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  1. #1
    Join Date
    Feb 2017
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    Australia NSW
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    Question Newbi needs to repair crack in old mower base.. tips ?

    Hey guys,

    I'm new to metalworkforums and pretty much to welding too. Last time I welded was back in high School (17yrs ago), when I did metal working class and work experience.. but that was mostly using Mig (even then i didn't know how to use it properly :/)

    Not too long ago I took up a hobby repairing old mowers. The current mower I'm stripping down, doing a complete re-paint, I noticed 2 cracks in the base.. which Ill have to repair before I can paint.





    I know nothing about welding.. just wondering, can I weld this, approx 3" crack, in an old mower base with an ARC welder? The metal is about 2-3mm thick.

    Also, a 2nd crack, about 4mm long in about 4mm tick steel.

    I was told to maybe use 2.5mm rods.. so was considering getting a pack of these from Bunnings..

    Weldcorp 2.5mm Mild Steel Welding Electrodes - $12

    https://www.bunnings.com.au/weldcorp...-pack_p6330040

    The ARC welder I have access to.. is a bit.. old .. and dirty.. though should still be operational.. hopefully...

    20170201_202052.jpg

  2. #2
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    Maybe a forum member who lives nearby to you could help you out, widget. It definitely looks weldable, although it would be great if you had experience welding. Personally I'd drill a hole at the end of the cracks, groove them out a bit with a die grinder or small cutting disk and use my tig machine but if I practised on stick again I'd be willing to give that a shot too. Not with beginner skills though, unless I didn't care if I stuffed it up.

    If it's 3mm or 4mm thick that'll be heaps easier than if it's 2mm thick, especially with limited skills.

  3. #3
    Join Date
    May 2013
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    Rockhampton, QLD
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    Welcome to the forum.

  4. #4
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    Jun 2010
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    If you haven't welded for 17 years, and never with stick, and you're using an AC buzz box, I fear you're going to have a bad time.

    If you're keen to have a go, I'd get the rods you plan to use, find some scrap steel of similar thickness and then practice until you're confident.

  5. #5
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    Dec 2010
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    Syd
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    Is this a restoration for appearance sake? Paint....and bog, can hide a lot of sins!

    If it's for actual use, I'd be seeing if someone has a mig nearby, probably a minute job if prepped for them. In all likelihood, probably run perfectly well for years as is too.

  6. #6
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    Hey, thanks guys

    If I drilled the hole, is it just a matter of filling it up with the welder?

    I've used ARC a few times.. the rod getting stuck when first striking I didn't like. Used MIG more though.. I liked it, seemed easier to use.

    Yep, it's for restoration.. though would much prefer to weld it up.. at least to help prevent it getting worse if it does get used.

    It's gonna be a challenge.. but I have some scrap with similar thickness to practice some beads

    What should I look out for when welding? Is it possible to be too cold thus not welding the metal proper? if too hot, it'll melt through the base steel ? With a thin crack like that, what width bead should I be aiming at.. 5mm ?

    I've been watching some youtube videos (chuckE2009) on welding (ARC), trying to educate myself a bit more before jumping in.

  7. #7
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    The hole is to stop the crack propagating. Yes, you fill it in. Just a small drill, 2mm or 3mm max should do it.

    When welding, to increase chance of success make sure it's positioned so it's flat and you're above it (the 1G position). If it's angled in any way you'll be more likely to struggle.

    Yes amperage is important. You need to be in the right range and then the arc needs to be the right length. Other variables include electrode angle and travel speed. Too cold won't matter hugely for this project. As Hunch said it probably doesn't need to be welded other than for cosmetic reasons. Too hot and you could blow holes, but less likely the thicker the metal is. If you do blow a hole, stop immediately. With practice you can fill them on the fly, sometimes. Without practice it's better to stop and let things cool down and then if you haven't stuffed it too badly you can fill afterwards. But preferably don't blow holes anyway. If it's 2mm material that's going to be a bit more difficult for a beginner.

    If it's 1G you should be able to set to the middle of the electrodes' recommended range as a starting point and that should be fine. I find limits of the range apply to out of position work or unusually thin or thick material.

    Sticking will be less likely with sufficient amperage and well prepped work and electrodes.

    Don't aim for a bead width. The process will determine that. You don't need to weave or anything, just run a straight stringer bead. A 4.0mm electrode will run a much thicker bead than a 1.6mm electrode but as you mentioned a 2.5mm electrode will be fine for this job.

    The grinder will most likely be your friend. With some minor skill you could make the repair invisible. Even I could do that.

