Hows my penetration

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So today I got some practice time rosette welding, joining 18 gauge to 20 gauge.  For the end project, I'll be joining 16 gauge to 20 gauge (at least I think it's 16 gauge--thats what the shop told me.  But taking a caliper to it, I think they may have sold me 14 gauge.    But that's for another thread.)Anyway, the question is--how is my penetration?  I just wanted to know how the bottom side should look.  If anyone has comments on the fill side, those would be appreciated as well.The holes for the plug welds were punched with a HF punch and flange tool ( 3/16ths) and were welded with a Lincoln 100HD using .030 flux core.  I'm still pretty new to this, so any comments would be appreciated.Cheers. Attached Images
Reply:Looks good from here man, the underside looks like it became molten for just a second, is that what Im seeing? could probably back off the heat a touch (my opinion only) on the fill side, I cant really tell from the pictures but it looks like the puddle is still below flush, it could be argued that it should rise slightly above the surface and the edges of the weld befused well all the way around, no crater. But for just starting out and using .030 flux, I think your doing well. Are you just aiming at the center and fillin it up? or are ya slightly towards the edge and traveling around the circle?If I remember right from a previous post this was gonna end up as a floor pan right?Last edited by Burnit; 07-12-2008 at 10:52 PM.Reason: I can't spellYup
Reply:Burnit-Floorpan is right!  Your observations are about dead on.  Some of the fill spots are just a but concave.  I'll try to  make them stand proud a bit next time.My technique is to start in the dead middle of the hole on the thicker metal below.  As soon as I see a molten pool, I try to draw it out to the edges of the top sheet.  Total process takes maybe 2 - 2.5 seconds.So far, this is one of the easier techniques for me.  I have run some ugly beads in the past few sessions!  Cant tell y'all how helpful a resource like you guys are.  Thanks again.  Cheers.
Reply:Originally Posted by superkaz661So far, this is one of the easier techniques for me.  I have run some ugly beads in the past few sessions!  Cheers.
Reply:Start from the outside and go in......  That is how its in the book.You have enough heat.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by David RStart from the outside and go in......  That is how its in the book.You have enough heat.David
Reply:Depending on how good your coordination and view/eyes are, you may start the arc in the middle of the hole.  But then you immediately should put the arc and wire/filler at the edge of the hole and run around there.  Because the edge is where you are actually joining the two sheets together (a plug weld is sort of a derivative of a lap weld, where you weld the edge of the top sheet to the bottom sheet).  All the rest of the weld in the 'middle' of the hole is just to fill in the hole.  And the hole is there to give you that edge in the top sheet to make the weld to the bottom sheet.The plug weld is usually easier to see and control the weld, than to have two 'intact' sheets on top of one another and then to try and manually melt through the top sheet and start to melt into the bottom sheet and then to fill in all the melted volume with filler all while not blowing a hole right through everything.Oh, and concave welds are usually not the desired end shape.  Concave is usually a stress concentration point.  Add enough filler so that the weld is at least flat to slightly convex (proud).  A huge humped-up bead is not desired and is just a waste of filler.Last edited by MoonRise; 07-14-2008 at 03:34 PM.
Reply:the bottom side looks good other than the points that were already mentioned (concave, molten, etc.)... like it was already said, i would start at the edge and just work my way around, or start in the middle just to get an arc, then go right to the edge. the second method will give you more wire control in my opinion (i run the same unit).also, what are your heat settings? on the inner part of 16 ga sheet, i run at about 2.7-3.1 wire speed (your results may vary... find the hammer point and back off until it starts to have an even "frying" soud). and the heat is at B. when i weld butt-joints or corner joints on 16 ga, i use the "A" heat setting and do the same process with the wire speed... find the hammer point and back off a bit.other than that, brush off the welds using a metal brush (i just use a SS brush... last a lot longer and stay cleaner) and a small putty knife (chips off the slag a lot better than a chipping hammer). after you clean the welds up, then take some more pictures.Later,Andy