Welding Tips and Tricks

While breaking the bike down for an unrelated problem, I noticed the radiator mounting tab was cracked. The previous owner used JB weld to repair it. While I was able to get a used radiator on ebay cheap, I thought i'd try to weld this tab back on for a spare. I ground off all the JB weld, wire brushed it and cleaned with acetone, both sides.
I think it's some kind of alum alloy and figure I've got nothing to lose .... Anyway, I just couldn't get 5356 or 4043 to wet out into it . After a lot of trying, I was able to get the outside edges to fuse but the whole middle of the crack just refused to weld. Anyone have any ideas on filler rod or weldability of this ? As a test, I ran a few decent beads on some 1/16 scrap aluminum which welded fine so everything else is working. Thanks much

Welcome aboard!

I don't have a ton of experience to bring to the party, but I'm surprised 4043 isn't doing it. But you've got me thinking...I have a scrap motorcycle radiator out in the shed...I'm gonna go out tomorrow and light up on it and see what I can achieve. Maybe at least we can compare notes.

Kym

crank up the heat and try to get a tack to work off of.
craig

I've welded several dirt bike radiators and I don't remember having any real problems with them. Maybe your problem is with argon coverage. You might need a dam or something to help with coverage. Just a guess.

Thanks guys. I tried the argon from 15 up to 25 cfh ... I was at 42 amps ac (pedal), 1/16" 2% lant, I tried 120hz and 250hz , I tried anywhere between 30 and 45% EP ...I was able to get the very outside edges of the cracked piece to wet out fuse after much trying ...but the middle just wouldn't take filler ... it would just blob , I ground off the blob and tried again.
Maybe I wasn't hot enough ? I never had any burn thru issues, and I welded on a scrap piece of 1/16" 6061 box channel testing my setup next to the radiator. IDK , it just didn't seem like regular aluminum and the fact that it cracked right off with no bend . Big gear head, what amps and filler did you weld those radiators with ?
This tab is about 1/16" , it's for my daughters Kawi KX100 .

Again, thanks much guys !

It's been several years ago, so I don't recall what amps. I used 4043 wire and an old Miller Syncrowave machine. You may not be getting a puddle started on the parent metal before adding filler. You must get the parent metal to melt before adding filler to it. You might want to try some kind of backing material to keep the metal from falling out the back side.

How about making a new bracket?

You say you think its aluminum. No offense but have you put a magnet on it?

subwayrocket wrote:Thanks guys. I tried the argon from 15 up to 25 cfh ... I was at 42 amps ac (pedal), 1/16" 2% lant, I tried 120hz and 250hz , I tried anywhere between 30 and 45% EP ...I was able to get the very outside edges of the cracked piece to wet out fuse after much trying ...but the middle just wouldn't take filler ... it would just blob , I ground off the blob and tried again.
Maybe I wasn't hot enough ? I never had any burn thru issues, and I welded on a scrap piece of 1/16" 6061 box channel testing my setup next to the radiator. IDK , it just didn't seem like regular aluminum and the fact that it cracked right off with no bend . Big gear head, what amps and filler did you weld those radiators with ?
This tab is about 1/16" , it's for my daughters Kawi KX100 .

Again, thanks much guys !

I think you need more amps. I set the machine to 180 for 11 ga. I don't need it all after I'm started, but to get the puddle established takes some serious amps, and don't be afraid to preheat that sucker to about 325F. You have no fear of blowing a hole in the radiator because of the way it broke.

Steve S

Steve, at what temperature do you think the braze joints would start to come apart? That would concern me a little when preheating.

I agree with Steve on the amps you diffiently need more amps. Except for the preheat don't see any need to preheat this. You are welding thin material nothing real thick. I am guessing this is 16 gauge or so. So at least 120 amps bury that pedal once puddle forms give it some rod to stabilize it and you will be able to control amps with pedal. At 42 amps you where just putting heat into part. Remember with aluminum get that puddle going and then use pedal to bring amps down to control heat. I use art least 80 amps when I play around with soda cans.

