silpad or mica for to247 in F1

eyoung · 29th November 2010, 02:41 AM

I can't resist starting this debate over, however I am looking for firsthand experience . I am looking for insite to use mica/silpad and with which goop for insulating my To247 trannies to my heatsinks...all my old amps have mica, but I thought I might progress into the next century since I am already 10 years into it...

Regards,El

Gyuri · 29th November 2010, 06:59 AM

You know my kind friend, there are things, which for the centuries do not hurt.
So I think MICA.

Gyuri

eyoung · 30th November 2010, 01:11 AM

Gyuri my dear friend thanks for your input, I am feeling the same way however a source for mica to247 is hard to come by in my small neighborhood,,,
If any one has a source for mica insulators TO247 Please let me know.. it never occurred to me to ask our friends at tech-diy whence came my silicon iritations.

Regards, Elwood

jupiterjune · 1st December 2010, 01:35 AM

If any one has a source for mica insulators TO247 Please let me know..

Elwood--

I am hopeful that the sheets of mica sold by McMaster Carr are the right type for this service.

Part number 8802K16 is a 3x5 sheet of muscovite mica, .004 thick, for a measly $2.17.

I have a roll of thermally conductive kapton film that I will be trying first, though, obtained from the same supplier.

JJ

PierreQuiRoule · 1st December 2010, 01:41 AM

The sheet of Mica you are referring to works fine. Just cut a piece the size you need and off you go.

If you want to go crazy and reduce the thermal resistance further, with an xacto knife you can actually "slice" the sheet of mica into thinner sheets. It is easier to do than it sounds.

Pierre

Andrew Eckhardt · 01:47 AM

For class A amplfiers it's not such a big deal to have the extra thermal resistance of a silpad so long as you hit your particular desired junction (channel) temp after warmup... because there's not much dynamic about dissipation.. Far as cycling, you know, are you going to turn the thing on and off 500,000 times, or not? Not. A little rubber just means a bit more sink and you're good to go.

budwiser · 1st December 2010, 02:56 AM

looking thru my spare parts container I think I found some mica pads. What are the characteristics I should be looking for. Kind of light yellow in color. I was able to get the edge to flake.

AndrewT · 1st December 2010, 10:47 AM

mica comes in a wide range of thicknesses. The thinner, the less the thermal resistance.
"silpads" and similar come in an even wider range of thermal resistances. Choose a thermal resistance that suits your $ and your device temperature.

There are very few "silpad" types that can better a 2thou (= 2mil = 0.002inch) thick mica for thermal resistance.

PierreQuiRoule · 1st December 2010, 10:59 PM

Quote:

Originally Posted by budwiser

looking thru my spare parts container I think I found some mica pads. What are the characteristics I should be looking for. Kind of light yellow in color. I was able to get the edge to flake.

Sounds like mica to me !

29th November 2010, 02:41 AM	#1
eyoung diyAudio Member Join Date: Aug 2007 Location: Sunny SC,USA 15 min south of Charlotte NC	silpad or mica for to247 in F1 I can't resist starting this debate over, however I am looking for firsthand experience . I am looking for insite to use mica/silpad and with which goop for insulating my To247 trannies to my heatsinks...all my old amps have mica, but I thought I might progress into the next century since I am already 10 years into it... Regards,El __________________ "when you open your mind to the imposible, soon you will find the truth...."

29th November 2010, 06:59 AM	#2
Gyuri diyAudio Member Join Date: Nov 2003 Location: Budapest	You know my kind friend, there are things, which for the centuries do not hurt. So I think MICA. Gyuri __________________ Those who would have deserved the life they are all dead already. "Oh, my dead dears!" - Captain Cat

30th November 2010, 01:11 AM	#3
eyoung diyAudio Member Join Date: Aug 2007 Location: Sunny SC,USA 15 min south of Charlotte NC	Gyuri my dear friend thanks for your input, I am feeling the same way however a source for mica to247 is hard to come by in my small neighborhood,,, If any one has a source for mica insulators TO247 Please let me know.. it never occurred to me to ask our friends at tech-diy whence came my silicon iritations. Regards, Elwood __________________ "when you open your mind to the imposible, soon you will find the truth...."

1st December 2010, 01:44 AM	#6
Andrew Eckhardt diyAudio Member Join Date: Nov 2005 Location: PA	For class A amplfiers it's not such a big deal to have the extra thermal resistance of a silpad so long as you hit your particular desired junction (channel) temp after warmup... because there's not much dynamic about dissipation.. Far as cycling, you know, are you going to turn the thing on and off 500,000 times, or not? Not. A little rubber just means a bit more sink and you're good to go. Last edited by Andrew Eckhardt; 1st December 2010 at 01:47 AM.

1st December 2010, 10:47 AM	#8
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	mica comes in a wide range of thicknesses. The thinner, the less the thermal resistance. "silpads" and similar come in an even wider range of thermal resistances. Choose a thermal resistance that suits your $ and your device temperature. There are very few "silpad" types that can better a 2thou (= 2mil = 0.002inch) thick mica for thermal resistance. __________________ regards Andrew T.


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

1st December 2010, 01:35 AM	#4
jupiterjune diyAudio Member Join Date: Nov 2006	If any one has a source for mica insulators TO247 Please let me know.. Elwood-- I am hopeful that the sheets of mica sold by McMaster Carr are the right type for this service. Part number 8802K16 is a 3x5 sheet of muscovite mica, .004 thick, for a measly $2.17. I have a roll of thermally conductive kapton film that I will be trying first, though, obtained from the same supplier. JJ

1st December 2010, 01:41 AM	#5
PierreQuiRoule diyAudio Member Join Date: Feb 2004 Location: Ottawa	The sheet of Mica you are referring to works fine. Just cut a piece the size you need and off you go. If you want to go crazy and reduce the thermal resistance further, with an xacto knife you can actually "slice" the sheet of mica into thinner sheets. It is easier to do than it sounds. Pierre

1st December 2010, 02:56 AM	#7
budwiser diyAudio Member Join Date: Jan 2004 Location: Greenwood, IN	looking thru my spare parts container I think I found some mica pads. What are the characteristics I should be looking for. Kind of light yellow in color. I was able to get the edge to flake.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
mica insulators	aarifah	Everything Else	0	20th August 2008 07:26 PM
Where am I able to get some silpad?	DJ Exprice	Chip Amps	7	28th May 2006 12:23 PM
WTB: 6x Silpad 2000 TO3P	kasra	Swap Meet	1	3rd February 2006 07:33 PM
Stupid Silpad ?	kestrel200	Parts	6	4th May 2005 10:19 PM
IRFP240-IR = to3 or to247?	Edwin Dorre	Pass Labs	7	25th April 2002 01:22 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read