4643 filler?

[Trip59]

Been watching a ton of YouTube videos lately, TV programming just pisses me off (when will this 'reality' crap end) and I came across some things. Watched a ton of videos from Keith Fenner, you may not know the name, but he's the one that did that big cylinder build up repair Jody featured pics of in one of his TIG videos.

Well... he got to talking about 4346 filler being his choice for aluminum castings and that got me wondering. One of the main things I'm working on now is getting up to speed on AL castings, primarily motorcycle related, and I hope to be able to offer it as a service along with re-machining the parts. Of course, I want the best possible outcome. I've seen 4043 mentioned often for castings, but what about 4346, or other alloys? Thoughts, experience, recommendations?

[jakeru]

I've not used 4643 before, but I understand it leaves a heat-treatable Silicon-Magnsium alloy deposit. So it would be perfect for welding say, 6061 especially when it is going to be post-weld heat treated.

There are actually probably a lot of cast alloys that are heat treated Silicon-Magnesium alloys, so I could see it potentially being useful on those. Often a heat treatable alloy even if not heat treated after welding or casting will "age harden" just with the normal passage of time, to some degree. So yeah, I could see 4643 being useful potentially even for parts that aren't post weld heat treated.

I like 5356 for when good "as welded" strength is needed, although it is not recommended for anything but low sustained temperature applications. In that case 4043 would be typically recommended.

There are other exotic alloys available. I've got some 4145, for example. It's got some copper in it (among other things) and is good for welding some uncommon alloys, especially those having some copper in the mix.

Another alloy for welding some cast aluminum that would fall into the exotic category is A356. That is a pretty close match for commonly used sandcasting alloys.

I know Jody and others have recommended high-silicon alloy 4047 for cast aluminum, I think because it has a lower melting temperature, it can help it "wet out" better. I haven't tried that yet, but would if I could pick some up without it costing too much.

I usually get by pretty well with just 4043 and 5356. Hope this gives you some good food for thought!
http://www.alcotec.com/us/en/support...tion_Chart.pdf

[Trip59]

Thanks for the info. That chart scares me a bit... looking at the chart, and figuring from literature I've seen, the cases would best be welded with 4145... nice, at $55 a FRIGGEN POUND.

My only real concern is that 4043 is only listed for about half the cast alloys.

I'd really love to find something definitive on the alloys HD used throughout the years.

[Rambozo]

I'd really love to find something definitive on the alloys HD used throughout the years.

It seems that the consensus is that original HD is cast in 319 while most aftermarket is cast in 356.

[Trip59]

It seems that the consensus is that original HD is cast in 319 while most aftermarket is cast in 356.

Not that I don't believe you, but consensus from where? I ask because of my earlier concern, the AlcoTec chart calls for 4145 for 319, I'd hate to burn $55 a lb to find out it was 357 or 359 or something.

Any guess as to why 4043 isn't recommended by them for 319 to 319 welds?

[Rambozo]

For the aftermarket a few of the manufacturers give the alloy like http://www.delkron-mfg.com
For the stock HD it's mostly a general web search. There are a few good hits from welding and general casting sites. So far all have said 319. While that doesn't make it for sure, (why I said consensus) I don't see any info to the contrary.

A lot depends on what you are trying to do. Are you repairing cases that have cracked from stress, repairing corrosion or road rash damage, or modifying good cases? 4043 will work for some things and not for others. To do it right the case would need to be stress relieved and heat treated after welding, if this is a stress repair. On the other hand if this just making it oil tight again, because of some minor damage, then yield strength may not be that important. If you are modifying to correct a design flaw, then you might need greater strength than what it originally had. This is where you might use a different alloy to weld on additions.

[everlastsupport]

I attempted to get some 4145 from WSI a few months ago. They did not have any and said special order and as I recall it was $$, but less than those nickel rods. So I passed. They are like the 4043 just a different mix (silicon).

I might drop in PraxAir, I really want to have them around for when 4043 did not want to cooperate. I bet Prax will have them, but they normally make you buy a lb. and the price will be higher. WSI will sell you 1 if you wanted.

We get a lot of these broken aluminum fences, had one yesterday (A large lady fell into it so the guy said). We used the IMIG-200 with 4043 (hotter than normal) and it welded up nice. But I know with the motor repairs you will want to use the TIG..

[Spike]

Well, for the tapped holes I would use the harder filler rod. Harley cases are a magnesium alloy very similar to 6061 (a365 I think is the number). So any of the filler rods that work with 6061 will bind just fine with the cases.
for the transmission ears and things like that I'll use 4043 because it's a softer filler rod, and since the mount ears are going to be put through lots of vibration and torque pressures, it's always a good bet to give up a little tensile strength to gain a lot of ductility and elasticity. The softer welds will resist cracking a lot better.

I have to agree that heli-coils and studs are a beautiful thing. Whenever I rebuild an old engine I put studs in all those cover plate bolts. It will help keep any ham-fisted mechanics from ruining your work down the road!

However you decide to weld up the bolt holes, the gasket surface will need to be lapped/machined to a true flat again. Otherwise you'll get leaks and drips, even if you did everything else perfect.