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freefallillusion1
Veteran user
Cincinnati, OH
369 Posts
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Posted: Apr 30, 2012 11:29am
Hey all,
I need plywood that measures, say, five feet by five feet (or larger). I can't use any type of wood strip to screw into, as I need the surface on both sides to be the original thickness. Does anyone know if it's possible to do a simple glue butt-joint? I've never heard of this being done with plywood, and probably for good reason. It seems like the edges would not bond as with hardwood, and I would also think the plywood would have a tendency to warp when clamped. Any solutions?
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freefallillusion1
Veteran user
Cincinnati, OH
369 Posts
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Posted: Apr 30, 2012 11:37am
BTW, I forgot to mention that I have seen a couple of places that do carry widths up to 60", but if I need something even larger? Thanks!
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makeupguy
Inner circle
1255 Posts
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Posted: Apr 30, 2012 11:47am
I would dado both sides... and use some sort of thinner plywood, with the grain going in the opposite direction to use like a lap joint... but make sure to put the cross grained wood on both sides.. and use plenty of glue.. and sand bags or weights to weight it down. Sand the joint to make it smooth.
you certainly can't butt joint plywood.. it would have no strength.. even using modern glues.
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hugmagic
Inner circle
6548 Posts
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Posted: Apr 30, 2012 11:51am
I would do a lap joint on the two piece with plenty of glue.
Richard
Richard E. Hughes, Hughes Magic Inc., 352 N. Prospect St., Ravenna, OH 44266 (330)296-4023
www.hughesmagic.com
email-hugmagic@raex.com
Write direct as I will be turning off my PM's.
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gimpy2
Special user
575 Posts
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Posted: Apr 30, 2012 12:55pm
Baltic birch sheets are 5x5. If it only needs to be a bit larger you could glue up some hardwood strips on the edges. The strips can be put on with biscuts or a spline.
Gimpy
www.gimpysmagic.com
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Flip Disc
New user
14 Posts
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Posted: Apr 30, 2012 3:45pm
The wider the lap joint the better. I'm saying something like a 4" lap. I would use a slower setting epoxy. Coat both laps and clamp it good.
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EsnRedshirt
Special user
Newark, CA
899 Posts
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Posted: Apr 30, 2012 4:55pm
Flip's got the right idea, I think. To make sure it glues flat, set several really heavy things (buckets of bricks, etc.) across the lap while it's drying. Easier than finding a clamp with a 2 1/2 foot reach...
Self-proclaimed Jack-of-all-trades and google expert*.
* = Take any advice from this person with a grain of salt.
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Michael Baker
Inner circle
Near a river in the Midwest
8454 Posts
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Posted: Apr 30, 2012 7:08pm
Or pop a few screws through the joint to snug it up until the glue dries. They can be backed out later and the holes filled. I think wood glue would produce a better bond than epoxy. Some epoxies degenerate over time.
Agreed on the wider lap. Cut rabbets with a hand-held router, beginning at the shoulder and gradually working toward the edge to remove the waste.
~michael baker
The Magic Company
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Bill Hegbli
Eternal Order
Bill and Bill in Fort Wayne Indiana
12874 Posts
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Posted: Apr 30, 2012 7:12pm
All my magic boxes I have used a simple box joint, they have held up for over 25 years. I did use Finland Plywood, with corner clamps and glued and nailed the edges in place. Then a small amount of putty covers the finishing nail heads.
I have never experienced glue causing the wood to warp, it is ususally that the wood was already warped prior to assembly.
If you have a good multi-layer plywood, there is not reason why the butt joint would not hold. If you only want to use glue, then you will have to invest in several cabinet pipe clamps to clamp the edges. Depending on the weight you are going to put on the wood, corner blocks may or may not be necessary.
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Pecan_Creek
Veteran user
The Nation of TEXAS!
331 Posts
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Posted: Apr 30, 2012 8:29pm
http://www.performancepanels.com/single.cfm?content=app_pp_group4
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Father Photius
Grammar Host
El Paso, TX (Formerly Amarillo)
15701 Posts
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Posted: Apr 30, 2012 9:48pm
I'd go with lap joints and be sure you get a solid core plywood. One where all the plys are solid.
"Now here's the man with the 25 cent hands, that two bit magician..."
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Pecan_Creek
Veteran user
The Nation of TEXAS!
331 Posts
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Posted: May 1, 2012 11:22am
If it is going to be painted you can use MDO with a lap joint glued and screwed . I would leave the screws in and countersunk .
If you want a really flat, tight joint make cauls twice as wide as the lap/scarf,one on bottom, one on top ( don't forget wax paper or plastic to keep the cauls from being permanent) and screw through the panels every few inches to get a good amount of clamping force.
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EsnRedshirt
Special user
Newark, CA
899 Posts
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Posted: May 1, 2012 12:06pm
Now that I think about it, if you've got a really good router and jig, and high quality plywood, you may be able to get away with dovetail joints (a lot of them.) It all depends on where the most stress will be placed on the panel.
Self-proclaimed Jack-of-all-trades and google expert*.
* = Take any advice from this person with a grain of salt.
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Dr. Solar
Elite user
Citrus Heights, Ca.
500 Posts
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Posted: May 2, 2012 2:07am
Ping Pong tables are over size. They used to come a full 5X9 or 10. How thick are we talking? How about laminating thinner sheets like Lauan plywood criss crossing them just like traditional plywood? You could use a good flooring glue/ mastic then roll over it with a linolium roller to spread the glue and force contact. You could even sandwich it all between 2x4 cleets and screw them together until it sets then use a wood filler to fill the screw holes. If you stagered the butts, you could make a 10' x 10' even. You will have a very solid sheet of material believe me.
