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  1. #1
    Join Date
    Apr 2020
    Location
    Kentucky
    Age
    24
    Posts
    1

    Default Cast iron dilema

    I’m restoring an old gas stove. I broke a screw off in a cast iron burner top while trying to dismantle everything. I tried everything to remove the screw but I ended up drilling it out. I know it was cast iron, but I didn’t stop and think before I welded the hole in with 6011. My plan was to weld it full, drill it out, and tap it with a 10-32 tap. One of the three spokes holding the center part cracked after welding. I tried drilling it out, but it was too hard. I tried tempering the weld to soften it a little but then developed another crack. Now I can’t drill the weld and I can’t anneal it because it will crack again.

    I know there is someone smarter than me on here that can give me some advice. I would really appreciate it as these parts are very difficult to find online.

  2. #2
    Join Date
    Oct 2004
    Location
    Southern Highlands NSW
    Posts
    1,894

    Default

    As an alternative to repairing or finding a replacement, would it be possible to have a new burner cast?
    A possible benefit would be that you could make more, and provide them to others.

  3. #3
    Join Date
    Jun 2012
    Location
    SA
    Posts
    1,649

    Default

    The only option as I see it is to remove the weld with a carbide burr in a die grinder.

    Trying to drill and tap in any stick weld fillet is never going to be a good idea.

    Depending on how hot the burner gets, bronze brazing may be the only way to fix the mess. It sounds like a throw away to me, but if time is no issue you could give it another shot.

    Given the 6011 welded to the cast iron OK, you could also try GP rods with an oxy torch.

    In each case when using mild steel filler or welding rods it will be much less likely to crack or separate if you peen the weld (use a needle descaler in preference to a single point chipper).

    A lot of people think you can only arc weld cast iron with cast iron rods, but that is not so. You can use GP rods provided the cast iron is the correct type and you peen the weld.

    Good luck.

    Cheers Rob
    The worst that can happen is you will fail.
    But at least you tried.



  4. #4
    Join Date
    Dec 2007
    Location
    Sydney
    Posts
    396

    Default

    A photo would help.
    I think a pattern and corebox for this would be an interesting project to spend this lockdown on.
    You could possibly bog up etc the original for a pattern and make a corebox or slice the original for the corebox and make a pattern from scratch.
    Then all you have to do is find a jobbing ferrous foundry willing to do a one off.
    Good luck.
    I think Rob is on the right track.
    H.
    Last edited by clear out; 11th Apr 2020 at 11:03 AM. Reason: Final comment.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  5. #5
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,945

    Default

    Should anyone come across that problem again and it has to drilled out, try a small drill bit first, then open it up with a next size up, until there is like a coil spring left. This should then be able to be pulled out. Failing that, repairing the thread with Helicoils or similar is a good option; https://www.youtube.com/watch?v=9rtiFBC0wms
    HTH
    Kryn
    To grow old is mandatory, growing up is optional.

  6. #6
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Hi Wetenkamp,

    Welcome to our MetalWork forums.
    As a new members its nice to be able to look around the forum you have just joined.

    Goto the FORUM box in the top left hand corner of the page and click the down arrow. This will bring up a pull down menu that has Forum Home at the top.

    Click Forum Home which will present a scroll down page with Forums and members help areas.
    Our rules, the Terms of Service are right at the top ,I encourage you read them.

    Below that are all the various help pages and subforums that make up our MetalWork forum.
    Perhaps you might like to make a post in the Welcome Wagon ( found on the scroll down page ) area and introduce yourself.

    We look forward to your questions and contributions of knowledge to the Forum.

    Welcome

    Grahame

  7. #7
    Join Date
    Aug 2011
    Location
    Melbourne
    Posts
    4,779

    Default

    Apparently you can't oxy cut cast iron. I have heard you can use this to advantage in removing damaged studs or bolt in CI by using an oxy torch to cut/melt them out without damaging the CI.

    Never tried it though...

    Simon

    Sent from my SM-G970F using Tapatalk
    Girl, I don't wanna know about your mild-mannered alter ego or anything like that." I mean, you tell me you're, uh, super-mega-ultra-lightning babe? That's all right with me. I'm good. I'm good.

  8. #8
    Join Date
    Jan 2004
    Location
    Mackay North Qld
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    6,446

    Default

    Quote Originally Posted by Wetenkamp View Post
    . One of the three spokes holding the center part cracked after welding. I tried drilling it out, but it was too hard. I tried tempering the weld to soften it a little but then developed another crack. Now I can’t drill the weld and I can’t anneal it because it will crack again.

    Ho Wetenkamp,
    Apart from the inherent difficulty in welding cast iron, the most problematic facet of the repair operation is the geometry of the part you hope to repair.

    First up what specifically are you referring to.The hob that the gas flows through or the frame that supports the frypans and saucepans?

    The support frames are typically are formed with spokes. This frame is made up of a combination of thick and thin sections. The difficulties arise from the cast iron being heated up from welding. Those thick and the thin sections cool at different temperatures and therefore widely different cooling rates, to each other.

    The trick will be to keep the entire piece at the same temperature. You have already found out what happens when
    the frame cools unevenly.

    I would go with the advice of Nearnexus and braze the piece. It does require Oxy Acetylene unless you expert with brazing with Propane/LPG.

    In fact while one person braze welds its not a bad idea to have a second person with a LPG torch going over the frame keeping up the temperatures.

    When complete the frame goes into a bin of lime or dry sand and covered up and cools out slowly and evenly.Check the next day.

    I did the first couple of years of my apprenticeship welding almost nothing else but cast iron repairs. I have been involved with repaired of everything from Caterpillar 4 cylinder diesel heads ( typically the injection chamber pockets ) heavy industrial presses and right down to domestic items.

    If you cant do it yourself be careful when you put it out for commercial repair as many will claim they can do the work but in reality will tell you anything to get your business.

    Sorry! There is no cheap or easy procedure.If you are going to tackle it yourself I am happy to help.

    Grahame

  9. #9
    Join Date
    Jan 2004
    Location
    Mackay North Qld
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    6,446

    Default

    Quote Originally Posted by simonl View Post
    Apparently you can't oxy cut cast iron. I have heard you can use this to advantage in removing damaged studs or bolt in CI by using an oxy torch to cut/melt them out without damaging the CI.

    Never tried it though...

    Simon

    Sent from my SM-G970F using Tapatalk
    Well you can, sort of.

    The big 1 ton C press we were involved in repairing required the crack to be veed out and welded. The cross section was the throat of the C section and was 300 x 150mm in dimension and cracked.

    To remove the metal the cast iron was heated red hot and a bar of steel oxy acetylene gouged directly at the top of the crack.The gouged material would wash out a track out of the cast iron. It was slow but still quicker than grinding.

    I only saw the technique used once and that was 50 years ago ( yikes! thats a long time ago).

    It was slow but quicker than grinding. It was hot difficult work.

    Grahame

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