How Would You Repair This Cast Metal Part?
Close
Login to Your Account
Page 1 of 2 12 LastLast
Results 1 to 20 of 23
  1. #1
    Join Date
    Dec 2017
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1

    Default How Would You Repair This Cast Metal Part?

    Picked up a vise for $20 bucks. It's an older Chinese model, 5 inch rotating. Yes it's a china knock off, but I took a risk for only 20 bucks. It works fine, so I took it apart to clean years of grease and dirt. Discovered the cracks in the pics (below).

    I have been reading about how to weld cast, and while I am not a "welder" I do have "above average home owner/handy man" experience with a typical stick ac/dc (older century) welder. No trouble making good solid welds in mild steel. Have been welding ac/dc for over 20 years for typical repairs, fabrication, and built a few utility trailers for on and off road, etc. I know what a good weld (and penetration) looks like..

    Just not familiar with cast iron. I will grind/recess the cracks, clean as best as possible, preheat, and I will keep the part hot while welding and cool slowly (I have a powder coat oven to heat things up as well as cool things down in the oven slowly) or place in sand.

    Planned on using Hobart "nomacast". The length of the crack (one on each side) is about an inch long, maybe a little less, and I can access the parts being welded from the front and from the back side, so I can really build things up from both sides if needed to ad strength.

    The cracks are at the inside of the 90 degree, the line you see circled in yellow (in last pic)is just a casting mark and is not a crack.

    I plan on grinding the cracks, heat part up, run a bead, peen the bead, keep a torch handy to keep part hot if things are going slow, peen some more, then going to the crack on the other side, run a bead over there, peen, then let cool slowly, work my way from one side to the other.

    My question is, running multiple beads to build the area up for strength and fill. Should I make multiple passes in one session? Should I make single pass on each side, let cool slowly, grind if needed, reheat, then make another pass or two? Multiple passes without grinding?

    I was planning on building things up with multiple beads for strength, as well as welding things up from the other side to make the area stronger also. This is the part that the acme rod passes thru and is torqued when the vise jaws are closed on an object, so I am thinking I need to reinforce and build up the areas that are cracking.

    I know it is a 20 dollar Chinese vise. It is big beast, seems to be built better than some of the current Chinese models, and I could put it to use it if I can successfully weld the cracks up and make it solid. If I fail, then at least I have a boat anchor and some experience with welding cast. Gotta start somewhere. Any advise on the welding or repair would be great. Thanks for your time, KD


    img_5899.jpg

    img_5904.jpg

    img_5905.jpg

    img_5904_li.jpg

  2. #2
    Join Date
    Mar 2011
    Location
    Geneva Illinois USA
    Posts
    4,852
    Post Thanks / Like
    Likes (Given)
    1913
    Likes (Received)
    1813

    Default

    I would open up the cracks leaving just enough material to hold the pieces together and then braze it. Those corners are high stress areas where the ductility of the copper alloy will handle nicely.

    Tom

  3. Likes Scottl, Ken hosford, Newman109 liked this post
  4. #3
    Join Date
    Aug 2006
    Location
    montana
    Posts
    378
    Post Thanks / Like
    Likes (Given)
    188
    Likes (Received)
    151

    Default

    that's a poor design for a vise. I would try to put in a couple of reinforcing pins first, then grind out the cracks and silver braze it.

  5. Likes Scottl liked this post
  6. #4
    Join Date
    Nov 2013
    Location
    Eastern Massachusetts, USA
    Posts
    4,101
    Post Thanks / Like
    Likes (Given)
    3814
    Likes (Received)
    3654

    Default

    I would second using a brazing process. Welding cast iron successfully takes practice and for a Chinese part of unknown composition unless you preheat and protect from rapid cooling it will likely crack again. IMO the general design looks failure prone.

  7. Likes Ken hosford liked this post
  8. #5
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    10,232
    Post Thanks / Like
    Likes (Given)
    17296
    Likes (Received)
    5312

  9. Likes Oldwrench, thermite liked this post
  10. #6
    Join Date
    Dec 2017
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1

    Default

    Thanks for the replies, and the advice.

    I really did not really consider brazing and have to admit I am disappointed because I kind of wanted to attempt this repair myself to gain some experience. Also disappointed as I do not have an oxy torch set up but probably can get my hands on one to use. But then again, only really have experience with SMAW of steel.

