HT1's Insane overpowered new furnace build

I have finally built what I thought was going to be my dream furnace, it's more like the monster under the bed, but I did accomplish both of my goals ( wish I had not) I wanted to melt brass from cold in the mythical 35 minutes Mifco claims for their B301 https://mifco.com/foundry-furnaces/high-speed-melters/
I really wanted to see if that was possible, I thought Mifco was FOS, they were not

Here is the video of me making Brass in 32 minute


Just bear in mind, there is no doubt that the Blower is Insanely overpowered, Mifco uses a 150 CFM somehow I ended up with a 166CFM blower designed for CARWASHES
https://www.kleen-ritecorp.com/p-61...120v-vacuum-motor-1-speed-8-4in-diameter.aspx

not only did I use gate valves to throttle the air on the discharge side I have to use a router rheostat to slow the motor, or I still blow the flame out the lid exhaust, the first time I fired up the furnace to tune it it in, I have molten droplets flying OUT of the furnace, brass, not aluminum, Brass!!! flying out the lid

DO NOT build a furnace with this much blower , I may even drop down to something closer to say 135CFM, but at $175 it's a big pill to swallow


i got tons of help and advice from this thread, go read it start to end
http://forums.thehomefoundry.org/index.php?threads/larger-moya.780/

I cant thank Andy Oldironfarmer enough he was defiantly instrumental in this build especially for the insulated fire brick idea.. we will hit that more later http://forums.thehomefoundry.org/index.php?members/oldironfarmer.299/


I started with an open top 55 gallon drum with a center bung hole , remember I wanted a Mifco B301 their measurements are within fractions of a 55 gallon drum, so we are good to go their
https://mifco.com/shop/furnace-repair-parts/b301-empty-steel-shell-with-nozzles-and-guide-tube/

at one point I even considered buying the relining kit for the B301 , I price checked a replacement liner KIT basically everything you need to build a furnace save the shell , so all the firebrick, insulation, and patch material $2119.00 + shipping , that idea went right out the window!!!



i needed the interior height to be 18 inches, the top of the drum the lid was going to be the bottom of the furnace, the center bung becomes the drain hole I cut the drum at 19.25 inch to get the 18 inch interior height, the lid is inset into the drum , why 18 inches? just so happens, that is 2 standard 9 inch brick heights , look close you can see i have welded the lid onto the drum permanently, because I wanted to use the ring to reinforce the top of the furnace to keep it going out of round, if you don't have a MiG welder, get a second ring, this was a PITA


this is the bottom of the furnace, I'm starting to mount the wheels, I ran a 1/2 inch rod through the drum, reinforced it with some angle iron, and later cut out the interior section, it was in the way for installing the brick, you can also see the drain, a 2 inch diameter wood dowel was screwed to an aluminum plate that was screwed to the bottom of the furnace, all to be later removed, the dowel of course burnt out on the first firing

to create the tuyere I had to cast blocks of kast o'lite 30 li insulated refractory in these forms, which replace 2 bricks , the pipe 2 inch muffler pipe created the hole through the furnace wall, the pipes where removed


here you see it cast, the form is screwed together , just unscrew, disassemble, and remove the pipe... dont use pipe if you can avoid it, it was pure hell to get out, find a cardboard tube the right size and use it or even a wood dowel, the od is about 2.375 so all I had the right size was the muffle pipe , the cardboard or wood I could have left in place and burnt out , I probably could have left the pipe f i trimmed the interior flush to the block, but I really wanted to avoid that



Here is the completed wheel assembly



reinforced the bottom with 1/2 inch rebar, probably not necessary, but i felt I needed to.


here I'm welding the closing ring to the top edge of the furnace to reinforce it , made a minor mistake should have centered the ring opening to the rear whoops!


to be continued

V/r HT1

 

