Lil Scrapper

[Harry]

Building a small scrapping furnace. It took me pretty much all day to get it set up and the insulating layer in. I placed the hotface on the floor so I could embed the pipe for the drain trough into it before putting in my inside forms. ID of the bore is 14" after the hotface goes on with a depth of 17" which would take me up to at least a #60 crucible if I ever decide to go that big, I doubt it though as I want a tilting furnace for big pours so this furnace will be mainly for scrapping.



Side out drain, solid refractory all the way across the floor. There is half a bubble of fall (1/2" per foot) on the trough and I will be doing some grinding on the refractory spout to make it drop dramatically once it leave the furnace.

[Harry]

The hotface was firmed up well but still pretty wet so I pulled the light and put in a torch to help push the water out. Thats a new tank and turned down pretty low so it should last awhile.



Here is a look at my hand trowel finish job



and the spout



and here is the lid, as I said I made it over a year ago, it is as heavy as it looks too. Not sure if I want to put a hinge on it or handles because I will probably want it out of the way for scrapping and swung open it might be in the way of working the ingot trays.



I am thinking of forming up a dished piece of refractory with a drain hole in it about 3" less diameter than the bore, this would sit on a plinth that has a trough on one side of it to funnel the metal to the trough in the floor. The thought here is keep everything up above the tuyere so there is a clear path for that initial flame loop.

I have had problems in the past with either parts being melted or steel parts that come out of them piling up in front of the tuyere. Keeping that area clear would be nice.

[Harry]

12 pack burn in, we were both lit up pretty good



Couple of heads



Another wheel



filling ingot trays



100 lbs of ingots



The steel and dross that was left over



I put down four more of those grates for a pouring floor. They are welded together and welded to rebar driven into the corners.

[Harry]

I came across this screw motor that looks to be from a power lift chair or a hospital bed. I had been looking for a satellite actuator arm but this was even better because I did not have to set up 12v, just plug it in and go. I welded a short nipple to the end of my manual lever that had a hole drilled through it to match the hole in the sliding part of the screw and I dropped a 1/4" bolt in it. I can lift this bolt out and still use the manual lever if I have trouble with the motorized portion.

Here is the motor, I just slid it under the steps and backed it up with a chunk of 4x6 that was laying in arms reach.



This shot is the lever system I was using. It worked but I could not tend the ingot try and operate it at the same time also it was up or down, with the screw I can leave it at any angle.



The bugs were crazy, really crazy... at times it was so bad the smell was getting pretty powerful, the only other smell was the varnish burning off the wheels.



About half way through, a wheel working its way in and the ingot pile growing. I lay the wheel flat on the top and let the center melt out then flip it up on edge.



This is the end result of melting down 8 wheels, about 150 lbs of 2lb ingots. I made this new tray using some 3" pipe with flat bar welded on the ends. The pipe after being cut in half was then angled on the ends about 10* to help them release and they come out of the mold quite nicely with a few raps. 4 ingots gives me 8 lb capacity so two to three trays per wheel. Total melt time was about two and half hours.



And a couple of short videos on my FoundDreaming channel on Youtube. One is pretty dark but you can see the metal flowing and the ingot tray filling the other is just the furnace moving... I was working the camera in one hand and the other was going back and forth between the up/down switch and my skimmer which I was using to slide the ingot tray along as each one filled, the bar that passes by in the other video is the manual lever.



UPDATE***
This furnace lining fell apart during my last scrapping session. It was only a 1/2" hotface on this furnace and I really abused it because the bore was too small for the wheels I have been melting. It did see close to a ton of wheels through it so not a total loss. This furnace will be rebuilt a larger crucible furnace and the Big Scrapper I am working on will take over that duty.

[F.C.]

Sweet... about the only thing I see OSHA compliant is the sign warning of an open trench..LOL.

[Harry]

Yeah ummm, about that... I was wearing boots and sunglasses

[Harry]

Just got the insulating layer in the Lil' Scrapper. The old lining had deteriorated to the point of falling apart so I broke it out and am rebuilding it. I did leave the bottom because it was still in good shape and saved me from having to form the channel in the bottom again.

