Appx wattage needed for solding aluminum tubing with soldering iron?

[mikerj]

Currently diving into the many variations of welding machines that include TIG.

The cost of the machine is just one aspect, make sure you figure in the cost of and availability of the shielding gas (bottle rental and refills) and a suitable grinder/grinding wheels for the electrodes (you will contaminate frequently when starting out).

[beanflying]

The Rental is far less an issue now than it used to be. Here in Oz finally we have several pay up front for a bottle and no rental, this was always a major deterrent in the past and even more so now. Bottle payback to rental costs are under 4 years then you are clear. You do pay a little more for Gas over Rental rates but for home or low volume use it still makes more sense to buy.

Way back in one of my first jobs I worked for a Welding Gas and Gear centre and bottle rental and handling was a duopoly locally and mass extortion of tradies for lack of options (30+ years ago)

[pipe2null]

Won't try and talk you out of a good Tig welder as I talked myself into one late last year 

Oh...  Don't you worry, I need no encouragement, just (barely) sufficient (excuse) well researched justification (really just a good excuse) for diving into the welding side of things.  I already had some of the TIG basic gear, and earlier today I hit a holiday sale at harbor freight to pick up most of the rest: heavy duty welding cart, baby starter welding table, basic magnets/clamps, and misc other stuff.  Added a few MIG and stick specific items to the mix as well (not for my current project, but future use).

@mikerj:  Good points.  I already have most of the basics for TIG, including one of those tungsten grinder attachments for a dremel, from when I was messing around with a TIG machine at a local Maker's Space.  The previous gas supplier I worked with for my oxy-propane torch charged full price for tanks but you just brought them in and swapped them and only pay for the gas, or just hang out for a bit while they refill the same bottle.  I have since moved and haven't selected a new supplier so no sure yet what the locals offer.

@wizard69:  Thanks for the tip on Swagelok, I'll check them out.  My water cooling project is mostly about seeing if I can do it successfully when no off-the-shelf part exists or is ridiculously expensive (commercial CPU water blocks for narrow ILM server CPUs are about $120 to $200 per CPU socket per dual CPU server last time I priced them), and with the exception of one fried motherboard out of the stack of 4 servers, it has worked out more or less ok.  All these machines are old retired enterprise servers and no one in their right mind would put in the massive effort (CAD, 3DP, fabrication, etc...) to water cool them unless it's a project, or like me, want my servers running very quietly next to my workbench instead of a sound-proofed closet far far away...
If these were newer servers or any consumer grade desktop with plenty of off the shelf solutions, I would definitely NOT go this route.

General FYI: I went with Aluminum literally because I could get 8mm square aluminum tubing on Amazon and didn't easily find available copper square tube around that size.  Using square tubing because the flat sides are convenient for heat transfer from other flat things.  True, connecting square metal tube directly to round silicone tubing is a PITA, but doable.  Plus going the aluminum route is CHEAP at least for materials.  Example, I built one heat exchanger that uses an Al plate as heat spreader brazed to the square tube, and this cools 2x Dual Ten gigabit ethernet chips (4x 10 GbE).  I had to 3DP a bracket to mount the exchanger on the riser card that had no heat sink mounting holes since the original heat sink was epoxied onto the glass flip chips (PITA to remove). Total part cost was about $5.


Please feel free to suggest welding machines I should look at before I finalize my purchase...  I'm currently looking at the Weldpro Omni 210, but there are other machines I'm considering...  My budget is somewhat flexible depending on bang for buck, but I'm not buying any cheapo machines (<insert FIRE emoji here>).  The Weldpro Omni 210 is about $1500, but I could probably go up or down if there is good reason.  Miller Multimatic's are attractive, but I can't justify $4k.  I messed with a Lincoln Electric Square Wave TIG, but I can't justify $2.4k for a machine that only does TIG...  Etc...

