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THE AM BULLETIN BOARD => Technical Forum => Topic started by: aa5wg on June 10, 2010, 09:03:35 AM



Title: RF Proof Adhesive/Glue?
Post by: aa5wg on June 10, 2010, 09:03:35 AM
Hi to all:
I am looking for RF proof adhesives/glue that will work in the frequency range of 1.7 - 100 MHz?  This RF field is at maximum power and the adhesive/glue should not melt down, catch fire and be impact reistant.

I am bonding copper to glass epoxy G10/FR4 (fire retardant fiberglass). 

Thank you to all.
73,
Chuck


Title: Re: RF Proof Adhesive/Glue?
Post by: Rob K2CU on June 10, 2010, 09:14:25 AM
Just go for non organic glues...no rubber....and test it first in your microwave. put a sample of your test glue in its dried state along side a small cup of water and nuke for a minute. if the glue is warm, it is lossey....at least at 2.4GHZ. if it is room temp, then it will prohably be fine at 100 mHz or less.


Title: Re: RF Proof Adhesive/Glue?
Post by: WA1GFZ on June 10, 2010, 04:45:33 PM
Echobond 45 if you can still buy it. I put a little blob on my coal stove door and it is still there after 5 years.


Title: Re: RF Proof Adhesive/Glue?
Post by: WBear2GCR on June 10, 2010, 04:52:55 PM

Maybe clear silicone rubber??

                    _-_-bear


Title: Re: RF Proof Adhesive/Glue?
Post by: N5KAT on June 10, 2010, 05:17:27 PM
Try Duco Cement. I guy I knew used it as coil dope on VHF rigs and said that it had great dielectric properties....he also tried some homebrew approaches such as dissolving polystyrene in solvent and said the Duco was just as good.

The idea of zapping a dry blob in the microwave as a check is probably a good one.


Title: Re: RF Proof Adhesive/Glue?
Post by: aa5wg on June 10, 2010, 08:29:17 PM
Thanks guys. I will keep trying.
73,
Chuck


Title: Re: RF Proof Adhesive/Glue?
Post by: W2PFY on June 11, 2010, 11:20:23 AM
I was told that Q-DOPE is the same adhesive as was used on many of the old B&W coil forms. While it won't last forever, it will last more than 20 years from my observations of old coils.

http://www.hmcelectronics.com/cgi-bin/scripts/product/3480-0016/GC-Electronics-10-3702/ (http://www.hmcelectronics.com/cgi-bin/scripts/product/3480-0016/GC-Electronics-10-3702/)

They also list many other adhesives on their web page.


Title: Re: RF Proof Adhesive/Glue?
Post by: W3SLK on June 13, 2010, 12:14:32 PM
The best luck I had was I redid a B&W 850A coil that had succumbed to moisture absorbtion. I took clear acrylic (Plexiglas like material), and dissolved it in acetone. I then used the same acrylic material and cut it into strips for coil supports and applied the dissolved material over top of the coil turns and onto the supports with a popsicle stick. I waited for it to dry and placed it back in service. It worked quite well with the exception of small bubbles from the acetone evaporating. A solvent with a lower vapor density may work in lieu of acetone to prevent the bubbles but the piece is pretty solid so I'm not going to complain about success.


Title: Re: RF Proof Adhesive/Glue?
Post by: aa5wg on June 13, 2010, 05:06:33 PM
W3SLK:
Thank you for your information. 
73,
Chuck - AA5WG
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands