How to install molly bolts in a hollow core door

Question

I need to screw some hooks into a hollow core door, so I'm trying to use molly bolts and I'm having some problems with them.

When I insert them into the hole, I tried using a hammer to lightly tap them in until the spikes on the rim of the bolt get some purchase in the wood, but with about 90% of the bolts, the inside expanding portion falls off inside the door.

If I don't tap them into the wood, the spikes bend and flatten against the rim when I try to screw the bolts in, then the whole thing just spins like a stripped screw.

I also tried holding a flat blade screw driver against the rim to hold it while I tightened the molly bolt, but that's too difficult to do and I just wound up with scratches across the back of the door.

What am I doing wrong?

Answer 1

As mentioned in the comments, the molly bolt might not have a thin enough collar to bite down on the skin of the door. This would explain the stripping/ spinning.

If you must use a molly bolt, use the right tool to set it. For example, not an endorsement: molly bolt setting tool

(image from Amazon listing above)

Although they're bothersome to work with, as they're basically non-removable, I'd lean toward a standard toggle bolt.

Answer 2

If need to use screws, this might be a good job to use a wood dowel(1/2 inch or larger).

Drill a hole to just fit the dowel though one face of the door.

Cut dowel to size to just fit the outside of the door skin.

Use wood glue on the dowel inside end and the hole in the door. Let dry

Drill a pilot hole for the screw and screw the hook on.

Answer 3

If you're dead set on using the molly, drill your pilot hole for the molly, then drill a tiny hole for one of the spurs to get a grip into.

As you start to screw it in, one of the spurs should catch in that little pilot hole (helped by the fact that you place it there to start with), and it will expand the hole as you tighten it. The other spur should penetrate the door skin on its own, but if you're finding that it doesn't, let it make a little mark, back the whole thing out, then drill a pilot hole in the middle of the mark for the other spur.

Answer 4

Well, after much research and fiddling, I think the answer is that molly bolts aren't made for use in wood (despite the recommendation of my local hardware store). The spikes just aren't strong enough to pierce and hold in wood. They're for drywall only.

I ended up using E-Z Ancor 1 in. Hollow Door and Drywall Anchors https://www.amazon.com/Ancor-Hollow-Drywall-Anchors-25-Pack/dp/B004G2PK7G

Answer 5

Searched wall anchors for 1/8 hollow core doors.Copy and paste address.( https://www.amazon.com/Hard-Find-Fastener-014973264901-18-Piece/dp/B00OHXA82G). Walmart has these listed also. The best way to support a door mirror. I have had all the other methods. They work loose opening and closing a door and even fall the mirror and break. Though what I used are non removable type. Sell the mirror with the house if you move.
A little expensive because of the freight cost now days.But the only way to fly with a 1/8 hollow door skin.