Page 1 of 21 12311 ... LastLast
Results 1 to 10 of 208

Thread: Gearing up for sand casting

  1. #1
    Senior Member Tobho Mott's Avatar
    Join Date
    Oct 2013
    Location
    Ottawa, Ontario, Canada
    Posts
    1,931

    Gearing up for sand casting

    Following up from a post I made in the 'what I did today' thread, cause I guess a couple of you thought there might be something here worth being able to find again after a couple weeks have gone by: http://www.alloyavenue.com/vb/showth...l=1#post188429

    I haven't done anything here that I didn't learn to do from you guys here on the forum or from one or two casting books most of you have probably read too, but I figure maybe someone will point out a few mistakes I may be preparing to make and warn me ahead of time; who knows, could be a big help to me, and perhaps others getting started with sand casting as well.

    I've been playing around with lost foam for a couple of years now, lots of Hallowe'en skulls and stuff like that, plus a couple of anthill castings and a few little things where I carved the styrofoam myself rather than buying it at Michael's or the dollar store. But I've always wanted to try sand casting and other techniques too. I just love melting stuff for some reason, and in the process of building what I need in order to do that, I've learned that I love making stuff and learning how to make and fix stuff too. I was never a real handyman type guy, but I'm working on it... So life is good.

    Last spring a friend of mine who is aware of my molten metal obsession asked me to help him with a group project he was working on for a club he belongs to in Guelph, Ontario - making a few (strictly decorative) cast aluminum hatchets. Their group was pretty big so they could afford to spend some money since they would each only have to kick in a little. Each a of them also played some role in it - the guy with a 3D printer made a pattern, the guy with the sandblasting equipment did the finishing work, my friend ordered the green sand from Smelko Foundry Products in nearby Milton, and so on. Of course I agreed to road trip out with a little portable charcoal furnace to show them my best myfordboy impression to show them how to do it and try to keep them from filling their boots with molten metal! I'll add some pictures in later of what we came up with, but it worked out ok and we had a lot of fun despite some snags which I think I've posted about before. Point is, I came home with 100 pounds of green sand in my trunk and almost enough refractory to build my new furnace which is the subject of another long thread. (I stopped at Smelko while I was in the area - amazing tour of the warehouse. My son spent the whole time playing with the shredding machine in the office, he had almost as much fun as I did...) So anyhow, I have had the beginnings of what I need in order to level up for about a year, sitting in buckets in my shed. And a very small amount of hands-on sand casting experience. Time to put it all to work! Aluminum skulls and anthill casting tree sculptures are fun and I'm not saying I'm all done with that stuff by any means, but I want to make some unique items that are also practical in some way too. Not that my lost foam skull belt buckle doesn't keep my pants up every day, but it is the exception to the rule. That and the 'Mom's purse' hook I made. She never asks me if I've seen it lying around somewhere anymore, even though it always still is...

    You can see a bit of what I've been working on in the link to the 'what I did today' post (bronze axe pattern and core box, aluminum sand rammer pattern, and a flask, if you don't feel like clicking) but I have more pix of how I made the core box and other things. I'll start gathering up attachments and links about all of that and add them in to upcoming posts here rather than spend all day editing one giant post and probably losing it all somehow by accident. Hopefully you guys will have some comments and questions and suggestions, and I'm sure I'll be asking questions of my own at every stage as well. But right now I better go make sure the kids are not driving their Mom up the wall, it is Mother's Day after all...

    More later,

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  2. #2
    Senior Member Tobho Mott's Avatar
    Join Date
    Oct 2013
    Location
    Ottawa, Ontario, Canada
    Posts
    1,931

    Tools for pattern making. And for the foundry... And for in general.

    More background.

    Been accumulating stuff with sand casting the bronze axe in mind for a few months now, some of which I have already posted about here and there.

    Like my new (used) band saw:
    image.jpg

    And a belt/spindle sander like this. Found good deals on both, used, from local sellers online.


