Need Help I Need A Plan B For My Failed Installation Of Foam Letters

[printhog]

I noticed you're using dots of silicone. I was trained to use long seams of it, around the perimeter with a gap at the bottom for drainage. Silicone works by surface tension and perimeter beads get better adhesion and have less edge exposed to elements.

Home depot and Lowe's have consumer products, your best choice is www.RSHughes.com as they specialise in the entire industrial Loctite, GE and 3M lines. (GE is now Momentive I believe). Their staff is helpful and pricing is often better than the box stores.

I agree that you need some physical load bearing support like studs to handle the bulk of the letter weight.

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[vincesigns]

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Hello Fellow signmakers,
Although I have been making and installing signs for 31 years, I am still learning and need
your suggestions for a better installation for these foam letters with plexiglas face.

I previously had made this type of letters before and they lasted 10 years plus.

This logo is falling off after 8 months.
Letters are 2 inch thick dense foam (not bead)
Foam was painted with Glidden brand primer (Gripper) front and back.
1/8 inch acrylic glued to foam with Dow Corning 732 clear silicone adhesive.
Wall was painted with exterior Behr paint from Home Depot. Paint is sticking well to wall.
Logo and letters glued to wall with Dow Corning 732 clear silicone adhesive and some 3M VHB Tape.
The section that fell off did not break.
The wall had no silicone residue and had a couple of sections of VHB Tape still hanging on.
The silicone removed pretty easily from the back of the foam logo.

So it appears my adhesive is not working well in this situation, although i have been
successful with the mounting method previously.

My thoughts for a Plan B remount of logo is:
Remove all silicone adhesive from both surfaces and wipe clean.
Paint back of foam and wall where logo goes using one shot enamel paint.
Add 4-5 plastic anchors into wall per section and leave a 1-1/2 screw sticking
out with the head cut off.
Slam logo over the screws sticking out and adhear again with adhesive. (not sure which though)

 

[vincesigns]

The only correct way to install the letters and logo is with studs and silicone. Sign foam will drill and tap well. If you try to install without studs the install will fail.

 

[rossmosh]

The only correct way to install the letters and logo is with studs and silicone. Sign foam will drill and tap well. If you try to install without studs the install will fail.

Sign foam/HDU has absolutely no grain structure. Drilling and tapping it is basically pointless. You could do that and I'll yank out the stud with fairly minimal effort. Now it may be satisfactory in this circumstance but generally speaking, it's the wrong way to install studs even by manufacturer recommendation.

The recommended procedure is to drill, fill with epoxy, Lexel, or Gorilla Glue and insert your stud.

 

[Moze]

Just restating what has already been said, but use Lexel, not silicone. On something this large, a few studs to carry the weight is a good idea. Might also be a good idea to grind off a few spots of paint on the building just for extra reassurance. Apply Lexel directly to those spots and you'll be good to go.

 

[Cunning Linguist]

Can't imagine hanging any foam letter, of any size, without a minimum of (2) studs per letter regardless of their size.
Here in Florida - nothin' sticks to nothin', and if id did it would come off within 1 summer of 'Hot Schwetty Balls Heat'...
Trust me on this one good man... 3M DP8810 adhesive. It's not cheap, but we've never had it fail with this type of installation.

Rots-o-ruck bro...!