# HF Alumiweld rods for joining AL sheet?



## strantor (May 26, 2021)

Anyone used the "Alumiweld low temperature aluminum brazing rods" from Harbor Freight to join two pieces of aluminum that actually have some mass to them? I've watched plenty of videos on them, they seem to work, at least well enough for my purposes, but in every single video I've found, they're clamping two little pieces of metal in a vise, brazing them together and doing the ultra scientific hammer smash test. I want to join two pieces of 1/8" aluminum sheet edge to edge along a length of 72". From what I can tell, it seems you have to get the workpiece up to temperature high enough to melt the rod, and my concern is that these sheets are going to be giant heat sinks leaching away all the heat. In order to get the joint hot enough, I'm going to need an acetylene torch which is probably going to make it so hot that it turns into a taco, which is exactly what I'm trying to avoid, and why I'm not just welding them.

Anyone here tried this or something similar? How did it go?


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## benmychree (May 26, 2021)

I'd be afraid of distortion/buckling with a joint that long.


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## strantor (May 26, 2021)

benmychree said:


> I'd be afraid of distortion/buckling with a joint that long.


Yeah that already happened. I tried welding it and it turned into a taco. I was hoping this stuff would be different. I'm not convinced there would be any difference and it sounds like you aren't either. I stopped and picked up some of the rods though. Since I already ruined a couple of sheets so I have plenty of material to experiment with.


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## Lo-Fi (May 27, 2021)

What welding process did you try?


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## strantor (May 27, 2021)

Lo-Fi said:


> What welding process did you try?


MIG w/ spoolgun. I have a tig but I didn't attempt it because I'm out of practice and even when I wasn't, I wasn't very good.


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## brino (May 27, 2021)

I have used these with success a couple times:
Bernzomatic aluminum brazing rods

....and both of my uses have been documented here!

on an aluminum replacement guide for a car window regulator: 
https://www.hobby-machinist.com/threads/repairing-an-automotive-window-regulator-mechanism.91146/

and on a little hackzall-based paint shaker:
https://www.hobby-machinist.com/thr...you-make-in-your-shop-today.67833/post-820961

My parts are much smaller than what you want to do.
I'd think a 72" long butt joint on 1/8" sheet would be very tricky.....if at all possible......sorry!

-brino


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## Lo-Fi (May 27, 2021)

TIG would be your best option. Precise, controlled, focused heat is what you want. But you really have set yourself quite the challenge!


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## strantor (May 27, 2021)

Lo-Fi said:


> TIG would be your best option. Precise, controlled, focused heat is what you want. But you really have set yourself quite the challenge!


Yeah, you're right, I know. But I also know my chances of success. Maybe for once I should consider paying someone else to do something I'm not good at. You know, like normal people do.


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## C-Bag (May 27, 2021)

One of the guys on a metal working forum when asked how he does such big panels without distortion says he works the weld with hammer and dolly as he goes. He does like 4-5” of weld then goes over it with hammer and dolly then another section, rinse and repeat. I would think a planisher would do the same.

I’ve not tried it yet as the project hasn’t come up, but it’s something I’ve filed away in my porous brain for later use.


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## nighthawkFmobil (May 27, 2021)

If you have the equipment just tig it. 1/8" is thick by most tig standards. A little practice/fun and you could save yourself some money if you see it that way. I'm sure a bunch of us here would be willing to help coach you through your practice if you have some scrap.


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## markba633csi (May 27, 2021)

"like normal people do"  that's a good one.  Oh you mean like the people that never create or do anything or learn anything new?
I think there is a distinct shortage of normal people around here


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## strantor (May 27, 2021)

markba633csi said:


> "like normal people do"  that's a good one.  Oh you mean like the people that never create or do anything or learn anything new?


Yeah! Those ones! They can't be wrong about _every_thing you know. Even a broken clock is right twice a day.


markba633csi said:


> I think there is a distinct shortage of normal people around here


Agreed, and that's why I like it here.


