Aluminum soldering fluxes: The Way It's Meant to be Soldered :D

Hi!

Thanks for the answers. This may be of interest for modders, looking to start a “solder the plate to the pill” craze. LOL!

Ended up ordering F61A (Ф61А) OEM.

Then seller merchant12 sent me this inquiry hours ago:

Hello! Before sending, I want to ask you. You have read the description completely? This soldering flux only works with zinc solders ( zinc-tin, zinc-cadmium). This soldering flux does not work with conventional tin-lead solders group. Are you sure of your choice? Best Regards!

I've explained him that I had read a couple of positive reports (I linked him) using conventional solders and that the required joint tensile strenght was negligible, that it was about maximizing heat transfer; just in case he said that because of this. Sent him this thread's link too.

Well, we'll see how it goes.

Peace & love, and cheers. ^:)

Well, that looks like you’ve got a conscientious seller, which is rare on eBay. You ought to give him any business that you can. :+1:

Latest update!

Received message from merchant12 at 17:08:

I understood you. And you need this soldering flux:

http://www.ebay.com/itm/282119668291
http://www.ebay.com/itm/282119668287
These will work with a conventional solder (tin-lead).

Solder flux that you bought only works with zinc solders. The name is similar, but it's a different manufacturer. In the description given - only zinc solders.
I can replace you for that you need. Let me know as soon as possible.
Best Regards!

Just replied this:

Hello!
0K so, as I somewhat suspected because of your inquiry, the F61A formulation I bought is different to the one which is reviewed in the eevblog.com forum…
Thanks for dispensing me such advice. Send me, then, the F61A formulation from Tehnohim (or the FTKA in case it could make joining big surfaces easier). Your advice is appreciated, no need for reimbursements in any case. :-)
Thanks a lot.

Best regards,
Salvador

Well, so far, a big :THUMBS-UP: thumbs up for merchant12!!!

Cheers ^:)

Did he say which of those two that he linked would work best for solder drivers to pills?

All listed things wont work as you think.
This fluxes was produced for electric purpuses (when alu and cu core wires need to be contacted and soldering is the only available method). There should be lots of videos on youtube if you enter their name in russian (Ф61А). First alu part should be pre-heated, when it achives 300C you need to scratch it fast with metall brush and tinn it with proper solder applying this flux. After this it tinned part should be able to solder as any other copper wire.
In fact Im not sure this method will work for big parts and surfaces. The only 100% workable alu solder is HS-* rods but using them require much more heat and enormous temperatures (500C or more).
P.S. To much russian-made items on blf. How do you find them?

No further replies I've received so, until then…

kiriba-ru, probably I should have said “provide better wetting ability” instead of “make joining big surfaces easier”.

In the opening post links they succesfully wet the aluminum with both fluxes without the need to scratch the surfaces. That's the main reason I am getting this stuff.

My plan is to put flux over the contact surfaces of each aluminum piece; maybe even pre-apply solder wire over it. Then use a blowtorch/hot plate to heat up the piece and, once the thing is hot, apply solder all over the desired place. This way I'll pre-wet all the surfaces which will make contact. At that point I won't be able to fit the pieces together (it's tight enough already without filling) but, as I heat one inside of the other, the solder on the piece receiving the heat directly will melt and this should provoke the melting of the in-contact solder over the other part. I'll have a good stick to push the stuff down at hand.

The solder pre-wetted alu pill should stick well to a clean and pre-soaked in alcohol/colophony underside of a copper baseplate.

Well, hope it works as I expect.

By the way, in the soldering-to-aluminum eevblog.com referenced thread someone comments this stuff is from… Bulgaria?

Cheers ^:)

Hello!

Just stumbled on this link I left on my bookmark list the other day: FLUX @ Radiofun.ru

Penultimate paragraph's translated quote:

The easiest way to use special fluxing F61A - flux for soldering aluminum. Highly active flux based fluoroborates, for tinning and soldering parts and surfaces of aluminum and its alloys. Pike made of tin-lead solders Group with a tin content of more than 60% (and the best solder pure tin) at a temperature of 250-350 degrees.

Interesting…

I have a roll of cheap SnCu (I think) solder, no idea about the composition, probably Sn99'3/Cu0'7. The tin pest stuff creeps me a bit, though.

Cheers ^:)

Are you not concerned about that eevblog reaction?
I’m no chemist but it sounds like really dangerous stuff…

I once had a flashlight with an aluminum pill that I was able to get solder to stick to it by first putting a bit of motor oil on the pill and then heating the oil with a soldering iron (while moving the tip) until it started to smoke and dry up. The solder stuck well enough to the pill and driver that I couldn’t move the driver while pulling on the spring by hand.

I gave the light away several years ago but as far as I know it’s still working.

No worries The Miller, before I ended my elementary education my brother had already taught me how to etch basic one layer PCBs using a combination of muriatic acid plus 33% (yes, 33%) hydrogen peroxide… :FACEPALM: We were drewing the layouts by hand with an Edding 3000 permanent marker; the thing worked quite nicely, LOL!

I have a few breathing masks somewhere, you can rest easy my dear.

Cheers ^:)

Well just keep on posting OK?
:wink:

Take a look at this pic, SIGShooter:

I'll have to trim off the inner heatsink an additional ≈7mm, or else the driver won't fit.

Anyway, this is going to be, at the very least, 150+mm² of contact surface, and no oil will stay over the aluminum while I vigorously file the alumina off all those surfaces, to start with. Ф61А, come home…

Cheers ^:)

Wow, this is getting more interesting by the moment! :partying_face:

The Biblical Magi committee arrived home today:

Drumroll!

Cheers ^:)

This stuff for al-al, al-cu, al-brass soldering. Solder paste. Same company I get Fuze Clean FS from. Not cheap but if you insist on soldering it might be the right stuff.

As is this stuff

I have some but haven’t had a chance to try it out

Da-da Da-da Da-da Da-da Da-da…

Barkuti, if you survive this… tell us how it goes!

You were reading my thoughts David. :stuck_out_tongue:

Well fellows, been doing some tests with the fluxes. I've been able to wet aluminium foil with it, that was the easy part. However, my trials over my aluminium test heatsink and over an old 16mm 7090 MCPCB have mostly been unsuccesful. The main problem is that once you make the solder stick on the alu surface (usually just a little bit), you better stop messing with the stuff because the slightest movement uncovers the surface and it insta-oxidizes. I've also tried applying solder with my iron's hot tip over the carefully pre-heated surfaces, without much success because I've had a hard time monitoring the stuff's temp (too much and the flux degrades), and of course because it's been a real mess avoiding the un-sticking of solder from the surfaces. :FACEPALM:

For my initial test I thought the flux would allow me to wet the heatsink by pre-applying a slight layer of the things; it failed, so I applied a lot more for a second test, which ended up with both FTKA and F61A mixed, in fumes & flames (a blowtorch was the heat source):

Up: FTKA; down: F61A. Solder used: mixture of Sn99'3/Cu0'7 (61%) and Sn63/Pb37 (39%).

I am seriously considering the preparation of a special soldering flux with these oily compounds. I just need to figure out how to make some finely grained solder powder. Maybe I could try on my electric coffee grinder…

Cheers ^:)

Try heating from underneath instead of direct flame, some fluxes are flammable and require indirect heat. Also. Wet sand the area using the flux as lubricant. This will clean the metal while preventing O2 contamination.