[TheForge] Re: Welding cast iron

[Ekaterina Harrison]

Hi Harry,

On the note of welding cast iron:

I personally do not particularly enjoy welding cast iron, but when  
push comes to shove here are a few things I have found to be effective.
Preheat the whole iron piece before welding to a uniform heat (dull  
red if possible) and prevent from cooling suddenly or quickly. Tricks  
I have used for this is wrapping the piece in Refractory blanket  and  
exposing only the weld area. After the weld is finished I seal it of  
with the blanket and let it cool slowly to room temp.

   Another trick applies to the weld process itself. when you get to  
the end of the weld  finish it of with a little extra blob of  
material. This little excess mass of molten metal acts as a reservoir  
for the rest of the weld to draw from as it cools and shrinks and this  
prevents it from cracking. This technique seams to work on any metal  
that is prone to cracking in the weld area. Also, using a tig torch I  
leave the torch over the piece until the shielding gas stops flowing  
and this seems to help. I believe this mostly has to do with helping  
it to cool slower and preventing a cold blast of air hitting it before  
the weld has set.

Another thing is that if a weld has cracked it is important to grind  
out this crack completely before welding over it otherwise this crack  
keeps reappearing. I usually make sure to put in a good bevel when  
grinding out a weld. I have found that in following these steps I was  
able to make the repairs with regular steel filler rod as well as cast  
iron rod. Te results seemed to be about the same.

I hope this helps in your next cast iron repair job.

Ekaterina

On May 21, 2008, at 2:03 AM, theforge-request at mailman.qth.net wrote:

>
> Message: 1
> Date: Tue, 20 May 2008 20:29:53 -0500
> From: IowaHarry <iowaharry at fastmail.net>
> Subject: Re: [TheForge] Re: Welding cast iron
> To: munlaw2 at hcsmail.com,	Blacksmithing List Sponsored by ABANA
> 	<theforge at mailman.qth.net>
> Message-ID: <48337B11.2020602 at fastmail.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> At this point McMaster Carr is the way I am going to go. A coupler  
> nut,
> some bits of steel to flesh out the rest of  it and there ya go. Of
> course this will all happen some time after the purchase of a new  
> vise.
> Thanks for the Mcmaster carr tip Bob.
>
> Harry