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## brino (May 27, 2021)

That's the beauty of it....... I can _*FEEL*_ normal here!

-brino


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## Lo-Fi (May 28, 2021)

Not directly related, but you can see how easy it is welding thin plate with TIG without turning it into taco shells. But the most important point: time = heat. More power = less time = less heating of the part. From experience, ali soldering with a torch flame requires quite a lot of faffing. And usually some swearing.

Now, like all "normal" people round here, you're going to go out and buy a $1000 TIG machine because it's required for this little job, right? We've all been there!  

Edit: there's a better video about the time = heat thing, but I'm darned if I can find it.


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## strantor (May 28, 2021)

Lo-Fi said:


> Now, like all "normal" people round here, you're going to go out and buy a $1000 TIG machine because it's required for this little job, right? We've all been there!


I already did that ! For another project a few years ago. I've probably used my TIG 20-30 times and each time I'm about as good (bad) as the last time. I can do decent TIG work with steel but aluminum kicks my butt. I'll watch your video and a few more, see if I can work myself up for giving it another go.


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## deakin (May 28, 2021)

i believe i have see the tinman do long gas alum welds w no distortion visible


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## C-Bag (May 28, 2021)

Be interesting to see which vid's you are talking about. I've got his vids on gas welding, brazing, and soldering aluminum. They all go at different speeds welding being the slowest. He and several elite metal workers use gas over tig. Could be that's what they are used to but all you have to do is watch them and the actual amount of heat put into the metal because of speed is way less with gas so is inherently less distortion. If you go at the speed they go at. They also work typically with thickness way less that the OP, like somewhere in the neighborhood of .035 to .040". 

I have no idea what alumaweld would be categorized as either braze or solder.


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## 7milesup (May 28, 2021)

You could tack it in 1" increments along the length with your TIG, It will not look the best when your done i.e. no "laying dimes" but most of us can't do that anyhow.
You are correct about the heat sink.  .125 along 72 inches is a LOT of metal.  I have tried different "Aluma-stick thingies" before I bought my Lincoln TIG unit and I never was able to make those things to work.  I ended up with globs of aluminum looking gum that I could flick off with my finger.  LOL.

One of the little tricks that I came across for getting a nice TIG weld is moving the TIG torch 1/3 the length of the puddle before you introduce your filler rod again.  You will end up with some nice looking welds utilizing the 1/3-add-1/3-add.  It was one of those epiphany moments for me.


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## strantor (May 28, 2021)

7milesup said:


> You could tack it in 1" increments along the length with your TIG,


That's what I did with the MIG/spoolgun but still distorted. I didn't even go an inch. 1/4" to 1/2" max, then go a 2 feet away and do it again, then take 5 while it cools, and repeat.

Granted That's not the same as TIG where you can control the heat, but still. Frustrating.



7milesup said:


> It will not look the best when your done i.e. no "laying dimes" but most of us can't do that anyhow.
> You are correct about the heat sink.  .125 along 72 inches is a LOT of metal.  I have tried different "Aluma-stick thingies" before I bought my Lincoln TIG unit and I never was able to make those things to work.  I ended up with globs of aluminum looking gum that I could flick off with my finger.  LOL.
> 
> One of the little tricks that I came across for getting a nice TIG weld is moving the TIG torch 1/3 the length of the puddle before you introduce your filler rod again.  You will end up with some nice looking welds utilizing the 1/3-add-1/3-add.  It was one of those epiphany moments for me.


Thanks, I'll give that a shot!


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## nnam (May 28, 2021)

Tig is much hotter than mig welding.  It does have good control, but I don't know.  Maybe research on youtube for people having done this before.

I read again and at 1/8", you probably can do it. 
Do a spot at the middle first, then move out maybe a feet, another spot.  I would do both length wise sides of the middle (center out).


Then go for 1/2 ft interval.  Only spot weld.  After that, a very thick steel heat sink the other side may help with 1/2" weld travel.


