Size of casting pot?

[Oldiron]

Digging around my stash I've come up with two 1000w ceramic heating bands for 6" pipe and I have a length of 6" in the scrap pile. I'm thinking of building a bottom pour pot for casting, not smelting with the goodies. My question is, the two heater bands will give me a pot a minimum of 5" deep and that would hold almost 60 lbs of lead if full. Is that too much lead for filling boolit moulds. The "head pressure" should be the same as any other pot of similar depth regardless of diameter but i don't have other pots to compare to. I have all the parts including PID, SCRs insulation etc. Opinions? Bob

[country gent]

I ladle cast from a big pot. It holds around 150 lbs of lead when comfortably full. I ussually have 1 or 2 friends over and we cast togehter from this big pot. All being older and or health issues it is a saftey thing since there is someone there to give help aid if needed if something should happen. There is nothing wrong with a bigger than normal pot and at times they are a plus. More mass takes longer for temps to fluctuate is one. Another is the batch of alloy is blended in larger batches in the bigger pot. I would say go for it. MAybe make it free standing with a spout on each side so a buddy can cast with you.

[Cowboy_Dan]

5" is a tad deeper than my Lee 4-20. My concern would be the diameter. That is going to leave a big surface open to oxidation. I think the Lee pot is closer to 3" or 4" diameter, and remember doubling the diameter quadruples the area.

[bangerjim]

One 1KW heater should be enough. If you absolutely must use 2, be sure you use a 50A rated SCR.

And how have you designed the valve assembly control mechanism for the bottom??? A very key portion of any bottom pour design is the valve and it's operation! Heating a pot of lead is easy. Getting it to pour properly and evenly and controllably is another.

Good luck on your quest. For $60, I would just buy a Lee 4-20.

banger

[Oldiron]

I'll probably make a lid for it to hold in heat and reduce oxidation. Anyone ever float a steel plate on top of the molten lead? That ought to cut oxidation way down if it worked. The heaters will have a separate SCR for each. The top heater will have an extra cut off switch and only be used for the initial melt on a full pot and then turned off. The PID "learning" cycle will be done with just the bottom element on and normally operated that way. For a valve, I was thinking about a conventional tapered stem and seat with a vertical lift like a Pro Melt uses. A screw to limit the open travel seems like a good idea also. What size hole is in the nozzle of most bottom pour pots? Bob

[runfiverun]

look closely at the magma engineering web site.
I use their 40 lb pot and made a 1/2" steel top for it the cap just sits on top of the pot itself but gets warm enough to melt ingots.
you can copy their handle set-up with the spring easily, and even set your pot up to use one of their double hole spouts to fill 2 cavity's at once.

as far as oxidization is concerned only the top of the pot is where oxidization occurs, you could float a steel cap on top of the alloy but it makes adding alloy a bit of a pain.
what many do that worry about it is to float kitty litter on the top.
I just keep my pot full all the time and let the oxides keep more oxides from building up.
I might reduce every thing back in every 3-400 lbs or not.
this seems to work just as well as everything else I've tried.
a double walled pot with insulation between them and two bands would melt a lot of alloy pretty easily.
80-100 lbs would be doable if you spaced the bands out just right.

[blikseme300]

Bob, this is what I have done and I'm happy as a clam. http://www.bliksemdonder.com/hobbies/cast-boolits/mother-of-all-melters/

[wv109323]

I see no problems with a 60 lb. pot. I agree you need an adjustable spout but I need to keep my Lyman 20 lb. pot full to create the head needed to cast full based bullets. I have found the quicker you can get the lead into the mold the better your bullets will be.

[Tazza]

I have some ceramic heating bands that i want to make some melting pots out of too. I also had concerns of how big i can make it with the wattage of the bands i have. Looking forward to seeing how yours work out.

Nice write up blikseme300, those are some sweet pots you built there.

[CGT80]

I am considering building a bottom pour pot as well, and maybe a bullet casting machine. Jmorris has posted on a few forums to tell about his. He used a new oven element and bent it around a pipe. Amazon has elements for $16. I wonder if a stove element would be better so that the heat is from the bottom. The spout would have to pass through the middle of the element and the weight of the pipe would be on the element, unless you made stand offs to hold the pot, or supported it by the sides.

