Casting a Historic Bronze Cannon Barrel, Scaled Down Replica. FarmCraft101

hey there welcome to farm craft I'm continuing on my quest to make a scaled-down replica of a historic bronze cannon this is my last attempt from the previous video and you can see I had a significant defect in it so many people were convinced that this was caused by an air bubble that as this thing poured up they thought that the air was trapped and caused this defect I didn't show it on the video but in this portion of the sand casting I actually had poked a wire through the the tallest part there was no way to trap air in there green sand is also very porous the more coarse your sand the more porous it is to air my sand is quite coarse so it air goes right through it so that was not an air bubble but I can prove it I didn't have quite enough metal if you look here you can see where my where my level was this is how high I poured too so I was flat kind of a cross there there's a little bit of a flat right here so I was missing the top you know maybe quarter inch of that circle but look right here it's flat across there so it filled all the way up to here now obviously when this was all molten it would have been flat across there because a liquid is going to find the level this defect then contracted in after the pore so that that was not because of an air vent issue [Music] I had a lot of different suggestions on what to do to fix the problem I had in my last video I appreciate all the comments let's go through some of the ideas a lot of people said to pour it like you would pour a beer basically if this was packed with sand pour it at an angle and pour the metal in like that so that it then runs down the side and goes into the bottom my problem with that is I think it would a road where that metal is hitting the side it's going to dig a channel into that sand that metal is very heavy and then you're gonna end up with this channel and then also when it does get to the bottom it's still gonna slam into the bottom and that's messed that up so it's a good idea if I did a sodium silicate sand then that would be more likely to work and what that means is you mix sodium silicate with regular sand instead of using green sand and you cure it with co2 and it makes that sand bind together and it's a much firmer robust mold that might have worked I don't know I don't have sodium silicate I don't have regular sand and I don't have a co2 canister so that would have been an awful lot of money and then I'd be trying something new for the first time who knows what problems I would have run into I really want this to be successful so I scrapped that idea though I think it's a good one a lot of people said to do the lost-wax method which is how they do it commercially and of course that would work but again it's a bunch of stuff that I've never done before and it's a bunch of materials that I don't have trying to do this within reason you know this is a hobby the two that I think were the best molding plaster this is eight thousand psi plaster when it sets up and make a cast of the bottom of this mold of course I'd have to do both sides and then I would put those together and so this would then convert into sand up here I would basically put this into the sand mold you know once I packed all the sand around it I can remove the pattern and I would have a green sand pattern with this at the bottom this is plenty robust to take that metal slamming into it that would work and that has an advantage of I don't need a vent I don't need a pour spout I just need a hole in the top that's big enough that I can pour in while the air is coming out it allows me to use all the metal that I have in my crucible I'm not wasting any metal anywhere what I would want to do is fill that all the way up to the top and then a little bit more to make a riser that would allow my casting pull from I have another suggestion that I think is better and that's the one that I'm gonna try and that is to pour down a sprue which is a channel that you're gonna pour the metal into and have it go to the bottom and then have a gate come over into the thickest part of the casting and the casting is gonna fill from the bottom up I turned this down on the lathe you make these tapered so that you have a constant flow of metal at the bottom I also turned this guy down and that is going to be my vent and riser that's going to come out at the top and that one is split so that's the plan let's see if we can make it happen now because I'm going to be standing this up I want something on the side here too to help support that sand as the metal is getting poured in I don't need anything up top because that's just the last little bit of pressure it's a lot of work ramming that thing up probably don't look like it on the video because I speed everything up so much all right I want a little well at the bottom of my sprue now would it be a good idea to put a piece of metal in the bottom of that like if I cut that much off of that pipe cut it in half and left that half down in there I think I'm going to because that metal just constantly hitting that sand it's gonna erode into it could potentially mess up this whole thing this would spread out the load and this is steel so it's plenty heavy it's not gonna float got a piece of metal there and I'm just gonna push it down into the sand I want about 63 pounds of metal in the crucible 50 pounds is enough to cast this so that's gonna give me an additional four slag and then additional for my sprue and my riser and that's about as much as I think I can handle there's my 49 pounds this is enough to make 14 pounds of gun metal I always change over to kilograms because man it's a pain in the butt doing this with imperial kilogram they're just so much easier once you start doing percents forget it I've had a lot of people comment that I use pounds sometimes kilos others well let's be real here the metric system is better that's just the way it is but I live in the United States and everyone's using pounds and gallons and all this stuff so by necessity I am familiar with both systems ideally everyone would use metric but they don't so learn both systems and quit griping about me using pounds or kilos or whatever just learn them both and you're gonna be better off so in order to make fourteen pounds of gun metal I need this much copper unfortunately I have to get rid of this shiny guy but it's all the copper I have I need five hundred and seventy three grams of tin right here and now I need zinc I've melted this gunmetal a couple times every time you melt you're losing some of your zinc it goes off a zinc oxide so I'm probably getting a little low on my zinc content gunmetal formulations range from two to four percent zinc I'm gonna go with four percent on this one just to up my Zink content of the whole mix a little bit training today and that's supposed to rain the next couple days so I have to do this inside I'd really rather not use this much molten metal inside my shop that's made out of wood but I think it'll be all right [Music] [Music] I didn't like it being inside so I do have a little overhang there so I just put the furnace out there I'm gonna do the pour right in this area here [Music] [Music] [Music] and [Music] [Music] all right I'm gonna get it good and hot I'm gonna skim it one