have made up couple leather  "tongues" that hang over top of shoe. Concerning molten metal, one time (just for grins) took a MIG to "full axial flow." That was some hot stuff. There is no sound from the machine as the consumable (fed rod) liquifies in the air (there is no short circuiting process-no popping sound.) Was over 300Amps (if memory serves) and (I could) do only on  a horizontal flat quite thick plate. Welding puddle was about 3/4 inch wide.

I have rounded up several out of date smaller propane tanks and R.O. tank and will use to make a propane refractory of sorts. Have messed with propane converted the Huskavarna Kawasaki 21 HP ZTR to "propane." Before converting, did do a survey of sorts, checking exhaust temps from each cylinder. Was surprised to find a restriction in flow from one bank and therefore, kept drilling holes in the (2>1)muffler until both sides were pretty close. Then made the switch and piped in via "demand" type regulator. As propane clean burning, engine oil never darkens albeit it synthetic and cools quite rapidly. Controls/mixture learning curve tad different depending  upon ambient temps.

Sorry, tend to wander, a product of old age, I guess. Re altitude,7500' tad high for my abused body, but can handle up to about 6200 without assist. I did review the Wyoming weather service and downloaded annual wind rose graphs. Yeah Bud, you do got some wind up that way. That not necessarily a bad thing though as one might consider building a wind generator (just for the &&&.) 

Take Care Guy

[TLeeBlanq]

MY BAD!!

George: Thought I was responding to your last, which was actually directed to Kentucky. Sorry. 

However, the dangers of casting would still be relevant.

br5409: Sorry, I did not mean to jump in your business but now that I'm here, think you best listen to some folk that have been around the block couple times. Good Day to You All.

[George N. M.]

TLee, no problem.  If that's the worst mistake either of us has seen today we are lucky men.

Yes, the wind can blow here.  They say the snow doesn't melt in the Laramie Basin, it just blows back and forth and wears out.

;-)

GNM

[br5409]

To all that have responded: Thank you for your input. I know that I have much to learn, that is why I am here. I do not think there is near as much danger in building the foundry (which is what I am asking about), now using it is a whole different story.

I have not been able to source the kast-o-lite anywhere close to me within 200 miles. I may be looking in the wrong spots. What sort of places should I be looking?

[Irondragon Forge ClayWorks]

Look no further than here. The IFI store, PM Glenn to order.

https://www.iforgeiron.com/forum/202-store/

[br5409]

6 hours ago, Irondragon ForgeClay Works said:

Look no further than here. The IFI store, PM Glenn to order.

https://www.iforgeiron.com/forum/202-store/

That would be OK if I were only needing a little. I only need 385 lb.

[br5409]

1 hour ago, br5409 said:

That would be OK if I were only needing a little. I only need 385 lb.

Sorry, math was off....286lb.

[Frosty]

Sorry I was pretty harsh earlier but I get jumpy when people want to take up really dangerous crafts without really knowing what they're getting into. 

How thick are you going to make the hard refractory liner in your melter?

I had to stop believing the required weights to cover data online and I can't find the HWI data either. I found it once after a long search and like an idiot didn't save it. Saved the link but it died immediately. <sigh>

Anyway, the statement that it requires 92lb per cubic foot is the mixed weight and the mixing directions on the sack are for a "gunnite" mix. The Kastolite is fired through a gun and mixed with a mist of water as it leaves the nozzle. It's used this way to repair furnace liners and is crazy too dry for our purposes. Gunnited coatings are also about max density for the product so it takes more per sq/in than we need or heck can get it packed on.

I don't think I've used more than one 2.lb coffee can of dry Kastolite to line a forge yet. One had a deck 1/2" x 20" x 30" and the forge itself was 6" x 10" x 18". for roughly 925 sq/in 1/2" thick. I didn't weigh what I used but don't think it was 5lbs. but maybe. My last two forges are smaller but I still must have 70lbs of Kastolite sealed in 2 plastic buckets. 

