Why am I getting cracks?

[fun4now]

FABMAN
its just a question of geting into a rythem. you can do it as you stated by letting off on the foot controle a moving but after you get good at it you will do it with just adding filler, i kinda whip the torch back onto the old bead as the filler goes in and cools the puddle then bring it back to start the next bead, ite just a kind of flick as you add filler.
it takes time to get good at, a lot of time. there are some tricks to getting a good looking bead when starting like you said by letting off on the amps but in time you will be able to do it without leting off the amps. i'm guessing you are new to it as you have the syncro200 so just find some time and some scrap and put in some seat time. i'm still fairly new to it and when i first started i did the heat dab, cool then start ofver but i think you get a beter weld by keeping it hot and using the filler to cool, its also important to use enough filler to keep the bead raised up, and to fill the crater at the end so you dont get that week spot in the weld.

[FABMAN]

Hi Fabman,
Once you have a puddle astablished, (base material will appear shinny). This is when you start adding filler. The way I get the rythem going is heat with the tungsten, cool with the filler, (touch filler at the leading edge of the puddle). Move tungsten forward approximatily 3/16". Repeat above. Heat, dab, move forward. Keep the tungsten in the middle of the joint.
Heat with the tungsten, cool with the filler, move ahead.
Good luck,
Gary

THANKS FOR THAT INFO GARY, I AM GOING TO GIVE IT A SHOT TOMORROW MORNING WHEN I GET OUT TO MY SHED AND PRACTICE....THANKS..

[Engloid]

Trying to change my bead spacing is easier said than done, I am into the same rythm every time with the heat and filler,

Obviously, what you're doing isn't working well at all, so changing it is your only option.


You shouldn't need any rhythm for your heat. Quit pulsing or pumping the pedal. You're jacking the temp of the metal up and down way too much, either way. Keep more continuous heat. Depend on the dabs of filler to make ripples, not fluctuating heat.

[Peter]

hi all,

technique's been covered but i would like a bit about filler selection.

there's been several recommendations of using 4043 as it's more forgiving. while it's fine for this job it shouldn't be used as a crutch.

4043 will not anodize well, is less ductile and has lower strength than 5356 (as welded).

there will be times when 5356 is required, so it makes sense to be confident using it. if good welding practice is observed (no craters/stress risers, correct joint prep and sufficient filler deposit) there will be no cracks

[Engloid]

hi all,

technique's been covered but i would like a bit about filler selection.

there's been several recommendations of using 4043 as it's more forgiving. while it's fine for this job it shouldn't be used as a crutch.

4043 will not anodize well, is less ductile and has lower strength than 5356 (as welded).

there will be times when 5356 is required, so it makes sense to be confident using it. if good welding practice is observed (no craters/stress risers, correct joint prep and sufficient filler deposit) there will be no cracks

The biggest advantage of 4043 is the weldability. The biggest advantages of 5356 are anodizing options and hardness. The tensile strength is really not all that much different. In fact, you will likely find that, reguardless of which filler you use, they will both break in the heat affected zone. Therefore, if you don't need to anodize, and you don't need the extra hardness, why bother with 5356?

[FABMAN]

FABMAN
its just a question of geting into a rythem. you can do it as you stated by letting off on the foot controle a moving but after you get good at it you will do it with just adding filler, i kinda whip the torch back onto the old bead as the filler goes in and cools the puddle then bring it back to start the next bead, ite just a kind of flick as you add filler.
it takes time to get good at, a lot of time. there are some tricks to getting a good looking bead when starting like you said by letting off on the amps but in time you will be able to do it without leting off the amps. i'm guessing you are new to it as you have the syncro200 so just find some time and some scrap and put in some seat time. i'm still fairly new to it and when i first started i did the heat dab, cool then start ofver but i think you get a beter weld by keeping it hot and using the filler to cool, its also important to use enough filler to keep the bead raised up, and to fill the crater at the end so you dont get that week spot in the weld.

FUN4NOW, thanks very much for the input. like you said, i will just keep practicing.
i have another question for everyone. lets say i am welding something aluminum, nothing real critical, but i dont know what type aluminum it is.
is there one filler rod that would be used as a first choice, like an all purpose aluminum filler rod ?
thanks again everyone for the help...

