Soldering Aluminium Sheet 3mm Thick

[flippineck]

Soldering Aluminium Sheet 3mm Thick

Grade/Spec: 1050A H14 - a commercial purity alloy giving excellent corrosion resistance. It is Ideal for welding, bending and moulding. It is also suitable for painting.

I have a sheet of this aluminium sheet, roughly 50cm x 40cm

I want to try soldering one of these LEDs http://www.ebay.co.uk/itm/161109303192 to it, hopefully via 4 small dots of solder one dot in each corner.. after putting a little heatsink compound behind the LED

I understand a pre-clean with stainless steel wire wool, and the use of a fairly harsh acidic flux may be neccessary along with a very specific grade of solder.. but most sites talk also about preheating the aluminium with a gas torch.. I'm a little worried about damaging the LED with too much heat.

Could a fairly decent high power electric iron with moderate preheating of the aluminium do the job? I guess pre-tinning of the aluminium sheet at the 4 target points too?

The safe alternative would be to drill and tap the aluminium sheet and affix the LED with small screws, but this would spoil the appearance of the reverse side of the sheet and that's something I'm trying to avoid.

Alternatively, anybody have any good ideas for securely affixing one of these LEDs to the aluminium sheet, ensuring good heat transfer, without the use of solder? Does something like a good double sided sticky back heat conductive heatsink tape exist?

I saw for instance http://www.ebay.co.uk/itm/350933892948 which looks great but, firstly I don't know how sticky its would be or how long lived, and secondly the listing does hedge it's bets a bit saying that if you used it for a CPU, you'd fry it. So I don't know how good it'd actually be, had no experience of it.

They talk about "thermal epoxy"? http://www.ebay.co.uk/itm/271180279856 ?

The whole shebang is going to become a lid for a fishtank.

That's it, finished editing.. sorry about all the changes if you were reading whilst I was half answering my own question. Advice from the experienced still very much sought & appreciated.

 

[Six_Shooter]

I haven't tried soldering anything to aluminium, but I have welded quite a bit of it.

Yes, having extremely clean surface that will be welded is of paramount importance. The oxidation that builds up and causes issues happens almost immediately, so it's important to weld it just after it's cleaned, otherwise you will need to clean it again, in most cases. I would imagine the same would be true trying to solder something to aluminium. I'm going to have try this myself.

If it was mine, I would use small screws and then place another full sheet of aluminium or other material over the back to have a nice look. With the LEDs screwed into place it make replacement, if it's ever need much easier and quicker. Also makes adjusting the position of the LED easier or just the removal of some, if there turns out to be too many to start off.

You do have me intrigued though into trying this at some point, soldering another metal to an aluminium sheet.

 

[flippineck]

This guy makes a nice job of it but, he's using more of an open flame than I'd be comfy with

Shows it's possible though

bit more info

http://www.superiorflux.com/aluminum_soldering_flux.html
http://www.superiorflux.com/aluminum_flux_cored_wire.html

I'm kinda intrigued about the arctic silver epoxy. Would that stick well to the ally?

 

[jpanhalt]

Look at the specifications for the LED. Do you think you or anyone can do it manually in 3 seconds at 260°C?

You can affix the thing to an aluminum heat sink any common way. Then solder copper buss strips to the connections. One of the connections could probably be screwed to the aluminum. I have used Loctite heat-conductive, electrically insulative epoxy with high power mosfets (1500W total at 12V). It works well. But, a 100 W-LED might be a different story.

John