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Vintage threads from the first ten years

R.G. Why NOT phenolic

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3/20/2005 6:35 AM
Dan	R.G. Why NOT phenolic Just curious. I use 1/8" thick phenolic because I have it in my stock. I just never considered anything else. R.G. Please tell. Thanks!

3/30/2005 10:18 PM
R.G.	It's not as mechanically tough, it absorbs moisture, and it stinks when you cut or drill it. 8)

3/19/2005 8:56 AM
KC	Garolite? I've seen this recommended for turret board only type construction (no PC traces). McMaster-Carr sells this stuff I think. Any reason not to use it? KC

3/19/2005 11:38 AM

I've been using Grade XX Garolite from McMaster with good results.

From the McMaster site:

Grade XX Garolite: Like all Garolite, Grade XX is lighter than metals but dense and strong. It's a paper-based laminate with a phenolic resin binder that absorbs less moisture than Grade CE or LE Garolite. Good for use as a template board or for gasketing and gears

McMaster says that most of the other grades of Garolite are "excellent electrical insulators", but for some reason this isn't mentioned on the web site concerning grade XX. I emailed McMaster, and they confirmed it was an excellent electrical insulator.

So, is there a reason not to use this grad in tube amps?

Steve

3/19/2005 12:25 PM

materials that absorb moisture--you can get "tweed disease". Weird leakage currents from conductivity developing in the insulation material I guess that can show up as voltage on grids and whatever else that could cause. Even when the material is new sometimes, apparently (but I suppose then that would be defective material). If you had to have the vintage type stuff for looks or mojo or whatever, I might choose the less moisture absorbing types (XXX?--I think phenolic material is known by "Tufnol" in the UK--a trade name). Or some vendors like Ray D. has some stuff that has the sort of look but has better characteristics than the vintage stuff IIRC. If you're going to experiment on the board a lot (replace stuff repeatedly etc.) maybe glass epoxy is one of the better choices. The thick stuff is mechanically very tough, doesn't absorb moisture, etc.

3/25/2005 4:33 AM
Dan	Re: Phenolic?? Are you saying Phenolic will absorb moisture??

3/25/2005 5:01 AM

you know carbon comps right? If you cut them open, the outer part I believe is made of phenolic (center core is the carbon--it's black). Absorbs moisture which IIRC is part of the reason they change value. Sometimes you can leave current going through it for a long time to cook out the moisture and they go back to the stated value. Yes, lol. If you google phenolic, look at the diff. grades, etc. that should tell you more.

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