Spray transfer and thick materials

[njc110381]

Well as usual, it's been a while since I visited the forum. Life seems to take over sometimes, but I am getting more into the welding slowly.

I got the R-tech 250 set up nicely and used my first bottle of gas. That didn't last long so I signed up for a contract on a 15.6/47.5kg bottle of Ferromaxx 7... That should do the trick!

I've stuck a few bits and pieces together, made a log splitter and have just started making a bumper for my Unimog out of 12mm channel. That stuff takes some melting I can tell you! The best way I've found so far (welding the offcuts) is to spray transfer it after putting a good chamfer on it first. With my 32a socket fitted the welder really goes. No more blown fuses! I'm glad I went for the bigger machine now.

Is this the point where I should be trying to multi pass it or will I get away with just slowing down to fill the chamfer as I go along? I've gone for the full fill in one on scrap and done the basic test of taking it outside and giving it a good seeing to with a sledge hammer but unfortunately I can't even bend it let alone make it snap!

 

[Omniata]

Any pictures?
There are many trained eyes on here that may be able to provide you with a bit of analysis...

 

[Arclikeharrypotter]

Njc personally I'd run multi pass on it. If you try to run slower you may just end up stacking weld on top of weld without actually penetrating the root. That was the advice given to me when talking with some instructors. Suppose you could always cut it and see how much penetration you are getting.

 

[Welderpaul]

You need to weld at the right speed to form the bead correctly. If you weld slower, to a point you are forming a 'stronger' bead as it is larger, but only up to a (fine) point. After that you are just pouring on excess metal where, in a multi run, the next runs don't properly penetrate into the weld (if that makes sense)

I'd bevel/prep the joint, whack the welder up as high as it will go and multi run weld the joint if needs be. Often just making sure the joint is properly designed means a stronger joint rather than just putting loads of weld on a badly designed joint.

 

[njc110381]

Pictures... Hmm, they're a sore subject. Just don't ask me what happened when I tried to polish the scratches out of my camera lens on my phone thinking it was glass. It is in fact plastic, so a high speed fine abrasive.... Well you can guess what happened after a few seconds!

I think I will multi pass. That said, cutting the offcuts weld is a great idea. I'll do that tomorrow if I get a moment and maybe take the camera out too. I've seen someone doing that somewhere before. Don't you paint something on there to make the weld more obvious?

I suppose several thin passes will guarantee that they all penetrate into each other properly as well as the work pieces. It's kind of obvious when you think about it but I hadn't really got that far. It's these little things that I hope will become second nature in time. Thanks chaps. I'll report back tomorrow if I get a bit of daylight time to mess about

 

[Omniata]

If you cut a slice through the weld, you can acid etch to see the penetration and haz I believe...

 

[Kent]

12mm ain't a bumper it's a battering ram!

 

[njc110381]

12mm ain't a bumper it's a battering ram!

It is to some extent. It has to support fittings for the front three point linkage and the sump guard, and the mog weighs 3.5t empty. When driving through woodland I don't intend to stop and get out with the chainsaw every time a small tree gets in the way. Pushing things over and driving on them speeds up the process!

 

[Omniata]

If you cut a slice through the weld, you can acid etch to see the penetration and haz I believe...

Linky: http://www.mig-welding.co.uk/wiki/Macro_Etch

 

[njc110381]

Thanks. I did the cut and had read somewhere that vinegar will do a similar job. Turns out it doesn't! I'll have to get some of that stuff.

 

[Omniata]

Only needs to be dilute, about 10% in water...

 

[njc110381]

Having studied it more closely my "leave a gap and see if it helps" lazy method didn't help at all. Now I've polished it more I don't even need an experienced opinion for it - it's no good. The weld has filled the gap but it's not melted in after about 4mm. Probably because the metal is that thick that it's pulling all the heat out? If I used the same settings on 5mm plate it would burn through for sure.

 

[Omniata]

Pictures?

 

[njc110381]

Pictures?

I can only refer you back to post number 5 of this topic unfortunately. I seem to have misplaced my proper camera because it's so long since I used it last!

 

[Omniata]

I can only refer you back to post number 5 of this topic unfortunately. I seem to have misplaced my proper camera because it's so long since I used it last!

Apologies... Sometimes you can polish scratches out with toothpaste and a buffing wheel, as long as they aren't too deep...

 

[njc110381]

Apologies... Sometimes you can polish scratches out with toothpaste and a buffing wheel, as long as they aren't too deep...

That was my plan. It was finely scratched so I attacked it with a polishing wheel and toothpaste. What I thought was glass was actually plastic, and it melted! Big streams of fluff started flying - and that ain't going to polish out!

 

[Omniata]

"Attack" might not have been the best plan...

"Gently massage" on the other hand...

What model of phone is it? I'll see if I can find a lens

 

[njc110381]

That's very kind of you. Thanks. It's a battered old Samsung Galaxy Xcover... They only cost about £150 so I'll most likely just buy a new one. The screen is cracked and the casing pretty ruined too. It was telling me it needed replacing when the camera couldn't take decent photos any more, I just had a half hearted attempt at dragging it's life out for a few more months. It's not worth the time to try to fix it. The casing is all glued for the IP rating so it will be a pig to get apart I'm sure.

 

[Liquid Metal]

Thick sections + spray transfer...... multipass.
Weaving welds and trying to build up high volumes per pass is just asking for lack of penetration ie defeating the point of putting a prep on the steel to start with.
Multipass it all the way out, straight lines no weaving, keeping the arc in the front of the puddle.

 

[njc110381]

I did notice that the side I did more of a weave on actually penetrated less. This is pretty interesting. I'm really enjoying myself learning all this stuff!