Oxy/Fuel Question

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I an brand new to welding and have a Harris Oxy/Fuel setup and a Linclon WeldPak 125 Flux core machine. I am kind of teaching my self the basics and feeling my way along.I am seeing two problems I cant overcome   1 )  When attempting to weld two perpendicular pieces (same thickness)         I get two separate pools, one on each piece with what appears to be a cool spot right at the joint where I cannot get a pool to form. If I continue heating at the joint to the point I can get the pools to come togehter I get severe undercut of burn though at the joint edge ...  What an I doing wrong2)    I also ofter get what appears to be a very thin crust floating in the middle of the pool that makes it very difficult to control. What is causing this ?What do I need to look for to determine if I am getting good penetration into each piece ?  Is it best to dip the rod into the poolThanks for your help and if you could refer me to a good beginners resourceRich
Reply:I presume you are using the torch, not the fluxcore machine.Try more heat (bigger flame) If you are at the max for your tip, up the tip size. Then, move faster to compensate. This will REDUCE then total heat put into the weld zone, and reduce undercut. The crust is slag. You can get more of less depending on the balance of the flame, but any crud on the material or in the material will contribute.If this is a tee joint, you can also try some preheat on the through piece (but not on the butted piece)-- this piece will pull more heat from the joint area (since heat can go both ways) than the butted piece (where heat can only go one way). The preheat wants to be the whole length of the joint. This applies if the butted piece is the one where you are having the undercut and burnthrough, not the through piece. (through piece: the 'top' of the T; butted piece: the 'stem' of the T)Note that I am nore of a TIG welder than gas welder at this point in my life, but the techniques are quite similar.
Reply:I have a similar issue with TIG. What I've found is that if I stick the filler rod in the joint, so I melt off a little glob from it, then that little glob will meld with both the horizontal and vertical pool, bridging the gap.Once that happens, you can move the bead along the joint without difficulty.- John
Reply:Good point about using a dab of filler to bridge the gap runchman.  It also helps a ton if joint fitup is tight, without any gaps.As enlpk implies, maybe the balance of the flame is affecting your crust/slag.  An oxidizing flame may cause this problem, try favoring the acetylene rich side of neutral to produce a slightly reducing flame.  This is what is recommended for brazing so as not to oxidize the joint.Yes, dip the rod in the pool, try to keep a regular beat, dip/retract, dip/retract.
Reply:NewbieRNI don't think you need a larger tip since you are getting a puddle.  It depends on how long it is taking for you to get the puddle.  Pay attention to the torch angle, also.  The tip of the inner cone is the hottest, thus it needs to be pointed where you want the heat.  Also, control the heat by moving the tip closer to or farther from the puddle.  Too large a tip will make i difficult to get into the corner without overheating everything around it.  Also, start at the edge of the metal if possible.  I use a neutral flame for welding.  Though as stated err on the side of Acetylene rich, though not as hot as neutral.Are you using filler, now?  What size metal are you welding?
Reply:I am welding 1/8 inch with a Harris 5 tip. When I use the rod I have a tendency to glob it on, looks good but I get very little penetration  (more like a braze than a weld) I think the melded rod is the pool but is just laying on top of the base.
Reply:You also might practice some with just running some beads on flat stock, not joining anything. Make a pool until you burn through a few times, just to get the feel of the 'limits' that you can push the metal to before catastrophe hits. Might help on the T joint, giving you a little better idea of what is the right amount of meltage. Hey I made a new word there
Reply:Originally Posted by runchmanYou also might practice some with just running some beads on flat stock, not joining anything. Make a pool until you burn through a few times, just to get the feel of the 'limits' that you can push the metal to before catastrophe hits. Might help on the T joint, giving you a little better idea of what is the right amount of meltage. Hey I made a new word there
Reply:Originally Posted by NewbieRNI am welding 1/8 inch with a Harris 5 tip. When I use the rod I have a tendency to glob it on, looks good but I get very little penetration  (more like a braze than a weld) I think the melded rod is the pool but is just laying on top of the base.
Reply:Rich, everybody seems to be assuming that you are welding steel.  Is that the case?  Sounds like it, but you never said what your base metal and rod are.  Is your filler rod and base metal clean?awright
Reply:Rich, everybody seems to be assuming that you are welding steel.  Is that the case?  Sounds like it, but you never said what your base metal and rod are.  Is your filler rod and base metal clean?I think the suggestion that you practice running a bead on flat stock while adding a little filler metal to get the feel of leading the pool along is a good one.awright
Reply:We're also assuming this is acetylene?I think Pulser nailed it.  Of course, Enlpck gave loads of good info, especially on the T-joint.