4643 filler?

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?

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

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.

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Originally Posted by Trip59

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

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

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Originally Posted by Rambozo

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

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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?

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.

Not sure how familiar you are with sportster cases, but there are a few things that "I" need and a few common issues I'm hoping to be able to do for others once all my machines are up and running.

On mine, I need to rebuilt most of the cover bolt holes, stripped, cracked, non-insertable condition. I also have a trapdoor ear to rebuilt and machine, as well as several small cracks. The biggest PITA is the generator ear snapped off, it was welded back on, but the idler gear boss is dead center in the crack. The area is solid (will be dye checking tho) and if testing proves sound, I'll need to build up the boss and machine it back out.

Now, I got a 74 case to tinker with, so I may just whack away with 4043 and try to break it or see how it runs, but I'd really prefer to do it right and maybe salvage the case. It has several broken areas, around bolt holes, etc. but the trans blew and cracked the lower rear section (very common repair). Good thing is the gen mount is sound and the idler boss is pristine, so I can use this one to measure and reference for re-machining mine.

I'm not a fan of 'just making the cut' so if it really is 319 and 4145 is really the best option, then I'm all for it and will just have to charge more than I was planning to offset the cost variance. If 4043 will work for most aspects, rebuilding screw/bolt holes, etc. then that's great.


Plans for the bolt holes for the covers was to vee them on the inside (inside the case, from the outside of the hole :) ) clean out the threads and crap with a carbide burr, build them back up and fair the inside with discs, mill the surface true, then mark, spot, drill, tap them again to match. The cracks will get vee'd and burred, the whole thing wil have several cleaning/degreasing, heating cycles to clean.

There are a few folks I know who do this specifically, but I am hesitant to ask, as I'll be directly competing against them once up and running.

From my experience with welding cylinder heads and blocks, I would use 5356 for repairing damaged threads. I find it machines much nicer and makes stronger threads. I still like to use heli-coils in any aluminum threads that will get frequent use such as covers and such (or use studs instead of bolts), the stainless just wears so much better. For places where internal parts have exited, like the transmission damage you mentioned, it sounds like you just need to make it oil tight, so I'm sure 4043 would work fine. For things like a broken mounting ear, do they break from being abused or from not being strong enough to begin with? Sometimes you can add gussets to help that, but you will need good strength and might need to heat treat to get that. I am not a fan of HD so I know little about them, except they have a real vibration issue, inherent in the design, that is hard on both bike and rider.

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Originally Posted by Rambozo

From my experience with welding cylinder heads and blocks, I would use 5356 for repairing damaged threads. I find it machines much nicer and makes stronger threads. I still like to use heli-coils in any aluminum threads that will get frequent use such as covers and such (or use studs instead of bolts), the stainless just wears so much better. For places where internal parts have exited, like the transmission damage you mentioned, it sounds like you just need to make it oil tight, so I'm sure 4043 would work fine. For things like a broken mounting ear, do they break from being abused or from not being strong enough to begin with? Sometimes you can add gussets to help that, but you will need good strength and might need to heat treat to get that. I am not a fan of HD so I know little about them, except they have a real vibration issue, inherent in the design, that is hard on both bike and rider.

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The generator ear typically from wrecks, gennie sticks out up front and hangs out the side, lots of stress to where mine broke in an impact situation. My main goal there is something durable enough built up inside to machine and press in the bronze bushing. When I opened it up, the bushing fell out because it wallowed out the boss, my guess is poor alignment combined with too-soft filler.

The other mount ears could be from various things, the trapdoor from a thrown gear in the trans, just like the crack in the rear corner, and that is just an oil-tight. The cover bolt holes would be from overtightening and repeated use, but they shouldn't be. Should be a once every few decades removal. Should be fine welded and tapped, not really enough room for an insert without thinning the outer web too much. I could build them up on the inside, but it would put a weak point on the outside by the time it was drilled and tapped oversize for an insert.

Will 5356 bond sound enough for the repair as I mentioned, opening one side of the thread, cleaning and filling?

It all depends on how well you can get to everything. What you will end up with a a mixture between the two alloys. Small threaded holes can be tough to weld. If you have enough material to drill them out bigger and hit them with a countersink, it's pretty easy. Another option is to cut a vee from the side if they are an external boss. You have to get good fusion between the filler and the base metal, and ideally not have the joint in the area where the new threads will be.

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Originally Posted by Rambozo

It all depends on how well you can get to everything. What you will end up with a a mixture between the two alloys. Small threaded holes can be tough to weld. If you have enough material to drill them out bigger and hit them with a countersink, it's pretty easy. Another option is to cut a vee from the side if they are an external boss. You have to get good fusion between the filler and the base metal, and ideally not have the joint in the area where the new threads will be.

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The ones for the covers

http://xlforum.net/photopost/data/12...tster_case.jpg

shows the holes around the perimeter, I was planning to vee them out from the inside of the covered area (no visible weldment on the outside of the web) fill them in and re-drill/tap.

You can also see where the door goes, the top right bolt on the cover, not the case, broke off and will be re-welded.

http://www.harley-oldschool-bobber.c...b3-468x352.jpg

In that one, big hole in the top right is where the generator goes, small bronze/brass bushing slightly below and to the left is what wore out, cracked that whole ear of and when they welded it on, the weld held but the boss wallowed out, as I said, likely a mis-aligned bore and possibly too soft filler.

Sounds great. I would drill out those cover holes before you vee them from the inside, so all the threads are gone and you have enlarged them past where the finished thread peaks will be. Do you have a template or jig to redrill the holes, or will you just be using the cover and some drill bushings?

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Originally Posted by Rambozo

Sounds great. I would drill out those cover holes before you vee them from the inside, so all the threads are gone and you have enlarged them past where the finished thread peaks will be. Do you have a template or jig to redrill the holes, or will you just be using the cover and some drill bushings?

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Well, for the right side case, I may have to do them like the idler boss, find it on the mill and mark the coordinates, since the cam cover actually holds the cams and must be in proper alignment. I believe I have enough good threads there I can split them into groups though, bolt 3 plus the alignment dowels, drill and tap the remainder, then rinse and repeat. For the left, I'll likely just use a transfer punch through the cover holes, do them all at once, since it is just a cover.

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.

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..