# Gluing Pressure treated wood to plywood?



## noela (May 22, 2008)

I have an application that requires that I attach 2x2's of pressure treated wood to 1/2" plywood. This wood needs to be permanently secured to the plywood, but I cannot get to the other side so that I can use screws. I can clamp the wood to the plywood, but I need some sort of glue to use for an adhesive. Effectively, this wood will be used as a handle, hence the need to have it permanently adhered. I originally thought of epoxy, but I don't think that will work. I am looking for suggestions, and really appreciate any input regarding this.
Thank you. 
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## Burl (Jan 2, 2008)

Is it going to be outside? I hear Gorilla glue works well for such applications.


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## Totalwrecker (Feb 26, 2009)

I'd toe in some sheet rock screws for added strength. 
I heard a rumor about Gorrila softening in humidity. 
John


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## Mike Reilley (Jan 2, 2008)

No matter what you use, you will be limited by the strength of the glue used to glue up the outer ply of the plywood when the sheet was made. If you use Titebond III, you'll get as good a waterproof joint as can be made...one that might even go all the way through that first ply. If your plywood is really OSB, you have other gluing issues. It's important to be precise here as OSB is mostly glue that you're gluing to...and frankly, I wouldn't even try.

Then we have the issue of the treated wood handle. I'm not sure that penetrating glues will penetrate treated wood...so Titebond III might make a very weak joint. I mean, some wood treatments are designed to keep water and critters out. I'd run a test first. 

Gorilla glue won't penetrate...therefore, your strength is limited only by the outermost fibers of the plywood...but it do stick like heck.

Is this plywood up against something that prohibits you from using a wall anchor...and getting some mechanical strength? With a mechanical and glued "handle", you'll not be limited by the strength of just the plywood glue. There are some good size ones out there, like this one. Wall Anchor


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## noela (May 22, 2008)

I apologize, I should have provided some more information. 
I need to put the handles behind the drip edge on the working side of my storage shed. 
The roof is OSB, but, where I am going to put the handles (to make it easier to lift up as there are some nails from the shingles in the doors). It is outside, but the water shouldn't get to the area where I am putting the handles. 
Obviously I do not have a clue as to the best glue, or something that will hold. I was toying with Tightbond III, or Gorilla Glue as I have used them before on other applications, and they seem to be fine where I have used them. On this application, I wanted to draw on the expertise of those that have done similar projects with success. I have chosen pressure treated wood, because that is what I have on hand, but if there is another material that I could use for this purpose I do not have a closed mind. The handle will serve two purposes, one to raise up the door, and the other to provide for a method of locking the doors to the building for security purposes. 
The following YouTube video shows the doors, there are 7 of them, and that is where I want to put the handles: http://www.youtube.com/watch?v=G7rmi_cTl48&feature=related 
Needless to say, I do thank you for the responses. I was hoping to finish this before old man winter got here, but there's a very good chance we're going to get 6-10 inches of snow this weekend, and when it snows this early, it usually sticks around for a while.


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## DKRickman (Mar 25, 2008)

I'm not quite sure why you say you cannot use screws. You don't want to go through the shingles, of course, but what's wrong with a screw through the 2x2 into the roof? If it were me, I'd do that (using stainless steel screws, if practical) and either epoxy of a good wood glue like Tightbond. Given the nature of your design, I don't think there will be a lot of tension on the joint, so the glue of choice should not be too critical. 

One thing about wood glue joints, though. They do not hold well if you just smear glue on two chunks of wood. If both surfaces are as smooth as you can get them, so that there is a VERY thin and VERY even layer of glue in there, and if the joint is properly clamped, the joint is stronger than the base wood. This has been tested and demonstrated many times, most visibly by trying to break off-cuts from glued up boards. Properly done, the wood always breaks before the glue.


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## Richard Smith (Jan 2, 2008)

Like Kenneth I don't understand why you can't use screws. But if you insist how about wooden dowels. Drill holes for a press fit, use a water proof contact cement on the dowels throught the handles and into the doors. The dowels will swell in place. Additionally a cap cam be brad nailed over the handles and dowel ends for additional seal. Of course a cap could be used over screws as well.


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## noela (May 22, 2008)

I am showing my lack of knowledge in this area every time I write. I am using 17/32 OSB, and yes, I do not want to have the screws go through to the shingles. Like the rest of the overkill I am used to performing when I build, stainless is my screw of choice when I am outside. My question on this matter would be regarding the screws, because if I can use them, along with glue, I would be happier than a pig in a stye. What number screw should I use. Should I use Flat head or pan head. How big a screw should I use in terms of length (how much of the screw should penetrate the plywood, i.e.: 3/8th, 5/16th, etc.). The dowels sound like a great idea, but if I could get the right screw, and the right glue I could drill pilot holes in the handles, clamp the handles in place and then screw them in. 
Thank you again for the suggestions.


