By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Aluminium solder

All Topics | Latest Posts

Search for:  in Thread Title in  
Robin29/07/2022 11:21:52
avatar
571 forum posts

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? wink

SillyOldDuffer29/07/2022 12:05:58
Moderator
8862 forum posts
1995 photos
Posted by Robin on 29/07/2022 11:21:52:

...

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?

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

noel shelley29/07/2022 12:54:46
1435 forum posts
23 photos

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..

Robin29/07/2022 18:21:17
avatar
571 forum posts

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 frown

Bezzer29/07/2022 18:33:47
170 forum posts
16 photos

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 face 1

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

thermo1.jpg

thermo6.jpg

thumbnail.jpeg

Bill Phinn29/07/2022 19:38:24
768 forum posts
114 photos
Posted by Robin on 29/07/2022 11:21:52:

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.

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.

Ebenezer Good29/07/2022 19:44:15
28 forum posts
2 photos

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??

SillyOldDuffer29/07/2022 20:17:09
Moderator
8862 forum posts
1995 photos
Posted by Robin on 29/07/2022 18:21:17:

I am supposed to melt it by touching it onto hot aluminium. ... 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 frown

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

Robin29/07/2022 21:13:03
avatar
571 forum posts

Hi Bezzer, glorious repair, I want to play too laugh

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.

Robin03/08/2022 17:13:50
avatar
571 forum posts
Posted by SillyOldDuffer on 29/07/2022 20:17:09:

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

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 smiley

Robin

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Support Our Partners
Dreweatts
Eccentric July 5 2018
Eccentric Engineering
cowells
Rapid RC
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

 

Donate

donate