Safety question about the beryllium oxide thermal compound

[kitendo1999]

Hey,

I was working on my beomaster 5000, Beovision Mx4000 and beovision lx4500 a few weeks ago, but lefted them asside for a few weeks  because they made me a bit scared. I became sceptic about the thermal pastes those were present in these devices and was wondering if someone could give me an answer on the following question.
I found out there was a beryllium oxide cooling paste in the past, but I read mixed answers about it. Aluminium oxide paste is introduced in the beginning of the 90s, beryllium oxide is used before the 80s, but then it was still present in a apple IIgs from the 80s,...And now I’m wondering if they really used the beryllium paste in de B&O devices? I already separated a transistor from the cooling element of the beovision Lx4500, without any mask/gloves. Also the transparant capacitor cover in the beomaster 5000 scraped a bit of the thermal paste off, which I couldn’t avoid :/.

 

Thanks in advance,
Kilian

[Roehrenonkel]

Hi kitendo1999,
 
welcome to the forum.

Only the inhalation (of dust) or eating this stuff is dangerous.

Good luck with the repair

[Phil1977]

Unfortunately the spectral resolution of your used camera doesn't allow remote analysis 

But: Don't panic! If you have a clear indication that there is beryllium oxide in the paste, then do anything reasonable to avoid inhaling it. That means, wear a dust mask while working, use wet wipes to remove residues, do not touch your face while working with it.

If it´s just old and there is no evidence for toxic content: Then anyhow avoid inhaling anything.

Beryllium is nasty, but remember: There were thousands of people working each day with this stuff, and many of them got ill. The chances of being harmed by one time exposure are not zero, but probably not much worse than common risks of life.

[Gyro]

Are you sure that's a reliable information source.

I've been using thermal compound for much longer than that and have never come across Beryllium Oxide compound. I suppose I can't rule out very specialized applications where absolute thermal resistance was critical, but it would never find an application in the sort of consumer stuff shown in your photos, the dissipation is too low and the heatsink too small for such a thing to make any thermal difference. The poisonous effects of Beryllium compounds have long been known, it would massively affect a consumer production line. High cost would be another factor.

It would be interesting to know the source.

[Karel]

I only remember that beryllium oxide was used in semiconductors e.g. RF power transistors like BLW96.
In the datasheet (Philips) was written:

PRODUCT SAFETY This device incorporates beryllium oxide, the dust of which is toxic. The device is entirely safe provided that the BeO disc is not damaged.

[Doctorandus_P]

Do not eat electronics.
It's not good for your health.

[squadchannel]

I have never heard of beryllium oxide in compound.
known to be found in TO-3 in powder form. (Rare, though.)

[tszaboo]

Hi kitendo1999,
 
welcome to the forum.

Only the inhalation (of dust) or eating this stuff is dangerous.

Good luck with the repair

Also don't wipe it into your eyes.
Or any other holes, really.

[Zero999]

Hi kitendo1999,
 
welcome to the forum.

Only the inhalation (of dust) or eating this stuff is dangerous.

Good luck with the repair

Also don't wipe it into your eyes.
Or any other holes, really.

In other words, abide by the normal, common sense, work hygiene practises i.e. don't eat or drink whilst working with it and wash your hands thoroughly afterwards and you'll be fine.

[kitendo1999]

Hey,

Thanks for the fast reply's and welcoming! First of all I was not planning to eat it :p, even it looks very delicious...

My apologies for the bad quality pictures, I'm afraid It wasn't my camera but me who was shaking ;p.

I couldn't find any warnings about the use of it neither in the service manual, but indeed from now on I will play safe handling the devices. Normally I'm very careful with these kind of things, with washing my hands a lot and indeed not eating/ drinking, so hopefully that kept me in some kind of way safe.

I find it strange if they used it in these kind of devices. Btw, on the pictures you can see the hor. deflection transistor of the beovision crt. But the cooling element is bigger than the picture shows. It's a metal plate that has a width more than 40cm and height from around 20cm and there are several transistors attached to it (others with mica). Sorry, the pictures weren't that clear and doesn't show it completely.

Indeed semiconductors sounds more logical, but there is also not a big amount of information about the thermal paste, so maybe it's even a rumor?


I really appreciate all the answers!
Kind regards,
Kilian

[amyk]

BeO is toxic enough that even decades ago when safety was nowhere near the paranoia level it is today, products containing it had ample warnings.

