Making a Sandwich

[Afterimage]

I'd like to make a sandwich but I am a rank amateur and unsure about what exactly I need. I was thinking along these lines:

- Cyan LuxIII emitter
- Badboy 400
- Connector and Bare Emitter board
- Arctic Alumina (to stick the emitter on?)

What about the goop that hardens between the boards? What's that? Am I missing anything? Is arctic alumina the stuff to use? I am going to mod the MM reflector so I don't need optics. That's the only part I really know how to do from experience.

Wayne should make some of these up; he has plenty of stock on the components. Then I'd happily wait.

 

[greenLED]

The goop that hardens is 2 ton epoxy. I use 3.5 tons 'cuz that's what I have available.

My first experience at building a sammie was "very educational", /ubbthreads/images/graemlins/jpshakehead.gif to say the least. I had all sorts of problems from poor soldering to a stuck Lux I had to deal with. I just went all the way into it without being prepared for it. Noob!! /ubbthreads/images/graemlins/blush.gif

You probably have more experience and have done your homework better than I did when I started, but here are some links where people helped me solve my problems (thanks everyone!). There are other threads out there, these just happen to be the ones I bookmarked.

I started here: the best visual guide I've found, by kj.
I built a little stand (not as fancy as the e-sink solutino) so that I could get the sammie height right. I'll try to post a pic, or PM me and I'll e-mail it to you.
checking my wiring, and potential shorts
what to do if you ever need to remove the lux
soldering tips
wiring diagrams
Wayne's webpage
badboy assembly questions
testing the board
I've thought of writing a "building a sammie for dummies" cheat-sheet but I've been too busy.

Oh, I forgot. There's a thread on The Shoppe's forum. Seems like Wayne plans to offer more finished products. I also remember reading that one of the serious modders was offering sammie-building services free of charge, but I forget who it was.

 

[Afterimage]

Great links! Thanks a lot. I might just hold on a bit to see what Wayne is cooking up.

 

[HgRyu]

I'm still confusing.
Do you use Arctic alumina(thermal compound) for goop ?
Or do you need another adhesive for goop such as "Arctic Alumina Adhesive (2 Part Epoxy)" or "DevCon 2 ton epoxy" ?
Thanks.

 

[Icarus]

Arctic Alumina Adhesive (2 Part Epoxy) is way too expensive to fill sandwiches.
You should use DevCon 2 ton epoxy mixed with some Alumina Oxide powder. /ubbthreads/images/graemlins/smile.gif

 

[greenLED]

I use "regular" 2-part epoxy for my sammies. The one I had available was a no-name brand 3.5 ton type. I think people use artic alumina when building drop-in modules (as for the Pelican M6, etc.)

Icarus, what does the alumina oxide powder add to the properties of the epooxy?

Afterimage, no prob; glad I could help.

 

[ErickThakrar]

The aluminum oxide powder adds a certain measure of thermal conductivity to the epoxy that is otherwise not present. In other words, your components that are potted with this stuff, has a much better chance of staying cool.

 

[Icarus]

Right, just like ErickThakrar explained. Thanks for answering this question in my place. /ubbthreads/images/graemlins/thumbsup.gif

 

[FNinjaP90]

So how well does 6061 conduct heat compared to Arctic Alumina Epoxy and Aluminum Oxide powder mixed with normal epoxy?

Are there any other Arctic thermal conductive products that stick two things together? Maybe not as stong a hold and not as expensive as Arctic Alumina Epoxy but still prevents stuff from sliding aorund?

 

[ErickThakrar]

Well, really you can make your own thermally conductive epoxy by simply mixing aluminum oxide powder with 2-ton epoxy. Play around with the ratio of mixing until you get the consistency you want and the hold you want. Probably 50/50 or 60/40 aluminum oxide/epoxy. I found a little bottle of aluminum oxide powder for about 8 bucks. Enough powder for several sandwiches from what I can tell.
The thermal conductance isn't gonna be anywhere near as good as straight aluminum. For any thermal compound. Stuff like the Arctic products are generally designed to provide a better mechanical contact between two mating surfaces by filling the miniscule valleys in the surface of the two mating surfaces. They are in other words designed to work in some very thin layers. But, never the less, when potting components with a thermally conductive, electrically non-conductive medium, you still get a far better thermal transfer than you would with regular, un-loaded epoxy.

 

[Billson]

Does aluminum oxide powder have any electrical conductivity? Will this thermal conductivity add to the elctrical conductivity? Is there a risk of shorting out the sandwich?

 

[ErickThakrar]

Nope. None at all. Aluminum oxide is essentially what's in Arctic Alumina. It has ZERO electrical conductivity. It's not a metal, it's a ceramic.