This article attempts to answer the question of mounting metal and plastic sign letters to hollow doors.
For mid to light weight lettering such as laser cut acrylic letters and flat cut aluminum, brass, bronze or even small stainless steel letters, the easiest method is to order the letters with double side tape. This can also be further strengthened by using small spots of silicon caulk on the backs of the letters which will take over in the event of the double side tape drying out. We use mostly very high bond type tapes from 3M when we produce letters here. Some of our distributed product from other manufacturer's may use other brands or may not offer a double side tape mount. DS Tape can be special requested with all our solid flat cut sign letters.
As the size or weight of the letters get larger and heavier, or for letters that have hollow backs such as Fabricated Stainless Steel, reverse channel letters, or Cast aluminum and cast Bronze letters, stud mounts will be the order of the day.
The first problem that arises with stud mounts is how to make a secure installation to a hollow core door. Normally, a stud type mount is designed to go into drywall or into solid walls made from plaster, stucco, block, concrete or brick. This is a very simple installation, just drill holes and fill them with silicon caulk then push the entire assembly into the holes. Once dry the silicon will hold them tight while allowing for expansion and contraction, plus seal the holes against moisture.
On a hollow door though, the skins are usually quite thin and the silicon caulk will not have much holding power. The following are some solutions that customers have come up with that may or may not work for you. As with all things, test on something else first.
1. MODIFIED PLASTIC DRYWALL ANCHORS:
If you take a few plastic drywall anchors, being careful to match the large open end to the size of the stud you will be inserting into it, nip the closed end off so that the anchor will expand in the back, as the stud is forced into it. Install the drywall anchors in the door using the mounting pattern. It is a good idea to use some caulk on the outside of the anchor itself to help it hold. Take the metal letter(s) and screw the threaded rods(studs) into the back, then coat the studs with silicon and push the studs all the way into the plastic anchors. As the studs go in, the theory is that the tapered anchor will expand behind the hollow door skin, effectively trapping the studs and securing the letter to the door.
2: MODIFIED METAL WING ANCHORS:
This is similar to the plastic anchor theory but uses the metal type butterfly anchors. The theory here goes that you would install the metal anchor into the door in the normal way, then remove the screw from the anchor leaving an open threaded shaft. At this point using a drill and bit size that you have determined beforehand as a suitable size to not remove too much material from the shaft of the anchor, drill out the center hole to remove the threads and allow the studs to slide into. This will provide a shaft for silicone to do its work. Fill the anchor holes with silicon and coat the studs, then push the letter in.
HOLLOW BACK, MOLDED PLASTIC LETTERS:
The best way to order these for doors is the pad mount. Coat the pads with silicone caulk, apply letter to door and hold in place with masking tape till the silicon sets, usually 24 hours.
This concludes our tutorial. We welcome your suggestions and tips.
disclaimer: None of the tricks and tips on this page are to be taken verbatim as expert opinion. You're adoption of any advice from this page is entirely at your own risk.