I like the prefabricated tuyere. Even in a monolithic build it would save some steps. I can't remember if I used PVC or steel but I cut a slit in the tuyere form tube so I was able to squeeze the tube making extraction easier.
Pete

 

well I missed alot of pictures, but here is the best I can do,



her is the rear of the furnace with the pipe for the lid mounted, I used some angle iron to get the pipe straight, and to spread out the load of the lid


here is the cam I created for lifting the lid, in 20/20 hindsight I would not have done a side swing , Lionels lever over design is better particularly since all my burners are to the side the rear is a better place to have the lid, especially hanging higher



here is the shell and lid with my old furnace


here I'm drilling the burner holes, to do this, drill the 1/4 inch starter hole, then install a long piece of 1/4 roundstock in the holesaw, so you can drill the angled hole , the drill bit in the hole saw will be too short, you can use a long drill bit, but it is much more expensive then the roundstock



Here is the 2 inch muffler pipe that the burner will go into, this pipe, goes just through the kaowool, and just a smidge into the Kastolite Tuyere


here is the interior of the furnace, with the tuyere's and bottom row of brick installed, you can see the wooden drain, we are ready to cast the 2 inch floor, I descided to cast the floor inside the brick, it could have been cast, before, and all the bricks trimmed to height, but since the 18 inch thing was so perfect, why not


Here I have cast the floor, and used Kaowool and the extra Kastolite to seal the larger gaps , this gets finished up later


Here you can see the burner inlets, and the bracket I built to support the burners, and the first failed lid attempt and the rope gasket, rated at 2300F this gasket turned to glass the first firing , I whooped the furnace, and blew out half the fire brick, so I abandoned the firebrick furnace lid , and went to Kaowool, I wanted to do kaowool board, but for some reason it's crazy expensive compared to kaowool



here is the air side plumbing the inlet is a 2 inch tee, I cannot find where I bought it, I spent hours looking for it, I think this is it https://www.verociousmotorsports.co...s/Buttweld-Short-Tees-Stainless-Steel?whence=

the flex muffler pipe was the best deal ever, I had intended to bend muffler pipe, when I saw the flex pipe much cheaper on the shelf https://shop.advanceautoparts.com/p...dDZticH3Yo-0nJRYEB8aArTjEALw_wcB&gclsrc=aw.ds

each burner has a plastic gate valve to help control the air flow , those where McMaster carr huge savings over the brass equivalent


to be continued

V/r HT1

 

not going to go into detail on the burners they are 1.5 inch Moya's I make them out of Black iron pipe from McMaster Carr the oil tube and plug I get the schedule 80 for longevity, since i'm a welder, I buy weld on saddles for the propane inlet rather then drill and tap the pipe, it's very heavy duty, and expensive $281.00 for the parts for the two burners, plug the gate valves for the air, and the clamps I used to lock them in place.


I decided the best way to deal with the blower was a box, i originally was going to make a metal (aluminum), so glad I did not . the box is 12x12 inch, because that is haow big the shipping box was, worked out perfect

, the blower is mounted to a piece of plywood that slides in and out, so if I have to replace the blower, it slides right out


I wired the blower to a Jbox, with a switch and a receptacle (never have enough receptacles ) and it's own designated cord, so I dont have another extension cord to trip on

I cut 4 inch holes on each side for the motor cooling (pictured) and the inlet air , I will cover them with a mesh to kep leaves out

the outlet is a slightly oversized hole that the blower nozzle sits in, the flex pipe from the furnace slips right into the hole and over the blower nozzle with no clamp required

here is the burners final configuration, I had to remove the needle valves I installed for fine adjustment to each burner, they restricted the flow burners work fine together without them, which just means I got the orifices' in the burners both the same size , the air inlet valves are only open 1/2 inch the quick clamp holds then in that maximum closed position , if they ever give me problems I will remove them and just install an orifices', I think about 3/4 of an inch would give me about the same flow , Note the small 1/8 plug in the end of the burner for the oil tube if I ever desire to burn oil , the burners are all set to go



Here is the furnace all set up to operate, that is the firebrick lid that failed, I have since replaced it with 2 layers of 1 inch kaowool rigidized


to be continued

V/r HT1

 

How big is the propane tank to feed that beast?. I expect the second crucible will take 2/3rds the time as the first, once it's all hot, but the gas cylinder will getting pretty cold.

