[TheForge] broken weld on mower deck

Sat Jun 10 14:28:44 EDT 2017

Exactly Bruce but fish plates aren't actually reinforcements, they disperse stress to prevent initiation points. Blacksmithing we call these points "stress risers" cold shuts fall into the category of stress riser.

Force is conducted through solids in a smooth uniform manner until the structural limit is exceeded. A stress riser interrupts the path of force making it stop and restart the other side. This results in severe stress between the stop and start and can cause material failure. This is how you "cut" glass by causing a stress riser with the scratch caused by the glass "cutter". The compression wave of force imparted by the striker is interrupted by the scribed mark and the material fails in a controlled manner. A rock chip in your windshield is another example of a stress riser.

Jer

-----Original Message-----
From: theforge-bounces at mailman.qth.net [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce .
Sent: Thursday, June 8, 2017 5:38 AM
To: Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] broken weld on mower deck

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 ><>
> > ______________________________________________________________
> > TheForge mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/theforge
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:TheForge at mailman.qth.net
> >
> > TheForge mail list group photo site is http://www.shutterfly.com
> > Login: blacksmithblacksmith at hotmail.com
> > Password: anvil
> >
> > This list hosted by: http://www.qsl.net Please help support this 
> > email
> > list: http://www.qsl.net/donate.html Message delivered to 
> > freemab222 at gmail.com
> >
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
>
> TheForge mail list group photo site is http://www.shutterfly.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> akfrosty at mtaonline.net
>
>
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
>
> TheForge mail list group photo site is http://www.shutterfly.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> akfrosty at mtaonline.net
>
>
> ______________________________________________________________
> TheForge mailing list
> Home: http://mailman.qth.net/mailman/listinfo/theforge
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:TheForge at mailman.qth.net
>
> TheForge mail list group photo site is http://www.shutterfly.com
> Login: blacksmithblacksmith at hotmail.com
> Password: anvil
>
> This list hosted by: http://www.qsl.net Please help support this email 
> list: http://www.qsl.net/donate.html Message delivered to 
> freemab222 at gmail.com
>
______________________________________________________________
TheForge mailing list
Home: http://mailman.qth.net/mailman/listinfo/theforge
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:TheForge at mailman.qth.net

TheForge mail list group photo site is
http://www.shutterfly.com
Login: blacksmithblacksmith at hotmail.com
Password: anvil

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message delivered to akfrosty at mtaonline.net