Homebrew PCBs

Hello,

Although I like your idea...

The MOST force you can get from a vacuum is 14.7 lbs/inch. At sea 
level. Most vac pumps are rated in inches of mercury, and this is 
29.92 inches. Most "common" vac pumps will give about 25 inches--or 
less-- of vacuum, so you're going to have even less pressure. I've 
done a LOT with vacuum clamping over the years, and use 10-12 lbs per 
square inch as a ROT (Rule Of Thumb<G>) I'm working near sea level.

So with a 2 x 4 inch board, we're gonna get 80 to 96 pounds of 
pressure. I'm no "Arnold", but I can surely do that with an iron...

BUT, as I first mentioned, I like your idea. And I think that the 
pressure attainable WILL be enough. But we CAN provide more with a 
handheld iron, IMO.

Another similar idea which seems to have gotten lost in the mix when 
it was posted; about using an electric frying pan, washcloth and a 
lead brick instead of an iron. 
Good heat control, accurate, repeatable even pressure (if your brick 
of lead isn't flat you'll need something flat between it and the 
washcloth). The only thing remaining is time, and that's easily 
monitored/controlled.

Your setup duplicates this, and "could" provide equally repeatable 
pressure. A brake bleeder tool--any Auto parts store-- will give you 
a simple means of accurately repeating the vacuum. 

Using an electric frypan/griddle (cheap new and even moreso at EVERY 
salvation army/thrift store everywhere<G>) and a weight (doesn't have 
to be lead, but diver's weights are resdily available, as are other 
sources of lead or similar "heavy" things, like thick steel plate.) 
is a simple effective way to avoid the need for a laminator, which 
still seems to me to be the best overall answer.

But I DO like your idea! 

Ballendo



--- In Homebrew_PCBs@yahoogroups.com, "Earl T. Hackett, Jr." 
<hacketet@c...> wrote:
> If you have a vacuum pump (even a good shop vac or vacuum cleaner) 
you can put the board and the artwork in a Reynolds Aluminum 'Bake 'n 
Bag", pull a vacuum and set the iron on it.  That should generate 
much more force (and much more unifom force at that) than you could 
ever generate by hand.
>   ----- Original Message ----- 
>   From: Bob Weiss 
>   To: Homebrew_PCBs@yahoogroups.com 
>   Sent: Monday, October 18, 2004 11:24 PM
>   Subject: [Homebrew_PCBs] Re: Questions about toner transfer 
method.
> 
> 
> 
>   I just made another "test" board using Staples Picture Paper and 
>   this time used more pressure and time under the iron and I am 
amazed 
>   at the quality you can achieve!! There is no going back to 
the "old" 
>   way for me...this works great! Thanks for all your help.
>