Tungsten balling up.....

[SicMonte]

I am trying to weld together two cam shafts...to make a closet clothes rod. Just a little project. The welder I am using is a Miller Syncrowave 200. I have the tungsten tip pointed and the electrode is set to positive. I have the amperage set to 125. When I go to make the weld...the tungsten just gets hot and balls up the point, no penetration at all. It seems as if the steel is unaffected by the heat. Any ideas?

[parsonsj]

Your machine should be set to DC negative.

jp

[wendell]

If you're positive you're setto "positive", then I'm with JP. Sounds like you're in AC.

[CRead01]

should be dcen for what you are doing. the heat is 70 percent to the posative and 30 percent to the negative. sounds like it is heating up the tungsten instead of the part you are welding.

[Don_Berry]

Make sure you are NOT using pure Tungsten. I used to use 2% Thorated, but that's been banned. I'm not sure what the new replacment is called.

[David Pozzi]

Most flat tappet cams are cast iron!
Aftermarket roller cams are steel, - good steel.
David

[SicMonte]

if they are cast iron...how do I go about welding that then??

[parsonsj]

Standard DC- is the machine setting. Cast iron has pockets of impurities that tend to burp and such as the puddle nears it. You'll also want to pre-heat the cam, if you can.

jp

[ntsqd]

For something like that I'll guess that a high nickle filler rod will do the job. Rockmount "Jupiter" would be great, but that's pretty spendy for such a project.
The problem with cast iron is that it is brittle. As such you can not get much thermal gradient in it or the differential expansion will have you chasing cracks.
I would take them up to warm, weld a short distance & peen while the bead cools to part tempature. Repeat. Back-stepping might be a good idea too. Keep the whole thing warm for the duration.

[SicMonte]

I got it to weld, but there are a lot of bubbles or like craters in the bead. I tried to go back over it but the same thing happened...??

[CRead01]

usually porosity is caused by lack of argon. If you are doing it outside make sure you are not in a windy area or you can just crank up the gas. otherwise you sould only need 15 to 20 psi. I am not sure of what filler rod you used but I have seen that with the wrong filler rod too.

[jamheg1101]

I got it to weld, but there are a lot of bubbles or like craters in the bead. I tried to go back over it but the same thing happened...??

Most likely a dirty cast material. Are you just doing this for fun or are you hoping to actually balance the cam and use it? Hopefully the earlier.

[SicMonte]

Most likely a dirty cast material. Are you just doing this for fun or are you hoping to actually balance the cam and use it? Hopefully the earlier.

just for fun...I am making a closet rod...hahahaha

[David Pozzi]

You would be better off brazing them together, cast iron is easier to braze than weld. Nickel rod is OK for stick arc. For a tig, I'm not sure what is best, but perhaps a low fuming bronze rod. This would be like brazing, but using a TIG torch for the heat source. This way you are not melting the parent metal.

David

[Jim Nilsen]

There is an easier way to put them together and it will look perfectly clean and will work for its intended use.

Drill the ends and tap them and then put a grade 8 set screw or bolt that you cut down, screw them together and your done!!

Using a lathe and a good center drill is recommended if you want perfect otherwise you can do it with a hand drill and a tap if your careful.

[Mathius]

There is an easier way to put them together and it will look perfectly clean and will work for its intended use.

Drill the ends and tap them and then put a grade 8 set screw or bolt that you cut down, screw them together and your done!!

Using a lathe and a good center drill is recommended if you want perfect otherwise you can do it with a hand drill and a tap if your careful.

OR, you could do what this guy said, and then weld or braze it after. Then you'd still have a smooth look, and you wouldn't necessarily have to worry too much about penetration.

I've never welded cast iron. Supposedly have to pre-heat, use a high nickel rod, and then let it cool slowly.

I've done some brazing before. IMO its a lot like soldering (architectural soldering, not like soldering iron on wire) but you have to move a little faster, because you're not moving the puddle around with an iron, you're using the rod, so it's burning off as fast as you move the puddle.

Not a lot of penetration with actual brazing or soldering. If you're getting penetration you're not really by definition soldering, because soldering involves melting the filler metal, not the parent metal by definition. Welding is for penetration of parent metal. A good weld should hold up longer than the parent metal.

Not sure where brazing falls on that spectrum. I would imagine it's somewhere in between.

Mathius

[SicMonte]

There is an easier way to put them together and it will look perfectly clean and will work for its intended use.

Drill the ends and tap them and then put a grade 8 set screw or bolt that you cut down, screw them together and your done!!

Using a lathe and a good center drill is recommended if you want perfect otherwise you can do it with a hand drill and a tap if your careful.

wow...I never even thought of that....too late now though!! I will get some pics up soon.

[Travis Rankin]

Cast Iron is one one the coolest wierd metals I've learned to weld..

The best true "Cast Iron" weld is done with a torch, cast iron filler rod and a special cast iron flux.. You have to grind the area all clean, and prep it with a huge "V" groove then preheat it.. focusing on the edge to be welded.. you will see carbon burn out of it in the form of graphite.. then you slather it up with the flux, and weld it up with the filler metal.. its really wierd to weld, as you can't really see a heat color change through the goggles.. the flux sparkles as it melts, and the texture when welding is like a really thick paste..
Give it a nice slow post heat, chip off the flux and the end result is a perfect color and texture match cast iron repair.

Not that you would want to go through all of that for a curtain rod, but it's just a cool technique that not many people know about..
I thought I would share it ;)