Hi. I found a batch of 30 surplus TO3 berilium oxide insulators. According to Peter Daniel they are the best sounding insulators and the TO3 size is perfect for the LM3875 case.
I got 30 of them. Some of them have some small aerosol paint on them otherwise they seem never used. The paint comes easily by scratching with a knife.
I sale them 1U$ each. These insulators seem to be quite rare, so hurry...
Bye.
I got 30 of them. Some of them have some small aerosol paint on them otherwise they seem never used. The paint comes easily by scratching with a knife.
I sale them 1U$ each. These insulators seem to be quite rare, so hurry...
Bye.
Attachments
I don't think I want to "scrape" these insulators, the powder is very dangerious to your health.
see this thread:
http://www.diyaudio.com/forums/showthread.php?threadid=4306
see this thread:
http://www.diyaudio.com/forums/showthread.php?threadid=4306
No real danger
The one I tried, the paint came of easily. It didn't even scratch the surface of the insulator that seems like hard ceramic. The dust can be produced if you break or crush them.
Just to be cautious, wear gloves and do the job in a well ventilated place. I did mine over the garbage can outside. 😎
The one I tried, the paint came of easily. It didn't even scratch the surface of the insulator that seems like hard ceramic. The dust can be produced if you break or crush them.
Just to be cautious, wear gloves and do the job in a well ventilated place. I did mine over the garbage can outside. 😎
Toxicity: the link had no real info..here is some.
BeO:
4 percent of the human population is susceptible to berylliosis..
Berylliosis is a condition where the lining within the lung becomes inert to the transfer of oxygen.
It is because the atomic size of the outer shell of berillium is very close to that of potassium, and it replaces potassium within the lining of the air sacs of the lung, rendering the lining inert and non permeable to oxygen transfer.
People who suffer berylliosis are suffering a lack of oxygen getting into their bloodstream.
There are no known tests that can predict which humans are susceptible to this disease..Humans do not contract berylliosis by ingestion of the ceramic. It is only by the powder getting into the lungs....deep in the lungs..
Since there are no known tests to distinguish the at risk population, ALL are considered at risk.
For more information as to the toxicity of BeO, go to the Brush Wellman website. They are the world's largest producer of BeO product, and you can find answers to any questions you may wish there.
BEO also has thermal conductivity half that of copper, and equal to that of aluminum, with a TCE of about 5 ppm/degree C.
Cheers, John
BeO:
4 percent of the human population is susceptible to berylliosis..
Berylliosis is a condition where the lining within the lung becomes inert to the transfer of oxygen.
It is because the atomic size of the outer shell of berillium is very close to that of potassium, and it replaces potassium within the lining of the air sacs of the lung, rendering the lining inert and non permeable to oxygen transfer.
People who suffer berylliosis are suffering a lack of oxygen getting into their bloodstream.
There are no known tests that can predict which humans are susceptible to this disease..Humans do not contract berylliosis by ingestion of the ceramic. It is only by the powder getting into the lungs....deep in the lungs..
Since there are no known tests to distinguish the at risk population, ALL are considered at risk.
For more information as to the toxicity of BeO, go to the Brush Wellman website. They are the world's largest producer of BeO product, and you can find answers to any questions you may wish there.
BEO also has thermal conductivity half that of copper, and equal to that of aluminum, with a TCE of about 5 ppm/degree C.
Cheers, John
So actually the danger mostly exists for people involved in production of those pads and not for those using them, right?
Correct for the most part
The only danger is for anyone who breaths the dust from them. And, what comes out of the BeO mines is dust. It is fired to final form at Brush Wellman.
When shipped, they do not have any dust...the manu makes sure of that. And they typically make sure the packaging method does not abrade them. Even bulk boxes I think are ok for small parts..but don't go by me on that..
Do not sand, machine, abrade, or chemically attack any of them, and they are of no danger..Unless you drop a 50 lb case of them on your foot..
BTW...this also applies to beryllium copper. It is a very useful metal, very springy and strong and used in many contact applications..the surface oxide of be copper will contain BeO, so it is a material that should not be machined, brazed, or welded without precautions.
Any component with BeO internally must have a beo identifier on it..I think that using a razor to clear the surface of paint is ok...but, I'd do it under a water stream in the sink. (Note: I do not recommend that, even though I think BeO is harder than the blade, and will not cause dust).
Ask Brush those kind of questions..They are VERY responsive to questions...they have to be.
Cheers, John
The only danger is for anyone who breaths the dust from them. And, what comes out of the BeO mines is dust. It is fired to final form at Brush Wellman.
When shipped, they do not have any dust...the manu makes sure of that. And they typically make sure the packaging method does not abrade them. Even bulk boxes I think are ok for small parts..but don't go by me on that..
Do not sand, machine, abrade, or chemically attack any of them, and they are of no danger..Unless you drop a 50 lb case of them on your foot..
