Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

previous by date index next by date
previous in topic topic list next in topic

Subject: Re: [Homebrew_PCBs] Determining copper weight

From: Don Jackson AE5K <don@...>
Date: 2008-11-06

Thanks for the suggestion(s) for determining copper weight of some
copper clad material. I'll see if the old micrometer can tell me
something. All three suggestions were to peel a little piece of the
foil and measure it.

I wonder if another simple method might be to measure overall thickness
of unetched material and then subtracting the resultant thickness of
totally etched (no copper left) material. (Take into account single or
double sided.)

I didn't easily find a reference to "ounces versus thickness", so for
anyone looking, this website has a nice chart:

http://www.standardpc.com/laminates.htm

or here is the info:

1/2 oz. 18 um 0.7 mil
1 oz. 35 um 1.4 mil
2 oz. 70 um 2.8 mil
3 oz. 105 um 4.2 mil

For various thickness of materials, here's the mm to mil conversions:

0.4 mm 16 mil
0.6 mm 24 mil
0.8 mm 32 mil
1.0 mm 40 mil
1.2 mm 47 mil
1.6 mm 63 mil

(OK, no quibbling over round offs!)

If anyone finds a neater form, let me know. I did spend a lot of time
looking at this groups resources online and may have overlooked this
information.

Regards,
Don