Will this affect my welds?

[Duker996]

I'm still only practising on scrap pieces at the moment but I'm getting a lot of inconsistency with my welds. I had a thought last night that it could be because I'm laying the metal flat on a heatproof board while welding.

Could the fact I'm laying it flat cause it to overheat and be causing me inconsistency?

 

[barny]

what thickness are you welding and what setup do you have?

 

[Duker996]

what thickness are you welding and what setup do you have?

1.2mm and what do you mean by set up?

 

[barny]

What welder, wire size, gas, weld types? maybe a picture of the problem would help.

Do you mean you are blowing holes?

 

[Duker996]

Ah right! I'm using a Clarke 150te turbo with 0.8 wire and plain co2. I'm using it on 3 min or 1 max with a wire speed of 4-5.

One minute I can get a weld I'm happy with then the next weld will blow through or sort of spit and crackle. Which I don't understand as I had it set up so I could hear the nice bacon frying sizzle! All I'm doing is laying straight welds on scrap pieces and also doing a few butt welds. Once I get a few consistent welds I try a butt weld and it goes bad again. Could it be the fact I have it flat on the board that will hold the heat? Should I lift it off so there's a void? Or should this not affect it either way?

I'm itching to get started on my land rover but I'm not going to until I get decent enough consistent welds.

 

[barny]

I'd try it with the settings on 1 min. I have a sealey 150 using .6 wire and that's enough power for 1mm sheet.
Check out the tutorial sections about butt welding thin metal as its easy to blow holes if you try seam welding.

 

[Tommy]

Are ya getting any build up on the shroud?? if your shroud is clogged it will block your gas flow and give ya a worse weld!!

It might not be blowing through because you have the weld supported from behind so it cant drop away, are ya getting a flat or raised run?? Ya might just have the welder set to high!

 

[mike 109444]

How are you able to lay it flat and have the earth clamp, I would have thought the clamp would have lifted atleast one sheet?. Could it be you have a poor earth/earth lead? (is m/c new) if not suspect the earth clamp esp on thin metal. So one minute the earth is good and your weld to then you move things around (to try a butt weld) and it goes t!ts up.

 

[Marty2005]

Do you quench your work piece between welds? If not I suspect the heat is building up. First weld on cold metal - great, second weld on now hot metal - blow holes in it as its now too hot.

 

[Duker996]

I'll try and answer in order! firstly I will try it on 1 min, a bloke I know who has a fabrication firm had a little play with it for 20 mins and set it to what it's on now, saying its just right and you can hear the sizzle.

The shroud does get slight build up but I keep an eye on it and keep cleaning it out so I don't think that's the issue. And yes they may not be dropping through because it's supported, I never thought of this!

I lie the metal on the heat proof board then put the earth clamp over the metal and the board. So half the clamp is on the metal and half is clamped on the underside of the board, could this be a problem? Also I put a new earth clamp on and didn't have the right sized ring connecter so the wires are just wrapped around and tightened down with the nut and washers, another possible cause? This is starting to make sense now!

No I don't quench the work, I just weld 1 corner, then another and keep working around an back and forth. The sheets have been warping so this is possibly another factor.

So far then, too high setting, bad earth and too much heat on the scrap sheet. Time to try again once I have my earth clamp properly fitted. Thanks all for your input so far.

 

[Drains]

Do you quench your work piece between welds? If not I suspect the heat is building up. First weld on cold metal - great, second weld on now hot metal - blow holes in it as its now too hot.

Never quench a weld. Let it cool naturally unless you want it to be brittle.