# Help with building planter box (type of wood, joint, etc.)



## nolo (Apr 14, 2009)

I need to build several planter boxes 30x15x10. I want to use sanded plywood (pine). I can buy hardwood sandeply for $13 more a sheet. I need two sheets total. Which type of plywood would work best? The boxes are going to be painted, and I'm going to use a rabbet joint for the corners. I will also use minimal framing inside. Is it fairly easy to use router bits on the hardwood plywood? Any suggestions are greatly appreciated.

Thank you


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## TGRANT (Jan 25, 2011)

If you are going to paint, there isn't a need to buy fancy hardwood. Sanded plywood should work fine. Hardwood plywood usually has a very thin surface layer of hardwood, so the glue holding the veneer core (which is likely made out of softwood anyway) is the toughest on the tools. It is true that some hardwood plywood’s might have a better core (less voids and so on) but good quality softwood plywood should be good. The cheap builder’s grade plywood should be avoided.


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## Taylormade (Feb 3, 2011)

Are these planters going to be outside and have plants in them?? If so, there's moisture in them and I'd advise to buy everything PT. They have pressure treated ply but honestly I don't believe it's something I'd venture into. I've always made my planters out of 1x material. Maybe I'm missing something.


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## jack warner (Oct 15, 2010)

i wouldnt use ply for a planter. water and plywood not a good combo


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## nolo (Apr 14, 2009)

The planters will be used for decorative purposes. They will have fresh flowers in them during the day and stored indoors at night. They will be used one day a week. I plan on using a good quality primer and exterior paint.


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## Kirkus (Dec 19, 2010)

I'd definitely use pressure treated material and stay away from the plywood. Even a short rain, or even fog could ruin your ply -- unless it's coated with titanium. 

This is from experience.


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## jschaben (Apr 1, 2010)

nolo said:


> The planters will be used for decorative purposes. They will have fresh flowers in them during the day and stored indoors at night. They will be used one day a week. I plan on using a good quality primer and exterior paint.


I agree with the TGRANT about sanded ply, save your money on the hardwood ply and spend it on paint. I would prime all six sides (edges, ends and faces) prior to assembly. Tape off the glue joint areas so the glue is wood to wood, not paint to paint. After assembly, prime again and finish. Would also suggest polyurethane glue (Gorilla glue).:thumbsup:


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## Just Bill (Dec 29, 2008)

No one suggested cedar, naturally resistent to rot. Make sure the bottom and sides are tied together to support the weight of whatever in is them. I would slot the sides and fit the bottom into that.


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## SteveEl (Sep 7, 2010)

I would put the plants in plastic planters, and use the box for decoration. Drain holes? If you don't trust the paint to protect the exposed cut edge of the plywood around the rim, you might top the rim of the box with solid wood, with a bevel or roundover to shed water.


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## dbhost (Jan 28, 2008)

I would avoid plywood for planters. I have built several for our home, and I typically get 4x4 rough milled cedar and mill it to dimension. I have also used Cedar fence pickets for the same job. They work really nice, resist the elements nicely, and take on a great red / amber patina after about 3 years...


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## Seth (Mar 23, 2010)

With the exception of using basic 2x2's for the framing, ive used cedar....all the way  I've made 4 so far and it's been great.


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## nolo (Apr 14, 2009)

Thank you for all the help. I have never used polyurethane glue before. How much stronger is it compared to Titebond II wood glue? Also, is it easy to work with (workable time, easy clean up, etc.)?


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## Rob (Oct 31, 2006)

I would consider using PVC sheetgoods. Machines like wood and will take latex paint.


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## dwendt1978 (Mar 13, 2010)

Very nice Seth. How big are they? Love the mitered corners.


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## johnnie52 (Feb 16, 2009)

I got to agree with the guys who say use cedar instead of ply. No matter how well you try to paint ply, you will have moisture from watering the plants and from the dirt the plants are in to contend with. Glued plywood does not hold together well at the edges of the pieces in the presence of moisture, even when you use gorilla glue.

As for the working time of gorilla glue, figure overnight for a full cure. Also, that stuff needs moisture on the wood for it to work properly and it tends to foam and expand as it cures. Any area where the cured glue is exposed will not take paint as well as the rest of the piece.


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## jschaben (Apr 1, 2010)

nolo said:


> Thank you for all the help. I have never used polyurethane glue before. How much stronger is it compared to Titebond II wood glue? Also, is it easy to work with (workable time, easy clean up, etc.)?