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## armorsmith (Jun 1, 2008)

If the 'treatment' of the pressure treatment is not dry, most adhesives will work less than as advertised, at best. Some may not work at all, depending on the chemistry. I do not know the name of the adhesive, but there is a polyurethane glue available that requires the substrate to be wetted before application, is an outdoor adhesive, and sticks like nobody's business. I saw it used on 'New Yankee Workshop' for some outdoor furniture they were making. The also recommended not getting it on your fingers, it would have to wear off, no thinners. 

Bob C.


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## Mike Reilley (Jan 2, 2008)

I really don't see much of a problem now. I snapped this photo from your video. 


Use Gorilla glue to glue the handle to the underside of the roof just behind the metal drip edge. You won't even need screws if you clamp it well as the glue sets. It's well protected, so it should stay affixed...and it's really got little stress on it given the way you'll lift the roof section. 

You might consider putting some rubber self stick insulation on the top of the 2x4s that the roof sits on to provide a better anti-bug seal.


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## Richard Smith (Jan 2, 2008)

For outdoors on my benchwork I use self tapping deck screws, the good ones not the cheapies. They will seat themselves down tight and a bit of caulking on the threads would provide a good seal in addition. The screws come in various lengths, around here 1-3/8" to 3-1/2". Take your pick. Even though the screws are self tapping I still drill 1/8" pilot holes so the screws go exactly where I want them. As a guide to quality the screws I use cost $7.95 a lb out here in Oregon as opposed to the $2.95-$3.95 lb cheapies. Don't let anybody kid you...there is a difference. 

If the screws will come through the doors just clamp a piece of wood to the inside of the door for the screws to go into. Provides additional strength to the handle as well. Glue would not be needed.


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## noela (May 22, 2008)

Thank you for the suggestion. Thank you also for the pix of the doors. How did you get the bubbles in the picture, you've directed folks to the very areas I was talking about, and a picture is definitely worth a 1000 [email protected] url(http://www.mylargescale.com/Providers/HtmlEditorProviders/CEHtmlEditorProvider/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css);


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## Michael Glavin (Jan 2, 2009)

Polyurethane glues are superior in this application, Gorilla Glue is brand name for a polyurethane (there are many). As was mentioned previously a light spray mist of water is required to allow the glue to migrate. These glues expand somewhat and are VERY strong and waterproof too. Pressure treated wood products generally have some sort of perforations which would allow superior penetration as the glue expands IMO. 

Clamps and a minimal amount of glue is all that’s required, I’d suggest some experimentation on scraps with the glue and clamps. Poly glues are superior in most applications but require some experience to prevent them from expanding more than is required ala the water misting. 

We use the poly glues in aircraft construction (foam core wing/stabilizers with balsa skin is an excellent example) of late and found it to be far superior to other products specifically because it permeates or expands like none other and does not react to heat adversely as epoxy glues are known too… 

Michael


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## DKRickman (Mar 25, 2008)

If I understand you correctly, you want to apply a 2x2 to the bottom edge of the 17/32 OSB roof, to serve as a simple handle when lifting the roof. Is that correct? 

First of all, stainless steel screws are not overkill at all. Steel (coated or not) *will* rust over time, and when it does it will loosen its grip on the wood. Stainless is the most reliable mechanical fastener material I know of for most applications. 

Assuming I am correct in understanding your design, you do not need much in the way of a fastener. The load on the joint would be minimal, and would mostly involve keeping the 2x2 from falling off, since it would be hanging by the joint. Construction adhesive might actually be the best option here. I also really like the suggestion of dowels, but it may be hard to drill the needed holes now that the shingles are already in place. The problem with any metal fastener is that it will fail over time, because the wood will swell and move and shrink, opening the hole and causing the joint to fail. Also, face-gluing to OSB is problematic because it is not that difficult to get the material to de-laminate. The dowels are by far the strongest and most reliable long-term solution, although I would use a good waterproof wood glue rather than contact cement. Simpler and easier would be a good smear of construction adhesive (outdoor grade, of course) with some screws up through the 2x2 and biting into the OSB, just to keep things registered and add a little extra clamping force. A deck screw would be my choice, and I'd drill out the 2x2 to allow the screw to pass through freely. Liberally smear more adhesive on the screw threads, to fill the hole and prevent water getting into the wood that way, as well as to allow a little bit of flexibility as the wood moves.


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## Mike Reilley (Jan 2, 2008)

Posted By noela on 28 Oct 2011 08:38 PM 
Thank you for the suggestion. Thank you also for the pix of the doors. How did you get the bubbles in the picture, you've directed folks to the very areas I was talking about, and a picture is definitely worth a 1000 [email protected] url(http://www.mylargescale.com/Provide...ad.ashx?type=style&file=SyntaxHighlighter.css);@import url(/providers/htmleditorproviders/cehtmleditorprovider/dnngeneral.css); 
I freeze framed the video at that point...captured the screen shot with Print Screen keyboard actions...then I pasted the screen shot into Visio...cropped it....added the annotations with Visio and saved it as a jpg. Kinda routine for me actually. Then I just uploaded it and posted it.


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