more time I'm gonna add my boss for copper and then I'm gonna pour [Applause] recover at the bottom of my mullet and molten metal just started pouring out but look out here it was the year but now that it's cooled here the Shrunk what I could have done to avoid this is have a sandbox full of sand that I put my my pores in my moles and then if I have something like this happen it's just gonna leak out into the sand why didn't I do that well it's more work and in this case it's also more height I actually thought about that because I wasn't thrilled about pouring it inside of my my shop it would have added more height which would have you know made it even more difficult for me to get that metal up there and pour it it was it was about everything I had to do what I was doing you know this looks like a total and utter failure and I'm not sure that pig blood I think this almost works that looks like offense was I all the way up there I just about done and failed that is not a cannon but what happened last time the poor was going quite well there was only six pounds of metal left in the crucible and the pattern went like that it opened up just a little bit but enough for all the metal to just come running out of it and I kept it closed and clamped it better I think I'd have a cannon right now let's take a second to talk about hydrostatic pressure how much force do you think was trying to separate my mold in this pour so remember I'm dealing with about sixty pounds of metal how much force do you think was pushing outward on my mold place your bets hydraulics are used for great mechanical advantage that's where they are used in back hoes and heavy equipment that require great amounts of force with hydraulics it's all about the pressure of the fluid in the surface area of what it's acting on let's say this cylinder has an area of one square inch and you're pushing down on it with one pound the fluid would then be pressurized to one pound per square inch or one PSI if cylinder two has an area of 10 square inches in force to would equal ten pounds so for my cannon the PSI is generated by gravity and it depends on the depth of the metal so I used an online hydrostatic pressure calculator my depth is 28 inches specific gravity of 8 means it's 8 times the density of water I look that up that's true for bronze and there's gravity and then I output my pressure in psi and I'm at about 8 psi at the bottom of my mold now this is linear so at the halfway point I'm at 4 psi and I can assume 4 psi average along the whole length now my cannon is about 4 inches at the breech 2 inches at the riser and about 2 and 3/4 at the narrowest part so it won't be perfect but we're just going to assume a 3 inch cylinder all the way down that gives me a cross-sectional area of 84 inches multiply that by 4 psi and you get an astounding 336 pounds [Applause] 336 pounds yeah I know that sounds ridiculous but it's true I've got a system set up here that's acting like a lever pushing outward in all directions on my box trying to separate it once I've got this mold rammed up and together I'm gonna put a strip of plywood right here I'm gonna screw it in and then just for good measure once I've got it stood up and ready to pour I'm gonna put a strap or two around it so that there's absolutely no way this thing is gonna separate I know a lot of people are gonna say I was lucky that it didn't explode well it's only gonna explode if it's wet that concrete never gets rained on it never gets wet and there is a dehumidifier running constantly in that room that concrete is dry it is not going to explode because there's no water in it when concrete explodes is because of steam now out here it just rained I'll admit that this is a little more dangerous I think people overstate the danger a little bit but but just keep in mind you know you probably shouldn't do what I'm doing unless you're willing to take the risks because there definitely are some melting metal to 2,000 degrees as a dangerous thing to do if you needed someone to tell you that maybe you shouldn't do it [Music] all right I'd like to see that come apart now actually no no I wouldn't I wouldn't like to see that at all so it took quite a while but I finally got all the metal remelted all these irregular pieces were kind of tough to fit in there remember the top of the pattern was like down at this level here it was a good four inches away from the top and the rest of it was that riser you can see the center of that riser shrinking down that is why you pour vertically because that's how it's going to shrink I can cut the riser off and if there's any shrinkage left in the center of the barrel that's gonna get drilled out so it's the next morning it's probably been 18 hours or so that is looking good even though I have that sand packed really really tight the metal pushed out into the sand so that's why I've got this this funny-looking finish down here as opposed to this up here so that's a negative of pouring vertically there's so much hydrostatic pressure I almost think I had to use a use plaster or something the green sand just can't take it but this is still usable I'm gonna machine this thing anyway so I can work with this here you can see the sprue and the piece of metal at the bottom that I use to protect the sand from eroding and then through the gate into the cannon I was surprised I didn't get as far up into the riser as I did I was expecting to have plenty of metal and maybe even some leftover so here's the sprue it looks like it was this way doesn't it but it was not it was this way and rather than getting narrower as it goes down it actually gets wider pressure pushed out that sand even though I rammed the heck out of it it pushed it out a lot that's an inch across this is a half inch so I think this cannon is bigger which is great that is good that's what I'm after [Music] let's see what size we got here okay so the pattern was 3 and 3/4 and this should be smaller than that but since it pushed out into the sand I'm actually at 3 and 7/8 so the next step is I got a I got the barrel now so I need to machine this cut this off drill it out and then I got to make all the rest of the parts the wheels and the whole structure that the cannon sits on the tilt mechanism you can see right now it's balanced it's a little bit back once I cut this riser off it'll it'll be if it sit like that and then you have a screw mechanism in the back that you can adjust the pitch so I'm really torn do I leave it with this nice cast finish or do I have a sheen it down and polish it and make it shine this looked ugly at first but now that most of the sand is out of it it actually looks kind of cool I don't know if I want to want to shine it up or leave it like this tell me what you guys think leave it rustic shine it up thanks for watching guys more work to do this is getting exciting we'll see on the next one [Music] [Music] [Music] [Music]

Channel: FarmCraft101

Views: 398,342

Rating: 4.9314909 out of 5

Keywords: gunmetal, gunmetal bronze, casting bronze, cast bronze, historic cannon, bonze cannon

Id: tqt7MjcyeAM

Length: 22min 31sec (1351 seconds)

Published: Fri May 24 2019

Reddit Comments

[u/afromagicdanny]

Now I can have a modern auto cannon with a 17th/18th century flare to it thanks

[u/Top-Cheese]

This guy must hate his house.