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Copper foil to fiberglass or carbon fiber bonding
3

Copper foil to fiberglass or carbon fiber bonding

Copper foil to fiberglass or carbon fiber bonding

(OP)
I am looking for recommendations on bonding copper foil into a fiberglass or carbon fiber laminate. The copper foil will be near the surface of the laminate but will not be exposed to corrosion environments.

I am having a hard time getting a good bond. Would the use of BR127 or BR6747 help me alot? I do not want to grit blast the copper foil if possible. I do want a pretty good bond though because of the CTE mismatch and a service temp going from -40 F up to 160 F.

Suggestions are greatly appreciated.

RE: Copper foil to fiberglass or carbon fiber bonding

Why is it wanted to join the copper foil to the laminate?

RE: Copper foil to fiberglass or carbon fiber bonding

Perforate the foil, or use screen or knitted copper cloth.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Copper foil to fiberglass or carbon fiber bonding

flyerfly
I think you had better explain what you want the foil to do. Are you looking for lightning strike protection, or static charge dissipation such as on a fuel tank, or for a radio antenna?
  Static charge dissipation on a fuel tank can use Adhesive backed foil tape, so can a radio ground plane or antenna.
 Lightning strike protection is another animal completely, and as Mike halloran says you would need a screen or Knitted material.
B.E.

RE: Copper foil to fiberglass or carbon fiber bonding

(OP)
I appreciate those that want to help on this issue. I am aware of the different uses and why not to use one or the other (foil vs mesh). Suffice it to say, in my case I need to use foil. My primary question is bonding, not why I chose a particular material. This application is not lightning protection it is EMI/RF related. I am already familiar with the tape and it is not applicable in this case. I just want to know about bonding promotion. Thanks.

RE: Copper foil to fiberglass or carbon fiber bonding

If that is the case an acid etch of the foil in the manner used for printed circuit boards is in order.
B.E.

RE: Copper foil to fiberglass or carbon fiber bonding

Yes, clean and etch the foil. Primer will not improve adhesion but will improve corrosion resistance and can be used to protect treated metal surfaces for later bonding.  

RE: Copper foil to fiberglass or carbon fiber bonding

I would try getting a good surface prep on the foil, maybe use a scotch bright pad. Remember to move in a horizontal and vertical pattern and not in circles. Then clean with acetone.

I would also do a water break test to see if I have a good surface prep for bonding. Have you tried using a polyester adhesive film for bonding? Finally I would vacuum bag the laminate for good compaction and throw it in an oven for curing. If possible perforating the foil would be a good idea as well.

Below is a random website I found for adhesive films. I hope this helped.

http://www.adhesivefilms.com/polyester_PAF.htm

RE: Copper foil to fiberglass or carbon fiber bonding

ASTM D2651 provides steps for preparing a surface for bonding.  In the case of copper the recommended procedure is:

1) Degrease

2) Immerse for 1-2 minutes at 77F (25C) in a solution of
    42% Aqueous FeCl2 soln. - 15 pbw
    Conc. HNO3 (s.g. 1.41) - 30 pbw
    DI water - 197 pbw

3) Rinse in cold running DI water.

4) Dry immediately with clean pressurized air at 77F

 

RE: Copper foil to fiberglass or carbon fiber bonding

Getting a bond to the laminate is the easier problem.

For EMI/RFI protection, you also need to terminate the edges of the foil, continuously or pretty close to it, to adjacent metal structure/ surfaces.  That's where the foil tactic, er, falls apart, especially if the joint has to be separable.

I don't have any good solutions for that problem, but I've seen quite a few tactics that didn't work.


 

Mike Halloran
Pembroke Pines, FL, USA

RE: Copper foil to fiberglass or carbon fiber bonding

What type of fiberglass are you using?   There is usually sizing on the fibers which will prevent getting a bond with adhesives.  I suggest using a PSA and laminate to the foil then strip the liner and laminate to the fiberglass.

Scott

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