New to welding aluminum, quick question.

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Hi, I haven't posted in while, but I have a question for some of you experts.   I have an aluminum swingarm (off a 600rr) and it has openings on the left and right side.  I want to fill in the openings by welding in a plate and grinding it all down so its smooth.  Its not stuctural in the least, and the welds would be all ground down, so I figure its a good project for me to learn on. My question is, if I weld in a plate and grind it all down,  will there be like a color difference, or will you be able to see like a light line where the weld was, or will it all look uniform (like steel does when you weld 2 pieces of steel togeather)?  I know there are all different types of aluminum.  I can't remember exactly what type the swingarm was off the top of my head, but heres what it looks like.  I want to fill in that hole and have it completely smooth.  thank you so much for any input, and also for a great sight with tons of info, it really is a great resource!
Reply:I would guess the alloy is 6061-T6 and I would also guess, from the photo,  that it has a clear satin anodize (201-R1) finish.   Can you weld it?  Yes, but not until you remove the anodize.   Will it blend in?  Sort of.   You can grind, sand and brush the patch so it blends in with the material around it and there should not be a noticible color difference between the patch and the swing arm aluminum.   There will however be a noticible difference between the patch and any area where you have not removed the anodize.If your serious about aesthetics, I would recommend taking the swingarm to an anodizer and have it acid stripped.    This will remove all the aluminum oxide coating and leave a mill finish surface.   This will also remove a tiny amount of aluminum and could affect the dimensional tolerances of critical areas.After your patches are in and you grind them smooth, then take the swing arm out to be re-anodized.   You can have it re-anodized, but unless you used 5356 alloy MIG wire, the welds will show up darker than the rest of the metal.   Even with 5356, there may be a slight color variance in the new anodize.      You could skip the re-anodize and just scotch brite rub the swingarm to the finish you want and have a clear coat applied, or even skip the clear and buff and polish the swing arm to a mirror shine.There are no small projects
Reply:I wouldn't use that as a project to learn on.  By welding on that swingarm regardless of whether what your welding in is structural or not the entire swingarm is and you could affect it structurally.  You'll also need to build a jig to hold the swingarm while you are welding on it to help keep it straight and will need to take precautions as your welding it to keep it straight - you don't want to screw up your geometry.  Your dealing with a bike that can attain VERY high speeds and could kill you easily.  A bike frame or suspension is about the last thing I would "learn" on.  JMO
Reply:Originally Posted by Steve St.LaurentI wouldn't use that as a project to learn on.  By welding on that swingarm regardless of whether what your welding in is structural or not the entire swingarm is and you could affect it structurally.  You'll also need to build a jig to hold the swingarm while you are welding on it to help keep it straight and will need to take precautions as your welding it to keep it straight - you don't want to screw up your geometry.  Your dealing with a bike that can attain VERY high speeds and could kill you easily.  A bike frame or suspension is about the last thing I would "learn" on.  JMO
Reply:i would also think that it has been heat treated so welding on it would mess that up tooChuckASME Pressure Vessel welder
Reply:I wouldn't do that if I were you. I'd just polish the arm really well, and be happy. That much welding on the swingarm without a super stout jig, preheating to relieve stress, post heat to relieve stress, it will twist up. Then, it is anodized, and heat treated. A bunch of reasons to leave it alone unless you have a lot of experience with bike chassis' . Just my opinion..... I used to race the VFR Honda's, and the RC30. We did have guys cut& modify swingarms. Most were just glorified abortions when they were done, and we always went running for either a works unit, or a bone stock one to replace the nightmare I was trying to ride on.
Reply:An alternative to welding that would probably give you the effect you are looking for is a sheet of aluminum, laser cut to the shape of the swingarm and glued on like a veneer.  It won't be structural and it will give the appearance of a solid arm without compromising the structural characteristics of the part.  Just a passing thought.Smithboy...if it ain't broke, you ain't tryin'.
