What is the best way to attach a 4x5 shape, cut out of 6mm ACM, onto an outside wall without fasteners showing on the front? If there is a way. Thanks
Can it be stood off the wall at all?
If so, you can make yourself some french cleats out of 1/2" PVC or MDO about 4" tall x 4' long each half piece. Attach the sign side ones with VHB, LEXEL and some really short sheet metal screws that won't penetrate through the face of the sign. You'll need to countersink the screw holes and use flat head screws so figure that into your screw length calculations. Don't skimp on the VHB, LEXEL and screws.
Figure out where the wall side pieces should be mounted and anchor them to the wall making sure you're level and the distance between the two match the gap on the ones on the sign. Same deal on the countersinking.
When you go install the sign over the cleats, squirt a bead of LEXEL along the angled edges of the cleats and it will bond once the weight of the sign compresses everything together.
Something like this.
stuccoWhat kinda wall and how high in the air is it ??
Is this the correct Lexel? https://www.lowes.com/pd/Lexel-10-5-fl-oz-Clear-Paintable-Solvent-Caulk/4714985
Due to the thinness of 6mm ACM, I'm thinking of just going with 12 or 19mm PVC. I could glue PVC standoffs tot he back, screw in some stainless screws and use those as studs. drill holes in the wall [stucco], fill holes with silicone and push in the studs. What do you think?
I see thickness details, but nothing for weight. They are quite nice....... if they work.
The problem with almost all hidden fasteners on ACM is that you can't screw into the back of the ACM to attach the fastener. And that leaves you depending on adhesive--but the hidden fastener is usually too small to have enough surface area of adhesive to hold the sign up. That's why screwing a larger piece of material to the wall (but smaller than your sign) is good. It allows a large surface area for VHB or adhesive, a surface which is smooth and provides good adhesion.