I bought two sono tubes, one 14" and one 12" to use as forms and used Kast-O-Lite 20-45 for the first layer using the 14" form. This stuff is pretty amazing to work with, much easier than the foam/dense castable mix I had used in the past. What shocked me about it was how much water it takes. A 25 lb bag take 4 gallons of water, it was very easy to mix up though and also easy to place. The spec says it is 28 lbs cu ft once dry which means it should insulate well, I am just hoping it will be strong and we will find out on that front as soon as I can pull the form.

I also molded a plinth from it using an old plastic tub, screwed up and did not put anything between the floor and plinth so hoping it will separate ok with breaking up. Will post some pictures later of it going together. This new setup with the 12" bore will be for a 20# crucible.

I bought 275 lbs of this Kast-O-Lite yesterday at $0.85 lb since i am planning on using it in the new Big Scrapper too so this smaller furnace is a good test. I only got 220 lbs of the Mizzou 3K* so it will be next trip to get enough to do the hot face on the new scrapper. I am thinking it is going to take about 500 lbs or more depending on just how thick I end up making the facing and at $0.90 lb I had to break it up a little, spent over a grand between with this, some wheels and more electrical parts for running power in the shop and foundry so I had to put off the rest of the Mizzou but I have some time in getting the shell set up and frame built anyhow.

Considering the cost per lb on the lightweight refractory it looks like it is going to make for a very economical filler along with doing its insulating job. It took 1 1/2 bags or 37.5 lbs along with 6 gallons of water to do a 3" thick layer. Service temperature rating is 2600* IIRC so it should be fine for any kind of heat I will be seeing easpecially behind a healthy layer of Mizzou.

[HT1]

Harry
you are either plain lucky, or the worlds greatest bargainer, I paid $1.17 / Lb for Kasto-o-lite 22, Though I only got 165 pounds, But I'm settling for a 10 inch bore

[Harry]

The place I buy from HT doesnt really sell to the public. they have crews that install these materials and my guess is they buy pretty large quantities and mark it up pretty good when they sell to people like myself. Its kind of funny because I thought it was a little high but I had not purchased any for some time.

I picked up almost three hundred pounds of wheels yesterday too... $1.00 a lb at the recycler, that was actually ten cents lower than the last aluminum I bought from them.

Heres the pictures.

Here is the haul I made, the blue bag in the Big Scrapper shell is a broken 55 lb bag of Mizzou they gave me. It was kind of funny because I backed in to the warehouse when I got there and the first thing I did was get them to help me reload my truck because I had just picked up the wheels and they were on top of some OSB and plywood I had gotten before that. I wanted the wheels under the plywood so I could stack the refractory on top. I think those guys thought I might have been crazy pulling into their yard and putting them to work but by the time I left we were like old friends

The stock tank is 42" diameter and 24" deep, I am thinking the final bore will be 32" x 20".

Here the Kast-O-Lite is in place and you can see the bottom I left in the furnace since it was still in good shape. That trough is sloped to the spigot on the side and works great for scrapping but wont be so well for a plinth to sit flat so the plinth is cast in place so it will have the shape of the furnace floor.

Here is the little plastic tub I used for the plinth. I cut it down to about 4" high and rolled up a piece of plastic packing material to fill the trough, also cut a rounded notch in the tub to match.

Just slop it in and use a stick to poke it around and make sure it is consolidated.

Filled to within an inch and half of the top. Between how thick this is going to be and the walls being over an inch thick I think this rebuild is going to last awhile.

Here is the plinth mold sitting on the #20 crucible. Still have to make tongs for this crucible, I am going to make them considerably lighter than the last ones I made.

Just a shot of the foundry wall. That still has the wood fence on the other side of it but I am working on closing off three sides of the furnace area so I can get a better draw of the exhaust fumes through the fans and less disturbance from wind gusting through the cracks. The OSB I picked up yesterday will be going on that back wall.

I will most likely be putting in a 36" fan in place of those two 18" ones to really give me a good draw, from where this picture is taken behind where I am standing is open so hopefully I will be able to get 100% of the fumes heading out of the molding/pouring areas and outside of the shop. Most times its fine but if the wind is blowing a particular direction it can be a little foul.

[Nudge]

Harry, that is a good sized furnace How meny do you have now?

You need to build an over head gantry, that way you can go to whet ever size you like.

I spent a day at a small 2 man foundry a few weeks back ( it was a great day )

Here is a pic of there tongs and pouring shank.

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The crucible that we where using was a metric A150 (150kg copper )
I have thought about using an A frame engine lifter to help out when doing big melts.