Thread: why hollows in my weld?

I though a bit more info may help
toolcraft 2.5
Welding on copper plate so it will not stick
Can't get electrode to run under 120 amps which is too much for the electrodes and for this job.
120 amps is ok on 1/2" plate but have to do short runs or the electrodes get red hot and the flux falls off. Is it me or the cheap welder or both?

I would think the silver solder could cause that, could also be too many amps,I have never had the flux come off over heated electrdes.

Methinks far too much heat and/or wrong electrode.

From this distance it looks like porosity.... if it was mig i'd say definately ...no gas...but is stick but it could still be a shielding problem if your flux is falling off...120 amps is a bit hot I would of thought for what u r doing 80 90 is usually adequate for 2.5mm rods. R the toolcraft rod just a GP rod 4812??? if they r a say a 4818 low hydrogen they will be hard to start, warm dry rods will also run better

For a point like u r doing there is no where for the heat to go except right there in the weld pool and makes it worse cos ur slag is most probably not covering the deposited weld pool, oxygen attacks the molten metal cuasing the holes
If it were me I'd back the current off, keep a close arc, and small deposits of weld... stop start to build it up pilot arc is good for starting the arc for something like this, voltage reduction device(VRD) can make starting a bit painful...a auto lens is also good as it allows u see the end of the rod so u can positoin it more percisly

Peter

I just rang CIGWELD and asked what I sould be using for the job and he told me mild steel. So I think I will patch them up with the MIG, he sugested TIG but I don't have one of them. The toolcraft are a 1560-A4 if that means anything to you I think they are high chrome molybdenum but I can't remember. They deposite tool steel. It says 75 amps on the packet but they just stick if I try that.

Try start it on the copper plate then move it on to the blade. Or grab a bigger rod. Running on 120 amps when the rods shouldn't be over 90 is no good.

The hollow is a certainly a gas pore that hs grown in the cooling weld.

It is from an impurity at that site and the zinc content of the silver solder is a likely suspect.

I believecommercial saw blades are balanced and have the warps removed after the tipping process.

This may make a sucessful job unlikely if you do not observe these processes.

If the blade value is less than $40 you may well exceed that in electrode cost and still have a saw blade that does not function to your satisfaction.

Grahame

I haven't bought a blade for over 10 years but they were $150 then I think. Will a mig overcome this gas bubble trouble or would an oxy be better?

Mig? Even more likelihood of gas problems. Oxy is the best way to go.
Is this blade a mill blade?

Yes a Lucas blade, thanks i will try and repair my mess with a mates oxy

I find it hard to see how any fix would work. Mild steel will probably be too soft..If you build it up with that and then get a tungsten tip soldered into position on top of the mild steel, over time when the blade is in use the mild steel seats may deform from the load placed on the tungsten tips.

I know what rods I would use to try, but they are not available in small packets...

What rods are they? Could I try using the tool steel electrodes with an oxy?

cobalarc 350, they are a hard facing rod but the deposited material is not that hard and is machineable..

Your biggest problem is the blade would be made out of a high carbon steel...High carbon steels are hard to successfully weld..