    I used the saw to cut out the axe pattern, and the sander to refine the axe pattern and add draft angles to both the axe and rammer patterns. Never used these type of tools before but it was pretty easy. I think the saw might be just a little out of square though, but I haven't yet learned how to do any sort of fine tuning. Likely it is user error anyhow. Good enough for what I've been doing though, and I'm sure there's a youtube video that will teach me how to improve things when I get around to working on that.

    Then I saw a small flux core wire feed welder on sale at Princess Auto that I though I could afford for making my crucible tools. Can't use my steel crucible for bronze casting. I used a bigger MIG machine to make my furnace last year using the same wire, so i have a little familiarity with that.
    http://www.princessauto.com/en/detai...er/A-p8538886e

    Soon I had my tongs and pouring shank made. I hope they don't give me any trouble when the heat is on, so to speak. I think I still have a bit of work to do on them. I want to reinforce the sides of the jaws on the tongs a bit and add a lever at the back end of the shank. But they're just about there, I think.

    image.jpg image.jpg

    The ring is a piece of an old temporary spare tire wheel. I used pieces of an old rake among other things to make the tongs.

    image.jpg

    Here are a couple I think have not appeared here before... Tongs open, tongs closed...

    image.jpg image.jpg

    I had to hang the mangler up on the wall on the left there as you can see, to make room on the bench to use the new tools to make the other new tools and the patterns.

    image.jpg

    Kids are acting up again, gotta go lay down the law. More later on the core box and patterns in progress.

    Jeff

    Edit - fixed messed up attachments
    Last edited by Tobho Mott; 05-08-2016 at 10:23 PM.
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  3. #3
    Senior Member Tobho Mott's Avatar
    Join Date
    Oct 2013
    Location
    Ottawa, Ontario, Canada
    Posts
    1,931

    How I made the core box

    So, I decided to use a piece of a hockey stick to make the core prints for the axe pattern, as it looked like it would fit pretty well. At some point after rounding it off on the sander and splitting it on the band saw I got a little ahead of myself and started cutting it in two to fit it to the pattern. Nothing for it but to tape it back together so I could make the core box. So the core box is a layer or two of masking tape bigger than the actual core prints, which I hope won't be a problem.

    I used some Lego to hold in the plaster, and built a dam of plasticine around the core print up to the parting line. Except on the flat end, which I put right up against one wall of the Lego box. Pix needed here...

    image.jpg image.jpg

    I poked a few dents into the plasticine with a screwdriver so the plaster would have bumps cast onto the bottom of it. Then I got out the ole sac o'grease and smeared some all over the inside of the Lego box and on the pattern to seal up the seams and act as a release, and keep the plaster from getting between the Lego and the one end of the pattern. Then I poured the first half of the core box. It isn't actually pop, it's something tougher like dental plaster, but made for hobbyist use. I had it left over from building some models for tabletop gaming several years ago. Hirstarts.com sells rubber molds for that and the site has lots of good tutorials for making molds and casting plaster, that's where I got the Lego trick from.

    image.jpg image.jpg

    Then once it dried, I took a part the Lego, flipped over the plaster, and peeled the plasticine off the other side. Then I built the Lego box back up around it, greased it, and poured the other half of the core box. It came apart great, and the core print pulled out with hardly any breaking at the parting line.

    image.jpg image.jpg image.jpg

    I'll try and get some pix of the patterns up here tomorrow. First coat of shellac has been drying as I typed this...

    Jeff
    Last edited by Tobho Mott; 07-03-2017 at 04:31 AM.
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  4. #4
    That's looking good.
    Your man cave is filling up nicely Jeff
    The only time You're not following your nose is when your going backward!.......Andy (ME) .
    Have you filed in "Who do you think you are?" "War Grade Report" " My photo's"

  5. #5
    Senior Member
    Join Date
    Jan 2012
    Location
    Buffalo, NY
    Posts
    2,649
    Nice technique with the Legos! I love the rake head on the lifter too. I find that on my bandsaw, and table saw for that matter (sort of), that the squareness of the fence is most important to prevent binding and flexing of the blade as the material is pushed through, so it is definitely important. But as long as nothing moves or wavers the cut stays straight because the point of contact on the blade relative to the fence doesn't change. It is difficult to keep the bandsaw blade from flexing sometimes though. I'm not a pro though, or even a great amateur for that matter, so take that with a pinch of salt!

