How NOT To Cast A Historic Bronze Cannon Barrel. FarmCraft101

hey there welcome to farm craft we are doing a test run on pouring a cannon out of gunmetal I'm using the loss foam technique and I don't have any foam that thick so I'm gluing together some I think this is inch and a half blue board using Loctite spray adhesive the reason for the test run is I need to do a test for and then check the strength of the metal what if I just tried sanding it instead of turning it so here's a 60 grit sanding disk [Music] the cannon should be weighted slightly to the back and it is because you have a screw back here to adjust the pitch on the on the final mechanism one foam cannon so I have made a form of sorts separate boxes with tabs to help when the alignment so that when you put them together they'll stay together okay so this is gonna sit in there like that I'm putting the breech down because air bubbles are gonna rise and I want the breech to be the absolute strongest part of this so a lot of times when you're doing lost foam moulding you just use regular sand I don't actually have regular sand I just have grain sand but I don't think it'll be an issue we'll find out so this is my first time doing lost foam it does seem like if I just had regular dry sand and just dumped it around this that would be super easy to do but would it work I guess the reason that this is a little different than a lot of lost foam castings people do is because I'm doing it vertically there's gonna be a fair amount of psi on the bottom of that so that loose sand might actually get just pushed out of the way by the molten metal I don't know maybe not maybe it'll cool right away and that wouldn't be an issue I pack this with green sand to make a pour spout for me get careful so that it's not like wedged against the side because it's going to expand as it gets hotter I don't want it to crack the crucible [Applause] I just realized I forgot to add my flux my new draw spoon that's gonna make that parts so much easier it may not have been entirely apparent in my last video but skimming the dross was very difficult because my spoon was so short my hands were getting burnt well I am really pushing it that crucible is built to the brim array I'm gonna shut down for a minute avoid the let oxide fumes and I'm going to skim the dross hopefully I'll have a little extra room in there let me heat it up a little bit more and then we will be gas it and pour it this is phosphor copper moment of truth oh well I see a problem either I figured wrong or it really pushed that sand out cuz it did not come all the way up this should have been about the top of the barrel and I mean all that metal is just down in the bottom I sure hope the sand all pushed out I hate to think that I figured the size that far off it's a foot down so my 2 foot 10 and there's 1 foot long not looking much like I can and see what it stinks really like that lost foam so I learned something else knocking the sand off and right there molten metal started pouring out so the inside of that look at that the inside of that thing is still molten so I'm gonna have to let this thing cool for a long time before I break it out of the mold it's been in there for 15 minutes I'm used to these small castings that just go off so quickly but I think it's pretty obvious that it did push out into the sand but that's alright this is still gonna give me the information that I want this area that I've uncovered is cooling faster than it normally would so I'm going to take samples from the underside that's where I'm gonna do my tensile strength tests so I've put bricks all along the bottom of that things are gonna boil and spray the heck out of me [Music] that's pretty cool I'm not used to dealing with something that's so big it just keeps staying hot so that time I think I was over skimming a little bit cuz this has a lot of metal in it it's quite heavy and I took a piece of the of the slag and I cut it and you can see it's it's metal so I definitely lost a few pounds there in in slag just over 43 pounds nineteen point six kilos my widest dimension on the pattern was about 3 and 3/4 oh yeah I'm four and a half if you look closely at this thing I have a smooth cylinder here and it looks like I've got a smooth cylinder all the way into here and then I've got these fissures of metal that are thicker at the bottom it's almost like they came out the bottom and then perforate it up along the sides see there you can see I've got a smooth cylinder there but the cylinder is much bigger than it's supposed to be if it had stayed the size of the pattern it would have been shrunk and been smaller instead I am much larger than my pattern was by almost an inch it's not a total loss when I took it out of the sand it was like this that's where the metal was leaking out so under here is where the the metal cooled the slowest so what I want to do is take a sample from this area down inside and see what my tensile strength is and that means I am going to have to chop that something like that this turned out to be quite a challenge first I used a cold chisel to take off some of the the ribs on the side and then I tried cutting with my bandsaw but it just wouldn't cut so then I put it on the lathe and I went through several different lathe tools trying to turn it down just trying to get the sand off of the outside I know I could use a grinder in about 50 cutting wheels after 2 hours but I'm trying to avoid that they're still sand mixed in with this casting this is a real mess so I can't cut it because it immediately dulls the the cutters so how do I cut this come on you you right there how do I cut this what no answer you're not gonna help aah I tried using a grinding wheel just to clean up one area so that I could then part it off uh that didn't work either I've been thoroughly cleaned my lathe does all the grits and the grinder and the sand is the worst thing you can do to a lathe well I have a bit of a crazy idea it's something that I've done with aluminum before it's just cut it with a circular saw so I am going to set this thing up and and see if I can't take a little metal off of it with a circular saw crazy as that may sound I've got it set to cut about half an inch that is a carbide