Resizing 55 gallon 200L Drum

The gate will be the hottest part of the casting as it is being heated by flowing hot metal whereas everything else downsteam is cooling. So, a gate should not freeze prematurely (as long as you are not looking for post-fill feeding.) There should be no need for feeding from the gate once the cavity has filled. I like thin wide gates for thin parts---easy to break off or saw.
Denis

 

I am back on the "medium" sized barrel project. When I welded the bottom and top to the sides, I did not pay attention to stuff like tack welding small sections and allowing it all to cool so as not to warp the material. As a result, my bottom has just enough extra material that it wants to 'oil can' in or out, reminding me of those bi-metallic jumping disks that we had as kids. The deflection is a good 1/4 to 3/8" (6-9mm) in the center, making it not sit flat and/or not easy to lay in the insulating fire bricks I wanted as a bottom layer. I think I have proven this is not (!) a time and cost effective means to yield a smaller shell from a bigger barrel...but part of me wants to succeed at this one.
Here are my current ideas
1. Hammer and torch in a permanent pattern/set that does not oil can and skip the IFB's and pour 2-3" (50-75mm) base with Kast-o-Lite 30i (need to learn K30i techniques anyways)
2. Cut some pattern like a 10" diameter circle and some slits radiating to the outer diameter and tack and weld the metal back flatter.
3. Cut out whole bottom leaving a flange and reweld old or replace with an oversized disk thicker metal resting on inside.
4. Abandon current reworked barrel, concede defeat, and either start size-matching or get something slip rolled.
Pictures of the bottom as an 'innie' and 'outie', approx. 16" (406mm) diameter and .04" (1mm) thick:

 

Tops, my experience with casting and associated metal working is that I learn more from the mistakes than from having the first attempt turn out perfectly.
With some judicious heat shrinking and a little hammer and dolly work that could be dead flat and tight as a drum. And you will have gained a new skill.

 

My furnaces have not had welded-on bottoms. I made a base that supports the lift/pivot lid opener and my hoisting tongs as well as as Blu-Ram and wool furnace bottom. The side sheet was split and wrapped around the Blu-Ram and wool walls. Then it was welded closed along the vertical seam and finally tacked to the base. It has been a good setup.

I think I’d saw out the bottom. You could also use some light angle to make a base and tack the bulging bottom to a couple cross struts to keep it in out-bulging mode and prevent popping back and forth. I see little advantage to a fully welded can-like base,.

http://forums.thehomefoundry.org/in...nace-build-14-dia-bore.1122/page-2#post-27225

Denis

 

Thanks Everyone, all of these ideas are excellent!

 

I decided to give it a go, with the idea that I could cut it out and start over if I needed too.
Besides, it's just a furnace and I needed to stop the thinking and start the doing.
I tried some freestyle heat shrinking (torch and wet rag) as I do not own bodywork hammers and dollies and a stump and such. Fumes were bad at times, a fan or organic vapor mask would have helped.
Then I washed and wiped and tacked and painted the seams and bottom with the end of a sputtery can of 'engine paint' to convince myself it is time to move forward.
The bottom improved enough between the shrinking the highs and raising the low spots to allow me to lay the IFB's without much trouble.
Cutting them was easy with an old hand saw and an old hoof rasp.
Sairset3000 mortar, slightly thinned and applied thin to the mating faces and a quick swipe over the top to prevent bricks from drawing moisture from the Kast-o-Lite 30i to follow (something I retained from talking to vendor).
Thanks again for the specific ideas and general inspiration!

 

Good to keep in mind Kelly, thanks. The next step will be the tuyere hole followed by a 3/4" (19mm) Kast-o-Lite 30i liner with 2" ceramic fiber outside of that to the shell. So the IFB and mortar should not be directly exposed to the hot metals. The supply house sent me home with a couple pounds of a wash coat as well. I used Mizzou in my little furnace before I knew the difference and it's held up really good over the ceramic fiber except for directly overhead on the lid. I may want to wash coat that when I am doing the new one.

