Welding Tips and Tricks

help needed from any one that has welded in engine ports mostly smaller motorcycle heads aluminum

Such as? Just what information are you looking for?

Basically, Clean well, use an open cutting burr to prep the area. Preheat to about 200 Deg F.
Use AC , and 4943 rod. Let the cleaning action of the AC work on the impurities, before adding rod.
Sometimes you need to clean between passes,

i welded some 2stroke headx. semms like i just used 4043 or 5356 if i recall

The 5356 alloy doesn't do well at elevated temps. ( Above 200F) You can research it online.
The 4943 alloy is stronger than the 4043, and I find that it wets in better when welding castings.
What was your experience welding those heads? Did the puddle flow well, or did it act like it was full of dirt?

Jody did a nice video welding a cast aluminum housing from a jet boat. It is well worth watching.
If somebody that knows how to post a link to that video, would do so, I would appreciate it.

VA-Sawyer wrote: ↑Tue Oct 11, 2022 8:24 pm Jody did a nice video welding a cast aluminum housing from a jet boat. It is well worth watching.
If somebody that knows how to post a link to that video, would do so, I would appreciate it.

I suspect this is the video you're referencing....... https://youtu.be/dyFo-JP4fDQ

dyFo-JP4fDQ

Thank You. Yes, that is the one. I learned a lot from that video.

If the weld puddle on the parent material seems very 'watery' in consistency then it may have been cast with a high silicon content alloy.

Can be common on some engines/parts when it's a combined steel/alu engine as it reduces the thermal expansion of the alu and there's less stresses where it meets any steel parts. Also allows closer bore tolerances on alu pistons in steel/iron bores. (makes it more brittle though, so that's the drawback..)

In that case a 4047 rod (high Si content) can also be a suitable option as it's reduced expansion/shrinkage also means it's less likely to crack on cooling, but it's a less common rod so often more expensive.

Bye, Arno.

4047 is a very good rod. It's what I use exclusively on all cast repairs.

VA-Sawyer wrote: ↑Tue Oct 11, 2022 8:24 pm The 5356 alloy doesn't do well at elevated temps. ( Above 200F) You can research it online.
The 4943 alloy is stronger than the 4043, and I find that it wets in better when welding castings.
What was your experience welding those heads? Did the puddle flow well, or did it act like it was full of dirt?

Jody did a nice video welding a cast aluminum housing from a jet boat. It is well worth watching.
If somebody that knows how to post a link to that video, would do so, I would appreciate it.

it welded fine. it was about 3yrs ago and i dont recall which rod i used but 4043 and 5356 are the only rods i have in my garage. i welded in the squish band of the head and machined it to a new profile. beside welding fine , it machined just fine also. other than the head ,ive welded a few 2stroke cylinders also (for enlarging the ports and such). im sure 4043 is what i used but again, its been a couple years

The 4047 rod is sometimes referred to as Aluminum brazing rod. It has a lower melting point than a lot of Aluminum alloys. It 'wets in' well, and can give good looking welds with practice. In my opinion, the only downside to 4047 is a strength issue.

The reason I keep going back to 4943 is this. It welds almost as easy as the 4047, but has even more strength than the 4043.

I have these 4 alloys in my rack (4043, 4047, 4943, and 5356), and a couple of special Aluminum alloys, too, I tend to grab the 4943 first, unless the low melting point of 4047 is needed. The 4043 is pretty much just a practice rod for me at this point, and I don't plan to buy any more. The 5356 is on standby for when the part will be anodized after welding.

There are a few pdf files out on the internet about using 4943 to do weld repairs on aviation piston engines. Worth reading if you want to improve your game on cylinder heads.

thanks to all how replied, it seems more like I cant control the arc.
miller 350 lx

"Hard to control the arc". Ok, what are your settings? With a 350A welder, you should be able to increase the A/C frequency to the 120-150 Hz range, and still have enough heat to do the job. The higher frequency will help stabilize the arc. As frequency goes up, the arc tends to act like the power has been reduced, even as it becomes more focused.

Balance (cleaning action), also affects the heat input. The EP (electrode positive) part of the A/C cycle is what cleans the oxides from the weld. It also results in heat being moved into the electrode. The EN (electrode negative) part of the A/C cycle puts most of the heat into the weld. I believe that Miller welders indicate the percentage of EN time on the balance control, so something around 70 to 80 should work. Smaller numbers give you more cleaning action, and more heat into the electrode. As DC is 100% EN, it allows a smaller electrode to hold up to the same current. Proper cleaning before welding, can help reduce the amount of cleaning action needed. Sometimes the impurities are IN the casting metal itself. About the only way to deal with that, is increase the amount of EP time in the cycle.

What flavor of electrode are you using? I find that the 2% Lanthanated works best for me. I haven't tried them all, so other folks may advise something else. It is kind of a Ford vs. Chevy thing, and I don't want to start another debate here.

Another thing that affects Arc stability is your amperage. A large chunk of Aluminum (4+ lbs, more than 1/4" thick) will need some real amps. I would hit it with something around 300 amps, to get the puddle established. You want a good puddle to form in 1 or 2 seconds. If it takes longer to get a puddle, then I suggest more amps. Once you get the puddle, then you can back off a bit on the power. As the part heats up, it will take less power to maintain the same progress rate of weld. If the part gets too hot, you will have a hard time controlling the puddle, and you need to stop welding for a bit. The real trick, is keeping you rate of weld progress ahead of the heat progress through the part. And remember, Aluminum is real good at heat transfer.