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## strantor (May 29, 2021)

Ok I tigged this thing together after clampingit  between a bunch of unistrut and weighing it down.




I tacked it from the other side, 1/2" bead-lets, then flipped it and ran full beads along this side, 3-6" at a time

Any predictions what will happen in the morning when I release it? Will it jump up like a fake snake in a can or will it stay flat?


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## Lo-Fi (May 30, 2021)

Nice. I'm betting relatively flat.


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## brino (May 30, 2021)

It looks to me like you got it!
Nice.

-brino


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## strantor (May 30, 2021)

Results are in. It still warped, but not insurmountably. I think I can live with this. Once I bolt it down to the steel frame it goes on, I think it will flatten back out.


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## strantor (May 30, 2021)

Here's some lessons learned from the experience. Maybe some of you will benefit from my sharing...

1. Get about 30 TIG electrodes, sharpen all of them, and keep them at arms length. That way you don't have to make 30 trips back to the bench grinder for the 30 times you jab the filler into the electrode, or the electrode into the puddle. This is assuming you're as dextrously challenged as I am.

2. 6061 is prone to hot cracking, so when welding it your weld should have lots of filler (4043), more filler than parent metal. For sheets of this thickness the cuts should be beveled. I didn't bevel mine and learned the hard way. This is what my first welds looked like:



It didn't help that I was laying on my belly across this criminally uncomfortable unistrut jig and therefore forced to use the torch with ON/OFF finger switch. Hot cracking can be minimized by using a foot pedal and tapering off the arc at the end so you don't get that divot - the divot is where the cracking starts. 

Since I didn't know that about 6061 hot cracking I didn't know that I should've beveled this until it was too late. So what I did was just use way more filler than I normally would, and that seemed to be a good enough bandaid although my welds are now really tall and probably don't have very good penetration. Still, I think it will be good enough. This is what my welds looked like after I got my "process," eh... "perfected."



3. Of course the usual: cleanliness, cleanliness, cleanliness. Have a dedicated grinder wheel, flap disk, wire wheel, and stainless wire brush labeled "for aluminum only." Wash joints and filler rods with acetone right before welding. I like to think that if I did only one thing right, it was cleanliness.


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## brino (May 30, 2021)

@strantor 

Thanks for the details of what worked for you.
I need to spend much more time on TIG before I even start to get comfortable.

-brino


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## strantor (May 30, 2021)

brino said:


> @strantor
> 
> Thanks for the details of what worked for you.
> I need to spend much more time on TIG before I even start to get comfortable.
> ...


I don't do it enough that I would ever get comfortable with it. Unless some radical change happens in my life, It's something that will always be a stressful (re)learning experience.


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## Weldingrod1 (May 30, 2021)

Another really important tip: preheat to reduce distortion.

Aluminum really doesnt give you any penetration into a butt joint (unlike steel and SST). If you scour down right before welding, -maybe-... bevelling is your friend.

Fixturing like you did was a good call!

Sent from my SM-G892A using Tapatalk


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## strantor (May 30, 2021)

Weldingrod1 said:


> Another really important tip: preheat to reduce distortion.
> 
> Aluminum really doesnt give you any penetration into a butt joint (unlike steel and SST). If you scour down right before welding, -maybe-... bevelling is your friend.
> 
> ...


Preheat? Never tried that. Do you use a propane torch? How how hot should you get it?

I'm wondering, if I knew to preheat, whether I would have done it or not. I had to lay across the workpiece and with how readily aluminum conducts heat, I may have been throwing myself onto a frying pan.


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## Weldingrod1 (May 31, 2021)

Any heating tool you have works. Getting up to boiling water temp is a big improvement. Yes, it would have notched up the suckage related to laying over the sheet. A piece of plywood on top of the unistrut would have helped, for future plsns... It also makes it feel more like welding on steel/sst: not so crazy many amps needed.
Just dont get too close to the tempering temperature.