 

It is Minro-Z, a zircon-based coating. Sounds like it is primarily used for aluminum even though max practical service temp is 3000F/1650C :

https://ssfbs.com/wp-content/uploads/2021/03/Minro-Z77-Data-Sheet.pdf

 

Kelly, It was just under 6$ US per pound from SSFB, dispensed into a plain plastic bag (your questions prompted me to label it better). They joked not to leave it on the dash of the car...

Everyone, I may have designed myself into a corner. My intention was for this to be A10 sized and able to run LP and eventually get into oils. Reviewing the rules of thumb on the forum at:

https://forums.thehomefoundry.org/index.php?threads/foundry-tutorial.1487/

Makes me think that my plans have run a bit amuck. I had started amassing components for a 2.5" OD Delavan style burner and then built this 2.25" OD Brute LP+drip . In my head I was going to make it all swappable and such...but now it looks like I'd be better off with keeping the burner towards the smaller side and that with the interior height being a constraint, I may not be able to run well on oil. I am not getting a warm and fuzzy feeling about my vent size either: per one set of rules it's too small, the other indicates too big.

Any ideas about the vent size and whether or not to rework to add height (seems that extra height helps with oil burning -?) or in general are appreciated!

 

I agree with Kelly that the vent size is probably not too critical whether for propane, wvo, or diesel. No matter what size it is, the furnace will be under positive pressure. So if the vent is smallish, increasing blower air will compensate and vice versa. The main thing is to find the optimal volume of air to allow good heat extraction from whatever fuel.

Given your point in development of your furnace I hate to again recommend dimensional changes. (The most important thing may simply be to go ahead and burn fuel to melt metal, afterall.) But, I do think your plinth could be a bit taller to allow more combustion to start to occur prior to the fuel/air stream encountering the crucible. I am thinking 4 to 5 height inches may be optimal. I think I have found this to be true and of some importance (more so than vent size, certainly) in my various furnace iterations and has been suggested by melters with more experience than I have. You do have a welder and some experience welding sheet metal. So, adding on some height to your furnace would not be too daunting---3 or 4 hours work amybe?

A tuyere oversize for one of your burner tubes can be easily stuffed with a bit of wool to seal it up against the mild positive pressure of your furnace. It is virtually impossible for me to get a truly tight seal around my burn tube so that a small amount of vapor blowby of the tube occurs. This seems to be of no consequence.

FWIW
Denis

 

Thanks Kelly, thanks Denis.
I have not begun to work with the castable refractory nor cut the tuyere and vent through the skins... so it would be a good time to make any changes if they help solve known issues.
I have more barrel skin at home and a slip roller at work. I definitely need/can use the welding practice

 

I took the remains of the cut-up barrel into work and made an extension piece to height/width using an ancient throatless nibbler that does not make the curly-Q as it cuts. I rough sheared it to length and used the tail end for some welding coupons. I just need to cut it to final length and butt weld, then tack and stitch to the existing can.

I also played with the notion of a lift and swivel lid and rotating the base/cart to suit the lid action in CAD. Seems like this might be an easy mechanism for a first go. I also got to thinking that letting either the lid or base castable stand proud of the shell might help cover over any sins of metal fabrication or molding the refractory. Drawing is showing 1/4" (6 to 7 mm).

 

I like the looks of your current design better by far than previous as it looks like there is more room for combustion. I have liked using my lift and pivot mechanism. I end up using some wool between the furnace and the lid to serve as a gasket. I know some folks here have managed to get a good fit, not requiring a gasket, and that might be worth looking at to see how they did that.

My lid lift mechanism uses the cam in the vertical shaft. The cam is connected to the lever, which when pulled lifts the lid and then I use that lever to rotate the lid into an open position. This is a one hand operation. And I find it very convenient.

Denis

This vid sort of shows the mechanism in action

 

Here is a better vid

https://youtube.com/shorts/nHPWD4D_aL0?feature=share

Denis

 

Design and efforts so far look great. I would suggest not having your burner tangent to the floor as it appears in your drawings. Your increased hight should allow some clearance allowance. There are several reasons that come to mind.

A buildup of debris could cause an obstuction.

A flood from a failed crucible could cause flow into the burner.

If your mist is immediately striking the floor upon entry it could contribute to pooling.

Maybe none of those things would happen to you but at least 2 of them have happened to me.

Great job.
Pete