Since I'm diving in the welding side and not just upgrading my lab/shop the absolute minimum for the project at hand, I want to make sure the welding machine(s) I get can handle multiple processes and all materials reasonably accessible to consumers, realistically for me would be mostly aluminum, but steel and possibly copper would make sense as well.  I gave up trying to find a multiprocess machine that does AC/DC TIG, MIG + spool gun, stick, and Plasma cutting, (flux core as nice to have).  They have machines that do just about every combination of those processes but they all lack at least one.  For example, there are multiple makes and models that do all of the above processes including plasma cutting but only can do DC TIG not AC...  It's irritating AF to find a bunch of machines that ARE SO CLOSE to a complete multi process machine but stop short.  So, I'll get a plasma cutter separately as a future fun purchase (with distinct urge to pair with CNC table) and continue looking for a single ACDC TIG / MIG + spoolgun /stick multiprocess machine that performs decently all the way down at 5 - 25 Amp AC TIG for very thin aluminum (<= 1mm), ideally with pulse and some of the more interesting waveform manipulation features that might be useful for really thin aluminum.  But still beefy enough for normal material thicknesses so the investment is still useful for other projects already bouncing around the back of my head.

Sorry about long post, I'm a little amped up about being so close to buying a whole new genre of toys (horrible pun intended)...  heh.

[beanflying]

As you are in the US have a good look at the Everlast range too. Plenty of reviews on Youtube for the various offerings.

For my uses I went with a more dedicated Tig unit that will do Stick and chose not to get anything MIG capable in the box. The thinking was that if I ever found myself in the position to need a MIG for bigger jobs then there is plenty of used quality more industrial gear (15kg spools) to consider. Flux core MIG and small spools is something I decided I can do without and initially I didn't want a second bottle of gas either.

Unloved thread I started some time ago I must post some of the adventures in. But it has some good links in the first post that might help https://www.eevblog.com/forum/mechanical-engineering/welding-stick-tig-and-mig/

[Siwastaja]

Use copper for computer cooling stuff. Better thermal conductivity, much easier to work with, can be soldered with standard tin. Can be welded with DC TIG which is cheaper than AC. Brazing with copper phosphorous alloy stick is also quite easy, I haven't done aluminum but I'd assume it's more difficult. So with copper, everything is better, except the price of the raw material itself, but at the scale of some small computer cooling system, does it matter?

[PaulAm]

If you have the space (and power), you may be able to find older TIG gear cheap.  I picked up a Miller Syncrowave 300 for $85 at an auction a couple years ago.  That's an awesome machine.

You could probably find a spool gun and use MIG, even one of those cheapie inverters, and get decent results for what you're doing.

[pipe2null]

As you are in the US have a good look at the Everlast range too. Plenty of reviews on Youtube for the various offerings.

For my uses I went with a more dedicated Tig unit that will do Stick and chose not to get anything MIG capable in the box. The thinking was that if I ever found myself in the position to need a MIG for bigger jobs then there is plenty of used quality more industrial gear (15kg spools) to consider. Flux core MIG and small spools is something I decided I can do without and initially I didn't want a second bottle of gas either.

Unloved thread I started some time ago I must post some of the adventures in. But it has some good links in the first post that might help https://www.eevblog.com/forum/mechanical-engineering/welding-stick-tig-and-mig/

After digging into it and resisting the urge to go with cheapie burn-down-the-house brands, and being too poor for brands like Miller or Lincoln Electric, I ended up buying Everlast:
- TIG/stick: PowerTIG 255EXT
- MIG/stick/Plasma: Storm 215C w/Spool gun for aluminum.
Will be delivered in a few business days.

Should be pretty solid across the board for TIG from thicker stuff all the way down to ultra thin stuff with it's minimum AC start at 5A, plus other bells and whistles that I've read help with thin material.  I did not "purposely" go for a dedicated TIG machine over a multi process one like the Everlast PowerPro or LightningMTS, but it ended up that was since the PowerTIG 210EXT and 255EXT are a little better for the thin stuff. 

I picked up the Storm to round out welding capabilities with MIG and make sure I had entry level plasma to cut up scrap for practicing.  Plus I have nephews interested in welding, thought MIG would be much better for them to start with so they don't lose interest too fast due to the pain of learning TIG and then go back to playing video games 247.  Overall should be a pretty solid starter setup.  I would have actually preferred to go with separate machines for everything, but the combo unit ended up being a little cheaper than dedicated units and I care less about MIG than TIG.