Reply:I appreciate the concern guys, but its already been welded on.  I had to cut part of the pivot mount down and had to reweld the end, I did this to fit it in between the framerails of a F2.  And I really dont want it polished, that is not the look i'm going for at all, so just polish it an be happy would not work, cause that would not make me happy.  lol.  I was planning on just clearcoating it cause i figured annodizing would highlight the difference in materials and all that.  Any idea on the cost to get the old anodization removed? Or anyone know of a way to do that myself?  I know its like chemically bonded, so I don't know if it would be possible to take it off myself...The reason I want to fill it in is purely aesthetic.  I'm an industrial designer, and i'm kinda designing/building my own bike from parts that I am modifying and customizing and all that hoopla.  I dont want it to look like it was just stuck on off another bike. I want something unique, and I was looking more towards MotoGP machines as inspiration.Like these:And yes, if i remember correctly i was told that it was 6061-t6 aluminum.So, all concerns aside (please) hypotheticaly, if I wanted to fill in that hole, I could weld in a plate of t6061-t6 aluminum, and grind it all smooth, and you wont see like an outline of the welds or any of that crap?  I mean, it will look like one solid piece, right?  Cause thats what I'm after.  Also, I have a friend that welds aluminum all day long professionally (he welded in the piece i needed last winter) and I could always pay him to do it if ppl think it really is that bad of an idea for me to work on it myself.  But i wasnt planning on just jumping in and going to town, i mean we have tons of aluminum scraps pieces for practice, so I was planning on practicing alot first!Oh, and btw, I have seen 1 other person that did this, and 1 that started too.  I havent been able to get in contact with the person that did it to find out how they did it or answer any questions, and the guy that started to do it, i havent heard from in a while so i dunno how it came out or anything.  Thats why I came to you all!  And thanks for the all the insight so far!Last edited by cbrf23; 10-24-2006 at 12:17 PM.
Reply:here's the one that I found thats been done, but never got a response from the guy http://www.borderlinecustomcycle.com/mygreen.htm
Reply:Ummm, dude, anodizing isn't "like chemically bonded", anodizing is a forced change in the actual layer of aluminum oxide on the surface of the aluminum itself.  The change is 'forced' by using electricity and having the aluminum piece be the anode in the electrical circuit, hence "anodizing".To strip anodizing, you can use mechanical means or chemical means.After putting your non-structural patch into the very structural swingarm via welding, you have possibly messed with the structure of that VERY important structural swingarm.  I think everyone here so far has recommended not to do that, and there are some pretty darn accomplished welders here.And smithboy's recommendation of putting a surface 'patch' over the main part of the swingarm would let you address the aesthetics without messing with the structural.
Reply:Yeah, i actually just read about anodizing a little while ago after i posted, lol.  Thanks though.  Like i said, I'm new to aluminum.  As for a surface patch (veneer) I thought of that, but decided it would not give me what I desired.  I'm a bit of a perfectionist, and I would not be happy with it unless it was perfect, and seeing and edge would bug the crap out of me.  And for some background info, I'm not some jackass with a welder looking to build a hillbilly bike.  I have actually built this thing from the frame up, including chopping half the frame off and welding up my own subframe.  And I already modified the swingarm and welded in part of it.  (check out www.fotki.com/cbrf23 if you wanna see any of that crap)  I'm not afraid of modifying (in fact I love it) things, but I want to do things RIGHT, not half assed.   In fact, I had the bike down at the dealership bout a week ago, and the techs there were very impressed and told me it looks like I did a really good job with everything.  SO please, if you are going to post something telling me not to do it, I think thats been done enough.  I'm not gonna back out of it because its difficult, but I would like to know what would be the proper way to do something like this.  I mean, if someone was willing to pay you whatever you wanted, how would you do it?I guess I was hoping more for advice on the correct way to do it, rather than just hearing "dont't do it".  I was thinking I could just weld a jig that holds the swingarm straight, and that should minimize the possiblity of it warping.  Also, I wouldnt mind building a jig cause I i've got plenty of scrap steel to work with (including 10 ft of steel tube) and I also might make more swingarms for sale, but I dunno, cause I do wanna keep it original.  But at the same time, I could just sell to ppl on the other side of the country, and I'll  still be original over here I also was wondering if I should go with a 4043 rod, since it supposedly is a little easier to work with and should blend in better with the rest of the aluminum when its all ground down.  I dont plan on re-anodizing it, I'm just gonna clear over it, so I think this would be better than 5356.Now, like i am new, so I'm just basing this on research into it, but from what I've gathered this would be the better choice for my application.
