Learning flux core - too hot or not?

  1. rich r

    rich r Member

    Messages:
    645
    North Yorkshire
    I've been learning flux core gasless with an £80 Lidl Parkside unit for a couple of weeks. I never intend to do anything more than the occasional repair and am really welding just for the fun of it so it isn't worth me going for gas mig at this stage (but I may do in future). I've some previous experience with 6013 rods on a cheap buzzbox so had some idea of how things behave when an arc is pointed at them.

    Following the tutorials on here and online videos, I've reasonably happy with sheet steel around 2-3mm for butt, lap and fillet joints. They're obviously not perfect but something I can practice to get neater and better. My approach is to start with thick metal then working to thinner metal and more complex techniques rather than jumping straight in with a cheap gasless welder and having a strop because I can't do car bodywork in the first week :)

    I've recently moved down to trying 0.8mm sheet with some success. At the moment I'm using the spot/stitch technique on lap joints. Then when I'm happy with that I'll have a proper go at butt joints.

    I'm waiting until I can see the weld pool melting the edge of the top sheet then stopping and letting it cool until it's more orange than yellow, then doing the next spot. Working left to right (although I find working towards myself easier, I think left to right might be a better direction to get right). Wire is 0.9mm flux core GYS Toparc, machine is a Parkside gasless PFDS120A2, metal is 0.8mm sheet offcuts about 10cm wide.

    So - my question is, in the photos below I think I've got too much penetration as the weld spots look rather wide and flat (about 4mm wide), and there are blobs on the back. I don't think I'm far off, but would the advice be to reduce wire speed, reduce power or change my technique?


    IMG_0024.jpg IMG_0025.jpg
     
  2. angellonewolf

    angellonewolf Member

    Messages:
    5,662
    Location:
    bristol england
    looks fair to me (im no welder just a hobbie as your self)

    the less you get on the front the better less dressing up out of intrest try a slight shorter burst id like to see metal on the oposite side to where im welding but that does seam a waste and more bouble on the inside the more the water catches if you are doing car work

    you are working on a bench and the metal is resting on a large bit of metal that will take some of the heat out of the work piece try lifting the metal up in the air and weld it it will be more like welding on a car

    there will be better people along soon that know what there doing to give better advice
     
  3. rich r

    rich r Member

    Messages:
    645
    North Yorkshire
    Thanks. I tried again but with it lifted up on a wooden lock (with earth clamp moved to the workpiece) so there's nothing behind the joint. First attempt I reduced the wire feed and power too much and it wasn't good. But increased them slightly and I've done a couple more welds that look similar to the one posted above, although not quite as neat. I'll keep practising though. I guess it's a case of repeating it until I get every spot the same as the last, and adjusting the settings if it doesn't look right.

    So maybe flux core on a Lidl welder on 0.8mm steel is possible, even for a novice like me. :) I doubt I'll ever weld on a car though, but it's all good practice.
     
  4. angellonewolf

    angellonewolf Member

    Messages:
    5,662
    Location:
    bristol england
    ah i cant believe one one else has posted on this to give more input im going to tag a few people in to see if they can add more input for you

    @Welderpaul
    @Wozzaaah
    @HughF
     
  5. HughF

    HughF Member

    Messages:
    5,955
    Location:
    Work: Dorchester, Workshop: Corfe Castle, Wife's place: Frome
    Tag received - will post a reply later
     
  6. Robert Mullins Member

    Messages:
    112
    Location:
    Salisbury, uk
    Ok, so my experience of light gauge flux-core is VERY limited, but I have used flux-cored in heavy engineering, out-door conditions: looking at the photograph, what I believe your not doing, is overlapping your stop/starts whilst using the make and break method: the holes that are present I believe to be weld crater shrinkage: your need to 'arc-up' burn out and fill the previous weld-crater:
    The higher your heat input, the greater your weld crater issues, get into the habit of filling the weld crater, by either welding back and forth over the weld pool, (pipe welders on the root), stopping and allowing the extra weld metal to build up and fill the weld crater, or stopping, allowing the pool to cool briefly, 2-3 seconds and then welding over (JUST) the weld crater: whatever works for you, BUT unfilled weld craters are bad practise, and if you work in this industry you will witness rejects and failures due to it
    There are more than likely a plethora of welders with infinitely more expertise with this method than i, but I found that the flux-core was 'ALRIGHT,' IT worked 'WELL ENOUGH' with the heavy steelwork, but lacks 'something,' waiting for the flux-core to gas, whilst watching the steel burn away would just send me reaching for a gas shielded set up EVERY TIME; ;
    My advice, from the heart, BIN THE CORED WIRE; invest in a solid wire/gas shielded set-up, and immediately the whole job is easier
     
  7. gaz1

    gaz1 Member

    Messages:
    11,366
    Location:
    westyorkshire
    your welds do look good on the bench though

    when nothing behind it aim for your first blob of weld even if it was cold it will aid in getting rid of that hot part as you weld

    id say about 10/15 degrees aim towards the blob of weld

    gasless wire is a git to use on thin metal but im naughty ive picked up if i move fast on holes i can get away with it
     
  8. rich r

    rich r Member

    Messages:
    645
    North Yorkshire
    Thanks for the advice. I will aim to overlap and angle a bit more to fill the crater and keeping it more consistent. I'm not going to invest in gas unless I know I'm going to be using it enough. At the moment I'm doing perhaps 30 minutes of welding practice a week and have no projects planned. But that's not to say I won't make the move one day.
     