If you have the space (and power), you may be able to find older TIG gear cheap.  I picked up a Miller Syncrowave 300 for $85 at an auction a couple years ago.  That's an awesome machine.

You could probably find a spool gun and use MIG, even one of those cheapie inverters, and get decent results for what you're doing.

Yea...  I blew up the budget buying everything at once, new, but now it's also done with all at once, so that's a big bonus.  I will definitely keep on the lookout for used Miller units, but when you're a beginner like myself, it's sketchy to buy anything used without taking a welder buddy along who knows what they're doing, which I don't really have at the moment.  Good tip on the spool gun, I picked one up and will try it out.  I am in the process of installing 240V in the garage, but these dual voltage machines will run at half their max amps on 120V until I finish the install and get someone out to add the new 240V circuit to the breaker box.  Well, we'll see what amps are actually usable on these dual voltage machines when I start tripping 120V breakers...   

Use copper for computer cooling stuff. Better thermal conductivity, much easier to work with, can be soldered with standard tin. Can be welded with DC TIG which is cheaper than AC. Brazing with copper phosphorous alloy stick is also quite easy, I haven't done aluminum but I'd assume it's more difficult. So with copper, everything is better, except the price of the raw material itself, but at the scale of some small computer cooling system, does it matter?

I have a helllllllllloooooooooovvvvvvvvaaaaa lot of TIG practice to do before I can actually finish my mini aluminum heat exchanger projects, but I'm moving forward on it again at least.  Will also play with copper too as my TIG skills improve.  And brazing with TIG instead of gas torches...  So many things to try with new toys.     I've added copper welding coupons to my shopping list.  Originally went with aluminum for cooling project due to cost versus thermal performance, then I decided I would rather use copper to get the extra 20-25% cooling perf, then I couldn't easily find copper square tube and ended up going back to aluminum since it was easily available on Amazon.

[PaulAm]

You can use argon for TIG and the aluminum spoolgun MIG welding, but you'll probably want a MIG blend for steel if you do any significant amount.  They add some CO2 and O2 to get better penetration and improve arc stability..  Two gas bottles, oh joy 

I use Q (80 ft^3) tanks for my MIG and an S size (120 ft^3) tank for argon.  I wouldn't get anything smaller than the Q size, but it will last for quite a bit of welding.

[Ground_Loop]

Wow! You blew right past the soldering iron idea. I have a similar collection and find more need to weld things than I would have ever thought. I think my mower deck has gained about five pounds in weld bead over the years.  Anyway, if you don't already have one, a metal cutting bandsaw is indispensable.

[pipe2null]

Wow! You blew right past the soldering iron idea. I have a similar collection and find more need to weld things than I would have ever thought. I think my mower deck has gained about five pounds in weld bead over the years.  Anyway, if you don't already have one, a metal cutting bandsaw is indispensable.

Yea, the high powered soldering iron idea was sort of a last ditch effort to find a much cheaper indoor-friendly solution I could use in my carpeted lab in nice comfy air conditioning, and just slap down a large silicone mat as the only thing needed for safety and to protect my wooden workbench.  At the end of the day, I just needed to exhaust all reasonable alternatives to justify the excuse to buy new more expensive toys, errrr, I mean TOOLS, because I've wanted to buy them for a long time, errr, I mean because they're the right tools for the job.  Eventually I might come up with a safe, well ventilated, and fire shielded mini work space for indoor low-amperage TIG of thin aluminum.  But yea...  not going anywhere near that until I'm proficient with the process, or just quit whining and get used to the heat of working in the garage.  Wah.  Horizontal bandsaw is definitely on the list once a budget exists again, and poor poor me, I'll just HAVE to struggle through and make due with plasma cutting in the meantime.   

You are quite right on the "how did I survive without a welder before" notion.  The moment I informed my dad that I was buying welding equipment, suddenly now he needs an oversized  metal toolbox for the back of his John Deer.  Heh.  And of course, every new project idea I've had in the past week somehow includes excuses to weld some part of it.  Do I really need to use a welded aluminum enclosure for my 3D printer resin curing box project?!?!?  NO, but I'll probably weld an enclosure anyway or at least aluminum UV reflectors.