tipped blade it's very old and beat up I just want to see if I can if I can do anything with this got my eye protection on I've got my ear protection on and I'm gonna have two hands with a death grip on the saw so did cut and actually pretty well so that's what I'm gonna do this is up too high I can't see what I'm doing so I need to mount this some other way I just have a little bit left right there so I'm gonna see if I can cut through most of it with the bandsaw and then I should be able to just break this thing off pretty pleased with this I don't see any pores and the grain structure is tiny I would have thought it beating so big and cooling so slowly that I'd get big grains its dirty from the cutting oil but those areas in the center you can actually see pretty pretty nice looking fine grain so I'm gonna cut that same way I just did circular saw lots of noise and bring you back after that it kind of looks like a log now like tree bark here's what happens to a circular saw blade when you absolutely abuse it I think there's still little hints the carbide left on those teeth but they're almost all gone and then one of the teeth finally bent and that blade is done but considering what I was doing with it I don't think I'm gonna file any complaints I used the belt sander to get the rest of the sand off so that I can now put on the lathe drilled some holes in it the final diameter came out to 400 and mm let's get this thing loaded so what do we want here I would love to get 50,000 psi tensile strength and that would equate to about just under 3000 psi so anything 2500 and up I would be really happy with quite honestly I don't expect to get that I'll be surprised if I get over 30,000 psi let's see what we get all right that's six hundred seven eight nine one thousand eleven twelve so kind of interesting it did break in the middle you can see the grain structure there it's it's linear but here's how the math works on this thing when you take that diameter 400 and mm that's 201 radius 0.2 zero one and you do PI R squared you get an area of 0.1 - seven square inches I held 1,200 psi that equates to it's four point three to four pounds per PSI so that equals 50 188 that only held half of that though that's how much pressure that the press was exerting on both sides so divide that in half this held a 2594 pounds so it held 2600 pounds and then you divided by the area divided by 0.1 to 720 thousand four hundred you know that's actually not too bad shooting black powder like the maximum chamber pressure you're gonna get is about 27,000 I just need to make sure I have enough wall thickness there that it's going to be able to withstand that 27,000 20,000 psi I can make a cannon out of that I won't stand beside it when it shoots so how do the commercial guys make this metal stronger because this have a much higher tensile strength than I'm getting here I think what they're doing is they melt it and pour it then they're forging it you know they heat it to exactly the right temperature and they they run it through presses and rollers and roll it out and that changes the grain structure as they work it and they end up with a much stronger final product and that's just not something that I have the ability to do here now that said neither did the old-timers you know the guys that were doing this back in the year 1500 imagine that they mined all this or with a pickaxe and then smelted it got copper got ten mixed them together melted literally tons of it at a time and poured it into molds and made cannons and then they drilled the cannons out by hand they didn't have electricity they didn't have propane they didn't have hydraulic presses and power saws and any other stuff that that we use hats off to a man it's amazing but one thing I'm certain of is that they did not Forge it they casted it and that's what they got so they probably had a similar tensile strength to what I'm getting if someone out there knows different I'd love to hear it I turned down another sample and tested it off camera and got similar results see that one fractured linearly again well for those of you who are wondering how is he going to separate the sand from that metal that part's easy to melt it the sand will float to the top you skim it off the question is what am I going to do as far as my next attempt this metal is not as strong as I would like and I'm concerned that this cannon is is going to be terrifying to shoot that said I still kind of want to do it what I think I'm gonna do is I'm gonna go back to what I know with the mold I'm gonna make a wooden split pattern and I'm gonna mold this thing with a regular green sand pour I'll Ram it really tight and I think I'll do just fine like that then I'm gonna drill out the cannon I'm probably gonna keep the bore smaller just for safety I'll drill it out at like probably a 3/4 inch bore I'll shoot it and I'll have some fun with it and then when I'm done I think I will drill it out bigger an inch and a half maybe even two and I'm going to press in a sleeve of 4140 that I know will hold anything that I can put in there and then I don't have to worry about the cannon exploding I'll still have the cannon to to play with in the future and I can shoot it with people and not worry about anyone in danger before I put the sleeve in there I'll probably only shoot it with with nobody in line of sight of the cannon myself included I'll light a fuse and get behind a barricade and let it fire I'll let the cameras watch it but I'm not going to watch it myself just in case so what do you guys think is that a good plan I think that's what I'm gonna do unless someone convinces me otherwise this has been a lot of work thanks for watching guys I'll see you next time hopefully with something a little more substantial at the end [Music] [Music]

Channel: FarmCraft101

Views: 1,062,017

Rating: 4.6141834 out of 5

Keywords: bronze cannon, historic cannon, model cannon

Id: jVD-P-77B24

Length: 21min 0sec (1260 seconds)

Published: Fri Apr 19 2019

Reddit Comments

[u/ecodick]

I've been watching this guy's videos for this whole process, wow, he's persevered. So many attempts went into this, I'm glad to see he finished the casting

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