Heatsinking 1 Watt LED

I have this LED G18580 -
I am running it at .4 watts and it produces some heat. On the back is a circular metal plate. How can I attach a heat sink to it?

Its designed to surface-mount solder to aluminium-cored circuit board. It can be screwed down to an
metal heatsink using soft washers around the edge to pin it down, then solder wires to the leads. I've
made a torch from a similar emitter before, and I happened to have some nice soft silicone rubber
washers at the time.

There is a trick I use to solder down DPAK (smt) voltage regulators. They are designed
to use pcb copper fill areas, eg 1/2" x 1/2", for heatsinking.

On my pcbs, besides the usual copper area, I add a good-sized pad (about 80 mil i.d.)
under the DPAK layout, and use it to flow solder underneath the part during mounting.
Then, I fill in the pad with a nice blob of solder. I figure the solder blob is more effective
than the copper fill areas.

I was just playing around tonight trying to attach a LED bead like yours to an aluminum bar using "alumaloy" to tin the surface. Alumaloy (AKA "Durafix") was a popular product back in the late 80s for welding (not the right word) aluminum together using just a propane torch. I bought a 1/4 lb pack off eBay for under $10 and that included shipping.

It seems to work OK -- I got it one to stick on plenty tight enough -- but still need to do more testing. It appears to be specific to leaded solder (or pure lead) and rosin flux. I tried plumbing solder and flux and it didn't seem to want to stick. Need to scratch some rosin off my spruce tree tomorrow and fiddle with it some more.

As an aside you can buy 1W and 3W LED beads at sureelectronics.net for much, much less than at Electronic Goldmine.

When mounting the aluminum "star" led heatsink base I use nylon shoulder washers like the ones used with TO-220 transistor mounting. This way you dont short the solder pads to the heatsink.