Jmorris used a 3500 watt element, IIRC, and he melts 60 lbs at a time, but it will hold more.

I need to go to my metal supplier and find a remnant of pipe and then work from there.

[Tazza]

A stove element is an interesting idea, if it's all insulated, i see no reason why that wouldn't be effective too. Possibly make the base heavier to hold more heat?

[Oldiron]

Well here we go. This is the pile of parts so far minus the insulation. :)

[Tazza]

Looking forward to seeing how this goes, i have a few heating bands to make a few pots too :)

http://i903.photobucket.com/albums/ac233/tazza_/Casting%20machine%20and%20sizer/20160323_151951.jpg

[CGT80]

I stopped by Industrial Metal Supply, today. They had a 13" section of 6 1/8" ID x 1/4" wall pipe in the remnants area. It was also uncoated on the inside, which is great. Much of their pipe is galv. It cost a whopping 5 bucks. I also picked up a rem of 3/8" plate for 6 bucks that I can cut a base from. The pipe is beveled on one end, although I would likely use more bevel for my tig weld on the bottom. I have some 1/4" plate around here, if I just match the wall thickness for the bottom. The CNC plasma machine is up and running, that my dad and I built, so I plan to use it where possible for my build.

That is a 5" grinder and a pair of tilman 750m gloves for size. I didn't set the pipe next to my lee 4-20, but I know it is huge. I was also considering cutting it to 6" deep. The lee pot sucks when it gets below half full. It seems that 6"x6" of lead would weigh 80 pounds, if I found a decent calculator for volume and lead weight. This was with a quick google search on my phone while in the steel warehouse.


http://i1112.photobucket.com/albums/k484/CGT80/Welding%20Fabrication%20and%20Building/IMG_20160504_223258778_HDR.jpg

[Tazza]

Impressive find.

The pipe i have is gal :( but some HCL and it will be gone easy enough, still more work. Yours looks like hydraulic cylinder tubing, so no seam from a weld on the inside.

It will make a pretty awesome pot, that's for sure.

[CGT80]

Last night, I also ordered a heating element to try out on my pot. It was just under $15 shipped on amazon prime and it is an oven element at 2585 watts with 1/4" terminals. Hopefully it bends as easily as jmorris said his did. The stove burner seems like it would put the heat in a better place, but it complicates things too much, at this point.

Here is the link: http://www.amazon.com/Exact-Replacements-Erb44t10010-Bake-Element/dp/B004FO8JZ0/ref=sr_1_4?s=kitchen&ie=UTF8&qid=1462073580&sr=1-4&keywords=heating+elements
(http://www.amazon.com/Exact-Replacements-Erb44t10010-Bake-Element/dp/B004FO8JZ0/ref=sr_1_4?s=kitchen&ie=UTF8&qid=1462073580&sr=1-4&keywords=heating+element)

[Tazza]

I can't see why it wouldn't bend as you hoped it would.

Will you need some sort of clamp to hold it in place? As it heats up, I assume it will expand and move. A dab of weld or a tab to stop it sinking maybe?

Keep the details coming

[CGT80]

Jmorris said he used a stainless sheet and wrapped it around the heating element. I plan to do something similar to hold the element, but I may end up insulating the pot and building an outside case/cover that is square. It would be nice to make it look well finished and like something you would see advertised for sale from a manufacturer. That would satisfy the OCD in me and also give me more of a challenge with my fabrication skills. Only time will tell how far I take it.

It looks like my current PID should work for the 240v heating element. The PID will work on 120v or 240v and the ssr is 25 amps (more than double the load of the new element), and I would just have to change the plug ends to 15a or 20a 250v style and double check that my wiring is correct on the inside.

There are some other projects that I need to get finished (custom base for a 5500 watt onan generator, a fab table with holes for clamping, and brackets for wands and a DI water tank that the generator goes on) before I get going with the pot. Also, I am still learning CAD and working on getting bugs worked out of the CNC Plasma machine. It is really cool to draw parts and "print" them from sheet metal and if something is off, I can adjust and "print" again, vs. hand cutting parts.