"look for me in all things forgotten"
www.drsolar.com
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Jay Mahon
Special user
986 Posts
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Posted: May 8, 2012 12:58am
What's the application. If you need a massive sheet of ply something is off.
Can you explain what you are trying to do?
J
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freefallillusion1
Veteran user
Cincinnati, OH
369 Posts
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Posted: May 8, 2012 12:05pm
Quote:
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On 2012-05-08 00:58, Jay Mahon wrote:
What's the application. If you need a massive sheet of ply something is off.
Can you explain what you are trying to do?
J
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Sure! I am in the process of building ATA cases for all my illusions. I have a base that measures 5' by 5' (actually a fraction more when you account for the trim). As you know, when building cases, you have to build the case larger than the prop to allow for the foam padding, so a 5' sheet of ply would be off by an inch or so. Now, I've seen special extrusions that allow two pieces to be edge-joined (sort of an edge-to-edge double channel as opposed to the regular 90 degree double angle extrusion), but those would result in an extra piece of aluminum running down the face of a panel, and I really want the clean look. So, I don't really need to extend the sheet by all that much, just a little extra.
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EsnRedshirt
Special user
Newark, CA
899 Posts
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Posted: May 8, 2012 12:23pm
Any reason why you can't use a steel joining strip on the inside, so it'll be concealed by the foam?
Self-proclaimed Jack-of-all-trades and google expert*.
* = Take any advice from this person with a grain of salt.
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Jay Mahon
Special user
986 Posts
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Posted: May 8, 2012 4:27pm
Let me see if I understand this correctly.
You are looking for a way to make your prop cases look pretty? That is a recipe for disaster. These should be strong, not pretty.
Frame the inside of the box around the thing you are trying to protect. Then attach sheet goods. Anywhere there is a join, you can simply run a 2 by 4 down that seam and screw both sheets to the 2 by 4.
These are not meant to look great, they are meant to keep the contents looking great. You joinery ideas are fine, but what do you do when a truck accidentally backs up and hit the box? Or a forklift gives it a shot in the center?
With your method of joinery it will be weak but pretty especially as a HUGE seamless surface. Pressure in the center of that panel will be pretty easy to break through.
If you really feel this is the right way, that is fine, but I must recommend you drop the idea of pretty boxes protecting boxes and get more practical!
J
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freefallillusion1
Veteran user
Cincinnati, OH
369 Posts
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Posted: May 8, 2012 9:04pm
Quote:
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On 2012-05-08 16:27, Jay Mahon wrote:
Let me see if I understand this correctly.
You are looking for a way to make your prop cases look pretty? That is a recipe for disaster. These should be strong, not pretty.
Frame the inside of the box around the thing you are trying to protect. Then attach sheet goods. Anywhere there is a join, you can simply run a 2 by 4 down that seam and screw both sheets to the 2 by 4.
These are not meant to look great, they are meant to keep the contents looking great. You joinery ideas are fine, but what do you do when a truck accidentally backs up and hit the box? Or a forklift gives it a shot in the center?
With your method of joinery it will be weak but pretty especially as a HUGE seamless surface. Pressure in the center of that panel will be pretty easy to break through.
If you really feel this is the right way, that is fine, but I must recommend you drop the idea of pretty boxes protecting boxes and get more practical!
J
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Whoa, easy there. I know how to build cases, and no offense, but I would certainly never include a 2x4 inside as you suggest. I am building cases to protect my props and transport them safely, and the main concern is not to look pretty. However, once I have met that requirement, then yes, I would like to show up at a venue with a professional appearance. This would be the all black ATA cases, not a hodge-podge of heavy plywood crates. I was simply asking around because although "this ain't my first rodeo", I am not an individual who thinks they know everything, and I thought that someone might have a suggestion on how to get a few more inches out of a plywood sheet. The good news is that this forum is frequented by many knowledgable builders and they have offered me some great suggestions! Thanks everyone!
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George Ledo
Magic Café Columnist
SF Bay Area
2197 Posts
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Posted: May 11, 2012 3:30pm
Okay, not to toot my own horn, but you may want to ask around and see what people think of my book "Boxes, Cases, and Crates," published in January by Leaping Lizards. It's precisely on the subject of making travel cases for magic stuff, although I do mention that ATA-style cases aren't always necessary. Michael Baker did a review a month or so ago; you can find it in the book-review section here in the Café.
That's Burt, aka The Great Burtini, doing his famous Cups and Mice routine
Latest column: That's cool, but why are you doing it?
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Michael Baker
Inner circle
Near a river in the Midwest
8454 Posts
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Posted: May 11, 2012 6:27pm
http://www.themagiccafe.com/forums/viewtopic.php?topic=461777&forum=110&0
~michael baker
The Magic Company
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AngeloR
Veteran user
343 Posts
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Posted: May 27, 2012 3:12am
Biscuit joinery can be used to join solid wood edge-to-edge. It should work with high-quality (i.e. no voids) plywood. Baltic birch plywood is pretty expensive but would fit the bill. I think biscuits can also be used to join mdf, but mdf is denser than plywood. As a result, a given volume of mdf is significantly heavier than an equal volume of plywood and may be a poor choice for your application.
Biscuit joinery requires that rather precise "slots" be cut into the wood surfaces. This cutting can be done either with a dedicated piece of equipment called a biscuit joiner (go figure ...  ) or a special router bit designed for the purpose. The wooden biscuits that fit the slots are available online or through a woodworkers retail outlet, such as Rocklers.
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