You can use argon for TIG and the aluminum spoolgun MIG welding, but you'll probably want a MIG blend for steel if you do any significant amount.  They add some CO2 and O2 to get better penetration and improve arc stability..  Two gas bottles, oh joy 

I use Q (80 ft^3) tanks for my MIG and an S size (120 ft^3) tank for argon.  I wouldn't get anything smaller than the Q size, but it will last for quite a bit of welding.

Thanks for the tips on tank size, that purchase/rental is happening in the next few days, so perfect timing on the tip.  I'll probably try to avoid rentals, but don't know what the local suppliers offer yet.  I'll probably stick with aluminum to start for both TIG and MIG so I don't need to deal with the second tank yet or figure out what gas mix will be ideal for general purpose MIG, many many learning curves.  But perhaps I can work out a deal with the supplier?!?

Crossing fingers the gas supplier is beginner friendly.  The last time I went into a welding supply shop, as a total newb, to pick up oxy-propane torch parts, the good ol' boys running the place sent me to another shop down the street for the tank adapter, and the next place said they were out of stock and sent me to a third place a few blocks away, and the third place said I could mail order the adapter or go pick one up at their other shop in the town next over.  Before going out of town to pick up the adapter, I finally fiddled with my regulator and the propane tank enough to finally figure out that pretty much EVERY propane tank's valve stem has external threads for your gas grill kinda connector, but it also has INTERNAL threads that will DIRECTLY connect to an acetylene/propane regulator (pretty sure CGA510), no adapter required.

[coppercone2]

this is ridiculous, use a flaring tool to make a decent fit and solder it with a damn blow torch. If you are just soldering with aluminum solder its not so bad. braze is bad for Al, solder is ok. Solder it with the special flux that comes with the aluminum solder.

[PaulAm]

AFAIK, gas tanks in the US are purchase and then refill by exchange.  I tend to use AIrgas, but my local suppliers have no problems exchanging tanks.  Heck you can even buy them through Tractor Supply, but you'll probably get a better deal from a local place.  They might call it a one time lease payment or something.   It's been a few years since I had to get an additional tank.  The good news is you never have to worry about recertifying , just swap the tank out..

Try to be educated before going into a welding supplies store.  They have to deal with the unwashed public who insist on loading filled propane or acetylene cylinders in passenger cars (not quite so bad with a nonflammable gas, you only suffocate in that case instead of getting blown to bits), so try to not look like a total noob.  Get 5 points for showing up with a pickup.

Years ago I had to lease acetylene and oxygen tanks; that adds up after a couple years..

Oh, btw, they generally do not like to swap say an argon tank for a Mig mix, even though they look the same.  I did swap an extra argon tank once for a Mig mix, but it took a little cajoling, so eventually you'll want 2 tanks.  Mig is great for quick work, Tig is much slower.  That tool box will go a lot faster with Mig, but it might have prettier welds with Tig.

[pipe2null]

@PaulAm:

Very good advice, thanks!  I will put that to good use in next couple days.

this is ridiculous, use a flaring tool to make a decent fit and solder it with a damn blow torch. If you are just soldering with aluminum solder its not so bad. braze is bad for Al, solder is ok. Solder it with the special flux that comes with the aluminum solder.

You can chalk it up to inadequate skill on my part.  You are correct about the blow torch soldering, which is exactly how I was doing it for some parts, I even got a cute widdle jewler's oxy-propane torch for it.  Torch soldering a piece with one joint worked well even when the whole piece was also soldered to a heat spreader plate.  But for pieces that had multiple joints 2cm apart, with each joint needing solder on 3 or 4 sides of the 8mm square tube, this is where I had problems with that process.  The moment I started working on the second joint, the first joint filler (less than 2cm away) would remelt and form holes as well as leak into the inside of the tube creating difficult to remove obstructions.  I tried adding heat sinks between joints, but that just made really hot bits of metal stick out from the workpiece as previous joints remelted anyway.  Perhaps I could have done a better job prepping and jigging, but using TIG to at the very least tack the joints together should yield a much better result than solely soldering/brazing, when the joints are so close together and need solder on multiple sides.  And as my skill gets better, TIG welding the entire joint is ideal.  Flaring tool is still necessary for some of the connections.