  9. rich r

    rich r Member

    Messages:
    645
    North Yorkshire
    Following the advice, I've got a lot better after a few more practice sessions. So now with the metal clamped to a block so the joint has nothing behind it (held with a magnet to to a tack at each end, then magnet removed). I've moved back partially over the previous spot before it cools and the result looks much better to me. No more sagging craters and more even, if a bit spattery. The blobs on the rear are only specks above the surface level rather than blobs. I need to practice more to improve the consistency and straightness.

    It almost feels like I could do a continuous bead but I suspect it'll put too much heat in and burn through. The wire feed and power settings are much higher than I had first assumed was needed for 0.8mm steel, but I guess being a lap joint it's conducting the heat away more quickly than a since sheet would do. The steel changes colour about 15-20mm from the joint (I should have left that in the photo, but I'd already wire brushed the whole piece by then).

    Many thanks for the help - I'll keep practicing this to get it neater then try working with the metal not flat on the bench. And I guess I ought to think about butt joints.


    IMG_0033.jpg
     
  10. angellonewolf

    angellonewolf Member

    Messages:
    5,662
    Location:
    bristol england
    if you feel you are geting near that every time you might want to move on a bit and hold the metal in the air as you would be when welding a car panel as at the moment gravity is helping you try it with the metal vertical you will find it quite differnt
     
  11. gaz1

    gaz1 Member

    Messages:
    11,366
    Location:
    westyorkshire
    certainly looks alot better look more like a uniformed weld there more than your previous attempt

    just holding the trigger a little too long as is really ackward to disenguage that trigger quickly after pulling it on

    if you want to try do a pull move into your weld then move back over your weld as a continuous weld but beaware you may burn through the metal
     
  12. Brad93

    Brad93 M J B Engineering

    Messages:
    10,404
    Location:
    Essex
    Are you doing a bunch of little tacks or some sort of whip and pause?
    Just do a straight run. Pulling the torch.
     
  13. rich r

    rich r Member

    Messages:
    645
    North Yorkshire
    Thanks - yeah, I'll do a few more flat until I'm happy that I'm getting it more consistent, then I'll clamp the metal at an angle. I don't actually have any need to work on car bodywork, but I'm finding learning how to weld thin sheets together interesting, and hopefully it's teaching me better fine control of the torch. Perhaps I might see if I can borrow a gas mig set to see how I get on with that much cleaner setup, although I'm not finding the slag too big a deal, it's quite light and comes off with a wire brush easily. Not like when I use 3.2mm 6013 rods :D

    I'm using the technique described in the tutorial section - overlapping little tacks (starting on the lower sheet right in the corner, then moving in a sort of small circle to move the weld pool so it melts the edge of the top sheet and back into the previous tack), letting it cool slightly before doing the next one. I did try a straight run, but it has a tendency to burn through and leave the metal glowing yellow. Perhaps it's possible, but I don't think it's going to be easy with a cheap gasless setup. All of the tutorials I've read or watched use this sort of stitching technique for gasless on 0.8mm metal. I'm prepared to have a few more tries of moving constantly with pauses though.
     
  14. chilskater New Member

    Messages:
    3
    Location:
    Borneo
    IMG_20201016_153313.jpg
    1.2mm square tubing.. i struggled to weld this square tubing.. my machine doesnt has label for Voltage, Amp/Wire Speed..
     
    • IMG_20201016_153144.jpg
  15. chilskater New Member

    Messages:
    3
    Location:
    Borneo
    second one is 3mm angle iron to 1.2mm square tubing..
     
  16. gaz1

    gaz1 Member

    Messages:
    11,366
    Location:
    westyorkshire
    the outside spot welds are right but never weld in the corner of the angle iron like you have done

    best off just welding from the inside to the outside as one weld
     
  17. Robert Mullins Member

    Messages:
    112
    Location:
    Salisbury, uk
    YET MORE ADVICE!! Sharp edges and corners readily absorb more heat and burn away than the flat face, also, the inside corner of the RSA is not only a flat face (provided) that it's positioned without a gap, it's(usually) radiused and thicker by X2 than the flanges;
    What this means is that whilst the amperage/voltage setting may well fuse the two toes and the heel of the angle, the thicker material, and the flat face require somewhat more power to achieve the same result:
    As to welding the joint, I'm making the assumption that it's to be fully welded, I'd weld the outside fillet & butt first, the inner fillet weld I would start at the toe, weld into & around the corner and complete the weld upto the other toe without stopping:
    Try to avoid starting to weld in a corner, weld into, and then out of it without stopping
     
Advertisements