Which kapton(polymide) tape to replace insulators

[spooney]

I'm working on an earthquake d200hc mark 2(more of a restoration really) and i would like to replace the insulation tape that came on the amp as i poked a few holes in it trying to remove the fets from the heatsink. I know i've ordered kapton tape from McMaster-Carr before but i can't remember which kind i ordered. I was hoping somebody could chime in here and tell me what to buy. I'd hate to buy the wrong stuff and destroy this amp.

[spooney]

would this stuff work : http://www.tapecase.com/p.2528.644/1...ape-500-f.aspx

[Perry Babin]

7648A34 at mcmaster.

[spooney]

thank you perry.

[Perry Babin]

The tape you listed should work but I've never purchased from them.

The following ebay item is also good but it has to be cut to size which can be a pain.
160354064298

For those who find thread this after the auction has ended, look for Kapton MT under 'insulators' on the following seller's page:
eBay My World - jandrelectronix

[spooney]

Does heat transfer better with one type of insulator as opposed to another? Are mica or silicone insulators superior or inferior to kapton tape?

[Perry Babin]

The Kapton tape is not the best insulator (with regard to the thermal transfer properties) but it's easily good enough for the power supply FETs (in all amps) and for the output transistors in class D amps. For the outputs in class AB amps, I'd probably use the Kapton MT instead of the tape but I've used the tape in plenty of class AB amps with no problems.

'Thin' mica insulators are probably better than the Kapton but they're a pain to deal with when there are a lot of transistors.

Metallic insulators are probably the best but are expensive.

The silicone insulators vary quite a bit. Different materials will have different transfer characteristics. Their performance also depends on the pressure applied (typically, more pressure = better transfer). If you can find the material to use as a replacement, it's likely to be expensive.

The Kapton tape and the Kapton MT are essentially all I use.

[spooney]

I just bought some of that kapton MT from ebay and I did not realize that it didnt have adhesive on it. Do you use anything to secure it down Perry other than the fets themselves?

[Perry Babin]

There's no need for an adhesive. The heatsink compound will hold it in place well enough until you get the transistors clamped down on it.