[Tazza]

I want to try my hand at a CNC plasma too, but another project to the ones i have now....

That is how i want to look too, it may take more time but the effort is worth it in the end, i'd like to go round like the magma pot, but i think a square housing is easier with the gear i have on hand. More room for insulation too, so it may be a better option.

Even though something works just as planned, you still want it to look good and work. By biggest hurdle is getting it to work in the first place :)

[Oldiron]

What did I start? :shock: It's good to see other methods all headed to the same finish line. Not much to report on my progress other than a reminder of my own stupidity. I turned a nice needle and seat last night out of 316 stainless steel. Went to lap them in and got a reminder that 316ss likes to gall. I managed to twist the 1/2" piece of 316 I made the needle out of and never did get them apart. Stainless seat and drill rod needle for the next attempt. At least the compound is still set for the mark II version. :-D

[CGT80]

My heating element showed up today, but it will have to wait.

That is too bad that your needle and seat became one. I am no machinist, but I have a small hobby lathe and hope to turn a decent set. Unfortunately, IMS did not have any 3/8" stainless rod in small sections. There was plenty of 1/2" dia. I almost got a 4" piece of the half, but held off.

Why did you choose to use stainless?

I assume to reduce the rusting that I see on my lee 20 pound pot. Polishing steel parts or even tools such as punches, seems to help keep them from rusting. Part of it is likely the polishing compound that I use, but a smooth surface seems to not hold the moisture as well. The heat and lead might kill that idea.

For the exterior of my pot, I half considered using aluminum sheet. Stainless is an option as well, but more costly and harder (I don't have much experience with it) to work with.

Also, I am debating on what type of material to use for the double spout, which will be removable from the bottom of the pot. Steel is easy and cheap, aluminum melts at a much lower temp and may react more, and brass or stainless will be more expensive or harder to find a remnant of.

This thread is great. There are many wonderful and similar ideas.

[toallmy]

Possibly copper flashing

[Oldiron]

Not a lot to report. I did manage to make a new needle and nozzle. I used O-1 drill rod for the needle and a 1/2"-20 grade 5 bolt for the nozzle. The 1/2" rod was reduced to 5/16" dia. for about 1 1/2" at the end and a 60 degree point turned. The reduced shank won't come out of the bolt/nozzle when in use so no alignment issues, I hope. The seat in bolt was roughed in with a drill bit sharpened to a 60 degree point. It was finished in the lathe with a Dremel stone. The stone was shaped by putting the shank in the lathe chuck and a diamond dresser in the tool post with the compound still set to the same angle that I cut the point at. 60 degrees, more or less, but they match. Finishing seating was with valve grinding paste, course, fine and then automotive polishing compound. The bolt will go into a tapped hole in the bottom of the pot and then tig welded around the hex. Kind of a poor boy way to insure things stay square when welding. The O-1 rod was because I had a piece. :D Bob

[Tazza]

That puppy will be water tight!

I'd bet that the commercial units aren't machined with this much precision.

Keep the updates coming, one day i'll get to making mine too.

[CGT80]

Oldiron, do you have any pics of your valve? It sounds very nice.


My pot is on hold. I managed to finish building my fabrication table and I picked up an old monster air compressor for the garage (which needs some tlc) and I started laying out my new mig welder cart. Oh yeah, I just got the smog papers for my daily driver, so I need to change the intake gaskets (hopefully that is all that is going on, at only 20k miles on the engine), make sure it doesn't still burn oil in number 7, get a new cat, and have it smogged. Komnifornia sucks!

I will watch the other pot builds and keep looking for additional ideas to use on mine.