The recommended 12.5 oz of water per 100lb sack should be ignored as impossible in our world. We have to mix it wet enough to be able to form it. I did it by eye and feel so I don't know how much water I added. At a guess about 1 cup water per one 2lb. coffee can of dry refractory a little at a time as I went. Mixing even that wet it's hard work, you can NOT stir it well at all. Once you've stirred you some need to kneed it HARD. I have an old stainless steel spoon I use to turn it then crush and smash it before turning it again and it takes some time! Another friend stirs with a spoon and uses a piece of pipe with an iron cap like a mortar and pestle to crush the lumps out. The real killer is the working time it starts to set in about 30 minutes and it can take 15-20 to get it  mixed. You can keep it workable for a wile longer, sort of by continuously mixing

I can't see you needing more than 1/2" thickness and 35-40lbs. the way I mixed and applied it. Were I lining a keg melter I'd roll the Kastolite mix into a sheet like pie crust. and wrap it around a form the ID of the melter. scrap linoleum works well for forms with the linoleum facing the Kastolite and you really need to grease anything it comes in contact with. Kastolite sticks to dang near anything. The grease will let you strip the form out without too  much heart ache. 

To roll it I'd lay a sheet of plywood on the concrete floor in my shop and cover it with Saran wrap. I'd use 1/2" square steel bar as the depth guide. Wrapped in Saran wrap and held inn position with nails around them. Space the depth bars the same as the depth of your melter's chamber, full length of the plywood. Mix half a sack of Kastolite with a shovel and maybe hammer. Spread it on the plywood and spread it then using a plate compacter drive it into a uniform 1/2" thick sheet. Once it's against the guide bars wrap it around your form. 

Wrapping might be hard to keep from tearing it so lay an old sheet on the plywood under the Saran Wrap so you can use it to support the refractory as you lift and wrap it. Hopefully the ends will overlap, cut it in a close zig zag and use a mallet to hammer the joint together. If there is enough left on the plywood cut some for the melter floor.

This is a standard method for relining wood stoves with similar castable hard refractory. 

Frosty The Lucky.

[br5409]

Everything is good man. It is good to be on the lookout for the inexperienced.

I need to get the exact dimensions again, but it will be Tuesday before I am back in the shop.  The cylinder is 22.25" tall by 15.5" diameter. Of course the bottom and top are beveled. Been too many years since I had Calculus to figure the top and bottom exact. The best I can remember I measured the sides where it is straight to be 14.5" tall not counting the top and bottom. I have 2" ceramic blanket to go in all of it. My calculations are 1/2" thick on the kast-o-lite.

I calculated everything from the 92lb per cubic foot stated in the data sheet, so from your statements I have no idea how much I need, lol.

[Latticino]

So lets assume a simple can shape with closed top and bottom.  This will be the approximation for the amount of castable needed. If you have a 2" thickness of insulation all the way around the outside of the can will be approximately 18" tall and with a 11.5" diameter.  If you go with the 3/4" thickness I would recommend (so you can do a much simpler casting with inner and outer cylindrical forms) the inside of the can is 16.5" tall and 10" in diameter.  The volume of castable needed is just the outer cylinder volume less the inner cylinder's volume, with the two end caps added.  Outer cylinder is 1869.5 cubic inches and the inner one is 1296 cubic inches.  End caps are a nominal 11.5" diameter and 3/4" thick (78 cubic inches each).  1869.5-1296+ (2x 78)= 729.5 cubic inches.  729.5 cubic inches is only 0.42 cubic feet.  at 92 lbs/CF you only need 39 lbs of castable.

I believe you can purchase this castable in 50 lb bags, so that is what I would do.  I got mine from an industrial insulation supplier nearby.  Maybe you will be as lucky, or you could always take a road trip to one of their sites: https://forum.brickwoodovens.com/t/harbisonwalker-locations-global-sourcing-centers/1122

 

[Frosty]

Nice of you to do the arithmetic Latticino, I don't anymore unless it's weird odd shapes or something. 

Good deal, I come on too strong sometimes and regret it when I scare someone off. Lots of times warnings and cautionary posts are louder than maybe necessary but the person being addressed isn't the only person we're writing for. There are around 60,000 subscribed members to Iforge and who knows how many more non-members just reading, around the world. The last I heard around 150 different countries. Soooo, when someone asks questions about dangerous some REALLY dangerous activities we tend to go into safety ranger mode.

Back on topic. 

You'll need to rod the refractory between the forms, it isn't going to flow, the aggregate is crushed and "keys" together (locks like jacks in a bag) so it doesn't flow unless you get it WAY too wet. Way too wet is a bad thing. Use a 1/2" steel rod long enough to reach the bottom with enough extra to hold comfortably. Add the refractory a little at a time, say fist size globs and "ram" it into the mold. Keep moving around the form. If it starts stiffening up so you can't get it to compress with the rod stop it's setting. Don't worry, the next batch will rod in and stick seamlessly, well almost any visible joints will have zero effect on strength or heat resistance. Kastolite is formulated to take and make patches and be as strong as the original liner. This is a good thing if your melter liner is damaged, you can mix up some and patch it with a trowel. EZ PZ.