    Good advice on posting over at those welding forums, I think that is what I will do next. Then figure out plan B. Again thanks for the replies. YD

  11. #7
    Join Date
    Jan 2015
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    363
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    161

    Default

    I've been successfully welding cast for 30 plus years, I'd braze it also..., my second choice would be tig with what we call 55/45.

    My last choice is ARC ( Smaw ), prep the joint, heat it in the BBQ, preheat a plate that you will set it on so the table doesn't suck the heat away, weld it up, peen it with a needle scaler, if you don't have a needle scaler use a chipping hammer with a dull point, don't sharpen it, reheat it after its peened and wrap it in insulation, We use our fibreglass fire blankets folded over about 4 times, it really holds the heat for a good long cool down.

    Good luck, you dont need to search any farther, this is not rocket science, just make sure you over build the part, its the under cut that will hurt you the most, try to round and contour everything, sharp corners will lead to cracks.

  12. Likes thermite liked this post
  13. #8
    Join Date
    Oct 2005
    Country
    UNITED STATES
    State/Province
    Pennsylvania
    Posts
    10,232
    Post Thanks / Like
    Likes (Given)
    17296
    Likes (Received)
    5312

    Default

    Quote Originally Posted by Portable Welder View Post
    Good luck, you dont need to search any farther,
    It's a home shop grade Chinese vise, please read the rules the owner of the site has posted in reference to the aforementioned.

  14. #9
    Join Date
    May 2009
    Country
    UNITED STATES
    State/Province
    Wyoming
    Posts
    3,017
    Post Thanks / Like
    Likes (Given)
    6591
    Likes (Received)
    4638

    Default

    That piece of Chinese iron is worth a lot less than the rod, fuel and time required to preheat it and do the job. The most you're gonna wind up with is a repaired POS vise. Believe me, I completely understand the powerful drive to fix up something you got cheap, but it's dumpster material.

  15. Likes thermite liked this post
  16. #10
    Join Date
    Jan 2015
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    363
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    161

    Default

    Digger Doug, I'm about helping people, the advice I gave holds true no matter what the part is or where it came from.

    Old Wrench, your right, those are junk vises, I broke my uncles vice about 30 years ago due to, too big of a hammer, it was the same type, I brazed it back together and never used a hammer on it again. I only have old American made in my shop nowa days.

  17. #11
    Join Date
    Jan 2002
    Location
    West Coast, USA
    Posts
    7,288
    Post Thanks / Like
    Likes (Given)
    355
    Likes (Received)
    4213

    Default

    Agree with Oldwrench on this. This isn't going to be a vise you can trust not to fail again, even with the best of brazing. Could be the vise just failed from inclusions in the cast iron -- and tightening it hard not hammering on it. Might still be crappy cast iron left right next to where you'd braze it?

    Often enough the purpose of a large vise is to do exert enough force -- bending rod and the like -- where you're likely to hurt not just the vise in a sudden failure. FWIW, the tensile strength on a good vise is about 2x most of the cheap Chinese ones -- and that's not even including porosity and inclusions.

  18. #12
    Join Date
    Aug 2015
    Country
    UNITED STATES
    State/Province
    Illinois
    Posts
    858
    Post Thanks / Like
    Likes (Given)
    711
    Likes (Received)
    366

    Default

    Grind a V on each side of the crack. Preheat to 800F. OA weld using cast iron rod and borax flux. Slow cool. Crappy Chinese iron will probably break again outside the weld.

  19. #13
    Join Date
    Dec 2017
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    4
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1

    Default

    I know it's cheap Chinese, but tossing it will not gain me any knowledge. Reading your posts (most of them) and giving some of your suggested methods a try is how I will gain knowledge. Even with a failure. This is number 5 of the vises I own. The others are all good solid vintage "American" vises of various brands from 3 to 5 inch that I acquired over the years. Again, this vise will be a "teaching" tool so to speak.

    So 20 bucks for a vise, 20 or 30 in welding materials, and how much value is knowledge will I have gained in the process. Even with a failure. I now know the different types of rods used for welding cast, the methods, the process, the pluses and minus etc., and am currently reading up on brazing. I will know the process behind that in the next day or two.

