Page 5 of 7 FirstFirst ... 34567 LastLast
Results 41 to 50 of 68

Thread: Novice Casting Questions

  1. #41
    Senior Member
    Join Date
    Dec 2010
    Location
    Vienna, Austria
    Posts
    690
    Blog Entries
    4
    Nice casting.

    Is your moulding board that peice of OSB? Do you sometimes have issues with separating the cope from the drag cleanly? I use a really smooth finished ply (printers plate? not sure of it's english name, it has a sort of phenolic coating).
    Mark

  2. #42
    Senior Member
    Join Date
    Jan 2012
    Location
    Buffalo, NY
    Posts
    2,422
    I think your last picture shows the cooling effect pretty well. It looks like the shrinkage in the top is more symmetrical around the hub than in previous castings. It's still there though. Your narrow-neck riser froze too soon to give any effect. Your riser needs to have at least as much volume-and then some- as the hub and has to stay molten longer than the rest of the casting. You've got a couple of obstacles to that, mainly because your pattern comes so close to the top of the cope. Being open to the atmosphere doesn't help it either. An option might be to fill an open ended soup can with sand and set it over the full diameter hole to help insulate the riser. Another would be to use a two-part pattern, one for the disk and one for the hub with opposite draft angles and located with dowels. Ram the disk in the drag, flip, set the hub (you could incorporate the riser on the hub pattern), and ram the cope. That would put you further down into the mold. Put some weight on top of the mold so the cope doesn't float on you.
    I know enlarging the riser will make for more finishing later but it should remedy your shrinkage. We might be splitting hairs too because your shrinkage might be at an acceptable level and will machine away but that's up to you.
    Sorry if I seem like I'm picking. I'd don't know a helluva lot, but you keep cuttin' so I'll keep bleedin.
    This hobby is really infectious. I'm glad to see you jumping right in!

    Pete

  3. #43
    Member
    Join Date
    Mar 2017
    Location
    West of Tulsa, Oklahoma
    Posts
    36
    Quote Originally Posted by rotarysmp View Post
    Nice casting.

    Is your moulding board that peice of OSB? Do you sometimes have issues with separating the cope from the drag cleanly? I use a really smooth finished ply (printers plate? not sure of it's english name, it has a sort of phenolic coating).
    Mark
    Thanks! No, the OSB is just a rough work area. I'm using some oak veneer plywood that I lacquered. It seems to work cleanly, but I have thought of making a Formica (kitchen counter top) molding board. However it is so smooth the sand may stick to it.

    Quote Originally Posted by Petee716 View Post
    I think your last picture shows the cooling effect pretty well. It looks like the shrinkage in the top is more symmetrical around the hub than in previous castings. It's still there though. Your narrow-neck riser froze too soon to give any effect. Your riser needs to have at least as much volume-and then some- as the hub and has to stay molten longer than the rest of the casting. You've got a couple of obstacles to that, mainly because your pattern comes so close to the top of the cope. Being open to the atmosphere doesn't help it either. An option might be to fill an open ended soup can with sand and set it over the full diameter hole to help insulate the riser. Another would be to use a two-part pattern, one for the disk and one for the hub with opposite draft angles and located with dowels. Ram the disk in the drag, flip, set the hub (you could incorporate the riser on the hub pattern), and ram the cope. That would put you further down into the mold. Put some weight on top of the mold so the cope doesn't float on you.
    I know enlarging the riser will make for more finishing later but it should remedy your shrinkage. We might be splitting hairs too because your shrinkage might be at an acceptable level and will machine away but that's up to you.
    Sorry if I seem like I'm picking. I'd don't know a helluva lot, but you keep cuttin' so I'll keep bleedin.
    This hobby is really infectious. I'm glad to see you jumping right in!

    Pete
    I read your earlier suggestion at a full size riser and I didn't really understand. Everything would be simpler if the hub was just extended to the surface with no neck to act as a riser. I think I'll try that. It's about as easy to part off the hub as it is a small riser once you're set up.

    My original pattern had wood lathe center marks both ends which gave me lineup points to start machining from. Modifications have taken them away which is no big deal.

    You're not picking. You are helping me with my learning curve. My goal is not to make pulleys or sheaves but to learn foundry practice. When I cast a shaft fairly cleanly I chose a pulley as a next step. Rather than spend time making new patterns I think I'm learning a lot manipulating the sheave pattern to correct defects, whether they be fatal defects or not. Anything like this takes practice before you start to get a feel for it and then correcting mistakes will get easier, I'm sure.

    This is infectious. I really like turning cans into something useful. I have a limited amount of cast stock and lots of cans and extrusions. So as long as I'm making things for practice the cans are doing fine. And I think it will be a bit like TIG welding. I learned to oxy-acetylene weld with baling wire and got reasonably proficient with it. Then when I tried TIG it was easy, all the heat you want and no popping if you spend too much time in one spot. I'm guessing the transition from cans to cast will be similar. But my goal is cast iron and I want to learn bronze as a second step. Each metal has it's place.

    The hobby is infectious. And the pattern maker I met said he has lost his last foundry which would make one or two castings for a customer so he may have an occasional job for me. That would be great. I have a neighbor's tractor to repair so I need to slow down on the casting but I just don't want to and don't have anyone telling me what I have to do

    The more comments the better!

  4. #44
    Member
    Join Date
    Mar 2017
    Location
    West of Tulsa, Oklahoma
    Posts
    36
    I turned a new wheel for my pattern, and relieved each side.

