Need help with aluminum dock plate 1/2 thick

[tireman]

i think i am over my head in this particular job. i am welding some 5 inch long cracks on aluminum dock plates. i am preheating the aluminum with an oxy rose bud to 175 degrees then i use my millermatic and aluminum spool with 4043 to weld it. After it cools sometimes i here pop. i then see the crack again and i now wonder what am i doing wrong. Of course before welding i clean/grind aluminum with proper grinding wheel. After grinding i will use a cutting wheel to make a bevel then i heat and weld.

any suggestions would be great. i need to weld a few of these sheets.

using millermatic 210 with aluminum gun with 4043 wire.

[griff01]

i think i am over my head in this particular job. i am welding some 5 inch long cracks on aluminum dock plates. i am preheating the aluminum with an oxy rose bud to 175 degrees then i use my millermatic and aluminum spool with 4043 to weld it. After it cools sometimes i here pop. i then see the crack again and i now wonder what am i doing wrong. Of course before welding i clean/grind aluminum with proper grinding wheel. After grinding i will use a cutting wheel to make a bevel then i heat and weld.

any suggestions would be great. i need to weld a few of these sheets.

using millermatic 210 with aluminum gun with 4043 wire.

Nowhere near enough machine.

Griff

[MMW]

Besides the machine being to small......machine is only rated to weld up to 3/8".

--Type of joint or just random cracks in the middle of the pc.?
--Is it cracking after a complete weld or after the first pass?
--Are you welding it 100%? or just a small vee & one weld?
--When welding can you see the bottom of the vee & that you are actually melting it completely? With aluminum it is very easy to bridge a crack while not even welding the root, especially with a small machine.

Try pre-heating to 350-400 degrees. If flat (no joint) you should be veeing it out deep & making multiple passes, then flipping it over & doing the same on the other side.

[Tryagn5]

i think i am over my head in this particular job. i am welding some 5 inch long cracks on aluminum dock plates. i am preheating the aluminum with an oxy rose bud to 175 degrees then i use my millermatic and aluminum spool with 4043 to weld it. After it cools sometimes i here pop. i then see the crack again and i now wonder what am i doing wrong. Of course before welding i clean/grind aluminum with proper grinding wheel. After grinding i will use a cutting wheel to make a bevel then i heat and weld.

any suggestions would be great. i need to weld a few of these sheets.

using millermatic 210 with aluminum gun with 4043 wire.

First what wire size are you running? Second to little machine. Now if i did the job i would use a backing plate, fully v the weld, run 3/64 wire near 225-250amps...so 26-29 volts, also i would preheat to about 200 degrees.
Kevin

[tireman]

Besides the machine being to small......machine is only rated to weld up to 3/8".

--Type of joint or just random cracks in the middle of the pc.?
Flat Joint and yes random crack on one of the bolts on the side of steel guides.
[ATTACH=CONFIG]35001[/ATTACH]

http://www.vestildocs.com/Zoom/TAS.jpg

--Is it cracking after a complete weld or after the first pass?
its cracking after a complete weld.
--Are you welding it 100%? or just a small vee & one weld?
i am using an small aluminum grinding wheel with grinder and making a vee. Then one big weld.
--When welding can you see the bottom of the vee & that you are actually melting it completely?
i can see that i am welding the bottom of the vee and it looks like welding correctly. You are correct i may not be welding all the way so tomorrow i will redo it completely again with suggestions provided. i will try and take different pics and attemp to post tomorrow.

With aluminum it is very easy to bridge a crack while not even welding the root, especially with a small machine.


Try pre-heating to 350-400 degrees. If flat (no joint) you should be veeing it out deep & making multiple passes, then flipping it over & doing the same on the other side.

thanks for the advice

[MMW]

Not saying you can do this with the 210 because it's under powered but your best chance with what you have is grind a vee maybe 3/16" deep on each side leaving maybe 1/16" in the root, if you finish veeing with a cut off wheel I would go clean through the last little bit. Pre-heat the joint, not a large area, then weld root flip, weld other side out, then flip & finish first side. Try to keep it hot as it will tend to cool quickly.

Just my opinion.

[tireman]

ok guys i finished with the dock board and it looks good. i did take pics of the process and i will put them up in a bit. i did two of these dock boards and i need to finish 5 more. i am doing this job to help me fund my purchase of a millermatic 350p. thanks for your help.

[H80N]

ok guys i finished with the dock board and it looks good. i did take pics of the process and i will put them up in a bit. i did two of these dock boards and i need to finish 5 more. i am doing this job to help me fund my purchase of a millermatic 350p. thanks for your help.

You will LOVE the MM350P....

that job would be a breeze with the MM350P.... w/XR Alumapro push-pull or 30A Spoolgun..

No Fuss... No Muss....

Then... I Would probably switch to 1/16 4943 wire... stronger... less prone to hot cracking.... flows nicer..

http://www.hobartbrothers.com/product-details.html?name=Hobart%26reg%3B+MaxalMig+4943

http://www.hobartbrothers.com/downloads/HobartAluminumGuide.pdf

[MMW]

So how did you finally end up doing it?