fluxcore on 0.75mm

[G1zm0]

having to weld automotive spotwelds on 0.75mm steel .
I'm using lidl fluxcore machine and 0.9 wire

so far it's not filling the holes . I've attached pictures . I'm thinking of using copper as a backing heatsink to help fill holes .

what is the correct technique ? do I need thiner wire ?, the machine only has 1 know and it's at it's lowest

 

[Erie Fred]

If my conversion is right, .9mm is .035 wire ?
Do you have access to .030 (.76mm) flux core wire ?
How long is your electrical stick out ?

 

[Shedendman]

Are you cleaning off the slag after each spot/tack weld you're doing?
as @Erie Fred said,stick out is a big importance

 

[bricol]

My way with flux core was to drill 8mm holes, in the outer piece, nothing on the back one, or leaving it as whatever hole was left after drilling the original spot, as long as it was smaller then the 8mm hole.

If there was a hole in the back one, I'd use a lump of brass behind it.

I'd weld around the outside of the hole, then into the middle. Seemed to work for me.

Simply holding the torch still over the hole and pulling the trigger didn't do much other than melt holes through everything.

 

[eddie49]

If this is this your first MIG welding experience, or first with fluxcore wire, or even just the first time using this Lidl welder, you will need to practice on scrap sheet metal first, not on the actual panel.
The MIG version of a spot weld - known as a plug weld - is not easy, so start with simple straight beads. Initially use thicker steel, say 2mm, then drop down to the thinner stuff after you have got to know the machine.
Using fluxcore, as opposed to solid wire and argon/CO2 gas, is a hot, spattery, smoky process, and starting out on thin 0.75mm steel will be tricky. A solid copper backing bar ( even just flattened 22mm copper pipe ) will help.

Can you clearly see what is happening during the weld? If you do not already have one, get an auto-dimming welding helmet. Hold the tip of the torch really close to the metal, 10mm or 3/8". Does the MIG torch have a chromed steel gas shroud on the end? It is not necessary for self-shielded gasless fluxcore wire, so removing it will increase your visibilty of the weld pool. To avoid accidental shorts you can insulate the copper tip and it's carrier with heatshrink sleeving.
( Some gasless MIGs come without a shroud anyway, replacing it with a plastic or ceramic sleeve.)

 

[chris pruteanu]

your problem is the lidl machine, my experience with their gear its crap ! Sell the poxy machine and get a decent mig welder with gaS...

 

[Erie Fred]

If this is this your first MIG welding experience, or first with fluxcore wire, or even just the first time using this Lidl welder, you will need to practice on scrap sheet metal first, not on the actual panel.
The MIG version of a spot weld - known as a plug weld - is not easy, so start with simple straight beads. Initially use thicker steel, say 2mm, then drop down to the thinner stuff after you have got to know the machine.
Using fluxcore, as opposed to solid wire and argon/CO2 gas, is a hot, spattery, smoky process, and starting out on thin 0.75mm steel will be tricky. A solid copper backing bar ( even just flattened 22mm copper pipe ) will help.

Can you clearly see what is happening during the weld? If you do not already have one, get an auto-dimming welding helmet. Hold the tip of the torch really close to the metal, 10mm or 3/8". Does the MIG torch have a chromed steel gas shroud on the end? It is not necessary for self-shielded gasless fluxcore wire, so removing it will increase your visibilty of the weld pool. To avoid accidental shorts you can insulate the copper tip and it's carrier with heatshrink sleeving.
( Some gasless MIGs come without a shroud anyway, replacing it with a plastic or ceramic sleeve.)

Eddie, I seem to recall seeing a special spot welding shroud, had a couple of legs so you could press it tight, held the distance the same everytime.
Are they common in the UK ?

 

[Keithmac]

I've welded 0.6mm panels with 0.9mm Flux core (Lincoln Innershield NR211).

The welder and wire play a big part, I use an IGBT Inverter gasless "MIG".

You might be flogging a dead horse with the Lidl welder on thin metal.

 

[eddie49]

The Parkside PIFDS 120 A1 is a very good single-control "synergic" MIG welder. Forum member @willie.macleod has one and says that the voltage-to-wirespeed ratio is correct. If the OP has that machine, it should work OK, but maybe needs practice on thin scrap first, a backing bar, and an auto helmet.

 

[MattF]

Eddie, I seem to recall seeing a special spot welding shroud, had a couple of legs so you could press it tight, held the distance the same everytime.
Are they common in the UK ?

KelArc?

 

[eddie49]

Eddie, I seem to recall seeing a special spot welding shroud, had a couple of legs so you could press it tight, held the distance the same everytime.
Are they common in the UK ?

Yes, those MIG shrouds are available, but not too well-known. I think Frost Auto Restoration sell them. I have made one out of 15mm copper pipe.
However, I am note sure we are actually talking about spot ( i.e. plug ) welds here. Maybe tacks, or patching pre-existing but "wrong" holes, or fixing holes burnt-through accidentally....

