butt joining 2 pieces of aluminum

[jeff in west vi]

i am trying to weld together 2 pieces end to end.it is diamond plate. i have cleaned with SS brush and wiped with acetone. but when i try to join them the edges of the 2 piece just kind want to burn away. i am using 85 amps. is it torch angle? or what?

what am i doing wrong?!@?!?!?!?

[NorthernLights]

What machine / process (MIG/TIG)? What thickness of diamond plate? If TIG, are you using filler?

[jeff in west vi]

i am sorry i am tig. plate is 1/ 8th. i am using 4043 filler that is 3/32. tungsten is 1/16

[asad]

85A sounds low for 1/8" aluminum. Really low. Try starting at ~150 or so and moving the torch in a small circle as the puddle forms. Remember you're going to have to back off the pedal once the aluminum gets hot.

Oh, and make sure the fitup is good! It's hard to do a TIG butt weld when there's a gap!

Asad

[LarryL]

It sounds as if you're doing Tig welding. When butt welding the edges of your diamond plate, a tight fit of the plates' edges is a requirement - with no significant gaps between them. An edge is easily overheated and may melt away since there is less material surrounding an edge that will dissipate the heat from your torch. The flat areas away from an edge, on the other hand, have more material adjacent to them; the heat will dissipate faster from these flat areas, and, they won't melt as easily. When you're starting the initial puddle, move the arc across the joint so as to get most of the heat placed just inside each edge. Try not to overheat the edges or they will melt away quickly - as you've experienced. Initially it may be advisable to dip a little filler rod into the spot where the aluminum is beginning to melt. Once you started a small puddle, angle your torch's arc toward the unmelted side to get the puddle to bridge the joint. Then if your fitup is tight, you may be able to finish the butt weld without adding any additional filler rod. In most cases you will have to dip the filler rod occasionally into the puddle when you notice that the puddle no longer bridges the joint. With some aluminum alloys, such as 5052, you must add a filler rod such as 4043 to the puddle or the resulting weld will be prone to cracking.

Are your sheets of diamond plate anodized? If they are anodized, you must grind off all of the anodizing that you can see. Even then (because the anodized coating penetrates below the surface) you may find it difficult to produce a good weld. After all, the anodized coating consists of aluminum oxide, which is what you're trying to clean off when you wire brush the surfaces of your joints and do a final solvent wipe.

Proficiency in welding aluminum requires much more practice than welding steel. I suggest that you practice with pieces of scrap before you commit your finished pieces to your welding skill.

One final note. When doing AC Tig welding there is much more wandering of the arc than with DCEN welding. Even if you're using an AC inverter machine with pointed tungsten, balance predominantly on the negative part of cycle and AC frequency turned up high, the arc may have a tendency to wander from one side to the other. If this happens, you will have to move the electrode's point close to the surface you're trying to heat up or puddle. This sometimes requires you to be as close as 1/16" from the metal or puddle. This will increase your likelihood of contaminating the tip by touching the puddle or filler rod. Resting your torch-holding wrist on a steady surface to keep the arc steady will help a lot. In the final analysis you will need to practice and practice more to gain proficiency. One day your aluminum welds may even look as nice as those of Engloid, Dan, RockyD or other experts - but hopefully better than mine!

LarryL

[Bigger Valves]

Welcome to aluminum. Best advice is to have perfect fit up. Edges will disappear on you fast. It's all skill and practice. Practicing on aluminum cans might help. It's frustrating till you get the hang of it.

[jeff in west vi]

on cans?!?!?!?!? are you kidding? i cant weld something an 1/8 think!!!! seriously you think i should try cans too?

good info larry l. i need to start on the inside of the edge and not heat the very edge huh?

[Aeroweld]

i am trying to weld together 2 pieces end to end.it is diamond plate. i have cleaned with SS brush and wiped with acetone. but when i try to join them the edges of the 2 piece just kind want to burn away. i am using 85 amps. is it torch angle? or what?

what am i doing wrong?!@?!?!?!?

A couple of more suggestions to add to LarryL's:
Unlike doing steel, you cannot force heat into aluminum as fast
Start your amperage low until you get some heat built up in the aluminum. I sort of analagise it to to cooking a good piece of beef. If it takes 4 hours @ 350 deg., you cannot speed things up by cooking it at 1400 deg for an hour. Too much heat too fast and you will "burn" the aluminum. Let the heat build to a small puddle and gradually increase the heat creating a larger puddle.

Depending on how the material was processed you may have some contamination at the edge of the joint. Take a file and run it along both edges of the joint before you butt them together. Sometimes shearing and cutting will deposit "junk" into the edge. A quick clean-up with a file will usually solve that problem.

[Mortallis]

diamond plate is aluminem?

[Bob Sigmon]

It is if you buy aluminum diamond plate!

[Mortallis]

there u go :P hehehe