[coppercone2]

i thought you wanted to solder a tube inside of another tube, this is impossible to understand without pictures (this is standard plumbing even if its square)

if you want it at a right angle or something its gonna piss you off and be weak. the only way to make it reliable is to basically remake it so its a tube inside of tube in some way (milled slot) IMO. I think it will need to 'nest' to be any good at all.

[mag_therm]

this is ridiculous, use a flaring tool to make a decent fit and solder it with a damn blow torch. If you are just soldering with aluminum solder its not so bad. braze is bad for Al, solder is ok. Solder it with the special flux that comes with the aluminum solder.

Can you put up the name of the special flux and the name of the aluminum solder you use?
What 'blow torch" are you using?

This link is maybe useful and refers to > 300 C parent temperature.
https://superiorflux.com/techniques-for-soldering-aluminum/

[coppercone2]

the one I used is mg460 by messer welding, can't seem to find

i think this is the same one, at least temperature wise
https://www.harrisweldingsupplies.com/harris-al-solder-500-aluminum-solder-kit-500k/?sku=500K&gclid=Cj0KCQjw8amWBhCYARIsADqZJoUaf-2WaUmhgJ0aGdVOUwQ96q3KwH77Qxmpy3PzcYKg45N1FkrMM_YaAmWGEALw_wcB

[mag_therm]

Thanks Copper,
At $30/ounce it probably has high silver content where small amount is sweated in a joint as you mention.

To do a chassis with heatsinks I do butt joints needing about 1 to 2 filler rods per chassis.
Forney Al brazing rod is about $22 per half pound of 10 rods, so I use $2 to $4 per chassis.
The 6061 Al angle price has risen too so I would use about $12 of Angle  per chassis.

I could buy  nice, smooth, square, Hammond box for a few $ more !

[coppercone2]

well the secret to aluminum solder I think is Zinc, not silver. A high silver solder has too high  melting point, that is 500F. The idea is also it makes stronger joints by not being so hot because if you are careful heating the metal up the grain structure is not deformed as much, so for real world use, the difference between KPSI is not the only factor to look at. I bet there is a lot that goes into it.

Do you really need that much solder? Can you work on the fit up being better to use less? Its less strong as you get more.

The brazing rod for aluminum works like 750F, the solder I linked is significantly lower temperature, 250F is nothing to scoff at with aluminum. Saves gas/time too, and there is less dimensional change.

Like I said, I had excellent results with proper fit aluminum solder joints, but basically dog shit when it came to aluminum brazing, even with harris flux.

Again this is just for Al, for structural copper stuff, braze. Plumbing appears to have its nuances but engineers IMO will benefit from silver braze.

[coppercone2]

Like if you were tortured by lack of flow that led to excessive braze use, what I am saying is that aluminum SOLDER (500F kind) actually seems to flow. With braze I was eating rods too because that shit would just not go in . The solder should literarly creep in between the joint properly, you should not be making much of a fillet with this stuff! So long your joints are clean, tight, and you follow the procedure (do not over heat the flux), it should actually wick in. Once you start burning that flux (it has lots of organics if you look at the SDS), then you get soot and it basically turns off wicking. You gotta be gentle and thoughtful with the torch.

I think you should give it a try to make sure your solder consumption is as high as you think. The strength of the joint comes from the lap area, the 'fillet' IMO is brittle crap that gives a false sense of security.

 Again, I just COULD NOT get the braze to work like the solder does. I will say it a million times because I basically get heart palpitations thinking about doing an aluminum BRAZE job. When I got it to fill a clean hole by 65% that I felt good about putting a epoxy patch over it it felt like a miracle. I had the braze rods from the welding store that claimed to be prefluxed with some arabic styling on the text. I still have them and I basically know if I want to end the day pissed off at 2am to give it a try.

And for heat sinks, I think the high flow of aluminum solder will help you. The hard part will be good even regulated heating to prevent flux burning. Make sure the stuff is sand paper on glass flat before you solder to minimize the amount of solder you need. And it needs to be cleaned from oxides using a clean stainless steel wire brush before soldering and wiped with alcohol before fluxing.

