Woodworkers of Irate... Teak to MDF attachment

[AlxJ64]

My ex father-in-law, Tim, was helping me out on installing some flooring in my old truck project but that was a few years ago and things went sideways.

The boards are ripped 5/8" thick Teak deck boards from the Battleship BB-55 North Carolina. They were removed in the '90s and stored. Originally there were only 5 boards available so had to rip them to get the coverage possible to veneer the rear floor of the truck.

The boards were sawn, fit, and laid out on a piece of 5/8" thick marine grade MDF. Tim's idea was to essentially use flooring glue to attach them to the MDF and that way the entire floor was one big panel that I could pull in and out of the truck as needed. It also reduced the chances of the boards moving around individually due to the sheet metal floor of the truck having some deflection properties.

We got it all done and attached to the panel, but the flooring glue was not curing right. Let it sit over the weekend and still not much. So I put it in my storage unit and there it sat for a few months as I was working on other things.. came in and moved it one day and all but one of the boards pretty much fell off the thing. That was in 2019. In the meantime I got divorced, moved, blah blah, and am finally back to working on the truck.

So... I am wondering, was the flooring glue just the wrong stuff? He looked at the tubes and it was several, if not 10 years old so maybe thinking it went bad.

I would rather find a mechanical means to attach these but I don't want a bunch of exposed hardware. There are two rows of seats that also go into this thing, and they are installed with keys that allow the seats to be moved around into various arrangements.

Suggestions on methods to attach these boards to this deck and then the seat key hardware will hold the whole thing into the back of the truck? Try again with the glue thing?

 

[lt1yj]

Teak has a high oil content that makes it withstand the weather.

In order to properly glue teak you need to clean the surface with a solvent to remove the oil then you can glue to the appropriate substrate. I'm not familiar with flooring glue but have had good luck gluing teak to teak using Titebond III glue.

In order to use Titebond you will need a smooth surface. Rough sawn won't have enough surface area and will absorb an enormous amount of glue and not hold.

 

[ZSK]

Mechanically attaching seems like a really viable option. At 5/8" thick it seems a lot like flooring, you could probably toe nail one edge of each board and use some floating biscuits to tie the next board to the one that is next to it.

T nuts (or bolts) seem interesting also. Run a groove on the edge of the board and use a T nut with a countersunk bolt through the MDF.

T-nut

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T-Bolt

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[kf4zht]

Titebond 3. Good prep, you will want to have the backsides of the teak smooth. Use a pin nailer for some added strength against shifting during glueup.

I would buy new glue for a project of this size. Uncured glue does age, especially if its somewhere that allowed it to freeze and thaw.

Marine grade MDF? Seems like an oxymoron. What is in the first pic is not MDF. Good plywood is just as good a choice and might hold up better

 

[[486]]

Marine grade MDF? Seems like an oxymoron. What is in the first pic is not MDF. Good plywood is just as good a choice and might hold up better

prolly 'MDO' rather than 'mdf'

you know, the plywood that's got masonite veneer on the faces, like you'd use for forming concrete

 

[gladman]

I think mechanically connect the marine grade plywood to the bed, then adapt trex style fasteners from the teak to ¾" marine grade plywood.

 

[kf4zht]

prolly 'MDO' rather than 'mdf'

you know, the plywood that's got masonite veneer on the faces, like you'd use for forming concrete

Maybe, that would probably be an even worse substrate. I use masonite for bench tops since you can pop glue drips right off of it.

 

[AlxJ64]

Titebond 3. Good prep, you will want to have the backsides of the teak smooth. Use a pin nailer for some added strength against shifting during glueup.

I would buy new glue for a project of this size. Uncured glue does age, especially if its somewhere that allowed it to freeze and thaw.

Marine grade MDF? Seems like an oxymoron. What is in the first pic is not MDF. Good plywood is just as good a choice and might hold up better

prolly 'MDO' rather than 'mdf'

you know, the plywood that's got masonite veneer on the faces, like you'd use for forming concrete

Maybe, that would probably be an even worse substrate. I use masonite for bench tops since you can pop glue drips right off of it.

I think you guys are right, I think it is MDO. If I recall the original thoughts on that were because it was outdoor rated for signs and other such things.

I'm on the fence with using a Marine epoxy fastening system, or also weighing the thoughts of doing a hidden strip type setup. Cut a groove in the board edges, slip a strip of aluminum flat bar between the boards then drill in from the back with a drill with a stop on it, then drill and tap the aluminum strip and use countersunk 10-32s that are 1" long so they don't quite go through the other side of the board but will thread into the aluminum strip and hold the board down.
For the edges, I was planning on breaking and installing some trim sheets anyways with exposed hardware. I've got a buddy with an 8' brake that can do those for me, and I'll use the shrinker/stretcher for that.