BTW...this also applies to beryllium copper. It is a very useful metal, very springy and strong and used in many contact applications..the surface oxide of be copper will contain BeO, so it is a material that should not be machined, brazed, or welded without precautions.
Any component with BeO internally must have a beo identifier on it..I think that using a razor to clear the surface of paint is ok...but, I'd do it under a water stream in the sink. (Note: I do not recommend that, even though I think BeO is harder than the blade, and will not cause dust).
Ask Brush those kind of questions..They are VERY responsive to questions...they have to be.
Cheers, John
Re: Correct for the most part
It should not be that hard to understand. Its a very dangerous material, and you really dont want any of it laying around. The reason why those BeO pads are rare, is that nobody wants them. Most people have by now figured that they are not a must (plenty of other solutions), and therefore quit using them.
Welding of Be-copper is only to be done in a socalled aquarium, where nothing gets in or out, besides the ventilation. Sanding is a nogo as well. Machining is ok as long as its done "wet", ie. with coolant. Toolmakers does that on everyday basis.
So all in all. Dispose those BeO pads at your nearest chemical disposal center, and use common modern insulators.
Magura
jneutron said:
It should not be that hard to understand. Its a very dangerous material, and you really dont want any of it laying around. The reason why those BeO pads are rare, is that nobody wants them. Most people have by now figured that they are not a must (plenty of other solutions), and therefore quit using them.
Welding of Be-copper is only to be done in a socalled aquarium, where nothing gets in or out, besides the ventilation. Sanding is a nogo as well. Machining is ok as long as its done "wet", ie. with coolant. Toolmakers does that on everyday basis.
So all in all. Dispose those BeO pads at your nearest chemical disposal center, and use common modern insulators.
Magura
As long as you use them correctly and don't break one.
But if I was a "Company doing business" though, I am then dealing with a posable Enviromentally unfrendly product - incorrect disposal of such an item might have heavy fines or other legal problems. Consult your local EPA or equilivent.
YMMV.
http://www.semiconductors.philips.com/profile/env/information/safety/
But if I was a "Company doing business" though, I am then dealing with a posable Enviromentally unfrendly product - incorrect disposal of such an item might have heavy fines or other legal problems. Consult your local EPA or equilivent.
YMMV.
http://www.semiconductors.philips.com/profile/env/information/safety/
iCebReakEr409 said:"Best sounding insulators"....sometimes I really wonder if this whole thing is for real.
Dont think more about that....yesterday i read that cotton sounds better than PTFE for wire isolation.
😀 😀 😀 😀 😀
Magura
Algar_emi said:
I think clarification is in order😉
I only compared them to Sil-pad type insulators and at the time of testing I preferred the BeO insulators.😉
Now, the question to Algar_emi: are you sure those are berylium and not aluminum oxide parts?
Probably Aluminium Oxide
My mistake. By reading back the Gain Clone thread, I thought these pads type were berilium oxide, but in fact they are Aluminium Oxide. Much less dangerous...
🙄
Bye...
My mistake. By reading back the Gain Clone thread, I thought these pads type were berilium oxide, but in fact they are Aluminium Oxide. Much less dangerous...
🙄
Bye...
Not to crap on the thread, but Mouser.com is now carrying the TO-247 Aluminum oxide insulator, if people are looking for them again:
4180 insulators at Mouser
1 $ 0.700
100 $ 0.630
500 $ 0.560
1000 $ 0.525
2000 $ 0.490
I bought the 4170 part, which also fits TO-247 devices fine:
4170 insulators at Mouser
1 $ 0.400
10 $ 0.350
100 $ 0.300
500 $ 0.250
Aavid's page
--
Brian
4180 insulators at Mouser
1 $ 0.700
100 $ 0.630
500 $ 0.560
1000 $ 0.525
2000 $ 0.490
I bought the 4170 part, which also fits TO-247 devices fine:
4170 insulators at Mouser
1 $ 0.400
10 $ 0.350
100 $ 0.300
500 $ 0.250
Aavid's page
--
Brian
Brian,
I don't understand how you can use a TO-220 part. According to Aaavid they are only 550 mils wide; I measure my IRF TO-247 to be 620 mils wide. 😕
I don't understand how you can use a TO-220 part. According to Aaavid they are only 550 mils wide; I measure my IRF TO-247 to be 620 mils wide. 😕
The main reason that the 4170 was used in both the cases was availability. I have been unable to find any larger pads for the past year, and Mouser is the first vendor that I have seen carry the 4180 part. I would consider using the 4180 pad for the larger TO-3P devices, but for the TO-247, I feel that the 4170 works just fine.
--
Brian
--
Brian
BrianGT said:
It works very well, it is only slightly smaller and I don't consider it to be any problem. I had similar pads being used in my Zen amp for over 10 years with case temp. of about 50 deg.
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