[AT] welding problems

Alan Nadeau ajnadeau1 at myfairpoint.net
Sun Nov 15 11:46:07 PST 2009


Gene, I beg to differ with you.  Every 7018, but one, listed in my pocket 
reference is listed as AC or DC Reverse polarity.  The one exception is the 
7018AC, which is intended for the common home/farm shop welders which tend 
to have low open circuit voltage.

As for the original issues that started this thread, 1/8" **18 class 
electrodes should run fine at 180 amps.  The sticking/hard starting can be 
as much a problem of low OCV as amperage.   There is usually some sort of 
capacitance device in the welding circuit to smooth out the tremendous drop 
in voltage and rise in amperage when an electrode is struck.  I'm not sure 
what bad stuff happens when that fails but I'm pretty sure it causes the 
hard starting symptoms described.

As for it being the Hyundai electrodes I tend to discount that as long as 
they are labeled as conforming to AWS Specs.

Al Nadeau


----- Original Message ----- 
From: "Gene Dotson" <gdotsly at watchtv.net>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Sunday, November 15, 2009 8:54 AM
Subject: Re: [AT] welding problems


>    John'
>    Is your welder an AC only? Conventional 7018 rods are run on DC. There
> is a 7018 rod made to run on AC, but has to be specific.
>
>    If your welder has DC capability, you may be running the wrong polarity
> as 7018 DC is polarity sensitive.
>
>    I have a Lincoln AC welder and do most of my welding with 6011 and 6013
> rods. Get best penetration witt 6011 and 6013 works better on thin metals
> and gives a smoother weld.
>
>                    Gene
>
>
>
> ----- Original Message ----- 
> From: "John Hall" <jthall at worldnet.att.net>
> To: "Antique tractor email discussion group" 
> <at at lists.antique-tractor.com>
> Sent: Sunday, November 15, 2009 8:29 AM
> Subject: [AT] welding problems
>
>
>> OK stick welding experts, got one for you. The welder we have is a 40+
>> year
>> old Marquette, bought new for use here on the farm. I had to buy some 
>> more
>> welding rods over the past several months and unfortunately had to switch
>> brands. We had always used Hobart (or possibly Lincoln) rods. The welding
>> supply chain now only sells Hyundai rods in small quantities (10 lb)
>> boxes.
>> I can't justify buying 50lbs of Hobart rods.
>> Anyway, on to my problem. I picked up a new box of 1/8" 7018 rods to do
>> some repair on my subsoiler. I set the welder as high as it would go 
>> (180)
>> and could not get it to weld. All I could get was a couple of arcs and
>> sometimes the rod would stick.  Before you ask, yes I cleaned where I was
>> welding, cleaned the ground area, made sure the terminals on the welder
>> were
>> clean, and even cut off and reinstalled the end of the ground cable where
>> it
>> goes into the clamp. I also tried grounding and welding on 3 different
>> pieces--all of varying size and thickness.  I resorted to using 3/32 rods
>> with the welder set on 125. It would run those rods so hot that they 
>> would
>> almost turn red before it was time to switch. I know I have used 1/8" 
>> 7014
>> before, so my question is this--Is there a difference between 7014 and
>> 7018
>> that makes the 7018 require a higher setting on the welder, Is there
>> something wrong with the welder, or is it something to do with these
>> imported rods?
>>
>> John Hall
>>
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>
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