    IMG_1075.jpg

    Got the web down to about 0.40" from 0.75". Also put in a double gate to feed the thick rim and a large riser (I really do listen, just a little thick)

    IMG_1078.jpg

    Another nice pour, that thing sucks!

    IMG_1082.jpg

    Casting came out great, as everybody else already told me what to do. Thanks!

    IMG_1083.jpg

    I went prospecting, and found what I believe is some genuine wheelium.

    IMG_1085.jpg

    And out in the pasture, what is this? Pistonlite? I know what is on the fuel tank, that's pot metal.

    IMG_1086.jpg

    I was talking to some guys at a shop in town today, and they handed me a big piston, probably 4" by 6" long, flat top. Does it hurt anything to cut it up with a plasma torch?

    Getting ready to make my first core.

  5. #45
    Senior Member
    Join Date
    Jan 2012
    Location
    Buffalo, NY
    Posts
    2,422
    Nice sheave! It looks like you're an old pro!
    Seriously, that turned out nice. You're right it sucks. That's a pretty good illustration of the feeding.
    The rim is a winner. The pistons may or may not be great. Others may be able to speak to that. The potmetal is aptly named but unfortunately that's a real name, albeit a generic one, for zinc alloy.
    Keep up the good work.

    Pete

  6. #46
    Junior Member
    Join Date
    Jan 2017
    Location
    West Michigan
    Posts
    21
    Very nice! I am learning a bunch from this thread and not even doing any work!! This thread has really helped the stuff I have been reading, sink in to the "void between my ears".

    Old Iron - Are you turning your patterns on your metal lathe? I'm not sure if I like that idea or not ... but its all I have.

  7. #47
    Member
    Join Date
    Mar 2017
    Location
    West of Tulsa, Oklahoma
    Posts
    36
    Quote Originally Posted by Petee716 View Post
    Nice sheave! It looks like you're an old pro!
    Seriously, that turned out nice. You're right it sucks. That's a pretty good illustration of the feeding.
    The rim is a winner. The pistons may or may not be great. Others may be able to speak to that. The potmetal is aptly named but unfortunately that's a real name, albeit a generic one, for zinc alloy.
    Keep up the good work.

    Pete
    Thanks! I've about beat this little pattern to death. The only thing left I want to do is holes. I'm starting to understand why I'm doing what I'm doing.

    I forgot to mention, I used a thermocouple to measure the crucible temperature. First the flue temperature was about 1,800F. fire off, crucible out, aluminum was 1,435F. I waited until it fell to 1,325F and got a 1,295 F reading but it poured ok. On a link I think you posted on thermocouples I read where one guy said he burned the SS sleeve off his thermocouple but it kept working, for a couple of years. So I decided to just use a bare thermocouple with braided white cover. Cover burned back but the thermocouple still seems to work. I would have thought the two dissimilar wires would short. It now has an aluminum sleeve.

    I also had a comment about my crucible. I just welded it up out of 304 SS pipe and plate. It has had at least 16 heats in it now and I can't see any deterioration. I've read SS does not hold up, but I'm wondering if that is the 400 series culinary stainless.

    I greatly appreciate the help. This is a great site.

    I've heard that pistons are high silicon and should be good, may even take a 50% dilution with candemonium.

    Going to make a wrench next.

    Thanks again.

  8. #48
    Member
    Join Date
    Mar 2017
    Location
    West of Tulsa, Oklahoma
    Posts
    36
    Quote Originally Posted by Mister ED View Post
    Very nice! I am learning a bunch from this thread and not even doing any work!! This thread has really helped the stuff I have been reading, sink in to the "void between my ears".

    Old Iron - Are you turning your patterns on your metal lathe? I'm not sure if I like that idea or not ... but its all I have.
    Thanks! We're learning together. So far I feel I've been very lucky. Everything I've made has been usable. I really thought I'd be recasting the first several items. I'm sure that time is coming. I figured this thick rim might get me in trouble. Of course I'm of the school that, if I can, I just start doing. Not that I haven't been reading and thinking for several months but I was having trouble getting everything collected I thought I'd need. Now I'm spending a fair amount of time making tools.

    I don't like wood on my metal lathe either. Or the mill. The pattern maker I visited never does metal work, he had two nice Bridgeport's and a couple of old lathes. I had been hand turning up until this wheel but I knew I needed better precision than I was getting by hand. And carbide inserts don't cut walnut very well so I had to grind me a tool steel tool to cut the last wheel (I did try carbide, nope).

    I do have a 9" South Bend lathe I loaned out several years ago and it is coming back this weekend. It will be great for patterns. Belt drive lets it slip if something hangs up. The big lathe would just split the wood. And I have to make more lathe tooling like an arbor to hold a flat piece by the hole.

    Thanks for commenting.
    Last edited by oldironfarmer; 03-16-2017 at 01:20 PM.

  9. #49
    oldironfarmer, everybody lost interest in my post, my personality I guess, so thought I better see what your doing, excellent job your doing.

    Wish I had my lathe back and the the tools you have, and the walnut, its expensive here so I just use simple old pine, it takes alot of sanding to get a smooth surface ,it sure is time consuming but fun.

    I use Formica (kitchen counter top) also as a moulding board, but with my arthritic hands I need to be careful of everything slipping out of my hands, so have been using a clamp on each side.

    Great work,
    C
    If You Cant Be Handsome Ya Gotta Be Handy

  10. #50
    Senior Member
    Join Date
    Mar 2014
    Location
    Charleston, West Virginia USA
    Posts
    456
    Alright...wheelium!

    https://youtu.be/QOkbl61Hsiw
    Bones

Posting Permissions

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