Just started learning to weld . So welded in rear lamp panel then when i was grinding my welds flush just seem to fall apart and leave holes ?
It does sound like you are lacking in penetration. There are some smashing web sites giving us learners tips about welding. Don’t forget, every nice weld starts with cleanliness. Just practice on scrap or it’ll end in tears. Ozziedog,,,,,,,,,, are you using gas per chance
I did practice on scrap (looked good ) so stared bus . Again looked good when welded . Then when was trying grind them smooth few holes apeared
I found it a 2 or 3 stage process at the start. Weld it, clean it, weld the bits I missed, clean it, weld the other bits I missed, clean it. Keep going till you’ve got it all.
Hard to give advice without watching you weld but if I had to guess amps to low and travel speed to fast. Get someone to video on a bit of scrap with sound would be easier to give advice
Using a jogger on the panel makes it alot easier rather than a butt joint. There won't be much to flat off on the outside.You can make one out of an old monkey wrench.
You need to leave a metal thickness gap to allow penetration. Argon is different to Argoshield ( Argon is used in Stainless and Aluminium) rest is just settings and practice ... Mass produced cars are joggled and brazed