Potting in thermally insulating foam

At this point I thought you knew some osbscure detail about how raccoon fur is the perfect insulator.

Should be safe from the raccoon menace around here I think.

Nice, I guess it might be a size thing that makes fibreglass itchy.

George H.

I can ship you a bunch of cat hair. We have plenty.

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Yes, of course, cotton wool. Don't know why I am trying to make it complicated.

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You should consider milling out slots to thermally isolate the LTZ1000. One idea I've seen uses kind of a swastika design.

They're getting harder to find- last batch of highest accuracy ones had to come direct from LTC with a long lead time. 8-( Not cheap either.

Yes, thanks, I know about that, do a image search and you see lots of versions.

I am trying something else, put the device on a tiny board on the end of an FFC cable so it is embedded in polystyrene and isolated from thermal gradients.

That's where I get them from anyway, not cheap as you say. Lead time not particularly bad though.

By highest accuracy I assume you mean the "A" versions with an insulated die? They may be easier to control thermally but they ought to have worse ultimate accuracy because you end up having to run the chip 10 or

they are good for cleaning things, and removing adsive residue with the proper solvent. I use them with 5% distilled white vinegar to remove the dead skin around wounds.

I learned it from some construction workers on a jobsite as a teenager and never really cared how it work, just that it did. :) It may be that the thin film over the skin keeps you from getting microscopic cuts.

I use Scotchbrite for that!

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Two thoughts: 1) As John said, *anything* solid conducts better than air. The goal is to break up the convection currents with the minimum possible mass. Cotton, fiberglass, and foam are all thermal bridges. So, since it's a one-off, how about down?

My supplier shifted to sheared from routed boards on a recent shipment and I ended up with a fiberglass sliver stuck under a fingernail. We call that "quality fade". Have to specify everything with those guys..

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Hmm, now we are getting back to Spheros raccoon fur again :) You'll be making me skin kittens next!

Yes, doing that too to an extent (groundplane on one side of board). Still thinking about best arrangement.

It keeps the little b*ggers warm enough in the winter, so it's probably pretty good. I'd be happy to skin one for you, but the animal rights folks get snippy about how exactly they are dispatched. The hide can be tanned by spreading their brains on the inside.

I imagine one of your bigger heat flows is going to be the ribbon cable. Flex pcbs with narrow (like 4 mil) 1/2 oz copper traces are pretty good thermally.

A copper accessory could equalize pad temps: .--------------------. | | | .''''''.-. | | / O O \ \ | | . O O . . | | | | |

The flat sides of Styrofoam sheets glue together very well with Krazy Glue (cyanoacrylate), so you can build thermal shields like Lego.

Cheers

Phil Hobbs

Yes that's quite cool. It's along the lines of what I am already doing with the "thermal" groundplane, but more. That 30 oz copper thing you(?) posted would make the groundplane way better.

The spray-type expanding foam and the two-part stuff may have solvents that outgas and cause problems. Styrofoam (or any type of plastic foam) may cause a static problem. You might be able to use perlite or vermiculite from the gardening center. It's very inexpensive, and a fairly good insulator.

Sure. Just 2 oz (70um) copper vs. 1mm. Oh, I should mention the "accessory" covers the pad-tops, in case that wasn't clear.

Yep, t'was me. Dunno how much they want for it, but searches showed several pcb vendors offering "heavy copper".

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Chic kittens wear down. Birds too.