It's ability to bond to itself wet to dry means you can make your floor before you cast the cylinder. Just place the form on the set and cured floor and rod the Kastolite as described above it will bond solidly, no worries. 

Remember to make provisions in the melter's floor for spilled melts. Sometimes a crucible or the plinth will break or you might knock it over and dump the melt. If you slope the floor to one side and build in a drain any spill will flow out in a controlled manner and not stick in the melter. Nothing takes the fun off a hobby like having to try to get solidified metal out of the melter. It'll find every nook and cranny, it doesn't "lift" out, thing grinders and pry bars, or a new liner.

At least you aren't planning on a cupola melter, you get to chip those out after every use.

Frosty The Lucky.

[br5409]

wow Latticino, I must have been WAY off on my calculations. I was always told volume would be area*thickness. Another way to figure it...

sides before ceramic:

circumference of a circle-2*pi*r is 2*7.75*pi = 48.7"

area of sides: l x w=48.7 x 14.5 = 706.15" squared

sides after ceramic

2*5.75*pi = 36.13" squared

volume to cover sides after ceramic 36.13 x 14.5 x .5 = 261.94" cubed divided my 1728 = .15 cubic ft

Top and bottom

area of circle=pi*r*r = 176.71" squared

volume to cover top or bottom=176.71 divided by 1728 x .5 = .051 cubic ft

Total =

.051 + .051 + .15 = .252 cubic ft which is close to your calculation of .42 cubic feet(but you were using .75 thickness and flat top and bottom).

92 * .252 = 23.18 lbs (a bag will be way more than enough) If I messed up a calculation or how I figured it, please let me know.

Anyways, I was WAY off! I already threw my scratch paper away so I do not know how I came to the figure of needing 286lb. I must have been trying to fill the whole cylinder. Now see why it is good to ask the experts before you do something. I am glad I did because I was trying to justify pouring another $1000+ in to this. If it is like most other hobbies, I will drop that into it soon enough.

[Latticino]

Actually the way I calculated it I included extra for the top and bottom disks, which I had already included in the two cylinders.  So volume needed is just 1869.5-1296= 573 cubic inches (0.332 cubic ft), or 30 lbs.  Use the extra for casting doors (you will thank me).  Weld up simple frames and cast them at the same time.  Frosty is correct about the need to tamp down the castable in between the forms.  I usually cast lids separately so I can open things back up to reline.  Bring your door opening proud of the steel liner and you won't have problems with the dragon's breath overheating that.  Also cast your burner port in place.

Good luck.

[br5409]

I have decided on getting at least 30 lbs. I think this one is sort of large anyway, so I am thinking about making a smaller one too. I may just get a whole 55lb bag. I read that it has a shelf life of 12 months, maybe I can build another by then. Thanks for the information to you and Frosty.

[Frosty]

Ahhhh, Latticino shows the difference between someone who's built melters and someone who builds forges and only knows enough about melters to be dangerous. Making the barrel and floor separate to make relining easy makes good sense.

Shelf life is for an open sack. I closed mine up in a plastic bucket with a piece of baked sheet rock and it was still plenty good last time I opened one. If you bake a iece of sheet rock at 230f for an hour or so to drive out the hygroscopic moisture it becomes strongly hydrophilic, meaning it will attract any moisture to it and absorb it. The same thing as the little gel packs in a bottle of pills, etc.

Two plastic buckets lids about $8 ea.  at the local Wallyworld will hold a sack of Kastolite with room to spare. So, one 400mile day trip for a 100lb. sack means one liner and two rebuilds and patches. Know anybody who makes the drive regularly? If you don't trust them enough to give them the cash, buy it with a CC to hold for will call. There's a decent chance Iforge has members that might do it with a shout out. Hmmm?

Frosty The Lucky.

[JHCC]

On 10/9/2022 at 12:53 PM, Latticino said:

Bring your door opening proud of the steel liner and you won't have problems with the dragon's breath overheating that. 

Good advice. I failed to do that on my latest gas forge, and the steel has burned back almost an inch in some places.

[Latticino]

Also, try to avoid hitting that protective castable with large Damascus billets and breaking off a section like I did last weekend...  I need to take my own advice and stick to casting refractories at 3/4" minimum thickness (or just get more careful, but that was the largest billet I've attempted in my home forge: 6" x  2" x 1.5"  - only around 5.5 lbs; but it felt like a lot more, particularly when drawn out to 27" length).