Hi - First, let me make sure I understand your project. This is strictly a prop? Will, or should, never have dirt nor live flowers in it? If so, we're not really building a planter, just a painted box. :bangin:
As far as PU glue goes, it cleans up with mineral spirits/paint thinner. Excess will foam out but easily peels off after it is cured, paint before glue up, as previously suggested, and you have no issues getting paint paint to stick. I have never had issues with a good primer sticking to it anyway. Usually after removing any foam, you are just left with a glue line anyway. It expands about 5 times it's volume while curing so you just use a small bead on one side of the joint, spritz with a little water and assemble. Assembly time is 20-30 minutes. I especially like it for plywood because plywood is 50% end grain and this stuff climbs right in following the water. Don't get the wood to wet, just moist, or it won't crawl into the wood as far. 
Good Luck:smile:


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## nolo (Apr 14, 2009)

jschaben said:


> Hi - First, let me make sure I understand your project. This is strictly a prop? Will, or should, never have dirt nor live flowers in it? If so, we're not really building a planter, just a painted box. :bangin:
> As far as PU glue goes, it cleans up with mineral spirits/paint thinner. Excess will foam out but easily peels off after it is cured, paint before glue up, as previously suggested, and you have no issues getting paint paint to stick. I have never had issues with a good primer sticking to it anyway. Usually after removing any foam, you are just left with a glue line anyway. It expands about 5 times it's volume while curing so you just use a small bead on one side of the joint, spritz with a little water and assemble. Assembly time is 20-30 minutes. I especially like it for plywood because plywood is 50% end grain and this stuff climbs right in following the water. Don't get the wood to wet, just moist, or it won't crawl into the wood as far.
> Good Luck:smile:



Yes, the box is just used for decorative purposes. They will hold fresh flowers. There will be minimal water. If there is any water, it will be a few drops. The shelf could get a little moist. The boxes will not be used as a true planter box. There will not be any dirt or the need to water them. They might have to weather a light rain. Sorry for the confusion.

I purchased some Gorilla Glue today. I'm going with a rabbet joint. It says to dampen the surface before applying the glue. I guess I have a few more questions for everyone.

How deep should I make the rabbet joint? I puchased 3/4 sanded plywood. I am planning on using the router on the end pieces. Should I go half way through the plywood? I was going to try to set the depth to match one of the layers of the plywood. Is this a good idea?

As far as applying the glue, I just want to do it correctly. Basically, I only need to apply it to one side. Do I apply it to the entire rabbet joint including the shoulder? I can use a small brush to apply a thin coat. I was going to just get a damp cloth to dampen the plywood. Is it better to use a spray bottle?

Thanks again for all the help. This is a great site.


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## Seth (Mar 23, 2010)

dwendt1978 said:


> Very nice Seth. How big are they? Love the mitered corners.


Thanks! They were my first "real" project and were fun to build. If my memory serves me correctly I think I built them 30-inches long, 20-inches wide, and 16 or 20-inches deep. The brown one in my pic was my first one and I didn't like the brown color so I decided to leave them natural...I kinda like the natural better 

-Seth


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## jschaben (Apr 1, 2010)

nolo said:


> Yes, the box is just used for decorative purposes. They will hold fresh flowers. There will be minimal water. If there is any water, it will be a few drops. The shelf could get a little moist. The boxes will not be used as a true planter box. There will not be any dirt or the need to water them. They might have to weather a light rain. Sorry for the confusion.
> 
> I purchased some Gorilla Glue today. I'm going with a rabbet joint. It says to dampen the surface before applying the glue. I guess I have a few more questions for everyone.
> 
> ...


 
OK, that's the way I was reading your post. 

I usually make the rabbet 1/2 the depth of the recieving board. 1 ply depth would be a little slim IMO. I usually just use a pump sprayer and give it a few spritz' and let it set for a minute, Run about a 1/4", or a little less, bead of PU right down the corner of the rabbet. No need to spread it with a brush unless you want to, it will expand toward the moisture. Damp/wet cloth will work, I like the spray as I can get more even coverage. 
Good Luck :smile:


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## nolo (Apr 14, 2009)

jschaben said:


> OK, that's the way I was reading your post.
> 
> I usually make the rabbet 1/2 the depth of the recieving board. 1 ply depth would be a little slim IMO. I usually just use a pump sprayer and give it a few spritz' and let it set for a minute, Run about a 1/4", or a little less, bead of PU right down the corner of the rabbet. No need to spread it with a brush unless you want to, it will expand toward the moisture. Damp/wet cloth will work, I like the spray as I can get more even coverage.
> Good Luck :smile:



Thank you. I appreciate the help. I'll go half the depth of the plywood (3/8").


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## dbhost (Jan 28, 2008)

As far as glue is concerned. The PU glue is quite a bit stronger than Titebond (let's call it TB) II in this application. HOWEVER, this is the WRONG application for TB II. You would want either PU glue (Gorilla Glue etc...) or TB III which is water proof, not just water resistant, and intended for outdoor projects...

I personally prefer TB II and TB III for all of my projects. It's reasonably inexpensive, it does what the MFG says it does, and it's stronger than most of the woods I use. Typically when I have a joint fail, it's the stock that fails, not the glue... 

Gorilla Glue, or similar glues are great if you have an uneven bonding surface because it expands and makes up the gaps. It is lousy though in that it nearly sets up in the bottle as you watch, and as it sets up, it foams, leaving an almost expanding foam type residue by the joints it secures... Simply put, I do not like the stuff.


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