 

[Erie Fred]

KelArc?

No, this was just a shroud for the MIG gun.
Yes, the end looked the same with the prongs though.

 

[Erie Fred]

Yes, those MIG shrouds are available, but not too well-known. I think Frost Auto Restoration sell them. I have made one out of 15mm copper pipe.
However, I am note sure we are actually talking about spot ( i.e. plug ) welds here. Maybe tacks, or patching pre-existing but "wrong" holes, or fixing holes burnt-through accidentally....

IIRC the miller welders have an optional spot timer for just such welding.

 

[Shedendman]

Yes, those MIG shrouds are available, but not too well-known. I think Frost Auto Restoration sell them. I have made one out of 15mm copper pipe.
However, I am note sure we are actually talking about spot ( i.e. plug ) welds here. Maybe tacks, or patching pre-existing but "wrong" holes, or fixing holes burnt-through accidentally....

You can get them on ebay,but if you look at them,you make your own

Pardon our interruption...

I use these sometimes,but only with gas

 

[bricol]

Eddie, I seem to recall seeing a special spot welding shroud, had a couple of legs so you could press it tight, held the distance the same everytime.
Are they common in the UK ?

Sold just about everywhere - even Halfords (our less good version of AutoZone), B&Q (Home Depot - different company, but same colours and idea) Machine Mart (Harbor Freight - different company, but obviously have the same contacts in China) - I have two I bought aged 18 (that was a while ago), one in as new condition, one in pretty new condition - just didn't find them too helpful.

 

[willie.macleod]

@G1zm0 the machine you have should be fine for filling holes in relatively thin sheet metal in the right hands. As @eddie49 says it isn't clear what exactly it is you are doing, you mention spot welding but it does appear to be more filling holes? At a guess I'd suggest your stick out is too long and you might be struggling to see the puddle if you are using the fixed shade handheld mask that came with the machine. A bit more info about what you are trying to achieve and what you have tried already would be good.

 

[G1zm0]

@G1zm0 the machine you have should be fine for filling holes in relatively thin sheet metal in the right hands. As @eddie49 says it isn't clear what exactly it is you are doing, you mention spot welding but it does appear to be more filling holes? At a guess I'd suggest your stick out is too long and you might be struggling to see the puddle if you are using the fixed shade handheld mask that came with the machine. A bit more info about what you are trying to achieve and what you have tried already would be good.

hi, I'm using a auto darkening one from screwfix, one that came with it is pants .
what im trying to do is fill some 8mm holes that the spotweld drill has went through , and weld the new pieces of metal on top .

will a thinner gauge wire be better like 6mm

 

[willie.macleod]

hi, I'm using a auto darkening one from screwfix, one that came with it is pants .
what im trying to do is fill some 8mm holes that the spotweld drill has went through , and weld the new pieces of metal on top .

will a thinner gauge wire be better like 6mm

It will fill hole like that ok with the 0.9mm wire it comes with, just keep your wire stick out short and weld in short bursts for literally a second or two and then let the weld cool down a little for a second or two before restarting. You'll see the colour change when the weld puddle cools enough to restart. Move around the hole, once you get the first bead round the perimeter (in bursts) it'll fill easily.

 

[eddie49]

The Parkside PIFDS 120 A1 is a very good single-control "synergic" MIG welder. Forum member @willie.macleod has one and says that the voltage-to-wirespeed ratio is correct. If the OP has that machine, it should work OK, but maybe needs practice on thin scrap first, a backing bar, and an auto helmet.

So you have an auto-darkening helmet, but maybe some practice on thin scrap would help. Since you are trying to put metal back into a void ( the spotweld drill through-hole in the rear panel ) and then spotweld the new panel onto that, a copper/brass/aluminium backing bar will be essential.

This sounds like a difficult task. Maybe you should consider welding a metal strip behind the drilled-through rear panel ( i.e. a permanent "backing bar" ) ?

 

[G1zm0]

So you have an auto-darkening helmet, but maybe some practice on thin scrap would help. Since you are trying to put metal back into a void ( the spotweld drill through-hole in the rear panel ) and then spotweld the new panel onto that, a copper/brass/aluminium backing bar will be essential.

This sounds like a difficult task. Maybe you should consider welding a metal strip behind the drilled-through rear panel ( i.e. a permanent "backing bar" ) ?

I've made some holes in old metal and practice filling it, i used a aluminium backer and it filled ok , but it left pin holes that I tried to fill , but after grinding , they were still there .

I want to fill some holes , then weld the new panel onto of thoes holes .
is 0.9 OK for 0.8 sheet metal or should it be 0.6? .

I am tacking each bit then leaving for 10 secs then doing another bit .