[Dave805]

I have an Alpha TIG200X and get porosity on starts & stops, found a couple leaks in the torch, was able to repair one and not the other, in the process of dealing with AHP to get a replacement, another thing I noticed is when I purge gas & step on the pedal with the torch in the air it makes a buzzing sound like its arcing inside the torch, never used any machine that would do that usually I remember just hearing gas flow. Anyone experience issues like this? Also the tunsgten forms a weird formation on the tip that resembles a witch hat after only one bead and not dipping.

[AndersK]

How long have you set pre- and post gas ?
Try 0,5 s pre and 4 s post to see if start and stop improves. Dont move torch away while post gas flows.

That build up I think comes from dirty material but a picture would help you get more answers.

What material are you welding?

[Dave805]

I believe the pre-flow is programmed in the machine and not adjustable, post flow i usually have set around 4-5 seconds, welding mild steel, usually 1/8" thick & 3/16" thick coupons, I will have to get some pics together, what about the torch arcing away from the work piece?

[AndersK]

The sound you hear is probably the HF unit in the machine trying to ignite.
Move away as long as your hose allows and listen

[Dave805]

It's weird though cause other machines I have used with high frequency start like lincoln's or miller's I don't remember them ever doing that, but that set aside I have been cleaning the material with a flap disc then wiping down with acetone, cleaning the filler rod with acetone, sharpening the tungsten to a sharp point and still get porosity mostly on starts & stops and the weld looks like a dull gray not nice & shiny

[noddybrian]

Unless AHP have improved the model recently I think you are mistaken about pre-flow - it does not have any in built or pre programmed - it's common on many POS Chinese machines - I've sadly had to weld with several & to get pre-flow you use the post flow ! IE hit the trigger away from the work momentarily - then let off so you get post flow - now move the torch to the start of the weld within your post flow time & you have gas cover - if you don't do this then the arc starts as the gas solonoid is energized & you won't have gas flow fast enough so tungsten will suffer & you'll likely have porosity even if you have a good torch with no leaks - just something you live with at the price point - the noise you mention I think ( as others have said ) is HF - all the Chinese machines I've used do it - especially away from any ground - often if they don't initiate instantly they do it & you need to let off the power & ground the tungsten & try again.

[subwayrocket]

Hope you get it fixed . If not, look into a CK . I had a weird problem last year , thought it was my torch, CK sent me a whole new outfit no questions asked . Everything pointed to a crack in the brass head ...eventually I found the prob and it wasn't the CK20 . Needless to say, i'd recommend CK , they stand behind their stuff .

[Dave805]

Yeah your right there is no pre-flow on this machine, but come to think of it I remember using post-flow to shield the area prior to welding & not seen any improvement, new torch is on the way from AHP if that doesn't fix the issue I'm starting to lean towards contaminated gas.