How to secure screws in plywood going with grain??

Fasteners in tension are much weaker than fasteners in shear. I would get a steel T section and drive the center section into the rotted wood then drill from the FG outer skin into the T and install screws. This will provide a bearing surface and carry the bulk of the load. Use your existing holes in the section that fell down to transfer drill though the T section and then screw in place. Good luck on your project, and let us know how you make out.

ol Bombero-JC wrote:

Gdetrailer wrote:

John&Joey wrote:
One more shot at this.

Buy the longest pop rivets you can and use them. As they suck down they will get fat sideways looking for a bite.

:h

Did you bother to look at the OPs pix?

There is NOTHING for a pop rivet to grab, the wood has rotted and what is left is delaminated.

What the pix does not show is just how far up the sidewall the plywood has failed.. But from the pix I suspect it goes a good ways up the wall.

The OPs wooden part of the structure is pretty well weakened and really needs to consider ways to rebuild what is missing.. But sadly with fiberglass laminated to the now gone plywood it would mean having to strip back the fiberglass to make the repair properly.. Anything else short of that is simply a temporary at best "bandaid".

If the OP just wants to reattach the bottom trim, they can simply add a piece of sheet metal to cover the plywood edge to the steel frame. Then screw the trim into that additional sheet metal as I mentioned before.

Simple and effective without any need to resort to putties, epoxies, long screws or any other method which WILL eventually fail since the existing plywood left has no strength and the glue that held the plywood together is simply going to continue to degrade.

"John&Joey" - you're shooting blanks!
Re-study the pic. Don't think you get it..:(

Vote for - Your 3rd paragraph "If the OP wants to......etc."

Less grief than all the other solutions - and *way* more permanent.

:C

Another "view" of the OPs pix that I straightened and cropped that might be helpful..



Notice that the trim that the OP needs to put back up will have screw holes centered on the plywood edge.

That plywood edge is shot, nothing is going to go into that edge and hold. Even screwing longer screws into that plywood will just result in ripping the weakened plywood further.

Learned back when I was 12 or 14 yrs old just how frustrating it can be to nail or screw into a plywood edge.. Nails and screws just splinter apart the plys of the plywood..

Screws sometimes can be used on a plywood edge but it REQUIRES one to PRE-DRILL the hole before attempting to drive a screw into the edge AND it requires solid plywood.

Another option would be to carefully remove some of the leftover rotted plywood, then glue and screw a piece of "one by" wood fitted between the steel and fiberglass.

Gluing the wood to the fiberglass and carefully predrill some holes at the lowest point of the fiberglass (the trim should go up the side of the trailer covering the screws) and use short drywall screws into the new wood.

This would give the OP a new surface to screw into and also provide solid backing for the sidewall which should stop the side wall from buckling inwards which would create gaps in the caulking.

OP would have to figure out what tools they have that could do this, grinder might work, small circular saw (battery powered might be a good idea for control), perhaps a non rotatory cutting tool (rotozip?).. Small router (battery powered might be best for control since routers do have a mind of their own).. Hammer and chisel (slow but better control)..

Gdetrailer wrote:

John&Joey wrote:
One more shot at this.

Buy the longest pop rivets you can and use them. As they suck down they will get fat sideways looking for a bite.

:h

Did you bother to look at the OPs pix?

There is NOTHING for a pop rivet to grab, the wood has rotted and what is left is delaminated.

What the pix does not show is just how far up the sidewall the plywood has failed.. But from the pix I suspect it goes a good ways up the wall.

The OPs wooden part of the structure is pretty well weakened and really needs to consider ways to rebuild what is missing.. But sadly with fiberglass laminated to the now gone plywood it would mean having to strip back the fiberglass to make the repair properly.. Anything else short of that is simply a temporary at best "bandaid".

If the OP just wants to reattach the bottom trim, they can simply add a piece of sheet metal to cover the plywood edge to the steel frame. Then screw the trim into that additional sheet metal as I mentioned before.

Simple and effective without any need to resort to putties, epoxies, long screws or any other method which WILL eventually fail since the existing plywood left has no strength and the glue that held the plywood together is simply going to continue to degrade.

"John&Joey" - you're shooting blanks!
Re-study the pic. Don't think you get it..:(

Vote for - Your 3rd paragraph "If the OP wants to......etc."

Less grief than all the other solutions - and *way* more permanent.

:C

MEXICOWANDERER wrote:
Not exactly funny. The process is the same...

Nothing that a little bit of bondo and a bunch of 6" long screws can't fix :B

Otherwise use some fluid film, 303, and eternabond tape and if feeling frisky splash some bedliner on for good measure..

But keep in mind, for what ever you decide to do, put some LT tires on it for goodness sake, the existing tires must be STs and blew out since I can't seem to see them..

Well you can always do more work. Sometimes good enough will get you through a few years and trade it in.

Is that your place MEX? Siding and a coat of paint and you will have a fine place there. ;)

Not exactly funny. The process is the same...

John&Joey wrote:
One more shot at this.

Buy the longest pop rivets you can and use them. As they suck down they will get fat sideways looking for a bite.

:h

Did you bother to look at the OPs pix?

There is NOTHING for a pop rivet to grab, the wood has rotted and what is left is delaminated.

What the pix does not show is just how far up the sidewall the plywood has failed.. But from the pix I suspect it goes a good ways up the wall.

The OPs wooden part of the structure is pretty well weakened and really needs to consider ways to rebuild what is missing.. But sadly with fiberglass laminated to the now gone plywood it would mean having to strip back the fiberglass to make the repair properly.. Anything else short of that is simply a temporary at best "bandaid".

If the OP just wants to reattach the bottom trim, they can simply add a piece of sheet metal to cover the plywood edge to the steel frame. Then screw the trim into that additional sheet metal as I mentioned before.

Simple and effective without any need to resort to putties, epoxies, long screws or any other method which WILL eventually fail since the existing plywood left has no strength and the glue that held the plywood together is simply going to continue to degrade.

One more shot at this.

Buy the longest pop rivets you can and use them. As they suck down they will get fat sideways looking for a bite.

How deep is the rot? Drywall screw goes to 6".

Thanks

I've worked with west systems epoxy, By far my least favorite,

Way too much amine blush which makes secondry bonding troublesome, and the 4:1 mixing ratio leaves a lot of room for error. 2:1 is much better, but I prefer using to mix by weight. 100:45 or 44 or 43 depending on the epoxies I use.

West is kind of Ubiquitous, but few who work on boars choose it.