Vertical up or down on this weld?

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I'm working on extending my car trailer, that thread is here but this joint got me thinking.  I know welding vertical up is always the best but I'm still not very proficient at it (just don't do it enough) and doing it on a flat vertical surface like this is going to be even tougher than if it were a joint-T or somethingIn this picture below are the backs my first welds on this joint (just the 2" verticals on each end), these were just to hold this together and next I'll start to stitch it all up.  The welds shown are both vertical down and this is 4" x 3/16" channel, both edges are beveled.The vertical down welds look like they have lots of heat in the metal and good penetration in the center.  Do you guys think in an example like this that vertical down is sufficient or another example of when NOT to do a vertical down?  I forgot to take a picture of the other side, but I can do that later if you want.Thanks,Jordan
Reply:"I know welding vertical up is always the best" It is? What process are you using? GTAW don't care up or down. Penetration not direction of travel is the real concern.
Reply:I've got a MM175 mig welder, .030 wire, Ar/CO2 mix gas,
Reply:Vertical up.  With vertical-down, you are racing AGAINST gravity while trying to weld and make the puddle.And you should have rounded the 'corners' of your splices more (corners = stress-concentration).And where are the tack welds to line up and hold things in place while you get ready to run the complete beads?And a 175-class machine running solid wire and C25 is pretty much going to be running  at MAX for welding on 3/16 thick material.  The best laid schemes ... Gang oft agley ...
Reply:I don't think I'm going to run complete beads, I don't want to warp the material since it's the main frame.  What I've welded is just to hold things together for now and provide a backing so I don't blow through when I hit the other side hotter.I thought about rounding the corners but I've seen it done both ways and round makes it more difficult to cut and re-align.  I'll be fishplating the inside as well as putting another piece of 4" below this part of the frame to extend the tongue on the trailer, not too worried about that all breaking.I was running the dial at 7 (out of 10) on the volt dial and 70 (out of 100) on the wire speed and it's not quite undercutting.
Reply:its fully beveled on the front and back by the looks of the picture?, thus you dont have to obviously worry about full penetration as the complete joint should be full of weld metal. IF  you have already welded on the backside grind out your bevel a little more until you reach welded bead on the inside. Then by all means if you feel more comfortable running a downhand go for it, start by making a simple small hot downhand root pass and then cap it with one more downhand. The key to downhand pass's is heat you cant be afraid to use some heat. The reason for this is your travel speed is faster thus less heat input, and technically less penetration but you do not have to worry about strength issues. Especially if your fish plating like you state, but be sure to put a generous radius on those fish plate cornors!
Reply:Yes, they are fully beveled on front and back, down to a 1/8" edge.  I think I'll cut some 3/16" flat iron and do some testing/practicing with vertical up, see if I can get it dialed in on this welder and do it that way if possible.I have been fully rounding my fishplates, seems to be the norm over on Pirate4X4.  Also, many over there are also spacing 1.5" or so holes in their plates so the inside can be welded as well.  Anyone know the good/bad about that technique?  Seems like a good idea just maybe overkill in some applications.Thanks for the idea of grinding out the weld a little from the opposite side, I hadn't thought of that.
Reply:Ummm, dude, if you didn't already KNOW to at least partially grind out the back side of a weld before you run the bead on that side to get a nice, clean, full-penetration weld ...STOP !!!!!!Learn what good welding practice is, and PRACTICE, then practice, then practice some more BEFORE you go and weld a trailer frame.  The best laid schemes ... Gang oft agley ...
Reply:Vertical up is always best?? - For all situations?  All types of metal? All processes??Does anybody on this site actually weld?Vertical down GMAW is fine for the thin gauge steel you are welding.ɹǝʌo ǝɯ lloɹ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
Reply:Originally Posted by MoonRiseUmmm, dude, if you didn't already KNOW to at least partially grind out the back side of a weld before you run the bead on that side to get a nice, clean, full-penetration weld
Reply:I'd suggest you practice the v-up a bit and see if you can get happy with some coupons before you decide how to finish the splice. I'd personally rather weld uphill unless it is really thin material. If you do weld down, make sure you are hot enough. You will need more than the same uphill weld.From looking at the pics you have shown so far, I think you have the skill to do this job.Last edited by daddy; 01-28-2011 at 06:01 PM.
Reply:Fat Bastard and TSOR, haven't you all found out by reading on this forum that all position rods really aren't all position and everything has to be welded up when it's verticle or it will just fall apart?  I quit making any comments about welding quite awhile ago but I just couldn't help myself. I'm bored and feeling ornery this afternoon.