    Pete

  6. #6
    Senior Member Tobho Mott's Avatar
    Join Date
    Oct 2013
    Location
    Ottawa, Ontario, Canada
    Posts
    1,931
    The feedback is much appreciated, thanks guys...

    I am happy with how the Lego worked out; easy to build and rebuild the form to any size that way, and seems to work great.

    Yeah, I definitely think the blade was flexing a little, that was the user error I mentioned. But the table may also need to be micro-adjusted; even when it is tilted to 0 degrees, I think it is cutting at a slight angle. There is a screw for adjusting that, but it is hard to get a good read on how straight it already is - the blade guard doesn't go up high enough to fit my little square up against the blade to check. There is a control to adjust the tracking, but I have not messed with it. How do you tell if that needs adjusting? Could that make cuts seem not quite square, or would it manifest itself in some other way?

    And it is tricky to get the fence square to begin with; I line it up with the grooves on the table and/or use a square to get it to a 90 from the table edge, but then when I tighten it down, it always moves juuuust a little.

    Probably all just stuff that will improve with more experience. But don't let that stop anyone from offering up tips!...

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  7. #7
    Senior Member Toolshed's Avatar
    Join Date
    Jun 2014
    Location
    Independence, KY
    Posts
    592
    Tobho, Make sure your thrust bearings and cool/guide blocks are set up correctly. I just had to machine a new lower thrust bearing this past weekend for my little Craftsman bandsaw, it's about the same size as yours there. Mine had not only siezed, but the back of the blades had cut about halfway through the bearing , meaning I had been a VERY BAD SAW DADDY!!

    Now I have my guides set properly, the saw blade riding center of the wheels, and the thrust bearings BARELY touching the running blade.

    Could also be the fact I just put on a wider blade, but mine is tracking MUCH better now....
    "If you work with your hands, you’re a laborer.
    If you work with your hands and your mind, you’re a craftsman.
    If you work with your hands and your mind and your heart, you’re an artist."

    Saint Francis of Assisi

    Google Map of members:
    https://www.google.com/maps/d/viewer...hs&usp=sharing

  8. #8
    Senior Member Tobho Mott's Avatar
    Join Date
    Oct 2013
    Location
    Ottawa, Ontario, Canada
    Posts
    1,931
    Wow! I will open mine up later and make sure it's not starting to slice itself in half. If it's just one part that's getting chopped in two, I guess I'll know what a thrust bearing looks like! Hopefully not though.



    Thanks,

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

  9. #9
    Senior Member Toolshed's Avatar
    Join Date
    Jun 2014
    Location
    Independence, KY
    Posts
    592
    Google bandsaw cool block and thrust bearing.

    The better ones have the back of the saw blade running on the OUTSIDE of the "thrust" bearing and other bearings acting as the guide bearings.

    Mine has the setup where the saw blade runs on the FLAT of the thrust bearing. http://www.ebay.com/itm/Phenolic-Ban...-/131753474919

    This setup means, if that bearing ever stalls, your blade back is cutting into it....
    "If you work with your hands, you’re a laborer.
    If you work with your hands and your mind, you’re a craftsman.
    If you work with your hands and your mind and your heart, you’re an artist."

    Saint Francis of Assisi

    Google Map of members:
    https://www.google.com/maps/d/viewer...hs&usp=sharing

  10. #10
    Senior Member Tobho Mott's Avatar
    Join Date
    Oct 2013
    Location
    Ottawa, Ontario, Canada
    Posts
    1,931
    Good tips, I'll look into that. Thanks again TS!

    Jeff
    Tobho had learned to work Valyrian steel at the forges of Qohor as a boy. Only a man who knew the spells could take old weapons and forge them anew.

    How I built my oil furnace | My Photo Album | My Videos

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •