Silicone Failure, please make suggestions on what you use

[sigsignman]

I have been purchasing and using the GE brand clear 100% silicone for years; however, lately, I have have experienced extreme problems with it failing. Typically, the application is attaching letters to alumilite which have been mounted to a building. Recently, winds have blown off letters (combination mount with studs going thru some of the pads) and when we returned realized we could litterally peel the silicone off the back of the pad. I have tested two different batches of the GE silicone, both have failed my tests. Please see the below video and advise. I would like to use the Gorilla silicone but it is 12 bucks a tube - however, this may be cheap insurance. Any thoughts are appreciated!

 

[tbullo]

I have always used RTV 6708 on plastics like pads. Never had a failure, but it's about $23 a tube. Cures pretty fast too.

 

[henryz]

Have you tried White lightning silicone?

 

[MikePro]

silicone loses it's strength when you press it flat. pair with tabs of 3M VHB tape, and the ~1/8" gap that it creates allowes the silicone to set as a legit blob of adhesion.

edited: o wow, you're talkin' about mounting pads? I've always gone with an epoxy for this type of mounting. disregard my tape&silicone suggestion.

 

[strypguy]

I use Lexel. The VHB tape is a good idea too. I've used small amounts of VHB to hold the letters to the substrate until the lexel dries. John

 

[Billct2]

Lexel

 

[Starter]

ASI Adhesive, Lords, Plexus.

 

[sigsignman]

I use Lexel. The VHB tape is a good idea too. I've used small amounts of VHB to hold the letters to the substrate until the lexel dries. John

 

[sigsignman]

Thanks for your help and everyone's responses!...I have ordered a case of 18 tubes of the Lexel and we will see how it works! Their you tube video looks pretty convincing !

 

[sigsignman]

Thank you for all of the replies!...I have ordered a case of 18 tubes of the Lexel. Some of the other adhesives were great but set up too fast and Lord knows it will be my luck that at some point we have to remove the silly letters Thank you!

 

[Rico]

E-6000. sticks to everything, strong as heck. paintable and easier to clean up than silicone.

 

[humble sign co]

E-6000. sticks to everything, strong as heck. paintable and easier to clean up than silicone.

Love it! E-6100 is even stronger but not as sandable.
If the package doesn't have the word "adhesive", we do not use it as such. 100% Silicone is a sealant, and not an effective adhesive.

 

[TimToad]

Lexel is our choice of adhesive for dimensional letters combined with a few tabs of VHB to allow for a thicker bead of the adhesive to be created and squish through the holes in the pads. If you press the pads down too hard without that VHB barrier in place, the resultant adhesive film is so thin that any sideways movement will literally slice it off even if some adhesive has pushed through the holes in the pads.

If the letters are going in at ground level on a monument, we use epoxy to prevent removal of the letters due to vandalism.

 

[Moze]

Silicone is typically a poor choice for plastics, acrylics, etc. Lexel is far superior and worth every penny. It etches into plastic, acrylic, etc. and basically 'welds' into it.

 

[visual800]

beleive or not we take each pad and hit it with a mouse sander and wipe down with alcohol. YES! I have had silicone fail on this but once I did this it fixed it