    Again, someone could do it for you really easily unless you want to do it yourself and don't care if it gets ruined.

  8. #8
    Join Date
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    Given that you haven't welded for a good while and you are using an AC unit theres a good chance of a blow through.

    For sure, practice on some metal the same thickness as you will weld on. Clamp a striking plate under the earth to get each electrode end up to near running temperature - much easier to strike and run on the job when done this way.

    Use strike plate and then jump straight over and start the run on the job.

    A blow through would be easier to repair and dress from the outside. That will allow for you to grind the excess on the outside nice and flush for a good paint finish.

    A cunning stunt is is to weld from the inside and back grind back through from outside to the solid metal of the inside deposited weld.Leave the bead inside, as welded as it won't matter for visuals.

    Remember it is sheet metal and best done in short bead runs - EDIT ( for the 3" length) say 1" long not a continuous 3" one,unless you want it to warp. Spread the beads out-one end ,then the other,then the center. (Sorry originally I did not read the text properly-thought it to be longer)

    The heat then,won't concentrate and warp the sheet.
    Hope this helps

    Grahame

  9. #9
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    Thanks heaps guys,. much appreciated

    I picked up some 2.5mm General Purpose Red Mild Steel electrodes today.. it says they have an AMP range from 80amp - 130amp, DC - or DC + polarity (not sure what that means..). Weldcorp WCC0017 are the electrodes.

  10. #10
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    They're what's called a 6013 rod - pretty much the standard general purpose rod.

    I'd get some scrap steel, 3mm or ideally thicker, maybe give it a quick grind to get shiny bright metal (not required for stick, but might make things easier starting out) set the welder to 100A, or maybe a bit more, and start laying some beads. If the rod sticks too much, increase the amps, if things are going nuts and you're blowing holes, either move faster, or turn down the amps.

  11. #11
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    Being an old time teacher of welding I can't resist throwing in some practice tips

    As new welder you will need to develop some "muscle memory" on the sheet metal process with stick.

    One characteristic required , not to burn through the thin material, is the method of having both the suitable arc amp setting for the electrode and the material. Keeping the arcing electrode end at an even distance from the work is called arc length.

    If you intend to weld with stick, this distance,the so called "arc length" determines, more so, the successful outcome than any other factor.

    To achieve this with any skill requires a combination of correct angle presentation to the work,a consistent forward travel speed and a consistent descending manipulation of the electrode,all happening at the time time.

    The "arc length" if too long raises the inherent voltage and enlarges the arc pool and a melt through is more than likely.

    A well known rule of thumb was always the thickness of the metal core wire ,was the arc length distance.

    In practice there are always variations but generally arc length should be controlled as much as possible. For stop /start for example arc length needs to be longer.

    Beginners always have difficulty in maintaining arc length because as they manipulate the electrode to travel -drag it forward - the accompanying descending manipulation to compensate for the ever shortening electrode does not match and the arc length becomes longer and longer. That, I think will be the most difficult aspect to overcome.It is probably one of the reasons many go straight to mig or flux core.

    Arc length influences:
    * Heat input to the molten pool
    * The size of the molten pool - a big molten pool and too slow = burn through
    * Good penetration
    * Minimal spatter

    Some of these illustrations may serve to help you get a better grip on it.

    Arc length illustration.pngarc-weld-beads.jpg

  12. #12
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    Quote Originally Posted by Widget83 View Post
    Thanks heaps guys,. much appreciated

    I picked up some 2.5mm General Purpose Red Mild Steel electrodes today.. it says they have an AMP range from 80amp - 130amp, DC - or DC + polarity (not sure what that means..). Weldcorp WCC0017 are the electrodes.
    Are you sure they said 80 - 130A for 2.5mm electrodes. That's some pretty serious amperage for a 2.5 and it sounds more like what a 3.25 should run at. 45 to maybe 100A is more like 2.5mm territory.

  13. #13
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    Thanks guys , and thanks heaps Grahame for the info

    Karl: here's a pic of the info on the back of the pack.

    20170219_031846.jpg

  14. #14
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    Karl is correct. Try a very much lower amps (say 70 amps) and go north or south in your settings depending on what the arc did.

    A good place to start repairs is on the outrigger. Notice the crack starts from the notch formed by the placement of the weld.

    Its a corner edge almost and the arm flexes from that point. Do the repair to the shape of the curve. Make the flex spread over the curve and not hinge upon the notch.



    Notch repair.png

  15. #15
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    If I was doing that job I'd use stainless rods...they are a lot lot easier to arc-weld with, especially with low amps

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