What is the best way to close holes in auto floorboards caused by removal of screws?

Joined
Dec 11, 2011
Messages
1,010
Location
USA
I bought a 2015 F-250 that was in it's previous life was a patrol vehicle. Lot's of screw holes in the floor areas (computer mounts, radio mounts, etc). What is the best way to make sure these don't start to rust out since the galvanizing on the sheet metal is damaged and punctured? Screws are 5/16" hex head, so probably a #10 or #12 size hole.

I'm thinking one of the methods below:

1. Clean the hole, use cold galvanizing paint (same stuff I use on fencing after welding). Then caulk it.

2. Clean the hole, use rust converter, and then caulk it.

3. Clean the hole, rust converter, and then rubber plug it.

4. Clean the hole, body panel adhesive, smooth it out and leave it.

5. Clean the hole, JB Weld putty, mash it in and leave it.

Anyway, looking for ideas from all the great minds here at BITOG. Thanks.

Also, here's a video that is relating to rust converter versus rust encapsulation. News to me for sure:

 
Last edited:
I never thought of that particular situation before.
Wire brush each (or use a rust converter?)....temporarily back with a piece of steel (like a piece of can) and fill the hole with solder?
The carpeting or rubber matting punctured too, yes?
Were the screws #8 or #10?
 
I never thought of that particular situation before.
Wire brush each (or use a rust converter?)....temporarily back with a piece of steel (like a piece of can) and fill the hole with solder?
The carpeting or rubber matting punctured too, yes?
Were the screws #8 or #10?

Self tapping screws, 5/16" hex head (not sure of the size).
 
Clean the hole, metal prep it, then put in a (similar metal) Pop_rivet from below. Then Fluid film over the top of the mess.
I think the pop rivets would poke through the floor covering. It's not carpet - it's that plastic used on work truck floors
 
I bought a 2015 F-250 that was in it's previous life a patrol vehicle. Lot's of screw holes in the floor areas (computer mounts, radio mounts, etc). What is the best way to make sure these don't start to rust out since the galvanizing on the sheet metal is damaged and punctured?

I'm thinking one of the methods below:

1. Clean the hole, use cold galvanizing paint (same stuff I use on fencing after welding). Then caulk it.

2. Clean the hole, use rust converter, and then caulk it.

3. Clean the hole, rust converter, and then rubber plug it.

4. Clean the hole, body panel adhesive, smooth it out and leave it.

5. Clean the hole, JB Weld putty, mash it in and leave it.

Anyway, looking for ideas from all the great minds here at BITOG. Thanks.
How big are the holes?

I've done this in an older car and it worked.

POR-15
Remove all rust and any type of coating. Use Metal Prep. Allow to dry
Patch hole with POR-15 and fiberglass (1.5" circle) (coat and soak like fiberglass and resin)
Touch up with rust proof primer when POR-15 still tacky
Paint

Held for years
 
It would help to know what size the holes are, how clean the metal is, etc.. My bias is that any type of caulk, coating, etc. might crack or otherwise allow salty water seep under it and rust. Depending on your circumstances, I might just run a grease covered pan head metal screw into the hole from inside the car, then coat both sides in the grease. Use something like MolyKote 77, etc. Once a year inspect for grease coverage.
 
Screws are 5/16" hex head, so probably a #10 or #12 size hole. I'll post a picture of an example of the holes.
 
POR-15 is kinda nasty to work with and don't spill any! Never comes off. BUT it does have enough flex for floor boards. I had some 1/2" holes. Man did it stick, sealed perfectly.

Small hole maybe need only 1" patch, easy peasy, you could do just the bottom I guess (I did both sides) then fill any depression on topside with POR-15 while still wet (as you will still need to coat inside cleaned area)

Note: I had some hole that didn't need to be flush filled - I used bolts/screws and tons of HD Metal protector(waxy like) that worked well.
 
Here is an example of some of the holes in the floor pan. The installer was not a pro by any means, IMO.

Multiple holes drilled and then only installed one screw, so was maybe trying to "pre-drill" holes, but kept putting the holes in the wrong place.

So, drill another one!

IMG_7601.jpeg



IMG_7600.jpeg



IMG_7599.jpeg



Rust is already forming on some of the holes, so after I do some vacuuming and scraping, I think the rust converter is the way to go on this first.
 
Last edited:
  • Like
Reactions: GON
You'll need to triple clean that.

Think of food clean (ok that is how I am, sorry)

The rust needs gone and yeah POR-15 (yes I like the stuff)

It all depends how much you like the vehicle and how long you want to keep it I suppose.
 
I would use the RectorSeal EP 200 epoxy putty that you can find at Home Depot. For whatever reason, they keep it in the plumbing supply section, not with the adhesives or sealants. No other epoxy putty hardens like a rock/steel in 30 minutes and it is really inexpensive (~$4 per tube).

1723639630609.jpg
 
POR15 also makes POR Patch. This might be a good application.

I do like the pop/ Olympic divot idea, just put them in from the top.

Agree metal prep that to death then some more.

Best repair would probably be to weld them all up and metal finish but may not be practical.
 
I would use the RectorSeal EP 200 epoxy putty that you can find at Home Depot. For whatever reason, they keep it in the plumbing supply section, not with the adhesives or sealants. No other epoxy putty hardens like a rock/steel in 30 minutes and it is really inexpensive (~$4 per tube).

View attachment 235345

Not seeing it online at Home Depot?
 
I bought a 2015 F-250 that was in it's previous life was a patrol vehicle. Lot's of screw holes in the floor areas (computer mounts, radio mounts, etc). What is the best way to make sure these don't start to rust out since the galvanizing on the sheet metal is damaged and punctured? Screws are 5/16" hex head, so probably a #10 or #12 size hole.

I'm thinking one of the methods below:

1. Clean the hole, use cold galvanizing paint (same stuff I use on fencing after welding). Then caulk it.

2. Clean the hole, use rust converter, and then caulk it.

3. Clean the hole, rust converter, and then rubber plug it.

4. Clean the hole, body panel adhesive, smooth it out and leave it.

5. Clean the hole, JB Weld putty, mash it in and leave it.

Anyway, looking for ideas from all the great minds here at BITOG. Thanks.

Also, here's a video that is relating to rust converter versus rust encapsulation. News to me for sure:

I'd seal the holes with zinc oxide. This is what aircraft manufacturers spray on before paint. It makes a tough barrier to keep out moisture and will seal the metal. Then maybe use putty epoxy to seal up the holes
 
Back
Top