A big new foundry project... for me, at least

Discussion in 'Sand Casting' started by Tobho Mott, Jan 10, 2022.

  1. Tobho Mott

    Tobho Mott Gold Banner Member

    I've been working on a new project for a couple months now and it's been taking up all my free time, so I'm well past overdue to post some details and pictures!

    A friend who owns a blacksmithing school asked me to help him out by making some castings. Tools for a new class he wants to offer this year:

    7 sand rammers

    20220110_121611_copy_520x658.jpg

    7 strikes

    20220110_122348_copy_812x520.jpg

    7 rappers...

    20220110_124842_copy_945x520.jpg

    I got the 3d files for these patterns off of plmfoundries.com, youtuber swdweeb's web store. Cheap! Especially for the custom VANS logo on the rammer pattern, which is a fair match to the school's branding. If I'd had to learn CAD first to make these patterns, I'd never have had time to get these castings actually made in time.

    20220110_121734_HDR_copy_520x480.jpg

    ...Plus 56 15cm "Olfoundryman" flask sides (7 x 8 sides per flask)...

    Ie. Molding toolkits for 6 students and one instructor. And I don't have to machine or assemble the flasks! Phew, I just don't have the skills or tools to get the alignment pin holes drilled out square.

    So far I've got all 7 rammers, strikes and rappers cast, all off 3d printed then bondo'ed patterns.

    Problems encountered:

    The sawtooth edge of the strikes were tricky, as the patterns wanted to warp and not naturally lie flat like they were supposed to, so they would spring up in the middle in the drag when I flipped it over and removed the molding board. All I could do short of building a couple of new 2-print patterns and hoping for better was to dust the teeth really generously and be really careful fixing the drag where the flexing broke off some sand, as much as I dared, before ramming up the cope. I weighted down the centers of the patterns when facing the cope until it had enough sand on it to hold it down, which helped a lot. Most of them didn't tear out more than a couple teeth each, but I did have 2 of these castings that were just no good, they have since been recycled into a couple of the sand rammers. Of course the teeth need a little attention to remove some flash, but I'm actually surprised how little. I would never have made one of these for myself, but now that I have one of my own, I really like the sawtooth edge for striking most of the extra sand off of molds quickly. They are just long enough to strike off a 12" wide mold.

    20220110_124456_copy_999x276.jpg

    (These are all very short video clips)




    Rappers, no problems. Most of them seemed to cast equally fine gated into the end or the side of the handle. Mercifully, they fit in my little 7x7 flask if I gated into the side. Although I used a 12x12 for when I wanted to pour 2 in one go (I only have one 7x7 flask). I like these well enough to keep one for myself as well.



    Rammers... 4 of the first 5 came out basically perfect. I started using a bigger feeder after I saw tiny amounts of shrink on the butt end of the first one I poured (which has also been recycled). #5-7 all had a strange vein on the cope side of the cylindrical section.

    20211228_004156_copy_1040x520.jpg

    Only difference I can think of from 1-4 is they were poured in colder weather. The copes were perfect when the mold was closed. Any theories? Not a big deal, I can file that off; they are sand rammers not furniture after all.

    The peen end is narrower side to side than I'd really want for myself, but it's not unreasonably small for the tiny 15cmX15cm flasks. I do like the angle and how thin of a tip it comes to. Although it takes a bit longer to make bigger molds with, I still often find myself reaching for it anyhow, to make the first couple of passes, as I find it easier to feel the sand firming up under than my old cast rammer, so loose patterns seem to wander around in the flask less.

    20220110_121922_copy_877x418.jpg

    20220110_121747_copy_936x522.jpg



    And then there are the flask sides. The test flask I already made has messed up alignment holes on 4 sides and no VANS logo on the other 4, so I can't pass those castings along, but I can use it myself for very small patterns if I'm careful.