Reply:Since you have had some schooling, why don't you do a sample weld test? Actually do two, one vert up and one vert down and see what happens.
Reply:Originally Posted by Jay OSince you have had some schooling, why don't you do a sample weld test? Actually do two, one vert up and one vert down and see what happens.
Reply:Originally Posted by coronet440Bend in the vise or using a BFH and see if any break at the welds.
Reply:Nope, only have a rollcage style tube bender and a HF pipe kinker, likely take longer to adapt something to those than its worth
Reply:Vertical up or down aside, those corners are a heck of a lot thocker than 3/16th" aren't they?  Those are going to take some effort with a MM175. Some prep (grinding) will be important. A big key is what you do with the easy to get to side, the outside. Make sure you back gouge out to good weldment then fill 'er up. If you don't get penetration then gouging will show that real quick. I'd grind down to a bout 1/16th then leave a gap. Tack the gap good to make sure it doesn't close up. Good luck on the pulling and warping. "The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Did some tests this morning using scrap 3/16' angle iron in about 3" pieces. Vertical down was at 70 wire speed, 7 V.  Vertical up took me a couple tries to get something I liked, 45 wire speed and 5 V is what I ended up with.Vertical Down bend test, bent it back as far as I could with a pipe wrench, no cracks or failures;I adjusted the piece in the vise to bite the edge of the weld and hit it 10+ times with a 2 lb hammer, no cracks or failures;From the other side;Vertical Up bend test, same results as vertical down, no cracks or failures;I then bent them both back the other direction and they both broke right where the vice edge was clamping the material.  Outside of the welds.  Are my testing methods sufficient?   If so, I see no difference in methods when done correctly..... well I assume correctly since nothing broke.
Reply:And what did we learn today??ɹǝʌo ǝɯ lloɹ 'sıɥʇ pɐǝɹ uɐɔ noʎ ɟı
Reply:Our CWB welding standards in Canada say vertical up is the best way to go. I how ever did test and receive a vertical down welding ticket but that was on 1/8 max and only for the shop I worked at. So I guess they would say vertical down is somewhat frowned upon. Your down hands do look like they got decent penetration although there may have been a gap in the plates to allow the weld to come through. Not sure?Also when bend testing. We always weld a joint and bend it back over the weld not forward as you have done. You are looking for the material beside the weld to fail or not fail at all. If the weld splits, obviously the weld is not sufficient. The weld should tear out the plate material. There is a few different ways of testing the material and welds.So from what I have learned, always weld vertical up. I prefer a flux core wire or stick but hard wire can be welded vertical up as well. Takes practice but can be done.Last edited by oxygen454; 01-29-2011 at 08:13 PM.
Reply:Vertical up still kicks my butt. I use a an old Lincoln AC225, 7018AC rod, 120 amps. I have no problem with penetration, but the weld is ugly, the puddle runs out and forms big globs. Sometimes the weld comes out looking damn near pro, other times looks like my virgin run. Still trying to get a feel for it. There is a big difference between wire and stick though. I can lay a bead down with my wire that looks like yours every time, but I can't do it with the stick for some reason. I'm a hobbiest too... lots of projects here on the ranch to keep my practicing. Last project involving a piece of heavy equipment, I used 6013, I think it was, for the root pass. Then did a pass with the 7018, both vertical up. Visually I could see deep penetration. Cleaned up all the slag, chipped it out, ground it down, then did a vert down to make it look nice and close up all the gaps. Hasn't failed yet.
Reply:Originally Posted by oxygen454Your down hands do look like they got decent penetration although there may have been a gap in the plates to allow the weld to come through. Not sure?
Reply:So your grinding down the backside of the weld for weld prep and going for 100% weld penetration. Good call. It should hold fine. Another way of joining and welding a frame together is to use a fish plate over the splice after the inside weld is ground flush.
Reply:Originally Posted by oxygen454 Another way of joining and welding a frame together is to use a fish plate over the splice after the inside weld is ground flush.
Reply:If the welds are as good as they look then you should have no problem. Side note, a good looking weld is not always a strong weld. I have seen some nice welds peel off of steel.Your downhands beads are fine, just make sure to prep your material with a bevel, run small HOT down hand roots on the bevel but do not fill it all the way. Once your done your roots, turn down your machine slightly and run a capping pass.