Sent from my SM-G892A using Tapatalk


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## strantor (Jun 1, 2021)

It got acceptably straight after being screwed down to its frame.


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## brino (Jun 1, 2021)

it looks great!
-brino


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## strantor (Sep 11, 2021)

Check this out. Is he just using aluminum TIG rod?


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## RandyWilson (Sep 11, 2021)

Looks like I wasted a bunch  of money on boring heads and what-not. A very large precision shouldered fit can be cut with a flycutter in a drill press.


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## strantor (Sep 11, 2021)

RandyWilson said:


> Looks like I wasted a bunch  of money on boring heads and what-not. A very large precision shouldered fit can be cut with a flycutter in a drill press.


I have no idea why he did what I did, I don't speak the language, but I think he was adapting a different head to it. Sometimes in 3rd world countries things make sense that wouldn't anywhere else. They'll salvage things that have no business being salvaged. Whatever the goal or motivation, I don't care much about the why, just curious about the how. I've never seen anyone build up aluminum that way. Is it really as simple as it seemed in the video? Just melt a bunch of aluminum TIG rods all over the outside of a casting with an acetylene torch?


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## Tim9 (Sep 11, 2021)

I think he’s using aluminum Arch Stick welding rods to weld aluminum using an Oxy/Acetylene torch. I know I saw a video by Jody’s Tips &Tricks Chanel where he DC tigs using the same Arch stick welding rods to weld aluminum. He even cut the weld afterwards and it had good penetration.
  FWIW, I’m getting ready to try this in an hour or so to repair a cast aluminum bracket from my newly acquired 14” band saw. I’ll report back later with a progress report.


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## strantor (Sep 13, 2021)

Tim9 said:


> I think he’s using aluminum Arch Stick welding rods to weld aluminum using an Oxy/Acetylene torch. I know I saw a video by Jody’s Tips &Tricks Chanel where he DC tigs using the same Arch stick welding rods to weld aluminum. He even cut the weld afterwards and it had good penetration.
> FWIW, I’m getting ready to try this in an hour or so to repair a cast aluminum bracket from my newly acquired 14” band saw. I’ll report back later with a progress report.


Results?


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## Tim9 (Sep 14, 2021)

I’ll report back once I get to it. Hopefully tomorrow but I’ve had a lot of crap on my table. I purchased the bandsaw used but then fractured my hip the next morning. Then it was hurricane Ida. Today it’s rain from Nicholas. And my hip is still hurting like a SO#. Life is complicated but it’s all we have.


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## brino (Sep 14, 2021)

Ouch!
Get well soon @Tim9.
-brino


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## C-Bag (Mar 29, 2022)

I was asked to help a neighbor weld up a DIY inside rack for his SUV made out of aluminum sign material. He gave me several chunks to practice on which I cut up that appears to be .095 from scrapped signs.

Not having a TIG or spool gun for my MIG I decided this was the perfect excuse to have another run at OA welding AL as I fell down the rat hole several years ago and never got to the point of actually having a project.

I bought a whole set up from Tinman with AL solder/flux, AL braze/flux and AL weld rods/flux. Also a Mecco torch and assorted odds and ends along with a pricey pair of his patented cobalt glasses. I also looked at all the vids on HF alumaweld and it appears to be less of a brainer than the Tinman stuff so bought a pack. I'd also been watching a relatively new YouTube channel with this young Canadian guy Karl Fisher "Make it Custom". It's all hot rod stuff but great metal working tips and he's a great teacher. Does a lot of TIG but I feel like his tips for joining panels was a real boon as a lot of what I learned at this go around flys in a face of 50yrs of my OA welding experience of everything except AL.

#1 no gap! This is not like welding thick pieces of steel together so you don’t need gap or bevel especially. Penetration is not the problem, it’s melting through. You want ideally a fusion weld because anything above the level of the metal, AL or steel, will shrink and warp. It’s also paramount that each tack the level of the two pieces stay perfectly level to each other. Tacks are spaced out, then next tacks are closer, then another round of closer tacks and on and on. As the metal starts to pull you hammer and dolly right on the tacks to stretch the material back out. Here Karl is welding two door skins together to make one coup door on his Zephyr. It might be a little long but seeing the final product makes it all worth it.