    So, I've started work on 7 more flasks' worth of parts. The first 2 molds I tried pouring didn't quite fill. I blame having allowed the sprue to suck some air during the pour, but who knows. Those don't count! :)

    20211216_123444_HDR_copy_1040x520.jpg

    After almost getting frostbite making the 7th rammer mold, it was time to set up a crude winter molding station in the basement so I can get these all done more comfortably (before March).

    20220105_091059_HDR_copy_1040x520.jpg

    Hauling 12x12 molds up the stairs and out into the casting shed, then hauling 5 gallon buckets of mulled sand back into the basement, frankly, SUCKS, and I really hate how messy it is not having a bin under the mold to catch all the falling sand... but I think not as bad as working in the freezing cold, much less risking losing a finger or two. It's tempting to come up with some kind of sand chute so I could just dump good sand through a basement window, but this is a temporary setup... If I did want to try things like that, he 12x12 flasks are too big to push outside through my basement windows, unfortunately.

    The first 6 two-flask-side molds rammed up inside all turned out fine, so I've got enough sides for one and a half out of seven full flasks poured already as of last night.

    20220110_125141_HDR_copy_1040x520.jpg

    20220110_125322_HDR_copy_520x845.jpg

    Damn black spots again... In this case I guess they are bonus sand retention features :D

    20220110_125225_copy_1007x343.jpg

    Each of these 2-mold pours (4 flask sides) takes 2.5kg of cast aluminum to fill, plus a handful of sprues and gating added to the melt for insurance. I never had to go into actual production mode to cast multiples of anything before this, it's kind of fun to try and optimize how I make these molds through iteration, and I'm finding that knowing how much metal I need to fill each mold is really nice, this way I just have one maybe half sized ingot left over to pour instead of 3 or 4 big ones due to melting way too metal as I often have in the past as a safety factor on one-off hobby project castings. I'm using a petrobond ingot mold with 8 mini-loaf sized cavities. I can reuse these 5 or 6 times before I have to make a new one, so the one I have going now should last quite a while now that I'm only pouring one ingot per 4 cast flask sides (that's just 11 more ingots left to pour, if I'm lucky enough that everything fills). I might only have to dump it out once or twice more before I'm done...



    https://youtu.be/7pxPKTUD0tE

    I started weighing these castings with all the gating still on after 4 rammers were done. Turns out those took exactly 2 of their own risers plus a pouring basin to fill. Hey, maybe using all remelted risers was part of why the last 3 rammers I poured had those weird vein-looking defects on them? Not that ALL the aluminum I have right now that is ready to melt hasn't been poured by me at least once or twice before anyhow... I'm definitely going to have to cut up some more wheelium before these flasks are all done.

    Jeff
     

    Attached Files:

    Last edited: Jan 10, 2022
    BattyZ, HT1, Clay and 6 others like this.
  2. Petee716

    Petee716 Gold Banner Member

    Wow, look at you gettin in the groove! Kudos to you, Boss.
    Even though it’s only a few castings, I’m thinking the strike casting might have been a good candidate for a match plate. How thick are those things? (I haven’t watched the videos yet. Imma get a bowl of ice cream and plug in the AirPods).
    Nice work Jeff. Keep those fingers warm!

    Pete
     
  3. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    That's quite the project Jeff. That must either be a paying customer and/or you are a very good friend, especially given the Northern Winter. How about some insulation in that shed with waste oil heater or a barrel wood burner?

    Best,
    Kelly
     
  4. Tobho Mott

    Tobho Mott Gold Banner Member

    Thanks Pete. There's under 7 minutes of video total. and not much to hear other than my shed fan screaming, so you better eat your ice cream fast and keep the airpods low. The strikes are about 3/16" thick. Good idea about a matchplate, in retrospect... Oh well, each strike only needs a couple minutes of dental work on the bandsaw, I can live with it.

    I'm using a follow board to make the flask sides molds to avoid a lot of coping down, kind of the next best thing to a full matchplate I guess. :D

    Kelly, he's a little of both. I am too deep in crunchtime to deal with heat and insulation before the job is done, but heat in my shed would be amazing. The next version of my foundry shed will be bigger and warmer, and these castings will definitely help make that happen! The Ikea table in the basement should at least get me through this month with all my digits intact, hopefully without dropping too many molds in the snow on the way out the door...

