[TowerTalk] OT: Bonding to Teflon

[jimlux]

On 7/9/20 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
> 

Teflon (and UHMW PE) don't "bond" with adhesives. Non-stick is 
non-stick, after all.

There are surface preparations using either a series of acid treatments 
or small sparks that create tiny holes at angles, and then you can put 
epoxy adhesive can flow into the hole, harden, and "hold it" more by 
mechanical interference than "sticking"

Here's a summary of surface prep for various plastics

Polar Thermoplastics (Nylon, ABS, Polycarbonate, Acrylate)
Degrease with trichloroethylene
Abrade
Degrease

Polyethylene, Polypropylene
Degrease with trichloroethylene
Oxidize by immersing in a solution:
7 parts sodium dichromate
10 parts water
150 parts concentrated sulfuric acid
for 10-15 minutes
Rinse with hot distilled water
Dry and coat with adhesive immediately

Thermoset plastics (Epoxies, Polyurethane, Polyester, Melamine, Phenolic)
Degrease with acetone, MEK, or trichloroethylene
Mechanically abrade (sandblast)
Degrease


Chromic Acid (for PE and PP) is evil stuff. Not as bad as HF, but be 
careful.



> Gedas, W8BYA EN70JT
> 
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