 

I currently run 40's in a water bath, I will probably move up to 60s

 

As an Aussie, I had to look that up: pounds right?. All we're allowed to handle here without a gas company filling a permanent fixed installation is 9 Kg or 20 lbs which would be a real pain. I hear there's some physics based gas flow law that means 3 x 20 lbs ganged up to a common manifold won't all empty at once, with one cylinder flowing the most until it empties.

 

Nice report HT1.

If you were using propane, what was the smoke when you turned it off from?

Cheers Charlie

 

zinc plume from the metal i overheated it a bit,
it will take some time to get this tuned in, and learn to operate it well

V/r HT1

 

20s have an OPD which causes all kinds of problems , I have tried manifolding a pair of them. Just does not work, if the flow is too quick, which this furnace would be the OPD closes, thinking there is a leak , the tanks will not seamlessly flow , someone maybe able to find my post in AA which shows the dismal failure when I tried to manifold a pair of 20's

if you cannot get larger cylinder how does food trucks and propane forklifts get fuel??? forklift tanks are 8 gallons

US rules are stupid complicated
we have DOT tanks which is what we are used to the cylinders you pictured, BBQ cylinders and their larger cousins, which have to be recertified every 10 years

there is also ASME tanks, which are fixed larger tanks, and vehicle fuel tanks permanently attached ( I know this does not really apply to you the A in ASME stands for American but you must have options)
https://www.rvautoparts.com/6829-Manchester-Tank-Propane-Tank-ASME-Permanent-Mount-Tank_p_34216.html

ASME tanks don't require a certification, they are slightly thicker walled when I build food trucks, yes one of the many things I do is build food trucks, these are the tanks we "Hot Mess Custom Food Trucks" use , because all the stupid rules that USA propane fillers want to apply go out the window, they cant make you take the tank off the truck, it's designed to be permanently mounted, it does not have to be painted a "light color" it can be permanently plumbed since it has a separate fill and use connections, there is no inspections required, so no hydro test , nothing , also the gauges on theses tanks are actually accurate , Upright propane tanks with a gauge really only tell you when you are about to run out, the float spends most of its time pegged to the top , I dont know exactly what is going on in Australia, but I'm sure there are other options, How do guys using Propane for industrial applications like garages get theirs? I know the rules over there are Draconian for Acetylene . but I assume there are some options


V/r HT1

 

There are larger propane tanks available but they have to be chained to the wall of a building and attract attention of gas inspectors. There will be periodic inspections and all sorts of failsafes to be fitted and I hear insurance companies put you in the highest risk category if they know you are running a foundry furnace. Also the East coast of Australia has crazy prices, more than double the West coast where the state government requires local gas reserves to be set aside for domestic consumption. There was a spring manufacturer who found he could buy gas off an Australian gas carrier ship arriving in Japan cheaper than he could locally. The ship had to sail to Japan, sell it there and then ship it back to Australia on the same ship it arrived on.

Apparently cylinders full of gas connected together will not draw gas equally from each cylinder even without the OPD fitted so you can't hook up multiple cylinders to get higher flows. I heard a story of back in the 1960's the local gas company connected three regulators in parallel to try and get high enough flow to run a furnace off town gas and it would only flow the same as one regulator. These were some style of regulator that relied on liquid mercury to weight a diaphragm.

Anyway that's enough derailing of the actual topic but using propane gas in Australia is complicated.

 

Looking good!

You can't close your air valves tight enough to avoid using a VFD?

