Eyelet Board Material

[selloutrr]

has anyone had luck with stone?

[Aurora]

I know what I've been reading on this and a couple of other fora, but I really want to caution people against using masonite or hardboard, or any wooden fibrous material, in particularly in combination with the high voltages in guitar amps. Any material that can possibly trap humidity, and in addition is flammable, should absolutely be avoided! A piece of plywood and some nails is OK for a quick testbed, but not for a lasting product.

Formica is OK I guess, but garolite and regular FR4 fiberglass PCB material is recommended. While I can understand the wish to use thicker material, like anything thicker than 1/16 or so, it is really not necesseary. Just use more mounting and support. I've been in electronics for many years, and most commercial products, even for tough uses, have regular 1/16" PCB - with proper mechanical mounting and support. I have seen broken tracks on PCBs and loose solder joints, al from insufficient mechanical fixing of large and heavy components, but I've never seen a broken PCB, execpt from extreme abuse. I actually have a large panel of 2.5 mm FR4 PCB that I plan to use for this purpose, so there's nothing wrong in using belts and braces.... just stay away from the wood! There's a good reason for us using it in our stoves....

[Structo]

Yeah, I like the G10/F4 1/8" Garolite board material.

Stiff enough to not need a backing plate and also strong enough to only need supports every 8 inches or so. Very strong material.

And it doesn't cost too much.

McMaster Carr or Watts Audio are two companies that sell it.

http://www.mcmaster.com/

http://www.turretboards.com/

Also Hoffman carries it.
http://www.hoffmanamps.com/MyStore/perlshop.cgi

We have all seen the wooden circuit boards and the formica boards but common sense and safety tells us we should use approved products designed for their purpose.

Remember, we won't live forever and these amps will either be inherited by your children or possibly auctioned off at an estate sale.
So you don't know who will end up with them.

So with that in mind, build them to the current safety standards to ensure whoever ends up with it won't get electrocuted or burn their house down as a result of shoddy workmanship.

[Andy Le Blanc]

What was that waxed board in old fenders?
Or the old stuff glued to plywood scrap in old gibsons and ampegs.

It does beg the question, what is a minimum acceptable rating for any material
used to the purpose of a component board in a valve circuit?

I've been in enough old gear, some really had shoe eyelets in waxed paper.

muscovite will take over 900 F

hard fiber is next at over 400 F

G-7 338F.... G-11 320F

[martin manning]

What was that waxed board in old fenders?

fishpaper

[Andy Le Blanc]

I think its....

MIL Specification MIL-I-695A
UL Rating UL 94HB

[Andy Le Blanc]

Hard fiber exceeds the minimum rating for garolite LE/CE

Hrdf... 200 v/mils

The range of variance of the dielectric strength is minimal for hard fiber.
You might expect 500 v/mils with garolite but only get 140 v/mils

G-7 has the only predictable character besides hard fiber.

[Furtz]

Anybody try cowhide? I've got some of that out in the barn. It could be cut to size, stretched, dried, and soaked in varnish and baked. Might cut some up tomorrow.

[Aurora]

Old PCBs were often a phenolic -paper sandwich - far from the mechanical strength of garolite and the likes. It also got scorched a lot faster than fiberglass. Arc-overs from carbonized tracks under and around hot components was a very common failure in tube TVs, as well as rotting solder joints around hot components.

[daydreamer]

I would also include thinking about eyelet boards in your builds. You can make your own eyelet boards for less than $3.00 each. I have seen prices for turret boards around $39 and up. For me the savings makes a difference and I have the means to cut my own board material. I buy my eyelets 10,000 at a time in order to get a great price. I don't know the availability of the raw materials in your area.

mcracer wrote this in in another discussion, perhaps search for his build photos, or he may even chip in with a material supplier?!

Andy

[mcrracer]

McMaster Carr has the Garolite just search their site for the material you want to use. I wear a respiratory mask when cutting my boards with a bandsaw. I have a couple of guys who partner up with me to share an order of eyelets.

[Cygnus X1]

I've had good luck using lexan.
Thin enough to use eyelets with too.

[img:680:360]http://img404.imageshack.us/img404/8867 ... tlarge.jpg[/img]

[M Fowler]

I was wonder why we couldn't use lexan or other plastics, perhaps smell when heat hits it?

[PWE Amplification]

I was wonder why we couldn't use lexan or other plastics, perhaps smell when heat hits it?

Lexan melts very easily and is prone to static charge.

[Cliff Schecht]

I was wonder why we couldn't use lexan or other plastics, perhaps smell when heat hits it?

Lexan melts very easily and is prone to static charge.

It probably won't melt at normal amp temperatures but ESD could eventually ruin some of the low voltage electrolytics and such. Passive components do suffer from ESD effects too.