[dcuplover]

I recently bought a Miller 200 Dynasty and started to teach myself how to tig weld. I have been playing around with aluminium and was trying to use the scratch start option ommy machine. Occassionaly I get the tungsten stuck at the beginning of my start. When this happens do I need to resharpen my tungsten? I would think this would contaminate the tip. I do see a poor quality arc after it happens so am thinking this is due to the stuck tungsten on start up. Thanks

[dave powelson]

I recently bought a Miller 200 Dynasty and started to teach myself how to tig weld. I have been playing around with aluminium and was trying to use the scratch start option ommy machine. Occassionaly I get the tungsten stuck at the beginning of my start. When this happens do I need to resharpen my tungsten? I would think this would contaminate the tip. I do see a poor quality arc after it happens so am thinking this is due to the stuck tungsten on start up. Thanks

HF start on AL eliminates this immediate contamination.
Do yourself a favor---download the Miller manual and setup sheet for this machine; which will
give you the basic, starting parameters to setup and run the machine....and accelerate your teaching program.

[dcuplover]

I do have it already. I know the tungsten won't get contaminated when you do this as long as all goes well. I am concerned when I get the tungsten "stuck" to the aluminium when it doesn't start up as planned.

[Braehill]

dcuplover,
The simple answer is not to use scratch start on Aluminum. But to answer your question yes you need to resharpen your tungsten and grind out the remnents of it out of your weld if this is a critical weld. You can not scratch start any kind of metal without contaminating the tungsten and the base metal to some extent. There are techniques you can use to lessen it, but not eliminate it.

If this is just practice I say try whatever you like but you'll mostly be practicing sharpening your tungsten, and making ugly welds, and who really wants to get good at either of them.

Len

[rick9345]

Scratch start alum not a good idea, use HF

if you iinsist/must scratch start alum try a small copper plate next to bead to light off on.


See Braehill answer

[Graveyard]

I read that you are teaching yourself to tig aluminum which is not an easy task. I'm not the most proficient Aluminum welder but when it comes to aluminum i cant see using anything else but HF with the foot pedal. With you being new i assume you just can't get used to it or are hesitant to try it. I started off tig welding with scratch tig machine and i thought they were the cats ass and for some applications they are but in this instance you would be better off breaking down and learning to use and control the foot pedal. Once you get it down you won't want to do it any other way. Good luck and have fun.

[dcuplover]

thanks guys for the tips. I have used the HF start already but just wanted to try other options and since the machine is capable of doing it I thought I would try. Nothing vntured nothing gained...even if it is just sharpening the tungsten!

[dirtmidget33]

Nothing wrong with learning different way to use machine. after all there might come a time when you can't use HF on a piece of equipment because of damage it can cause. Lift arc or scratch start is good to know for those times.

[dcuplover]

went back to HF start and it went fairly well. I can see how difficult it is to weld an area that has contamination within the weld as I was trying to fix some bad welds I did with my spool gun. I think I ended up grinding the welds down with a flapper wheel that I also used on my car trailer steel metal work. Over heated a few spots but otherwise was able to achieve what I started out wanting to do.

[zank]

There is no need to scratch on a dynasty. It's a lift start. Simply make contact with the part, hold it there for a second or two, give the pedal some juice, and then lift straight up to start your arc. It keeps the tungsten in much better shape compared to scratch.

[dcuplover]

yes i meant to say lift start and not scratch, thanks

[steeldr.]

why would you want to scratch start the weld process when you have HF? if you have a foot control,place tungsten within 1/16 IN. from work, the HF will start the arc,no tungsten contamination. You should be using pure tungsten, so no need to sharpen, just break off the contamination part and start welding. The welding process will round the tungsten to the required shape......ron

[dave powelson]

..... You should be using pure tungsten, so no need to sharpen, just break off the contamination part and start welding. The welding process will round the tungsten to the required shape......ron

......well ron, OP is using an inverter, which performs much better on AL AC with anything but pure tungsten.....and the
tungsten point is sharp--to focus the arc--which is a big deal.
Lanthiated holds a point pretty well.

[dirtmidget33]

why would you want to scratch start the weld process when you have HF?

Sometimes the unit you are welding has computers in them, which is almost everything now, by using lift or scratch start you do not introduce the high frequency into the work piece. HF might damage electronics or erase memory or EPROMS. If welding on a car now days it would prolly be best not to use HF. I consider it a valuable thing to learn. There is a reason HF inverters give us the option of turning it off to do a lift start Because sometimes we just can't use it.

Would really suck for a car to drive in shop then be towed out because CPU memory is screwed up or erased.

[dirtmidget33]

Before I get corrected should have used PLD (programmable logic device) instead of EPROM. PLD covers most programmable chips since EPROMs are not really used any more. What can I say I had EPROM burners in late 80's and early 90's. Think I still have some of that stuff somewhere. Now days that's ancient technology