[osteodoc08]

I'll probably make a lid for it to hold in heat and reduce oxidation. Anyone ever float a steel plate on top of the molten lead? That ought to cut oxidation way down if it worked. The heaters will have a separate SCR for each. The top heater will have an extra cut off switch and only be used for the initial melt on a full pot and then turned off. The PID "learning" cycle will be done with just the bottom element on and normally operated that way. For a valve, I was thinking about a conventional tapered stem and seat with a vertical lift like a Pro Melt uses. A screw to limit the open travel seems like a good idea also. What size hole is in the nozzle of most bottom pour pots? Bob


Ive always used a layer of melted beeswax for this

[CGT80]

It was finally time to get a start on the monster lead casting pot.

Here is the pipe partially blasted with 220 grit garnet and marked where it will be cut for the proper height. I went with 9" tall x 6.125" ID and it should put me at 102 lbs of liquid lead, according to an online calculator. In reality, I don't plan to fill it that full. The Lee 20 pound pot needed at least 2" of lead to have good flow and when it was filled to 3.5", it did not have enough material for me to do one casting session. It also was very slow to catch up when adding more than a single sprue. 4 to 6 inches in the new pot should give me 22-45 pounds on top of the 2" which gave good pressure at the spout. I don't know if the larger diameter will have any effect on pressure.


http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20160815_194101387.jpg

I didn't take a pic of wrapping the heating element around the pipe, but this shows how the pipe fits in my big vice to make it easier to wrap. It wasn't tight enough, so I stuck a section of 6" thin wall tube in the vice and wrapped the element tighter. Then, when I wrapped it on the 1/4" wall pipe, it fit snug. I still need to mount this vice to a bench outside. It is 14" from the jaws to the table and 22" front to back. Last week, I finished restoring them. The little parker is likely 70 years old, from what I could find on it. You can also see the fabrication table that I finally finished. It came in handy to clamp the pipe when I ground a bevel on the bottom of it.

http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20160815_203630537.jpg

My thought was to drill and tap the bottom of the pot for a 1/2" pipe thread and to use a pipe plug as my spout. It would hopefully seal up and be easy enough to remove if I had to work on the spout for any reason. I don't have a 1/2" pipe tap or the proper size drill bit, but I had a bung that I cut on the lathe for another project but didn't use. It is 1" OD on the small part, so I will cut a 1" hole in the 3/8" bottom plate with an annular cutter and the mill and then tig weld the bung in place. A 60 degree counter sink should make a nice spout opening for a tapered rod to go into. I will probably try to turn that on the lathe.

http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20160815_194301778.jpg


The heating element is 2585 watts 240 volts. Amazon has ceramic insulation for $27 that is 1" thick and will just cover all four sides of my pot. The outer skin will likely be stainless sheet which will screw to the edge of the 3/8" plate at the bottom and it will be in the form of a box with a round hole in the top to be screwed in the top edge of the pot. The stainless is a couple of door kicks that never got used, which are in the scrap pile. I will tig the joints and unfortunately don't have a brake so there will be plenty of edges to weld. I have only welded a small amount of stainless, so it will be good practice. I could do it with my MIG with tri mix gas, but it will likely look better to tig it.

I have not decided on a stand yet. My goal is a stand that will automatically fill and empty a boolit mold, but that is a ways out.

[Tazza]

Looking good so far. As usual, i haven't gotten to fiddle with my pots, hopefully I will one day though.

I'd like to see how the element handles a pot of lead, the hardest thing to know is just how many watts you need to melt and more importantly, keep the pot molten. If the insulation is done right, it should handle it pretty well.

My master caster pot has ceramic wool insulation, just as you were planning on using. The insulation went around the sides and also around the base. You mention the 4 sides, it would be a good idea to try and do the base too. The MC pot has two pieces of round about 1" diameter threaded internally that the pot sits on (it also serves to hold the casing on the pot). It gives a space between the base and the case to put insulation. You can make your mount to bolt to these points and hold the casing on. If you cut a recess with your mill into the metal you have welded to the top of the pipe you could make it so the casing is held on with these bottom fasteners.

Hopefully some of that made sense. If not, let me know and I'll scribble something down to make it easier.

[CGT80]

Insulation on the bottom isn't a bad idea.