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## woodchucker (Mar 29, 2022)

I used the Hobart stuff to make my follow rest. I did bevel it as I wanted a flat joint. The only danger is heating the base metal too much. Even using mapp, it's easy to do. I got the rods to fix a garage sale band saw that had a gear box on it. The damn thing had so many cracks......

Anway, the brazes came out great.  last pick in #13, and 14








						South Bend Lathe 9 Need an opinion of drilling the carriage for a left side follow rest.
					

That works well, but you can also just turn the QC tool holder around so that one of the dovetails face to the right to mount the tool right under the FR jaw or very near to it, this does make the locking handle sit in an inconvenient location, but I just remove it temporarily.  well, since I...




					www.hobby-machinist.com


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## C-Bag (Mar 29, 2022)

My OA trek was more convoluted. I took an angle and a piece of the sheet and cleaned them up. I used my smallest torch tip on my regular OA torch and tried to make a bead and what a mess. No matter how much I seemed to throttle back the torch it still blobbed it up. No penetration or stick. So I decided to get out my old acetylene plumbers torch. No cigar, seemed the opposite problem where it didn’t seem to be getting hot enough.

Supposedly you heat the AL and if above 700f just touching the Alumaweld rod to the place to be welded it should melt. I don’t have propane torch so decided it was time to finally get out the little Mecco torch. Dialed it back on the O and A pressures and remembered a trick a member reminded me of. Take just the acetylene flame with the soot and run it over the area to weld. Then go back to a regular OA flame. The soot burns off at 700f so using that as a guide (which I was really having a problem seeing when it was hot enough) pushed the rod in and whatdoyaknow it flowed right in! The other really hard thing for me to get used to is unlike braze or solder AL won’t flow to the heat. They explain in the Alumaweld pamphlet you use the rod to kinda scrape it in. Still kinda thick but finally a strong weld that’s stronger than the parent metal.


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## woodchucker (Mar 29, 2022)

yep, you are not sweating, you need to rub it. I found that out this time too, as it was over a year since the last time I used it. I sweat pipes more than I braze the Al so I had forgotten that. but playing with it I figured it out. It also helps having a infrared thermometer. I don't have OA here.


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## C-Bag (Mar 29, 2022)

I was using a cheapo infrared thermometer and it wasn’t working right. Dunno if it was the thermometer or funky batteries. That’s when I remembered the soot trick. Works perfect. Now just need to get a couple more practice pieces and get it consistent.


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## jwmelvin (Mar 29, 2022)

C-Bag said:


> I was using a cheapo infrared thermometer and it wasn’t working right.



Did you try the IR thermometer after the soot burned off? I’d be curious what it read. Aluminum should be a tough surface to get an accurate temperature with IR, as I think they are usually tuned for emissivity of 0.95 or so. Bare Al is way below that.

(I imagine a reading from the soot-covered surface would be pretty accurate.)


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## C-Bag (Mar 29, 2022)

jwmelvin said:


> Did you try the IR thermometer after the soot burned off? I’d be curious what it read. Aluminum should be a tough surface to get an accurate temperature with IR, as I think they are usually tuned for emissivity of 0.95 or so. Bare Al is way below that.
> 
> (I imagine a reading from the soot-covered surface would be pretty accurate.)


No I didn’t. As usual when it’s not really giving me what I want I abandon it. But your assessment could explain part of my problem. The pointer laser wasn’t working consistent so that’s what made me think the button batteries were kaput. The soot was very accurate in showing where the AL was up to temp. The problem is once it burns off it’s gone. Maybe once I get more experience with this I won’t feel so frantic as it seems things go from 0 to meltdown in a heartbeat.


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