SP-100 no penetration

[Jholden47]

So I'm printing you to welding I picked up a Lincoln SP 100 in a trade.

I have been experimenting it. I can't seem to get any kind of penetration, I am using .035 wire, in a gasless set up.

I have the wire speed at 2 and the amps cranked all the way up and still cannot get any penetration?

Is there an issue with the welder? If so, what is it likely to be?

 

[dave h 2]

Normally you have to reverse the lead polarity for gasless manual

 

[Nix2]

Normally you have to reverse the lead polarity for gasless manual

This is true, but the polarity itself has no effect on the welding current (i.e. penetration depth) but only on the quality of the weld/spatter, etc.

 

[Erie Fred]

This is true, but the polarity itself has no effect on the welding current (i.e. penetration depth) but only on the quality of the weld/spatter, etc.

It doesn't ?

 

[prepman]

It doesn't ?

FFS

 

[tom2207]

This is true, but the polarity itself has no effect on the welding current (i.e. penetration depth) but only on the quality of the weld/spatter, etc.

best you have a rethink on this statement .

 

[Nix2]

And what is there to think about... Ohm's law says what it says :-) Maybe I should write more precisely that polarity has a small effect on the welding current, but that's it, I maintain.

 

[8ob]

And what is there to think about... Ohm's law says what it says :-) Maybe I should write more precisely that polarity has a small effect on the welding current, but that's it, I maintain.

The bigger question would be what thickness material are you trying to weld?

Bob

 

[Nix2]

Yes, it's also important, but I quote the author- "I can't seem to get ANY KIND of penetration"

 

[8ob]

Yes, it's also important, but I quote the author- "I can't seem to get ANY KIND of penetration"

You wouldn’t get any penetration if you were testing on 6mm plate, I would have thought the max you would be experimenting with would be 2mm.

Bob

 

[Nix2]

It depends on what the thread author understands by the term "penetration"... but it's a tiny MIG welder and is designed for thin sheet metal, that's correct.

 

[tom2207]

And what is there to think about... Ohm's law says what it says :-) Maybe I should write more precisely that polarity has a small effect on the welding current, but that's it, I maintain.

you cant teach someone something they think they already know.

 

[Nix2]

you cant teach someone something they think they already know.

A very objective statement, suitable for a philosophical forum.

 

[Erie Fred]

A very objective statement, suitable for a philosophical forum.

Says the person who doesn't understand welding polarity......

give a man a fish, feed him for the day, let him crack a book, and he'll never stop learning.

 

[Mark 5]

you cant teach someone something they think they already know.

Unless of course you can get across what they think they know, sucks!

 

[Nix2]

I haven't seen such OT for a long time, but oh well... democracy :-)

 

[eddie49]

Back to the original question:

Is there an issue with the welder? If so, what is it likely to be?

The SP-100 is rather different in that it is a transformer-based MIG welder but has fully-variable control of the output power by means of two thyristors ( SCRs ). They act like a "light-dimmer" feeding the primary of the welding transformer. These components, or the pulse-generating circuit that triggers them, may have failed.
I suggest you start by measuring the output voltage, from the tip of the MIG torch to the work return clamp, at the minimum and the maximum power setting. This voltage would usually vary from about 15v to 30v DC, but due to the type of control circuit, you may see a fairly constant value.
If the voltage is high enough when checked with a voltmeter, the usual reason for lack of penetration is that when high welding current is drawn, voltage is getting dropped across a high-resistance joint somewhere in the welding path. Check for loose, burnt, or corroded connections at the MIG torch, work clamp, return cable, and where these parts connect inside the welder.

 

[Erie Fred]

I haven't seen such OT for a long time, but oh well... democracy :-)

we are all waiting for your teaching us of the OT subject that YOU brought up in post #3

 

[Stupoty]

I haven't seen such OT for a long time, but oh well... democracy :-)

I've really been digging the value of the beer at lidl recently , always makes tool shopping there extra fun

Stu

 

[Erie Fred]

Back to the original question:


The SP-100 is rather different in that it is a transformer-based MIG welder but has fully-variable control of the output power by means of two thyristors ( SCRs ). These act like a "light-dimmer", feeding the primary of the welding transformer. These components, or the pulse-generating circuit that triggers them, may have failed.
I suggest you start by measuring the output voltage, from the tip of the MIG torch to the work return clamp, at the minimum and the maximum power setting. This voltage would usually vary from about 15v to 30v DC, but due to the type of control circuit, you may see a fairly constant value.
If the voltage is high enough, the usual reason for lack of penetration is low current, often caused by a high-resistance joint somewhere in the low-voltage high-current welding path. Check for loose, burnt, or corroded connections at the MIG torch, work clamp, return cable, and where these parts connect inside the welder.

There are (2) versions, one with a "T" on the end, it's the most common, simple tapped xformer.
The continuos variable "Non T" version is more expensive, and less common.

would be good to get clarification from the OP.