[Engloid]

FUN4NOW, thanks very much for the input. like you said, i will just keep practicing.
i have another question for everyone. lets say i am welding something aluminum, nothing real critical, but i dont know what type aluminum it is.
is there one filler rod that would be used as a first choice, like an all purpose aluminum filler rod ?
thanks again everyone for the help...

4043 is the most commonly used aluminum welding filler metal.

[FABMAN]

4043 is the most commonly used aluminum welding filler metal.

thank you very much ENGLOID.........

[fun4now]

it seems i read some where that its best to do repair work with 5356 but at the same time you dont want to use the same filler for repair or an old bead so maybee its due to 4043 being commenly used.
my guess would be you would end up with to high of level of silicone or magneaseum depending on if it was 4043 or 5356.
maybee Engloid can clear this up or give a better explanation as he has a lot more knolage in this. i'm still lerning and just herd it some where.

[Engloid]

If I'm not mistaken, 4043 has a higher content of manganese and silicone. The manganese will provide better ductility (less brittle), and the silicone helps to get a more smooth puddle and increased penetration.

[sparx]

grab a coffee....

This might turn out to be a long reply, so just prepping everyone ahead of time.

:note: the following is taken from the welding aluminum theory and practice book second edition.
(my bible.)

"The selection of filler alloy for each welding circumstance is both simple and complex. It is simple when structures are to be built of the common alloys usingcommon fabrication practices and when they are to be exposed to common service conditions. However, special base alloys, special fabricating procedures, or special service conditions may call for special filler alloys inwhich case the selection is more complex.

Alloys 5356,5183,and 5556
These alloys were designed originally for welding the 5*** series base alloys. 5356 has become the most commonly used of all aluminum filler alloys because of its compatability with most base alloys, its good strength and its good feedability when used as a MIG electrode wire.
These high Magnesium content alloys (5%) are used whenever the 5*** series alloys are to be welded to themselves or to heat treatable alloys such as 6*** or 7*** series. However, they have one important limitation which is their unsuitability at service temperatures exceeding 150 F (65C)"

Alloys 4043, 4643, 4047, and 4145

Alloy 4043 was developed for the welding of the heat-treatable base alloys and specifically the 6*** series. It has a lower melting point and more fluidity than the 5*** series filler alloys, and is pereferred by most welders because it "flows and wets better" and is less sensitive to weld cracking with the 6*** series base alloys.
however, these filler alloys are not well suited to welding on AL-MG alloys and especially they should not be used with high MG content alloys such as 5083, 5086, or 5456 because excessive magnesium-silicide can develop in the weld structure to decrease ductility and increase crack sensitivity."

Special cases:
While 4043 is the normally preferred filler alloy for welding the 6*** series base alloys, in architectural application where the components are to be anodized after welding, the welds turn a very dark grey after anodizing and are very noticable. This is usually unacceptable and an alternative filler alloy is sought. A 5*** series filler is better but the color match can never be perfect because the weld, being cast metal, will be always a different shade of grey from the wrought base metal."


hope you enjoyed your coffee...

[Sundown]

Nice read, thanks ... as for me I will continue to keep 4043 on hand in the shop and only buy 5356 if I need it for a specific job.

[Peter]

The biggest advantage of 4043 is the weldability. The biggest advantages of 5356 are anodizing options and hardness. The tensile strength is really not all that much different. In fact, you will likely find that, reguardless of which filler you use, they will both break in the heat affected zone. Therefore, if you don't need to anodize, and you don't need the extra hardness, why bother with 5356?

Engloid,

i was mearly suggesting that (for those new to Al) it would be beneficial to learn to weld 6061 with 5356 successfully. it does have advantages in certain applications, and so to be truely proficient it makes sense to be able to weld with it.

there might not be much difference in tensile strength between the two fillers but ductility has an effect too. remember Pile Bucks 'destructive testing on aluminium' thread? all his 4043 welds suffered a brittle failure. his welds made with 5356 bent significantly without failing

i know testing coupons like this isn't representive of a real structure- it does illustrate the differences between fillers though