A moderator here claims to have some actual BeO thermal compound: https://www.eevblog.com/forum/chat/beryllium-oxide-heat-sink-compound/

Then again, these days I see claims of Chinese audio equipment containing beryllium-coated speakers

[coppercone2]

berynium oxide may be found in a limited number of S.W.O.R.D variety #1's on Sirius 6B

[Conrad Hoffman]

I don't know if BeO paste was ever common, though I suspect not. The thermal paste/grease is a red herring. They're all terrible in absolute terms compared to something like aluminum. It's all about the flatness and gap between the parts and using as little paste as possible in the thinnest possible layer. If you want something good, look into the phase change materials. They're basically a wax loaded with some common conductive particles. When they heat up they go liquid and the gap can get as small as possible. Now, if your surfaces aren't flat, all bets are off. Extruded heat sinks should usually be finish machined in the mounting areas to get them flat.

[CatalinaWOW]

BeO is a dangerous material.  But put it in perspective.  You are very unlikely to get sick from being in the same room with it.  I worked near a Brush plant that ended up closing because of inadequate control of beryllium products.  Some people who worked there for years got sick.  Others didn't.  Some of the ones who didn't were in daily contact.  Others who did were office workers with unknown source of exposure.  People working side be side had different outcomes.  The sensitivity varies from individual to individual for unknown reasons.

So for it to be a problem for you, you need to be on the wrong end of several low probability occurrences.  Direct contact, inhalation or ingestion of dust out of the paste.  Sensitivity to the material.  On top of the chances that the material is actually BeO.  The color could come from several things.

Bottom line, be careful but don't panic.

[kitendo1999]

I was also thinking, if there were indeed already warnings back then. Why would they use it in a paste that could dry out (almost powdery in worst case scenario's). But then I saw that post about the claim and the one of the apple II gs.

https://forum.vcfed.org/index.php?threads/how-toxic-is-old-thermal-paste-beryllium-oxide.1245809/

Others claim that it is only used in high tech and Military tech so probably that tells us, it won't be that common.

https://highvoltageforum.net/index.php?topic=1372.0
https://audiokarma.org/forums/index.php?threads/which-thermal-paste-heat-sink-compound.760692/page-2

Also bizarre to use it for speakers, ofc you'll have to do a lot of effort to break it accidently...

Ohno sounds terrible what happened there :/ Yes I will, I'm gonna get me a few ffp3 masks to be sure and to calm down my mind.

Thanks again for the answers, they have certainly calmed me down a bit. I really appreciate it.

[Psi]

Always be mindful of any body reaction you get to things. Sometimes your body will 'warn' you about exposure to things.

I'm not saying to 'expect' your body to warn you, clearly that would be stupid, but if you start to feel odd, get a headache or anything out the ordinary occurs when working with something new, or even just handling it, be mindful that it might be your body telling you something is very wrong.

I once touched some old metal can transistors that I found in an old box and got a quite strong headache come on strong and out of no where within 5min. I don't know what it was, but to this day I'm sure there was some toxic chemical on those transistors.

[radiolistener]

I once touched some old metal can transistors that I found in an old box and got a quite strong headache come on strong and out of no where within 5min. I don't know what it was, but to this day I'm sure there was some toxic chemical on those transistors.

Acute Radiation Syndrome?

After the nuclear plant accident, there was a lot of contaminated equipment and electronics that were buried in the exclusion zone. However, over time, they were stolen and sold at flea markets and online platforms. Such components can be heavily contaminated with dangerous radioisotopes and induced radiation. I recommend checking such purchases with a dosimeter.

[Alex Eisenhut]

I once touched some old metal can transistors that I found in an old box and got a quite strong headache come on strong and out of no where within 5min. I don't know what it was, but to this day I'm sure there was some toxic chemical on those transistors.

I'd think mold in the box is more likely.

[Psi]

It could have been anything. I kind of figured it was probably arsenic, but yeah, i dunno.

[coppercone2]

your skin is rather non absorbent on your finger tips, the only two likely routes for your headache is that it was present as a ultra fine powder (corrosion) that got airborne when you opened a box and inhaled it, or you licked your fingers that picked up a poisonous compound.

Nothing dry will migrate into your blood from dermal contact unless its on a special carrier in ion (dissolved) form, usually its some kind of oil (special formulation)

Apart from the possibility of a allergic reaction. I don't know much about this.


I suspect you inhaled old card board or whatever the container was made from that disintegrated. I always make it a habit in a lab to pay premium to get rid of card board boxes because their messy, if you ever worked near a clean room requirement you will learn to prosecute boxes aggressively.

and a cost of maintence is IMO to replace foam every... decade or so, before it goes bad. Buy a big sheet on digikey and re-line your stuff

[Zero999]

It could have been anything. I kind of figured it was probably arsenic, but yeah, i dunno.

Or just a coincidence? Perhaps you were tired, stressed or a bit dehydrated that day?