Hrmm. Best way for ripping the 1/8" groove in the boards? A router I guess?

 

[[486]]

Hrmm. Best way for ripping the 1/8" groove in the boards? A router I guess?

table saw?

 

[kf4zht]

Why not just do it like the wood truck beds? Or maybe that is what you are describing.

 

[FC4X4]

If you decide to glue again, you need 100% coverage, not blobs here and there. Liquid Nails and a V-notched trowel should do the trick.

The problem I foresee, is that when things are laminated onto one side of a substrate only, the panel is out out balance and changing moisture conditions will make it bow one way or the other, depending on which material more easily absorbs and desorbs moisture.

 

[gladman]

I think you guys are right, I think it is MDO. If I recall the original thoughts on that were because it was outdoor rated for signs and other such things.

I'm on the fence with using a Marine epoxy fastening system, or also weighing the thoughts of doing a hidden strip type setup. Cut a groove in the board edges, slip a strip of aluminum flat bar between the boards then drill in from the back with a drill with a stop on it, then drill and tap the aluminum strip and use countersunk 10-32s that are 1" long so they don't quite go through the other side of the board but will thread into the aluminum strip and hold the board down.
For the edges, I was planning on breaking and installing some trim sheets anyways with exposed hardware. I've got a buddy with an 8' brake that can do those for me, and I'll use the shrinker/stretcher for that.

Hrmm. Best way for ripping the 1/8" groove in the boards? A router I guess?

yep. I'd do it like that. set up your router table and they'll be uniform and it will look clean. Fasten the plywood from 'under' so that if you HAD to remove it, you'd have like 5 or 6 fasteners to disconnect and you could remove the whole thing.

 

[[486]]

maybe sommadat expanding foam subfloor adhesive like great stuff makes in their "professional" applicator gun thingie

 

[budget76]

I'm with someone above, at least similar anyway. I'd want mechanical based on the above comment that teak is oily

In my head: make it install like you're laying house flooring. Too late to tongue-and-groove it, don't waste what you have. Use a combination of a flooring stapler and biscuit joints. You have access to both edges and no walls in they way, so you can do the first board with staples on both sides, put a couple biscuit grooves in the inner side of the first board and the matching face of the 2nd board, lay in the 2nd board, staple the far side of the 2nd board, rinse and repeat. shouldn't take very long and I think it'd be nice and sturdy. If you want to throw some sort of adhesive underneath on top of the staples it might just solidify it more.


I laid 2,000+ft^2 of flooring with this guy. Think I had 1 misfire, and 1 jam when I double-fired by mistake. Definitely didn't pay $200, probably bought off Ebay. It gets the staples pretty flush with the board edges: plenty close to where you could use a small deadblow to dent the mating boards around the protrusion if needed

 

[gbiddlec]

I agree with the above. Use way more glue, like cover the entire panel, and toe nail with finish nails. I'd probably go with marine ply or advantech over MDO or MDF.

I've used gorilla glue with high-oil woods like IPE, Tight bond would soak in enough to get good bond. I don't think old/weathered mahogany will have the same issue though and I would worry about expansion with gorilla glue here. If you have any scrap left, test glue a piece to whatever backer you end up with and see how it bonds.

 

[Pony_Driver]

I think a mechanical fastener would be best. I am not an engineer, but I would think that the thermal cycling across that much width is what popped those planks off. Short barrel insert, fastened from the bottom. JMHO

 

[subybaja]

Don't reinvent the wheel. Go find out how boat builders make teak decks.

Installing a Teak Deck on ZATARA - Epoxyworks

by Ken Newell The Zatara refit project began two years ago when my partner Steve Gallo (a mortgage banker) and myself, Ken Newell (a materials engineer), decided that we wanted something to do with our spare

www.epoxyworks.com

No idea if this is the correct way, I just liked the pic.

 

[AlxJ64]

I ended up going with the slotted sides, 1" wide aluminum flat bar strips, SS countersunk screws in a 10-32 flavor so I have 4 threads of contact in the flat bar. Seems to give me a pretty good amount of clamping power with about a 12 to 14" spacing. I used the 1943 Bridgeport which was originally owned by the Navy to mill the slots. The clamps are set just above the thickness of the board and the router bit had a depth guide roller bearing on it. Just slid the board down the mill table and it cut great.