View Full Version : millermatic 251

02-04-2004, 03:09 PM
my boss just bought me this machine to use at work. just got it on monday. so far i like what i see, but i find that it isvery hard to get it dialed in to the perfect parameter that i need for welding race cars together.
the apperance and mechanics of my welds have to be 100%, for the job and my own satisfaction.
right now the welds are a little to hot for me, i tried messing with the settings but im getting no where.
the welder i was using before was a miller 185, i had it set on 3 and 45-48 for wire speed, and the welds were perfect(if ya ask me).

what have been your guys opinions of this welding machine, and are you having the same difficulty setting the machine up?

thanks , migmaster

02-04-2004, 03:12 PM
oh yea i forgot to add, that right in the middle of a weld the machine will spit and sputter, and cause all kinds of spatter.
i tried turning down the wire speed but then it kills the apperance of the weld.


02-04-2004, 03:51 PM
I have a MM251, and I've experienced no such problems. I've found the settings to be quite forgiving. I set the voltage for my material, and adjust the wirespeed to get the desired bead. I very seldom have any spatter unless the settings are way off. That said, I'm not building race cars.

Have you talked to Miller about this? They are usually really good about helping you dial it in if you need, or diagnosing any problems.

Scott S
02-04-2004, 04:34 PM
I assume you are using Gas/mig wire, not fluxcore? Be sure that you have the polarity set correctly: Dcep, electrode +pos.

fla jim
02-04-2004, 04:54 PM
On my MM210, I've found the settings on the door are very close.
A couple of questions.
1. What size wire are you using?
2. Does the tip and drive rollers match the wire?
3. Is your wire rusty, or dirty?
4. Is the drive tension adjusted properly?

Scott V
02-04-2004, 05:00 PM
What type,brand of wire are you using?Try some Hobart HB28 if you are using solid wire.Don't laugh either,because I have seen certain wire cause feed problems,also it might soften your arc a little.

fla jim
02-04-2004, 05:30 PM
What is HB28 equivialant to?

02-04-2004, 05:33 PM
I'm with Scott. That's the best wire I've used.

It really sounds like a wire feed issue. You might just recheck the hub tension and drive pressure, and alignment from the drive-rolls to the guide. Good luck.

02-04-2004, 05:35 PM

it's an er70s6. check this: http://store.cyberweld.com/hobhbmigwir2.html

I could tell the difference, and I'm no expert.

02-04-2004, 05:43 PM
i havent talked with miller about it, but if it continues to be a problem i will.

02-04-2004, 05:46 PM
One more thought,

A bad ground (work lead) could cause the same problem with the spatter and sputtering.

02-04-2004, 05:47 PM
i started from the settings on the door but they were way to high for me.
.030 national standard bare wire, not rusted at all.
tip and drive rolls are good.
as far as i know the drive tension is correct.

fla jim
02-04-2004, 05:58 PM
Did you check the tension like the manual says.
Point the gun at an angle at a piece of wood and pull the trigger, adjust the tension until the gun feeds good.
My the tip and drive rolls being good, you mean they're the right size for the wire and aligned?
Aaron 3.0 is right, I forgot about the ground.

Scott V
02-04-2004, 09:48 PM
Originally posted by fla jim
What is HB28 equivialant to?

it is ER70-6 wire.It its a little softer wire then even some of the other Hobart wire.It is the only ER70-6 wire they put on their 11/10? pound spools.

02-05-2004, 04:06 AM
I have a 251 and it took a little bit of work to get it dialed in but I did and it works fine now. I had poppy starts and adjusting the run-in fixed that problem. As far as the spatter in the middle of your weld that sounds like something you should have the boys at Miller help you with. I would recheck the drive roll tension and alignment, maybe have someone watch the wire at the rollers while you are welding and the problem arises. Maybe check gas flow also.
Good luck

02-05-2004, 09:51 AM

I do a lot of tube work as well. More cage than chassis. I also run a 251. For what I'm running on 1.75" diameter, .120 wall DOM, I like the settings at about 16.5 and the wire speed at about 175, depending on the temps and the joint. I run gas at about 20-25 CFH depending on the wind. The wire is ER-70S6 Hobart coming off a 10# reel. I have heard some issues with feed from certain manufacturer's wire, but never had a problem with Hobart.

Hope this helps.

02-05-2004, 10:22 PM

theres only a few parts on the chassis that are .120. most of it is .065 and .095. right now im set at 15.5 and 225 wire speed. i've done the drive roll tension on a piece of wood and that seemed to help quite a bit. turned the gas up to @ 25 or so.

maybe its me but the ground clamps that come with these new machines are a piece of s@#t if ya ask me.

thanks for your help.

what are you welding on?

i weld on these www.teopro.com

02-05-2004, 11:33 PM
hehe we live in WAAAAYYYYY different worlds man... That's some purdy stuff though...

Here's my latest project:

02-06-2004, 12:05 AM
blues - sweet work dude. You do that front bumper yourself? Are the tow points dropped in through the back, or are they just welded to the main beam front and back? Thanks.

02-06-2004, 11:47 AM
Junk, I did the tubework on the bumper myself. The main body is done by www.mountainoffroad.com

The tow-points are recessed through the surface and welded front/rear.

02-07-2004, 04:34 PM
thats some pretty nice work though, basicaly the same kinda thing i do. nice job!

02-07-2004, 09:21 PM
Blues, I'm into the offroad thing myself, but with Land Cruisers.

Mismaster - wow, that looks like fun stuff. I'm near Morristown, so not far from you at all. I have a cousin that races on the Nascar Weekly Racing Series. Even though I'm into offroading, I can definitely appreciate the keen craftsmanship that goes into cars. Very cool.

02-07-2004, 11:31 PM
morristown, man your close, TEO is only in vernon, cool.

wheres your cuz race at , wall stadium or strong island?
who is he?

what are you welding on?

is this enough ?'s, ?