Aluminum Penetration Through Root

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I went down to the lab today to do a demo. Penetration on a but joint w/o a backer vs. with a backer. Here are the results. Miller Dynasty 700 DX. HW18 Torch. 3/32 Ceriated. 20 CFH Argon. If you want to know all the setting let me know. First test plate without backer before welding.Burn through on backside after welding. Notice it did not tie in good. The other test plate with SS backerNow look at th penetration difference with a backer. It is much nice and ties in instead of just getting melt through. --Gol'
Reply:Looks a little like pigeon, well you know.  Then again, I have built enough stuff with 6011 to know that looks ain't everything. Better pix will be the deciding factor. If your welding pipe there is no backer and the backside of your root should look as nice as the face of your bead. I am not knocking you, I just want some better pix. I am just glad you are posting, some people (most people) are scared of the comments.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:Originally Posted by TozziWeldingLooks a little like pigeon, well you know.  Then again, I have built enough stuff with 6011 to know that looks ain't everything. Better pix will be the deciding factor. If your welding pipe there is no backer and the backside of your root should look as nice as the face of your bead. I am not knocking you, I just want some better pix. I am just glad you are posting, some people (most people) are scared of the comments.
Reply:Stay tuned for picsDavidHere is the bead with a backerThis is the keyhole I am talking about.  I butted one end and opened it up in a V.  this covers all the gap settings.Back sidesame back sideLast edited by David R; 01-16-2008 at 08:00 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Here is a bead with no backerReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Bend the one with backer first.  Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Thanks for posting the pics. I have the same problem with lack of penetration on the back side. I am truly curious as to why this is, and if there is a way overcome this issue.Miller Syncrowave 200Hobart Handler 140Thermal Dynamics Cutmaster 38E-Z Tube BenderPlasma Cam DHC2
Reply:BUT WAIT! Theres more.Next is 1/4" aluminum that has been in he salt for years.  This was a wheelchair ramp on the back of a dodge caravan taxi.  3" wide piece cut at several degrees....... I lopped it off with the sawzall on an angle.No backer.2 passes 185 amps, 150 Hz,  40% + wave. 1/8" tungsten.  I put the filler in the bottom of the Vee on the root pass.Here is the back side.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:One pass with the tig torch, no fillerSame thingA bead over the top on the back side.Q, I understand your question.  The weld was stronger than the 1/8" plate.David I played with the tig for a good part of the day.  I had a ball.Edit:  The beads in the pic in post #4 are 150Hz on the left, 75 Hz and 15 Hz.  Just to see what it would do.Last edited by David R; 01-16-2008 at 08:25 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:I found this on the web. It mentions that the lack of root penetration is overcome by backpurging with argon. The oxy acet bead looks great.http://www.tinmantech.com/html/alumi...ing_part_3.phpMiller Syncrowave 200Hobart Handler 140Thermal Dynamics Cutmaster 38E-Z Tube BenderPlasma Cam DHC2
Reply:This is cool.. I'll do the same thing tomorrow with gas mix.Results to follow..Go1lum..What kind of prep is done to the plates?Just to be fair.....zap!Last edited by zapster; 01-16-2008 at 09:43 PM.I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Go1lum, I would like to see the top of those plates.DavidLast edited by David R; 01-16-2008 at 09:51 PM.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Originally Posted by zapsterThis is cool.. I'll do the same thing tomorrow with gas mix.Results to follow..Go1lum..What kind of prep is done to the plates?Just to be fair.....zap!
Reply:getting there  to perform a root bend the cap should be sanded smooth first. the idea is to bend the weld around a radiused former, not the area next to it. with the cap in place it won't bend smoothly and most of the bending occurs in the HAZ (which is the softest/weakest area)IIRC aluminium is usually bent on a radius of around 5T. any cracks in the root and you got to try again
Reply:Dave i only have a picture of the one weld with a backer.  --Gol'
Reply:isn't 185 amps a little cold for 1/4 inch alum?Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain
Reply:Originally Posted by Joker11isn't 185 amps a little cold for 1/4 inch alum?
Reply:David that pass on the backside without filler got it done! I'ld call that a fix, too bad it can't always be the case that we can flip things over. City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:185 Amps on 1/4 would be alot easier with 100% helium shielding --Gol'
Reply:to get rid of the lack of fusion on the back of the root can't you just use a argon or helium purge? because ive seen people use a back purge on vessels and the weld on the back look just like the top. but im curious if its possible for aluminum.6G zirconium 702 GTAW 2" xxheavy6G P.E.D. carbon steel GTAW 2" xxheavy3G titanium Gr. 2 - Gr. 7 GTAW up to 3/4" 3G 316L stainless GTAW up to 1" 3G carbon steel GTAW up to 1" 3G Hastalloy GTAW up to 3/4"1G tantalum GTAW up to .060"
Reply:I have to try the back purge thing. I only have one tank of argon right now.  The other one is empty   When I get it filled, I will try it.David Real world weldin.  When I grow up I want to be a tig weldor.