    I have read countless articles and postings, along with watching vids, and so far I think I have my moneys worth already. The actual implementation (welding or brazing of the part) is the desert. Regardless of success or failure.

    A lifelong friend of mine has a set of torches, and I am heading down the road of brazing at this point. Again, learning experience. And again, I can and will literally use this as a boat anchor (rowboat) if I can't use it as a vise. YD

  20. Likes PlasmaOnTheBrain liked this post
  21. #14
    Join Date
    Nov 2008
    Location
    Madera county california usa
    Posts
    2,116
    Post Thanks / Like
    Likes (Given)
    19
    Likes (Received)
    491

    Default

    Suggest making filler blocks.

    The stresses are in the corners where a sharp corner exists and forces concentrated on a small area.

    So consider a few thoughts.

    use gas and braze it and get it flowing to where the filler fills in the crack.

    After that is completed do some filing of the surfaces to have clean faces and make some blocks that will fit in the corners to add support that also will fit inside where this goes.

    Consider drilling and pining into place then brazing to make solid.

    After completed some going or other finish work likely will be needed for it to fit.

    It is about learning any trying things...

    Sent from my SAMSUNG-SGH-I337Z using Tapatalk

  22. #15
    Join Date
    Jan 2005
    Location
    The Netherlands
    Posts
    5,326
    Post Thanks / Like
    Likes (Given)
    220
    Likes (Received)
    1224

    Default

    Drill a blind hole in it at 90dgr of the crack
    Thread it and loctite a piece of threaded rod in and be done

    Believe me if you have to ask how to its turning in to a disaster


    Peter

  23. #16
    Join Date
    Apr 2008
    Location
    Southampton, UK
    Posts
    26
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    2

    Default

    If you know someone who has a TIG ask them if they can braze it for you.

  24. #17
    Join Date
    Mar 2013
    Country
    UNITED STATES
    State/Province
    Washington
    Posts
    195
    Post Thanks / Like
    Likes (Given)
    115
    Likes (Received)
    152

    Default

    Sometimes the best repair is to not.
    Your a machinist right?
    Make a new one only better

  25. Likes JLarsson, wheels17, Pathogen liked this post
  26. #18
    Join Date
    Dec 2004
    Location
    uk
    Posts
    12,601
    Post Thanks / Like
    Likes (Given)
    3543
    Likes (Received)
    5674

    Default

    Welding castings is never a good fix when they broke originally do to poor weak design.

    Welding castings as a repair method only works when something exceptional broke them and its a event that won't happen again.

  27. Likes Oldwrench liked this post
  28. #19
    Join Date
    Sep 2011
    Country
    UNITED STATES
    Posts
    19,279
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    6097

    Default

    Quote Originally Posted by Portable Welder View Post
    Digger Doug, I'm about helping people, the advice I gave holds true no matter what the part is or where it came from.

    Old Wrench, your right, those are junk vises, I broke my uncles vice about 30 years ago due to, too big of a hammer, it was the same type, I brazed it back together and never used a hammer on it again. I only have old American made in my shop nowa days.
    Shop full of GOOD US made and Italian made (Gerardi) vises NOW, and yet..

    A Chinese - or maybe Taiwanese - made bench vise about two sizes larger than Harbour Freight stocks has been a staple for 20+ years.

    That said, even though it is far more stout than the one shown here, welding or brazing time and materials would be wasted on a $78 dollar vise, new price, even adjusted for inflation.

    Learned that much, first three over-rated Wilton "Bullet" vises as I busted, or saw others destroy. Pretty much good for pretty, not so much good for strong, those Wiltons.



    Also learned to not expect infinite reserves of strength from ANY vise, so...

    Take what the recyclers pay on mass. Put cash toward a vise as is not YET busted, and go do something more meaningful with the time saved.
    Last edited by thermite; 03-01-2018 at 10:17 AM.

  29. #20
    Join Date
    Jan 2015
    Country
    UNITED STATES
    State/Province
    Michigan
    Posts
    363
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    161

    Default

    Back when I repaired that chineses vise I was low on money, low on skill and a fair amount of time on my hands....

    What I gained from that repair... a junk vise that worked again for several more years, skills ( Experience )

  30. Likes PlasmaOnTheBrain, Pathogen liked this post

Tags for this Thread

Bookmarks

Posting Permissions

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