    Jeff
     
  5. Tobho Mott

    Tobho Mott Gold Banner Member

    I've been having to chop up failed castings and wheels to do the last few pours... Managed to talk the farmer down the road out of a nice stash of wheelium he had lying in the mud the other day...

    20220117_153522_HDR_copy_1040x520.jpg
    And not a moment too soon! The next day they would have been buried until spring.

    20220117_153717_copy_1040x520.jpg

    The catch bucket for my stack melter sprung a leak so I started cutting one up into big chunks with a recip saw and angle grinder so I could make those fit the crucible using my portable bandsaw, but I broke my last blade. Then I noticed even my hacksaw blade had somehow gotten cracked! And of course the snowplow came around again after we all went to bed last night and left a nice 2ft tall bank at the end of the driveway to deal with before my wife could get out to go to work...

    Got the last 4 sides for 3rd of 7 flasks poured as of yesterday though at least...

    20220117_220126_copy_798x520.jpg

    Jeff
     
    Petee716 likes this.
  6. Melterskelter

    Melterskelter Gold Banner Member

    Funny, when folks see a casting, I doubt they have any clue of the many backstories that went into making it. I know that is true for the castings I sell on eBay. People seem surprised I can’t just pop out a 40 pound casting in a couple hours and ship it on demand. Wish it were so. You’ve been busy!

    If one had a lot of wheels to melt, making an hydraulic muncher would be cool. Sort of like a nibbler but chomping out 3 or 4 inch square bites. Hardened jaw cutting edges. Crude but satisfying.

    Here’s an example—-more than what you need, but you get the idea.

    Denis
     
    Last edited: Jan 18, 2022
    Tobho Mott likes this.
  7. Tobho Mott

    Tobho Mott Gold Banner Member

    Munch munch munch... Yeah that sure would make quick work of these wheels! I got given a GC for Canadian Tire yesterday so I may take a look to see if they have some sort of tool that would speed up wheel chopping when I go buy new blades for my band and hack saws later...

    Jeff
     
  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Wouldn't it be easier to just start a wood fire, heat the wheels to hot short and knock them into small pieces with a hammer?

    Best,
    Kelly
     
    Tobho Mott likes this.
  9. rocco

    rocco Silver

    Last time I cut up an aluminum rim, I used my table saw with a carbide tipped, worked great, cut through the aluminum like butter, the chips however are quite nasty so a face shield and other appropriate PPE is essential.
     
    Wild Irish and Tobho Mott like this.
  10. Tobho Mott

    Tobho Mott Gold Banner Member

    Definitely considering the table saw idea... I don't have one, but a friend will let me use his. He doesn't have a carbide blade but I could grab one... This may end up being what I do, kill 2 birds with one trip into town, hit up Crappy Tire to buy various blades then stop by his place on the way home to make some noisy metal sawdust. I have these 4 truck wheels plus ~1.5 car wheels and one more from a motorcycle to deal with, but even if I just deal with a couple of them for now I should be fine. Lucky me, only the bike wheel still has a tire on it.

    Thought about the bonfire method too. I had some difficulty getting wheels out of the fire without them falling apart and the chunks melting into a pool at the bottom of the fire that I still had to break down later. Admittedly, I could probably have timed it better and had more success when I tried it... I guess all the snow and ice (and/or refreezing water by the time I'm done) wouldn't make it easier to collect the bits right now though, so I may revisit this method in the summer.

    Jeff
     
  11. rocco

    rocco Silver

    If you do go the table or circular saw route, it works great but I was serious about the chips, protect yourself!
     
  12. Chazza

    Chazza Silver

    I have the same wheel problem.

    I thought of an oil-fired retort-furnace which could be moved on the 3PL on the tractor, to a convenient spot. The metal could be poured into ingot moulds on the ground and the furnace tipped by hydraulic power if necessary.