Reply:MIG or TIG?   If you're going to MIG it, 4043 is soft and doesn't feed as well as stiffer 5356 (my boss refers to it as "trying to push a wet noodle up a wildcat's butt").    4043 solidifies slower and makes a more flexible weld.  5356 "freezes" much faster, the welds are marginally stronger, but more brittle.After grinding and polishing, they'll both look the same.BTW, well written re-tort about being told what you can't or shouldn't do.There are no small projects
Reply:To do it right, for a structural precision 6061-T6 aluminum swingarm, you should heat treat to stress relieve, clean it of all hydrocarbon residues, clean the weld areas of any anodising, prep the joints to allow for the proper introduction of the filler metal to achieve the proper alloying element dilution ratios in the final weld, clean it well, jig it, GTAW/TIG it, and then heat treat it.  Critical dimensions may have to be trued or remachined after heat treatment.  The recommended filler in this case is 4643.  And obviously your patch plate should be 6061 as well, for material and weld uniformity.For structural welding on heat treated parts, and 6061-T6 is a heat treated aluminum alloy, looks of the welds aren't everything.  The post-weld heat treatment is IMPORTANT, because otherwise the part has just had its strength lowered by about HALF.Let me say that part again.  Welding a 6061-T6 structural piece will pretty much reduce the strength of the piece by about HALF.If you don't KNOW what the base material is, aluminum welding can be a crap-shoot.  For a structural aluminum component on a motorcycle, you really-really-really should KNOW the material and what you are doing and all the steps to do it right.  And KNOWING what the base material is does not come from some guy on the Net saying that it looks like 6061-T6.
Reply:I'm not going to tell you not to do it.  http://www.lincolnelectric.com/knowl...comistakes.aspLast edited by gnm109; 10-25-2006 at 09:05 PM.
Reply:Hey man people here are just trying to aware you from a possible death...Anyway...the butt who´s gonna be on the ground is yours  But you got the answer now...sooo you should be happyBTW...another comment...saw the pics on your site...didn´t like you cutting the swingarm supports...you´ve make it weaker...but that´s my engineer point of view...seems you don´t want to get more warnings...Last edited by elvergon; 10-25-2006 at 11:21 PM.My Babies: HF Drill pressHF Pipe Bender3   4.5" Black and Decker angle grindersLincoln Electric PROMIG 175that´s it!
Reply:no, not that, i do appreciate the concern,  and its all valid points that i take into consideration.  It just seemed like nobody had anything to say on how it could be done.  Ya know?Anyways, I really do appreciate that [pst moonrise!I know its 6061-t6 cause thats what my buddy (who is a professional welder) told me last winter, and he welded a patch into it and it came out fine, so i would assume that means he was right, otherwise it wouldnt have welded in right, right?  I just couldnt recall off the top of my head the numbers till I saw that.  And based on my research, i did see that it was a heat treated metal.  I did not know welding would reduce the strength by half.  Could i get it re-heat treated after welding it?  I mean, like i said, I REALLY want to do this.  But I'm not gonna do it unless I can do it right.  If that means paying for something to get done, thats ok as long as I can scrape up the money.  I don't wanna die, so half-assing don't fly on my bikes.And I would be tig welding it.  Which is what i wanna learn this winter.  I am pretty good at oxy-acetalene (sp?) and from what I've been told the technique for tigging is similar to oxy-acetalene.Last edited by cbrf23; 10-26-2006 at 02:31 AM.
Reply:gnm109, thanks for the link.  I actually read a like every article on the lincoln site and a couple other sites as well when I started researching into tig. that article actually has me wondering (and tell me if this is just dumb, lol) but it says the temperature of the piece is raised to 400 and held there for a few hours.  Could this not be accomplished in an oven? Maybe even a powdercoating oven?  I mean my part is small enough to fit in one...also, the thing is, that the part is welded straight from honda.  I mean, the welds are exposed and you can see them in the picture (quite pretty, really) and so wouldn't that mean that the material has already undergone as much degredation as it is going to?  I mean, since its already been welded all the way around, would me welding it really make it any weaker?  Especially if i pwa it...Last edited by cbrf23; 10-26-2006 at 02:30 AM.
Reply:Originally Posted by MoonRise.....The post-weld heat treatment is IMPORTANT, because otherwise the part has just had its strength lowered by about HALF.....