Unfortunately, I can't quite picture your idea of where to mill. Originally, I planned to have the cover lift off and the top of the cover would have a round hole the size of the inside diameter of the pipe. It would look a bit like a tissue box. I could make the sides extend down another inch or so and then make a cover for the bottom that would slip up inside the outer box/skirt. I do like the idea of only two or three points of contact to support the pot, in an attempt to keep the heat from spreading to the lower support or casting machine.

Hopefully the heating element will be enough, but I could use two of them if needed. The single element will only be 10.7 amps. The lee 20 is too big for the size element they used, but not big enough to where adding another ingot or handful of sprues is only a small change in the temp. It seems that x amount of lead should take y amount of wattage no matter how much the elements put out. Bigger elements will just take less time to heat that, and the PID will regulate it.

Thanks for the tips.

[Tazza]

See if i can scribble something down, you will understand when you see it, just hard to describe :)

Good point about wattage, the big test will be when you hook it up and see if the extra element is needed or not. I like the idea of two elements to help spread the heat more, so the base isn't liquid and the top isn't.

[CGT80]

It is time to wake this thread back up!

http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161201_193828086.jpg

http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161201_193730492_HDR.jpg


I just wasn't sure about using plumbing fittings for a spout, so I drilled the bottom of the pot and ran a 60 degree counter sink in that hole. Then, I turned a steel rod in the lathe and attempted to match that 60 degree angle. Some aluminum oxide powder and grease served as a lapping compound. At that point, it was time to attach the pipe to the base. With the 5" angle grinder, I ground a bevel on the bottom of the pipe. I think I tack welded it together with my MIG, and then I preheated the thing on a hot plate and then hit it with the mapp gas torch. I set the TIG welder on kill mode (460 amps) and gave it two passes. It never got the full pedal, so I'm guessing I didn't go over 400 amps. The base did warp a bit, but it isn't too bad.

This week, I started in on the valve mechanism. There is a piece of 16ga aluminum under the valve mechanism, as a place holder for my final skin/box. I have a few stainless door kicks sitting around and wanted to use those as the skin, but they have holes drilled in them and I went bigger on my pot base, after I decided to allow room for insulation. So, I either have to fill the holes, or just build it out of aluminum. The vertical bars which hold the lever are cold roll 1/2" by 3/4". The lever is 1/4" by 1/2" hot roll, left over from another job. It was slow going when I milled the slots. My mill is a 1/4" diameter 90 degree drill point which I purchased to slot 3/16" material. For this heavier stuff, I set the spindle speed at 1200-1400 rpm and ran lots of mist coolant. My feed rate was an average of 30 thousandths of an inch per minute. I just went out and checked the drill/mill again. It took 1.5-2 seconds per thousandth of an inch on the handle of the mill. The cutter was just long enough to do a half inch in a single pass and I don't think it would have done it in multiple, with the drill point on it. I did not know the proper feed rate and the only way to find what that small of a mill was capable of, was to find out when it would break. Ruining a $25 cutter wasn't an option.

The flow control bolt is 3/8x24tpi, and I wanted to be able to adjust it with my welding glove on and without tools. If needed, I will add a wing to the bolt head so it is easier to adjust. The pivot bolts are 10-24, IIRC, and are too short. The cheap screws I had in there actually had slop in them. The cap head screws are nice and tight, so I will get longer ones and nuts to match. 1/4"x20 bolts hold the whole assembly to the ear (1/4" plate) that is welded to the pot.

Now, I need to make a base for the pot. My goal is to make this an auto caster, so I want to allow room for that down the road.

Does anyone have measurements for height and width under their pots? I don't want to make the base too small.

[Tazza]

"kill mode" i like that one :)

Looks great so far, what wattage element did you end up going for?

The height under the pot, are you talking under a master caster? or just a regular bottom pour pot?

[M-Tecs]

Looking forward to the next set op pictures. Nice work.

[CGT80]

My intent wasn't to take over this thread, but it is already started and has a bunch of great info all in one place.

I was asking about the space under a master caster, as this pot may turn into a DIY master caster and might end up automated down the road.

