It is currently Mon Oct 23, 2017 2:11 am Advanced search

How low on amperage can I go?

Stick Welding Tips, Certification tests, machines, projects

How low on amperage can I go?

Postby Aux » Sat Sep 30, 2017 2:45 pm

I've heard Jody recommend welding 7018 1/8 verticle up at between 110-125 amps. This produces good results on the first few beads but becomes hard to control without a serious weave as heat input accumulates in the practice plate.

Is it acceptable to reduce amperage into the low 90's to compensate for existing heat in the weldment? Will doing so have a negative impact on the mechanical properties of the weld? Beyond having to be more cautious about sticking the rod I feel more able to control the puddle welding in this range.

The attached image was welded in the 105-115 range. As you can see I'm having some difficulty controlling the weld pool.
Attachments
IMG_20170929_165210.jpg
IMG_20170929_165210.jpg (79.52 KiB) Viewed 197 times
Last edited by Aux on Mon Oct 02, 2017 2:08 pm, edited 2 times in total.
Aux
New Member
 
Posts: 13
Joined: Tue Sep 19, 2017 7:53 pm

Re: How low on amperage can I go?

Postby cj737 » Mon Oct 02, 2017 8:35 am

Aux wrote:I've heard Jody recommend welding 7018 1/8 verticle up at between 210-225 amps.
:shock: :shock:
Ive never heard of anyone using those amps for 1/8” rod!??? Perhaps it’s a typo, but I would restrict your amps to 125 and no higher
cj737
Weldmonger
 
Posts: 558
Joined: Thu Sep 29, 2016 8:59 am

Re: How low on amperage can I go?

Postby Aux » Mon Oct 02, 2017 2:07 pm

cj737 wrote:
Aux wrote:I've heard Jody recommend welding 7018 1/8 verticle up at between 210-225 amps.
:shock: :shock:
Ive never heard of anyone using those amps for 1/8” rod!??? Perhaps it’s a typo, but I would restrict your amps to 125 and no higher


Wow you are 100% right. That is a typo I meant 110 and 125. The question was regarding dropping the amps from that range to the low 90's. I'm going to make that edit thanks so much for pointing that out.
Aux
New Member
 
Posts: 13
Joined: Tue Sep 19, 2017 7:53 pm

Re: How low on amperage can I go?

Postby Poland308 » Mon Oct 02, 2017 5:32 pm

90 amps may be sufficient depending on weld size, and part size. If it’s a large part with several layers of beads then you may run the first pass a little hotter till things warm up then turn down the amps. Or if your ambient temp is 90f or above. Or if your using a preheat. I’ve run 1/8 7018 down as low as about 85 amps, but only under the right set of variables. Also accuracy of your amp control can come into play. Not uncommon to see 5-10 amps difference between two identical machines. Your 90 amp setting may be just as hot as the next persons 100 amp setting.
I have more questions than answers

Josh
Poland308
Weldmonger
 
Posts: 2222
Joined: Thu Sep 10, 2015 8:45 pm
Location: Iowa

Re: How low on amperage can I go?

Postby cj737 » Mon Oct 02, 2017 6:45 pm

LOl! I’m glad we got that sorted out...

To answer your original question about lowering the amps for successive welds, yes, it is common and appropriate to reduce your amps after adding a few beads. The accumulated heat will be sufficient to allow lower heat for following passes. How much lower spends on things that Poland posted.
cj737
Weldmonger
 
Posts: 558
Joined: Thu Sep 29, 2016 8:59 am

Re: How low on amperage can I go?

Postby Aux » Tue Oct 03, 2017 5:42 pm

Thank you both for the information (and correction). It's good to know this is an acceptable practice. I think I've been relying too heavily on the amp readout on my machine rather than paying attention to the puddle.
Aux
New Member
 
Posts: 13
Joined: Tue Sep 19, 2017 7:53 pm

Re: How low on amperage can I go?

Postby cj737 » Tue Oct 03, 2017 8:45 pm

Aux wrote: I think I've been relying too heavily on the amp readout on my machine rather than paying attention to the puddle.

Recognizing that is pretty much a guarantee that you’ll improve. Understanding why things happen, is the root for knowing how to adjust. The machine can’t tell you these things, only the puddle can. Then it’s up to you where appropriate to know how to adjust your machine (or pedal) to keep the puddle doing it’s thing properly-
cj737
Weldmonger
 
Posts: 558
Joined: Thu Sep 29, 2016 8:59 am

Re: How low on amperage can I go?

Postby Aux » Sun Oct 08, 2017 11:58 am

Just wanted to share an updated picture. I lowered my amps into the low 90's things see much more controllable and the issues with undercut I was having appeared to have been dealt with.
Attachments
IMG_20171007_135646.jpg
IMG_20171007_135646.jpg (135.21 KiB) Viewed 80 times
Aux
New Member
 
Posts: 13
Joined: Tue Sep 19, 2017 7:53 pm

Re: How low on amperage can I go?

Postby Poland308 » Sun Oct 08, 2017 3:47 pm

You may notice how your bead profile is humped up in the center. If you turn up your amps a little at a time you can get that to flatten out.
I have more questions than answers

Josh
Poland308
Weldmonger
 
Posts: 2222
Joined: Thu Sep 10, 2015 8:45 pm
Location: Iowa

Re: How low on amperage can I go?

Postby Aux » Sun Oct 08, 2017 4:02 pm

Poland308 wrote:You may notice how your bead profile is humped up in the center. If you turn up your amps a little at a time you can get that to flatten out.


I've been working to address this actually. I think part of the issue was that my arc length was too short. I was stubbing the plate with the slag before now I'm trying to hold 1 rod diameter (1/8 inch). It seems to allow me to run higher temperatures and flattens out the bead a lot. I don't really understand why.

I was hesitant to post this because it looks messy but this is me experimenting with way to much heat 130-140 amps with a 1/8 inch arc gap. The humping is back of course. The heat was so intense the base metal was running away from the top of the puddle, I was so surprised the metal wasn't dropping out the bottom. I don't get why adjusting the arc gap would allow me to carry more metal uphill? Maybe it spreads out the heat?

Anyway, now that I've experimented with running both hot and cold I'll work on getting consistent straight beads with good tie-ins. I'll try to post an update next weekend.
Attachments
IMG_20171007_154530.jpg
IMG_20171007_154530.jpg (110.15 KiB) Viewed 74 times
Aux
New Member
 
Posts: 13
Joined: Tue Sep 19, 2017 7:53 pm

Next

Return to Stick Welding/Arc Welding - Shielded Metal Arc Welding

cron