Aluminium solder

I want some of that aluminium solder that melts at 400C and flows like Ersin Multicore onto 60/40 tinned copper. The one that bridges huge gaps and laughs at hammers trying to break it apart. We have all seen it on YouTube, you know what I mean.

I have tried 2 aluminium solders so far and they definitely do not do what they claim on the tin. Here we see a wire that should go at 392C still holding shape at 450C.

Am I missing some wrinkle?

Where do I get the good stuff?

I think a wrinkle is being missed! It's the difference between heat and temperature.

Your iron can do temperature (centigrade) , but not produce enough heat (watts).

Aluminium is an extremely good conductor of heat and wrapping a length of Ali wire around an electric soldering iron is probably removing heat faster than a small electric iron can supply it. In the same way, a coal fire burning 900°C hotter than the melting point of Copper doesn't melt a boiler full of water because the water absorbs the heat.

Try cutting 15mm of the solder off and holding it in an insulating wooden peg. The iron might have enough grunt to melt it. But I think you need a more powerful heat source such as a blowlamp, or an old-fashioned soldering iron - the type with a hefty copper tip that was heated on a kind of gas ring. The solder is probably OK.

Dave

Dave has it on all points ! Whether it melts at 400*c or 450*c or some other temperature is not the point - you need heat in volume ! An ordinary soldering iron is unlikely to work, you need a flame of a size big enough for the job. All the demos I have seen use a flame ! The Important thing with this type of soldering/welding is IF you can braze or weld this is a REAL handicap ! forget all you know and do JUST AS THE INSTRUCTIONS SAY ! I have had great success with this process, particularly on a part that I thought would be a waste of time, it was still sound when the machine was sold years later Good Luck, Noel..

I am supposed to melt it by touching it onto hot aluminium. That would entail a lot less contact than I have with this soldering iron. I do have a thermocouple tip tester somewhere but the chances of finding it when needed are low.

I started with the MAP-PLUS torch and it laughed at me. I lugged a tank of Calor gas back from the workshop with a Sievert torch attached but I still couldn't make it melt without showing it the flame when I got blobs. I could not get it to behave which is why I started playing with soldering irons.

I think I am going to try Durafix Easyweld from Oxford Welding Supplies. They seem to have a reputation they might want to preserve with a bit of quality control. I just wish they would tell me the diameter of their rod not just the length

I use Bernzomatic solder rods 370-400C which work brilliantly on alloy, use propane/butane mix usually, even done the hammer test when I broke up a joint, took a couple of hefty whacks with a lump hammer

Only problem is seems they might have stopped doing them, I can only find their higher temp welding ones , might be some about somewhere.

What's the name of the two solders, Robin, and what do they claim on the tin?

I have two kinds of aluminium solder, one low temperature one [Durafix], and one high temp. [580C].

They both work as expected. The second kind gives what appears to be a stronger bond, but more care is needed when soldering because the melting point of the parent metal is not much higher than that of the solder.

What's the corrosion resistance like on these solders? I have a couple of outboards that need repairing, could be an alternative to the mig and a roll of aluminium wire??

Chronos sell Durafix Easyweld and their page has a video with a chap showing how it's used. He uses a medium sized torch and heats the job until the end of a solder rod dabbed on it flows. The rod isn't heated directly, he shows it blobs if you do. As always, the expert makes it look easy, but I expect it needs practice.

Can you report back how Easyweld compares with what you've got? I doubt the existing stuff has a quality issue because there isn't much to go wrong with the rods. All they have to do is melt at the advertised temperature. There's no flux. But it's essential the torch be powerful enough to get the area around the weld hot enough.

Dave

Hi Bezzer, glorious repair, I want to play too

I do a lot of tin/lead soldering so I went straight for the 300degC aluminium solder then I went for anything at 400degC that didn't come from China.

I am trying to make a rectangular frame from extruded aluminium channel cut at 45 degrees. Nobody else seems to have any problem using this stuff but I think maybe they have teething troubles.

Reporting back as instructed.

Durafix EasyWeld performed as it did in the YouTube video. I am most pleased and just about to order more.

If you would like the pile of rods that did not work for me, (for further investigation), simply PM me a mailing address and they are yours

Robin

Robin, was the Durafix the only stuff that worked?

The only stuff that worked for me. Soldering 1/8" thick aluminium channel with Calor gas.

It did come with a handy wire brush and instructions for zinc-based metals, aluminium and boat propellers.

The aluminium instructions required additional brushing of a hot, "tinned" surface. Apparently, "filling the open pores".

The duff rod is going in the bin soon if nobody wants it.

Robin

When watching YouTube an advert came up with aluminium solder rods, you heated up the material being soldered took the flame of the job and the solder just flowed and made a nice fillet along two bits of aluminium approximately 6 inches long. I think I saved the advert on my computer.

Bob

I might, at this stage, remind myself that most failures I have had have been down to me, not the tools. I don’t generally blame the tools - unless they are sub-standard (usually because they were cheap, diy-er ‘use once and throw away’ chinese tools).

Perhaps Robin needs to partake in a bit of reflection? I bought a long length at the last Midlands Exhibition. Worked a treat, with a little practice - and I am likely going to buy some more shortly.

Too late for that, I already have a lifetime supply of the Durafix.

Life expectancy 86, so 20 rods should do it easy

I have repaired several items with those rods with complete success. I right now have a job to repair 2 riding mower, mower deck gearboxes. They have a 1 5/8" bearing adjusting nut with a hidden locking setscrew. No one including Me seems to find it and ham hands the bearing nut off. The ID of the bearing bore needs built up and rethreaded. Will have to be getting on with the job and will try to get pictures.

Hi Robin I’ll take the solder off your hands if that’s ok

MickyT

There used to be a guy at Rufforth autojumble who was doing live shows with the stuff.

I used it once on my Son's alloy sump off a Clio sport. It had spider web crack after he hit a brick in the road going down the M1. Very successful repair. It always said make sure you brush the area with the supplied wire brush. Which i suspect was stainless steel.

Steve.

Not all aluminium solder rods are the same as shown in this Youtube video demonstration (using American brand materials)

https://youtu.be/fKIKsDfRAcs

All wrapped up, will try and post it when I go to lunch.

Robin