    Alternatively, Denis's link to the nibbler has got me thinking as well; the tractor could run a smaller one of them with ease.
     
  13. Al2O3

    Al2O3 Administrator Staff Member Banner Member

  14. Melterskelter

    Melterskelter Gold Banner Member

    It could be quite simple. Fixed stand mount. Weld tool steel faces on the jaws or have someone stellite (or equivalent) hard face them. Use an angle grinder to get them to match to some approximation---no need for a particularly close fit. Fire up the tractor for hydraulic power. Carry pieces to the nibbler. I like this idea as I think it is safer and less nerve rattling to feed the nibbler than watch for kickbacks and binding with a circular saw. I've sawn my share of aluminum on a table saw and with a hand-held circular saw. It works well enough. But it is mighty noisy, the chips are hot, and the constant threat of binding keeps me on edge. The nibbler just sits there and chomps away.

    Denis
     
    Chazza likes this.
  15. Smoking Shoe

    Smoking Shoe Silver

    Anyone here tried a log splitter?

     
  16. Petee716

    Petee716 Gold Banner Member

    We had a member at AA, BobS, who was quite a prolific aluminum caster - closer to a pro than most. A wood splitter was his method of choice if I recall correctly. I remember him testing a stack melter similar to Tobho’s but whether he ended up switching to that method is unknown. That leads me to believe that although he found the splitter to be effective, he was still looking for a better way. I think the sudden release of energy kept him “on edge”.
    Pete
     
  17. Melterskelter

    Melterskelter Gold Banner Member

    If a person were to use a splitter, making a spring -assisted, hinged, expanded-metal, box-like fence that could be dropped into place surrounding the piece being crushed would contain chunks that might be thrown. If pieces were also observed being ejected vertically, I’d add a top to the box. The splitter with a flat-faced ram looks pretty efficient and safe.

    Denis
     
  18. Peedee

    Peedee Silver

    As I remember BobS had the splitter as a tractor attachment, I assume that gave him a small amount of distance from the action?
     
  19. I had a Renault car aluminium wheel to cut up last year. I used my Bosch jig saw with a coarse wood blade and it cut the wheel up very easily. It even coped with the thicker parts of the wheel, but not the middle with the bolt holes. I made a small fire in the back garden using scraps of wood under a steel grill. cooker shelf I think, and it no only burnt all the paint off it also melted some of the thinner parts of the wheel. I did fan the flames with a piece of cardboard, but no forced air. Prehistoric man is alive and well and living in Cornwall, UK.
     
  20. Tobho Mott

    Tobho Mott Gold Banner Member

    Many of you may remember my usual method for breaking down wheels with a wood fired "stack melter". For anyone else, it is described here: http://forums.thehomefoundry.org/index.php?threads/tobhos-water-bath-bulk-scrapper-for-aluminum.20/

    The water bucket that goes under it rusted out on me. Plus my hose is closed for the season (reason: freezin) anyhow.

    Had today off so I managed to get another 4 flask sides poured with the last of my ingots and sprues before I went into town to get my booster shot and visit a table saw's house where a friend of mine happens to lives. Got one of the truck wheels fully chopped up. I cut it up much as Kelly describes in the post he linked above. It took longer than I thought, but it worked well. No blood. Wore leather from the neck down (jacket, apron, gloves, spats) with my hardhat face shield and glasses. The worst part was trying to see what I was doing through the frost on my face shield! That and running inside and down to the basement to flip the breaker for his garage half a dozen times.

    After I was done one wheel it was getting dark and I was half frozen and gave up for today. I've got enough to get me through the next several melts now at least. Chucked all the wheelium chunks and PPE in the trunk, put my toque on, pulled up my hood, got into the car and drove home. Took me about 20 minutes on the road to notice all the aluminum chips I'd dumped down the back of my shirt out of my hood. :(

    I still have to go shake out those 2 molds from this morning after I grab some dinner; hopefully good things are in the sand waiting for me...

    Jeff
     
    Mark's castings likes this.

Share This Page