[mag_therm]

Hi Copper, I am doing the classical single V or single U butt joints , both as shown in this welding link.
https://welditu.com/welding/tips/welding-joints-welds/
These joints are intended to be filled up with filler.
I don't have  a lack of flow, the stuff is like milk, so for example I can not  do a double V because the first one would run away when heating the second side.

The only Al brazed joints I can do are when the parts are nearly horizontal.

I know tig would be better than oxy acet for this Al, but for hobby use, I use the torch mainly for brazing steel eg  4130 bike frame sections with nickel bronze filler.
I used oxy acet for 40 years and no point changing now.

[coppercone2]

those joints are not good for brazing. You don't get strength doing it that way. Overlap not filler. Those kinds of joints are good for fill welding. Every joint suitable for brazing needs a high surface area of contact between flats. Double V is precisely the opposite of what you want in a braze job. For filling holes for repairs OK, but its not structural. And butt joint is acceptable only on large surface areas. Really you want to imagine you were going to rivet the parts together but use braze instead of rivets. So you fold metal over into to L shapes to make a box, not mate it with two thin flats. I.e. those corner joints (in MY picture) are going to be weak, you really should get a brake and bend it like you were gonna rivet. I.E. in the picture I linked, the dimensions need to scale. If you take two 1/8 inch metal plates and attempt to braze them perpendicular its gonna suck/be brittle. If you bend a 1/4 inch flat on one of the plates and braze it to a flat on the other plate, it will be strong. Same for soldering.

I.e. braze a angle piece to a plate and it will be OK. Butt joint two thin plates and its gonna be crap. Scarf joint is what you want for joining two thin flat bars *but its hard to grind it right*. Think of it like wood glue.




like this

[CatalinaWOW]

For those of us who don't weld or braze professionally (and thereby get the training and practice to achieve good joints consistently), the advice should be the same as is given for electrical wired joints.  There you are advised to make a mechanically sound joint, and then solder it.

Several of my reference books give the same advice for thin metal joints.  No butt joints or tee joints.  Lapped or rolled joints followed by solder, braze or welding if the application demands it.

[beanflying]

Straight butt joints for Aluminium brazing are a nono as there is no braze/weld penetration so you partially overcome that with v grooving. Even with Oxy/Acetylene and Bronze brazing into castings or thicker metals this is how it is done.

You cannot use a 'scarf' joint with Aluminium rods as they will not flow into a narrow close fitting slit it is nothing like wood glue you need to bevel the base metal on each side to increase your contact surface area.

As you can not groove thin sheet for a simple butt joint, brazing or soldering no method is any stronger than the contact area of the braze pool or the thickness of that pool. So this is not a place for this process if you need any sort of strength across that point. 99% Chances are any resultant joint will fracture the Aluminium Braze material if you breath on it to hard.

The Slip or grooved seam option below is what was taught for soft soldering sheetmetal way back in the day and is still valid for watertight roofing now as an example (silicone SUCKS). Providing you don't get cracking of the sheet at the sharp bends (use the correct grade will help) this will get you a really solid joint in Aluminium although cosmetically less desirable joint.

For Aluminium in particular Good technique and post braze normalization and PRACTICE is what is needed as much as Brand X or Y filler and 'magic' fluxes from obscure company B. Snake oil and misinformation is the one thing that is persistent in Aluminium Brazing consumables.

[coppercone2]

the Al solder should flow in a scarf joint, thats why I am impressed with it, compared to "mesh the cake in the joint Al braze"

and youtube video tests indicates that there are at least a few bad braze manufacturers out there that have specially poor wetting/flow. (not related to price 100%). If you really think your going nuts because the youtube guy seems like a absolute magician after 10 attempts try changing manufacturers.

I also notice the solder is actually flexible, the braze rods basically snap like dry pasta noodles

[beanflying]

A scarf joint is a zero clearance joint. Leaving a 'gap' between the two faces is not a scarf joint that is a badly prepared one. The correct preparation process is a V groove even with MIG and TIG that is how it is done and it is done for a reason.

There are instances where a 'scarf' joint can be done in metal like with silver soldering and more or less tinning one or both sides then remelting that meterial with flux but it won't work with Aluminium brazing.

How about instead of claiming 'magic' post a link to it?