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View Full Version : Gluing Down the Top of a DIY Stand, Without Screws?


SkyReef
07/22/2017, 09:59 PM
Built a RocketEngineer DIY Stand. About done with it. Thinking I will glue down the top of the stand, not screw and glue it. Reason: the top frame has been sanded and sanded and sanded and sanded, to make it even. It's good enough, but if you shine a light underneath the stand while the top plywood sits on it, you can see cracks of light through the plywood-top-frame junction in certain areas. Stated otherwise, there are stretches of the plywood-to-stud-frame perimeter, where the plywood is not contacting the stud frame beneath it. However, the non-contact points are not high off the frame, but only about the width of a hair. Moreover, it might make contact, with the weight of water in the tank, which has not yet been tested here.

By comparison, the empty tank, sitting on the plywood top makes full contact with the plywood top at every point along the perimeter of the bottom frame. Moreover, the opposite corners of the tank are level with each other, and not twisted.

My thought is this: if I screw and glue the top down, the screws will force the plywood to hug the top stud frame tight, spilling out the "excess" glue. This will merely transfer the hairline-waviness from the top frame, to the top of the plywood stand, causing the bottom of the stand to lose its pure-contact with the plywood around its perimeter. However, if I only glue the top down, and then weight it down lightly with the weight of the empty tank on it, the glue will not be completely forced out, as it would with screws. Instead the glue will act like a viscous leveler, filling in the hairline unevenness of the plywood top to the frame, making the plywood top have seamless contact all the way around the perimeter of the stand.

Does this make sense, or is this wrong? Your help is greatly appreciated.

michael.lemke
07/22/2017, 10:25 PM
Does the tank have a bottom frame or frameless?


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der_wille_zur_macht
07/22/2017, 10:32 PM
That sounds reasonable. The ultimate goal is a surface that is flat and true. There isn't exactly a lot of force on the joint between the framing and the plywood (basically, none) so it's not a big deal. These 2x lumber stands are generally waaaaay overbuilt anyways.

Might make sense to use a general purpose urethane construction adhesive (think: liquid nails brand, in a caulk gun tube) vs something like traditional wood glue.

SkyReef
07/22/2017, 11:27 PM
That sounds reasonable. The ultimate goal is a surface that is flat and true. There isn't exactly a lot of force on the joint between the framing and the plywood (basically, none) so it's not a big deal. These 2x lumber stands are generally waaaaay overbuilt anyways.

Might make sense to use a general purpose urethane construction adhesive (think: liquid nails brand, in a caulk gun tube) vs something like traditional wood glue.

Thanks, derWille. I was originally thinking Tightbond III, being waterproof, and all. But you raise an interesting thought. Liquid nails. Is this better or more viscous or stronger? I recall you built a huge plyood tank before. Is that what you used?


Does the tank have a bottom frame or frameless?

Thanks, Michael. Yes, it has a bottom frame.

der_wille_zur_macht
07/23/2017, 07:19 AM
You mentioned filling voids and self-leveling (I'm paraphrasing a bit) - I wouldn't use titebond for that. You don't need a lot of strength in this joint, you do need something with enough body to accomplish your gap filling goal.

The tank you're thinking of had screws, biscuits, epoxy, and gorilla glue holding it together. The stand it sat on had screws and construction adhesive. Generally, I use construction adhesive for rough work (clunky stuff that involves 2x lumber) and gorilla glue or titebond for finish work.

mcgyvr
07/23/2017, 07:55 AM
holy crap someone is overthinking... ;)

just glue on the top... titebond is fine..

billdogg
07/23/2017, 08:08 AM
As a gap filler, the construction adhesive would be the better choice just because it is much thicker than something like titebond III (the only wood glue I use, btw, and I use a lot)

I would put down I nice thick bead of the construction adhesive, place the plywood on top, then just hold it in place using the tank to apply pressure while it cures.

WillsNano63
07/23/2017, 08:13 AM
holy crap someone is overthinking... ;)

just glue on the top... titebond is fine.. LOL!! (something I used to do and got me nowhere! lol)

michael.lemke
07/23/2017, 08:59 AM
Glue her down and call it good.the tank frame is going to take care of the tank.


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SkyReef
07/23/2017, 11:11 AM
You mentioned filling voids and self-leveling (I'm paraphrasing a bit) - I wouldn't use titebond for that. You don't need a lot of strength in this joint, you do need something with enough body to accomplish your gap filling goal.

The tank you're thinking of had screws, biscuits, epoxy, and gorilla glue holding it together. The stand it sat on had screws and construction adhesive. Generally, I use construction adhesive for rough work (clunky stuff that involves 2x lumber) and gorilla glue or titebond for finish work.

Thanks, Derwille. That it clarifies it well. I'm going to follow your advice here.

holy crap someone is overthinking... ;)

just glue on the top... titebond is fine..

Thanks. Mcgyvr. Your point reassures me that I can't really screw this up. :)

As a gap filler, the construction adhesive would be the better choice just because it is much thicker than something like titebond III (the only wood glue I use, btw, and I use a lot)

I would put down I nice thick bead of the construction adhesive, place the plywood on top, then just hold it in place using the tank to apply pressure while it cures.

Thanks Billdogg that is a good explanation. I hadn't considered thicker adhesive before you and Derwille mentioned it. Makes sense.

LOL!! (something I used to do and got me nowhere! lol)

Over think now, sleep more later. :)

Glue her down and call it good.the tank frame is going to take care of the tank.

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Thanks, Michael. I'm going with the adhesive.

d0ughb0y
07/23/2017, 05:52 PM
.







Over think now, sleep more later. :)







Thanks, Michael. I'm going with the adhesive.


Would you be able to sleep knowing you only glued and not screwed?


Just kidding!

I'd say either way is fine.