Yeah I definitely put a magnet on it, non magnetic and also the burr ground it very easily. I just don't know what kind of alum or alloy it is ... I was trying to be careful not to burn thru it so yeah I think i'm low on amps...I did put a bead across a piece of 1/16" alum scrap right next to it, so I thought maybe the radiator was some kind of alloy mix . I'm gona grab a few bike radiators from my buddy's scrap yard tomorrow and try more heat faster , get a puddle, push some rod in hopefully. Maybe this is why it only fused at each end of the crack where the heat had less room to sink out into the piece. Guess I played it too safe. Thanks guys for all the suggestions. I'll try it again .

I got the used (ebay) radiator just now, opened the box, darn thing is cracked in the same place, seller desc said "used but fully functional" ...lol

http://www.hobartbrothers.com/product-d ... eg%3B+4943

I can see one rivet, but how was the tab welded / brazed to the header tank? Could be an awkward alloy, or copper plated?

If you are playing around with some scrap rads, try a standard collet body and a #5 ceramic.

You need to get a wet puddle in about 3 seconds or less, if not, you are probably only creating more oxide. So essentially that means you have to hit it hard when you first light-up, and once you are adding filler, you can probably back off reasonably hard too. Good gas flow, a little bit of pre-flow (1-2 seconds), keep the torch close to perpendicular, hold a tight arc, and bring your filler in at a very low angle.

HTH

Trev

Yeah, aluminum is a major heat sink. I like to hit it soft for a few seconds and let the cleaning action clean my initial start area and then stomp the pedal and get my puddle. Then back off to a manageable heat.

Stuff like you're doing I have my best luck spot blasting them real clean first.

Everyone is thinking what I am thinking; heat issue. Maybe you want to get a small drop of filler and keep working it around as you apply your heat, rather than waiting on the puddle to form before adding filler (did someone else mention something like this??) Great problem! Thanks for the post! I love reading about this kind of stuff!
Gary

Ace , I also tried exactly what you describe . The drop would just remain a ball and just didn't wana wet out into the piece . I also got little flare up's here and there and little crackles ... this thing is probably a mix of Alum and whatever else they had at the time...who knows ...lol All I know is I didn't have much problem getting a puddle going on a practice piece of 1/16' alum box channel sitting right next to the radiator , I used that to test my settings ... unfortunately those settings didn't translate to the radiator. I'm thinking (like many of you have said) prolly need more heat .
Off to the scrap yard shortly . Thanks again for all the suggestions, much appreciated !

subwayrocket wrote:Ace , I also tried exactly what you describe . The drop would just remain a ball and just didn't wana wet out into the piece . I also got little flare up's here and there and little crackles ... this thing is probably a mix of Alum and whatever else they had at the time...who knows ...lol All I know is I didn't have much problem getting a puddle going on a practice piece of 1/16' alum box channel sitting right next to the radiator , I used that to test my settings ... unfortunately those settings didn't translate to the radiator. I'm thinking (like many of you have said) prolly need more heat .
Off to the scrap yard shortly . Thanks again for all the suggestions, much appreciated !

Good luck, New Member! Again, this is a great thread! Keep us posted!

Since this piece is riveted, it may be 7075 aluminum (or something similar).
It's used in airplane wings for example and riveted together.
You can weld it but it will crack, often immediately.
Is this piece welded anywhere or only riveted?
If there is a weld then you may be OK.
Jack

Good point cptjackm

Or it could be 2000 series (e.g. 2011, 2014), same issues, high mechanical strength , but almost impossible weldability .

Trev

It had just the one rivet , but it has a coating of melted metal over the whole tab and top of the radiator .
As suggested, I went up to 60 amps and got it welded ...it was not easy, fun or pretty
...had to grind out poof's and soot a few times.
(Yes the piece was ground to shiny metal all the way around) I burned off a little of the side of the tab ...had to pulse and build that back up . Whatever this radiator is, it makes 6061 seem easy ...haha
Anyway, both radiators are welded now...and they sure aint pretty but I think they'll hold.

Well, sometimes "That'll do" beats pretty.

Glad to hear you made it work!

Steve S

I'm just starting out TIG welding ...that radiator metal was just weird. Here's some practice on 0.092" 6061 Aluminum about the same thickness as the radiator tab . I've got a long way to go, but the good thing I that it's a lot of fun learning . Thanks much guys, I appreciate the suggestions !
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It's been on her bike about a week now ...bottom radiator mount tab...it ain't pretty but it's holding so far .
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