[TowerTalk] OT: Bonding to Teflon

[Keith Dutson]

Forget about "strong" adhesive tape.  Teflon, like most high molecular
weight plastics (e.g., cutting board) tend to migrate, and no adhesive will
hold for long.

-----Original Message-----
From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Larry
McDavid
Sent: Thursday, July 9, 2020 1:52 PM
To: Gedas <w8bya at mchsi.com>; towertalk at contesting.com
Subject: Re: [TowerTalk] OT: Bonding to Teflon

"Glue" is historically made from animal products. Modern bonding agents are
"Adhesives." You will get better search results if you use "adhesive."

"Teflon" is a brand name and applies to several chemically-different forms.
One common form is TFE and is white in color. But, FEP is also common and
not usually white. Both types cold flow under load so will change shape
unexpectedly.

Neither TFE nor FEP can be adhesively bonded. You might get a "mechanical"
bond if the Teflon surface is somewhat rough but not a chemical adhesive
bond.

A mastic adhesive like that on thick double-sided tape will show some
adhesion to Teflon but not a chemical bond. It might be enough if the load
is low.

But, you can treat the Teflon surface to make it chemically active and
bondable with common adhesives, including epoxy. The most common treatment
chemical is sold as, "Tetra-Etch" and a simple Google search will turn up
many results. But, beware, it is pretty nasty stuff. Amazon does not sell
it. I've used lots of Tetra-Etch over many years and it definitely works; it
makes the Teflon surface adhesively bondable, at least at moderate bond
strengths. It turns the white TFE surface a light to dark gray in color. The
etched surface has reasonable, but not indefinite, active life; you really
want to adhesively bond the etched Teflon surface in a day or two at most.

My recollection is that Tetra-Etch contains an alcohol and sodium; disposal
is not simple... But, it works!

Larry


On 7/9/2020 11:13 AM, Gedas wrote:
> Pardon the OT post but we have so many knowledgeable folks here I was 
> hoping I could get a quick answer.
> 
> This is antenna & RF related so maybe not super far off OT hi-hi.
> 
> I have a 1/16" thick 3"x3" sheet of Teflon that I need to "glue" to 
> the front of a uW horn antenna to keep water, dirt, bugs, etc out of 
> it. Can anyone tell me what type of adhesive is known to adhere to 
> Teflon and is not too difficult to acquire? TU
> 
> Gedas, W8BYA EN70JT
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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