Homebrew PCBs

I just happen to have some good vacuum equipment in my shop that I use for vacuum casting.  Getting a hard vacuum isn't a big deal for me.  I've laminated some large plywood sheets with a shop vac and a BIG vacuum bag (boat building) which is about the other extreme.  Some associates built some fiberglass refridgerated rail cars with a similar technology.

I certainly wouldn't recommend going out and purchasing a $5000 or more vacuum pump just to make PCBs for a hobby.  It's a cheap simple way to get good pressure if the hardware is on hand.

By the way, I can't take credit for the 'Bake 'n Bag' idea - but the poor old gray cells can't remember who suggeted it to me....
  ----- Original Message ----- 
  From: ballendo 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Tuesday, October 19, 2004 7:11 PM
  Subject: [Homebrew_PCBs] Re: Questions about toner transfer method.



  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.
  > 






  Be sure to visit the group home and check for new Bookmarks and files:
  http://groups.yahoo.com/group/Homebrew_PCBs 


        Yahoo! Groups Sponsor 
              ADVERTISEMENT
             
       
       


------------------------------------------------------------------------------
  Yahoo! Groups Links

    a.. To visit your group on the web, go to:
    http://groups.yahoo.com/group/Homebrew_PCBs/
      
    b.. To unsubscribe from this group, send an email to:
    Homebrew_PCBs-unsubscribe@yahoogroups.com
      
    c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. 



[Non-text portions of this message have been removed]