Archived from groups: alt.comp.hardware,alt.comp.hardware.homebuilt,alt.comp.hardware.pc-homebuilt (More info?)
*Vanguard* wrote:
> "~misfit~" said in news:GIgkc.53$r17.21471@news.xtra.co.nz:
>
>>*Vanguard* wrote:
>>
>>>"~misfit~" said in news:jKKjc.1284$g52.60117@news.xtra.co.nz:
>>>
>>>>JT wrote:
>>>
>>><snip>
>>>
>>>>I have a mate who's into electronics and I remember him using
>>>>"thermal transfer compound" on some of the transistors/heatsinks on
>>>>his home-made power amplifiers 20+ years ago. I don't kmow what it
>>>>was made of but I do remember him telling me it was really toxic.
>>>>Zinc oxide? That seems to ring a (faint) bell.
>>>
>>>Zinc oxide is used as a filler in some low-grade thermal pastes. It
>>>is not toxic. Zinc oxide is that water insoluable white stuff you
>>>see painted on folks' noses to keep from getting sunburned.
>>>
>>>"Zinc oxide is ideal for the nose and ears while swimming"
>>>(http://www.healthcentral.com/mhc/top/001869.cfm).
>>>
>>>I don't remember reading any warnings about not touching the stuff.
>>>In fact, it usually needs to be reminded to users to NOT use their
>>>fingers to spread around the paste because of the oil on their
>>>fingers. However, I doubt any of the stuff is suitable for
>>>consumption (but touching it is okay).
>>>
>>>Maybe your friend was talking about a thermal adhesive because those
>>>do use solvents that are toxic (but not in the dosage to which you
>>>would be exposed for one heat sink, but maybe if you were on an
>>>assembly line). I mean, hell, SuperGlue is toxic but I don't see
>>>folks keeling over that accidentally got their fingers glued
>>>together. Acetone is toxic yet I occasionally dampen a paper towel
>>>with it to remove some glue, residue, or such, and my fingers are
>>>touching that Acetone wetted paper towel. Grain alcohol is toxic, but
>>>are you going to give up your beer? If so, I'll take it.
>>
>>I'm thinking now it was beryllium oxide.
>
>
> While beryllium is toxic
> (http://physchem.ox.ac.uk/MSDS/BE/beryllium.html), it looks to be so
> when inhaled and not through the skin. It is probably toxic if
> ingested, too. Hey, maybe we could send some to the idiot that sued
> Sears because the lawn mower he bought from them didn't say it couldn't
> be hoisted up and used as a hedge trimmer. As long as it doesn't say
> that it couldn't be used for toothpaste, maybe we could get this idiot
> listed in the next Darwin Awards (http://www.darwinawards.com/). Ah,
> damn, looks like it's not toxic when ingested
> (http://www.espimetals.com/msds's/berylliumoxide.pdf). That article
> also says it is not toxic through the skin even on an abrasion. It is
> toxic for chronic exposure, like if your job was as an assembler that
> applies it everyday for voltage regulators or high-power transistors.
>
> Keep trying. Maybe there's a paste with a cyano compound in it. ;-)
>
Aside from its not being toxic, I don't think finely divided beryllium
oxide in a silicone like carrier would make a good heat conducting
paste. The main advantage of solid beryllium oxide is that it's a good
electrical insulator while being a good heat transfer medium. It is
very difficult to machine, and the dust is toxic when inhaled. As has
been mentioned, diamond is also a good electrical insulator while having
excellent heat transfer properties. Unfortumately it has to be in
crystaline form and costs accordingly.
Virg Wall
--
It is vain to do with more
what can be done with fewer.
William of Occam.
*Vanguard* wrote:
> "~misfit~" said in news:GIgkc.53$r17.21471@news.xtra.co.nz:
>
>>*Vanguard* wrote:
>>
>>>"~misfit~" said in news:jKKjc.1284$g52.60117@news.xtra.co.nz:
>>>
>>>>JT wrote:
>>>
>>><snip>
>>>
>>>>I have a mate who's into electronics and I remember him using
>>>>"thermal transfer compound" on some of the transistors/heatsinks on
>>>>his home-made power amplifiers 20+ years ago. I don't kmow what it
>>>>was made of but I do remember him telling me it was really toxic.
>>>>Zinc oxide? That seems to ring a (faint) bell.
>>>
>>>Zinc oxide is used as a filler in some low-grade thermal pastes. It
>>>is not toxic. Zinc oxide is that water insoluable white stuff you
>>>see painted on folks' noses to keep from getting sunburned.
>>>
>>>"Zinc oxide is ideal for the nose and ears while swimming"
>>>(http://www.healthcentral.com/mhc/top/001869.cfm).
>>>
>>>I don't remember reading any warnings about not touching the stuff.
>>>In fact, it usually needs to be reminded to users to NOT use their
>>>fingers to spread around the paste because of the oil on their
>>>fingers. However, I doubt any of the stuff is suitable for
>>>consumption (but touching it is okay).
>>>
>>>Maybe your friend was talking about a thermal adhesive because those
>>>do use solvents that are toxic (but not in the dosage to which you
>>>would be exposed for one heat sink, but maybe if you were on an
>>>assembly line). I mean, hell, SuperGlue is toxic but I don't see
>>>folks keeling over that accidentally got their fingers glued
>>>together. Acetone is toxic yet I occasionally dampen a paper towel
>>>with it to remove some glue, residue, or such, and my fingers are
>>>touching that Acetone wetted paper towel. Grain alcohol is toxic, but
>>>are you going to give up your beer? If so, I'll take it.
>>
>>I'm thinking now it was beryllium oxide.
>
>
> While beryllium is toxic
> (http://physchem.ox.ac.uk/MSDS/BE/beryllium.html), it looks to be so
> when inhaled and not through the skin. It is probably toxic if
> ingested, too. Hey, maybe we could send some to the idiot that sued
> Sears because the lawn mower he bought from them didn't say it couldn't
> be hoisted up and used as a hedge trimmer. As long as it doesn't say
> that it couldn't be used for toothpaste, maybe we could get this idiot
> listed in the next Darwin Awards (http://www.darwinawards.com/). Ah,
> damn, looks like it's not toxic when ingested
> (http://www.espimetals.com/msds's/berylliumoxide.pdf). That article
> also says it is not toxic through the skin even on an abrasion. It is
> toxic for chronic exposure, like if your job was as an assembler that
> applies it everyday for voltage regulators or high-power transistors.
>
> Keep trying. Maybe there's a paste with a cyano compound in it. ;-)
>
Aside from its not being toxic, I don't think finely divided beryllium
oxide in a silicone like carrier would make a good heat conducting
paste. The main advantage of solid beryllium oxide is that it's a good
electrical insulator while being a good heat transfer medium. It is
very difficult to machine, and the dust is toxic when inhaled. As has
been mentioned, diamond is also a good electrical insulator while having
excellent heat transfer properties. Unfortumately it has to be in
crystaline form and costs accordingly.
Virg Wall
--
It is vain to do with more
what can be done with fewer.
William of Occam.
Facebook
Twitter
Instagram