[TheForge] broken weld on mower deck

[Bruce .]

Jerry,

There are YouTube videos that help as well.

Although I was aware of using reinforcements, I hadn't come across the
concept of fish plates.  The caveat of using material no thicker than the
base metal is a good one -- no sense introducing new stress points.



Bruce
NJ

On Wed, Jun 7, 2017 at 11:23 PM, jerry Frost <akfrosty at mtaonline.net> wrote:

> I realized I should've mentioned size. For thin stock like a mower deck
> roughly the size of a playing card will do the job. There were calculations
> and rules in my welding books but last I read those was something like 45
> years ago. Things change but rules of thumb  will usually do. If you're
> doing structural fabrication where getting it right is critical hire a pro.
>
> Frosty
>
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net [mailto:theforge-bounces@
> mailman.qth.net] On Behalf Of jerry Frost
> Sent: Wednesday, June 7, 2017 3:08 PM
> To: 'Blacksmithing List Sponsored by ABANA'
> Subject: Re: [TheForge] broken weld on mower deck
>
> On a large area like a deck you want to fish plate the ends of the welds.
> Drilling stop holes is even more important.
>
> Another place to use fish plates is splicing structural steel like I beam.
>
> I believe trying to fish plate a large area like Terry's mower deck does
> more harm than good.
>
> Jer
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net [mailto:theforge-bounces@
> mailman.qth.net] On Behalf Of Bruce .
> Sent: Wednesday, June 7, 2017 3:36 AM
> To: terry l. ridder; Blacksmithing List Sponsored by ABANA
> Subject: Re: [TheForge] broken weld on mower deck
>
> Jerry,
> Was that ONE fish plate over the entire crack, or one over each drilled
> hole, or what?
>
> Bruce
> NJ
>
> On Tue, Jun 6, 2017 at 8:48 PM, terry l. ridder <terrylr at blauedonau.com>
> wrote:
>
> > hello
> > ​<snip>
> >
> > my paraphrase.
> >
> > drill a stop hole at the end of the weld.
> > pull the broken weld together with gentle force.
> > clean up the broken weld and remove any paint in the area.
> > weld the broken weld.
> > take a similar metal and weld diamond shaped pieces over the repair
> > weld.
> > clean up welds.
> > spray paint with kubota orange.
> >
> > repeat as necessary ;-)
> >
> > On Tue, 6 Jun 2017, jerry Frost wrote:
> >
> > No, don't try heat treating the welds. First thing to do is drill
> > stopper
> >> holes at the ends of the cracks. After you weld it up, fish plate
> >> them it. A fish plate is a diamond shape piece of steel of the same
> >> or similar thickness as the piece being welded.
> >>
> >> NO! Do NOT use thicker steel it will defeat the purpose of fishplating.
> >> You
> >> want the fish plate to flex and spread the force over a distance.
> >> Slightly lighter weight steel is more effective. Fish plates are NOT
> >> reinforcements they distribute stress, two entirely different things,
> >> related but different.
> >>
> >> Fish plate the high stress or high flex zone. You lay the plate over
> >> the weld so none of the corners of the diamond line up with or fall
> >> on the weld.
> >> Perimeter weld it over the weld. Mig it is good, the smoother the
> >> beads the lower the stress at the edges. Do NOT torch weld, the HAZ
> >> (Heat Affect
> >> Zone)
> >> is way too large.
> >>
> >> What a fish plate does is distribute the stress formed by the ends of
> >> a weld bead which is a stress riser. A final touch to maximize the
> >> effect is to run the beads towards each narrow end of the plate and
> >> carry the bead past the point in a J shaped finish. Called a "J
> >> tail."
> >>
> >> The "J tail" distributes any flexing stress over a distance in a
> >> curve leaving no stress riser.
> >>
> >> I hope this is clearer than it sounds.
> >>
> >> Frosty
> >>
> >>
> > --
> > terry l. ridder ><>
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