 

I can try some more tinkering, but both valves need to be closed about the same amount, so I bought a pair of these
https://www.mcmaster.com/5070A11/ if this link is FUBAR try https://www.amazon.com/IRWIN-QUICK-GRIP-Handi-Clamp-2-Inch-59100CD/dp/B0000DD5XV


they hold the valve open exactly 1/2 an inch. I suspect the issue is that the blower creates enough pressure to overcome the valve being almost closed.

Again, this blower is insane

V/r HT1

 

Note to those attempting to open the link in HT1's last post from outside of the U.S., you might find it necessary use a vpn with the region set to the United States.

 

That only applies to natural-gas in WA. LPG for domestic use in the country is mega expensive; $150 for the big bottles.

 

OK the lid
sorry this picture is out of focus , but it is pretty simple, some of you may remember me getting a noticeable improvement , when I replaced the lid of my old furnace , by adding a Hemispherical lid
http://forums.thehomefoundry.org/index.php?threads/making-it-a-hemi.320/
SO of course I wanted to include that on my new furnace, once the IFB lid proved to be beyond my skill I went to rigidized one inch Kaowool, I started by cutting out 3 plywood circles of descending size and wrapping them with saran wrap to create the hemi... pretty simple huh?

again a little out of focus, I used a qurt can to make the vent hole, just push down hard and twist it will cut almost entirely through

see almost all the way through , do both pieces of kaowool at one time, I did them separate, and got the holes a little mismatch which made the process difficult

sit one layer of the kaowool over the hemisphere form, and hit it with your rigidizer of choice, for me Satanite ,


then put the lid over the


use some scrap kaowool to fill in around the edges, before putting the top piece of kaowool on, coat all this with rgidizer, and hit it with a torch, I used a weed burnerI let it sit for several days, here in florida, the humidity makes that just silly, you will have to put some heat to it , sorry there is no more pics, but i places the top piece of Kaowol on, and hit it with the torch, then moved it all to a preheated furnace, this was an issue, because the furnace is so damn hot, it's hard to get a few hundred degrees, and let it toast, so I actually built a wood fire in the furnace, to start drying out the satanite , and the next day put the heat to the furnace, I had to use alot of satanite on the top edge of the furnace to get anysort of seal at all, and it still leaks, just no way to get a perfect seal, I tried 2 different rope gasket materials, including one for a 1200PSI Marine boiler, both turn3d to glass, and still leaked



V/r HT1

 

Ok I did a full heat yesterday with the furnace, with the new A20 Super Salamander and all the new tools tongs and shank




The interior of the furnace took a beating , I suspect the worst of this was before I cut back the air , as soon as I started melting metal, the furnace began slinging it out the top , until I cut back the blower to about 1/2 it's insane, I'm seriously considering installing orifices' emplace of the gate valves , I also may plug up one burner, and run a couple of tests

on another note the A20 is all the Crucible I ever intend to use, I'm so Glad I did not Buy a 25, fellas, im 6'2" 250Lbs, and the A20 was Hurting me !!!, and that shank has to get a heat shield

I made 2 Pours in exactly 1 Hour , it would have been faster, but I froze up both my 40Lb Propane tanks , so I'm going to have to see if I can find some 60's for sale


V/r HT1

 

An A20 full of brass is right at the limit for one fit man. I'm the same height and weight, I've only ever had my crucible 2/3rd full and I have to use sheet metal radiant shield so I can grip the shank close to the crucible.

Edit: I see that guy walking past at the 0:34 second mark slows down suddenly to watch your pour.

 

he actually came back by several time's, but did not have the cahones to just stop and watch

 

Whew. Thanks so much! This is one helluva build thread for a helluva blaster. I am always most interested in the solutions for the various problems.

The overpowered blower, could you put a diverter to shove some of the output somewhere else? Like having a T at the outlet with a variable gate?

I see you already have another thread for the lid seal, so I'll wait to see that one in there.

Lawdy what a beast!