Screws necessary in sandwich wall construction?

[eagle24]

I'm planning to stick frame between 1/4" plywood inside and out. I'll either use Titebond II or Marine Epoxy (haven't decided). Are fasteners necessary to hold the outer plywood? or just glue?

[tony.latham]

I'm planning to stick frame between 1/4" plywood inside and out. I'll either use Titebond II or Marine Epoxy (haven't decided). Are fasteners necessary to hold the outer plywood? or just glue?

Glue is just fine. But if you go with TB2 you’ll need lots of weight. (And you can’t afford to have a glue starved joint of course.)

If you go with the TB2, make sure you have things planned out and have a friend help. You don’t have much time and you’ll have to have your ducks in a row.

Tony


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[bdosborn]

I didn't use any screws for mine and it's been fine over the last 9 years:



Of course I applied several tons of clamping force while the glue set by vacuum clamping the sides:



Bruce

[S. Heisley]

Just to clarify, you will want to use both glue and screws in your stick frame skeleton; but, simply gluing the plywood to the constructed frame has worked fine for many of us.

[bdosborn]

Just to clarify, you will want to use both glue and screws in your stick frame skeleton; but, simply gluing the plywood to the constructed frame has worked fine for many of us.

Good point!
Bruce

[eagle24]

Just to clarify, you will want to use both glue and screws in your stick frame skeleton; but, simply gluing the plywood to the constructed frame has worked fine for many of us.

I was planning to cut the wall skins (inside and outside). Glue the skeleton pieces to the inside wall and put the foam board in between. Then glue the outer wall skin on. Would I still need screws in the skeleton doing it this way? I'll probably use West Systems Epoxy to glue everything.

[S. Heisley]

Just to clarify, you will want to use both glue and screws in your stick frame skeleton; but, simply gluing the plywood to the constructed frame has worked fine for many of us.

I was planning to cut the wall skins (inside and outside). Glue the skeleton pieces to the inside wall and put the foam board in between. Then glue the outer wall skin on. Would I still need screws in the skeleton doing it this way? I'll probably use West Systems Epoxy to glue everything.

If you're going to use one piece 3/4 inch cut-out plywood for your skeletal wall, it should be okay, as long as you glue and screw all the pieces together (wall to wall, etc), which, I believe you will.

[eagle24]

If you're going to use one piece 3/4 inch cut-out plywood for your skeletal wall, it should be okay, as long as you glue and screw all the pieces together (wall to wall, etc), which, I believe you will.

Planning to stick frame it with some 3/4" poplar I have in my shop. My plan was not to use ANY screws. Bad plan?

[Tom&Shelly]

If you're going to use one piece 3/4 inch cut-out plywood for your skeletal wall, it should be okay, as long as you glue and screw all the pieces together (wall to wall, etc), which, I believe you will.

Planning to stick frame it with some 3/4" poplar I have in my shop. My plan was not to use ANY screws. Bad plan?

I did our floor almost that way. The teardrop is still under construction, so I can't comment from experience on how well it will hold up.

I first made a frame from poplar. Used biscuit joints at the intersections, glued with Titebond 3. I believe those joints, in general, are at least as good as any joints done with screws. The real strength comes from gluing the frame to the skins (also done with TB 3 in our case). My understanding is that the joints in the frame are there simply to hold the frame together until the skins (and foam) are glued on, and that the frame joints contribute (nearly) nothing to the panel integrity.

Again though, I have no direct experience with any long term issues...

Tom

[S. Heisley]

If you're going to use one piece 3/4 inch cut-out plywood for your skeletal wall, it should be okay, as long as you glue and screw all the pieces together (wall to wall, etc), which, I believe you will.

Planning to stick frame it with some 3/4" poplar I have in my shop. My plan was not to use ANY screws. Bad plan?

I wouldn't trust it; but, that's me. I'm human and I know it. I like the stronger guarantee of a second form of attachment. TB is good but nothing is perfect.

[bdosborn]

I think it's hard enough to make your framing plumb and square with screws, it would be pretty tough without them.

Bruce

[Tom&Shelly]

If you go with the TB2, make sure you have things planned out and have a friend help. You don’t have much time and you’ll have to have your ducks in a row.

Tony


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Just today noticed the jug of TB 3 says something about a longer open time (than what?: Titebond Original or 2, or Elmers, or Gorilla, or what?) Turns out 3 has twice the open time of 2:

https://www.thewoodwhisperer.com/articl ... ond-glues/

Still pays to know how you plan to glue up, have your friend fully "briefed", have clamps, rags handy, etc.

Tom

[eagle24]

If you go with the TB2, make sure you have things planned out and have a friend help. You don’t have much time and you’ll have to have your ducks in a row.

Tony


Sent from my iPad using Tapatalk

Just today noticed the jug of TB 3 says something about a longer open time (than what?: Titebond Original or 2, or Elmers, or Gorilla, or what?) Turns out 3 has twice the open time of 2:

https://www.thewoodwhisperer.com/articl ... ond-glues/

Still pays to know how you plan to glue up, have your friend fully "briefed", have clamps, rags handy, etc.

Tom

I'm gonna use the marine epoxy, so I won't have any issues with having time. I'll use a slow hardener. I'll lay the inside wall skin on a flat surface and glue all the framing to it. Was hoping somebody had done it this way. I may cut some lap joints. I'll know after the epoxy cures holding the framing to the inner wall if its gonna work. i have scarfed 2 sheets of 1/4" plywood for a 16' side on several boats I've built. The epoxy holds them fine without any fasteners. I'll take pics and post the outcome. Worse case I have to build another wall. Not the end of the world I guess.

[Esteban]

I used Tightbond II glue and a pneumatic 18 gauge 1/4" narrow crown stapler to attach the outer (1/4") plywood to the 3/4" inner framework. The stapler sped up the assembly process and considerably reduced the need to use clamps and/or weights to hold the pieces together while glue set up. The staples are permanent mechanical fasteners that strengthen and supplement the glue bond.

Prices start about $25 Amazon.com: pneumatic 18 gauge 1/4" narrow crown staplers

[Tom&Shelly]

I'm gonna use the marine epoxy, so I won't have any issues with having time. I'll use a slow hardener. I'll lay the inside wall skin on a flat surface and glue all the framing to it. Was hoping somebody had done it this way. I may cut some lap joints. I'll know after the epoxy cures holding the framing to the inner wall if its gonna work. i have scarfed 2 sheets of 1/4" plywood for a 16' side on several boats I've built. The epoxy holds them fine without any fasteners.

I expect that will work just fine.

Tom