I looked a pics from J. Morris again and a few others and took a stab at the dimensions required. My base is 1.5" square steel tube and is 1/8" wall. The heat shield for the element is 16 ga steel and I bent it by hand. The element was wrapped as tight as I could get it, but it expanded a bit after heating. It is still too hot to touch, after cooing for an hour or so.

The red wire is 18ga and is rated at 200 degrees Celsius. Quality wire is normally 105 C., so this is rated for double the amount of heat. It was left over from when I used to repair the heat lamps in Carl's Jr fast food joints. I also have some woven glass tube to run over the terminal and wires, until it exits the housing for the pot. The element is 2500 watts at 240 volts. It was pulling 10.5 amps. The pid has a 25 amp ssr and was wired for 120v, to run my drip-o-matic casting pot. It wasn't easy to fit the ssr in that little box with the PID, but it was clean looking. I may have to add a heat sink to the back and possibly a fan. It got pretty warm to the touch, but not overly hot.

Originally, I wanted to make a body out of stainless steel, but my remnants are on the small size and have some holes. Maybe I will try it for the heck of it, but I considered aluminum instead. Today, I started to wonder if aluminum was the right material. With a lead temp of 800 F., the outside of that pot will be extremely high. Then again, I plan to use 1" of ceramic insulation around the pot to help keep the heat in and away from the skin and myself. Hopefully, that will allow the pot to work even better. Right now it seems like the element is none too big for the amount of mass in the structure of the pot and the pot would take 50lbs of lead to just fill half way.

The frame, under the pot, got hot, but I could still touch the cross brace against the bench. The legs were too hot to touch. Since the base of the pot warped, from welding, I had to add spot welds under the corners of the pot so it would sit steady. Two 1/4"x20 bolts hold the base to the pot. It might help to have some distance between the bottom of the pot and the frame, but I wanted the thing to be rock solid.

My mig welder had flux core in it (I hate the stuff but will use it for mobile repairs) and I didn't want to deal with the splatter and fumes, so I tig welded the entire base and the tabs on the outside of the pot, along with all the parts for the mechanism. It was a good excuse to practice my tig welding. It also makes for small beads which I can leave, or make flush with minimal grinding.

The element is only held at each end by a tab. The screw is for my ground wire.
http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161203_230125499.jpg


http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161203_230131167.jpg

Back view:yes the ground should be bare or green, but I wasn't buying hi temp wire just for that. The green tape is good enough for me.
http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161204_195237461.jpg

http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161203_230311968.jpg


My plasma and welders are wired with 50amp 250v plugs (and my dad and brother also use the same plugs on their tools), so my dad, brother, and I all use extension cords made up like this. The tig welder has a 6ga cord and this garage is only fed with 6ga, so when I welded the bottom of the pot, I only had a few minutes to weld before the 50 amp breaker would pop. It pulls 104 amps at full power, on 240 volt service. Unfortunately, It wasn't a continuous weld, but it is water tight, and is lead tight. I considered a 15 or 20 amp plug for the pot, but the only other item in my garage with a small plug is the mill/drill. If I needed to run the lee pot, I could change the cord end back to 15a120v and the PID would be ready to go.
http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161204_195142994.jpg


It has no problem heating up the inside of a single car garage.
http://i1112.photobucket.com/albums/k484/CGT80/Shooting%20Reloading%20and%20Boolit%20Casting/IMG_20161204_195302412.jpg

[bajacoop]

I built a similar sized pot and used a 2600 watt heating band. And it takes about 30 min to melt 100 lbs. I dont have it insulated yet but i imagine that will cut it down some. It puts out enough to keep my 600 sq ft part of the garage plenty warm.

[CGT80]

I did some more work on my pot. It looks like it is going to turn into a master caster. This thread wasn't about a master caster and I have kind of taken over it. I think it is better to have my own thread, so I have copied my posts and will update progress on that thread. The link is below:

http://castboolits.gunloads.com/showthread.php?323841-DIY-100-pound-pot-master-caster

I thought about making my posts on this thread shorter, as it probably isn't great to have duplicate posts in two threads, but I have to look at it and make sure I don't screw up the flow of this thread either.