Gluing To EPDM

Antenna is 12" Wilson. 3/16 by 8" round galvanized steel. After considering the weight I went with a single 1 inch screw thru the middle with Dicor under and sealing the edges.

Thanks to all for the advice.

What size plate? Big enough for the ground plane or just the magnetic base? What size antenna?

A ground plate base for a 440 MHZ 1/4 wave, with aluminum tape radials probably has different needs for attaching it than a full ground plane plate for lower frequency.

Jim

How certain are you that the glue underneath the EPDM will hold it down?
I suggest 3 screws in a round plate and four screws in a square plate, seal with Dicor.

Kiwi, if its a small magnetic antenna, I just glued a small piece sheet metal to the top of the refrigerator vent. Has worked well for many years now.

I tried doing similar thing to what Kiwi wants. Covering the hole after I removed the TV antenna.

One problem with glue is that roof is not flat. Glue doesn't work well when there are gaps between two surfaces. Sealants fill the gaps, but I don't like that Dicor has a lot of flex, more than cheap urethane caulk.

Another problem is that EPDM rubber is very thin and I could see how it lifts off the plywood when something pulls at it. The plate - if glued properly - would stay on EPDM, and when enough force is applied, it will lift the piece of EPDM and rip it off.

Eventually decided to put 2 small tapping screws through the metal plate, with Dicor under it and around the edges.

Have two plates secured with dicor. Works perfectly despite the comments above.

Kiwi, I've added some thoughts after you've posted. Hmk is right, large rigid items should better be screwed through the EPDM to the plywood - not glued.

Almot wrote:
Few things you may try:

1) Urethane caulk.
2) Aquaseal neoprene adhesive in watersports isle, or Freesole in sport shoe-ware isle, same thing. Sticks to EPDM. Never tried it purposely on metal, but remember it sticking to it when dripping occasionally. Specs say that it sticks to metal:
Aquaseal

Dicor is soft when cures, it's a sealant, not a glue.

That is the only purpose I am using the Dicor for, seal the edges, reducing water getting under.

Few things you may try:

1) Urethane caulk.
2) Aquaseal neoprene adhesive in watersports isle, or Freesole in sport shoe-ware isle, same thing. Sticks to EPDM. Never tried it purposely on metal, but remember it sticking to it when dripping occasionally. Specs say that it sticks to metal:
Aquaseal

You may not like the results. Metal plate will stick to EPDM, but EPDM itself is a very thin material that is not always attached well to underlying plywood.

Using Dicor for gluing large rigid objects to EPDM is even worse. It is soft when cures, it's a sealant, not a glue.

not sure I would glue anything on my EDPM (rubber) roof. If it were me I would drill a couple holes in the plate, screw the plate to plywood underneath. Put Dicor in screw hole and screw before screwing in. Dicor the plate and edges.