Reply:if the part is 6061-t6 than that is the filler i would use and the part you like to add should be the same then send it to some one who can HT aluminum and you  will need to make some kind of jig to keeep it from warping and twistingChuckASME Pressure Vessel welder
Reply:Originally Posted by cbrf23gnm109, thanks for the link.  I actually read a like every article on the lincoln site and a couple other sites as well when I started researching into tig. that article actually has me wondering (and tell me if this is just dumb, lol) but it says the temperature of the piece is raised to 400 and held there for a few hours.  Could this not be accomplished in an oven? Maybe even a powdercoating oven?  I mean my part is small enough to fit in one...also, the thing is, that the part is welded straight from honda.  I mean, the welds are exposed and you can see them in the picture (quite pretty, really) and so wouldn't that mean that the material has already undergone as much degredation as it is going to?  I mean, since its already been welded all the way around, would me welding it really make it any weaker?  Especially if i pwa it...
Reply:Ok, awesome.  This is so much help.  I also finally heard back from the guy that started doing this last year.  Not the one picture, another guy I know, who's actually an aeronautical something engineer, so he does sh*t right.  He said he used 2024 filler. I asked him why, and he said that was "under the advice of the Senior welder at work, and he's certified by the AWS(american welding society)"  I asked him what kind of filler plate he used, so just waiting to here back.So, rather than boring everyone with "what kinda metal is it, blah blah" lol.  Anyone know how to test a piece to find out what exactly it is?
Reply:Originally Posted by cbrf23Ok, awesome.  This is so much help.  I also finally heard back from the guy that started doing this last year.  Not the one picture, another guy I know, who's actually an aeronautical something engineer, so he does sh*t right.  He said he used 2024 filler. I asked him why, and he said that was "under the advice of the Senior welder at work, and he's certified by the AWS(american welding society)"  I asked him what kind of filler plate he used, so just waiting to here back.So, rather than boring everyone with "what kinda metal is it, blah blah" lol.  Anyone know how to test a piece to find out what exactly it is?
Reply:To determine what alloy the metal is, you either get the information from the original supplier or you take it to a metallurgical testing lab and they tell you what the alloy is.Look, just because you or some else can make a weld on the aluminum that LOOKS nice (for now) does not really mean that it is RIGHT.Some problems with welding an unknown aluminum alloy is that you change the possible temper of the base aluminum (possible change in original design strength by 50% due to HAZ!!!), and you definitely change the alloy composition in the welded areas (possible crack-sensitivity, possible temperature sensitivity and strength loss maybe as low as 150 deg F, probable decrease in strength due to local alloying change as well as HAZ temper change). And regarding the heat treating in a home oven or powder-coating oven?  The oven can probably get the temperature up to the right range for tempering, but what are you going to do about the original part of the heat treating cycle where the aluminum is raised to about 1000 deg F, evenly and uniformly, just short of the melting point, in order to allow the alloy constituents to redistribute in solution and stress-relieve?  And then there is the controlled quench stage of the heat treatment cycle.  And after all that, -then- you finally get to the part in the heat treatment cycle where the part is raised to around 400-500 deg F.That aluminum swingarm on the bike has NO redundant part.  There is only that one swingarm.  If it fails, you crash.  And it would probably fail in a "loaded condition", so you would crash HARD.If you don't KNOW what the alloy on the aluminum swingarm is, I wouldn't weld it.  If you can't/won't redo the heat treatment after welding, I wouldn't weld it.I'd say you might be better off machining a whole new swingarm out of a new  billet of the appropriate alloy of aluminum, after you do a full design and engineering study of the needed strengths, strains, deflections, and safety factors for the swingarm.  Honda certainly did all that for the original swingarm.If you want to alter the appearance and not alter the structure of the swingarm, then change the appearance in a way that doesn't mess with the structure.  Welding definitely messes with the structure.  Drilling holes definitely messes with the structure.  Adhesively bonding a surface patch on should not mess with the structure.Most of the folks are saying to not weld it because there are so many unknowns going on here, all on a pretty critical part of the motorcycle.  And any good heat treatment facility is probably going to have about a yard-long stack of papers disclaiming any and all responsibility in the event of part failure of any kind.  They certainly don't want to be held liable, by you or your estate, if or when your modified swingarm fails.Hey, it's your butt and body parts on the line.  I wouldn't do it, there are too many unknowns and steps that are -waaaay- beyond what I'm comfortable with.
Reply:Well, I'm thinking I'm gonna price it out and see how much it would be to get it done professionally.  If its around 200, I'll probably spring for it.  If its more than that I'll probably hold off till I can afford it, or till I have enough experience to feel comfortable doing it myself.