12mm plywood for a portable bartop?

[ugleymatt]

Hi,

I'm in the research part of my build and looking at materials. I want to build a two player bartop using a 24in widescreen that i have. In order for it to pass the WAF (Wife acceptance factor) it needs to be relatively portable so that it can get put in the bottom of the wardrobe when its not being used.
Originally i was going to used 18mm MDF but reading around it seems that plywood is a lighter strong alternative. I then was thinking that 12mm plywood would allow it to be lighter still, but would it be strong enough?

[RobodocX]

MDF tends to be quite heavy per unit volume and not super strong at thinner thicknesses. It's also very porous.  It's primary advantage is cost and that it takes paint nicely. Keep in mind that there are a variety of different products that get lumped into "MDF" and they differ somewhat in weight.

You should be fine with 12mm plywood structurally for a bartop cabinet. Keep in mind that there are dramatic differences in quality and "workability" between different sheet goods. Some of these plywood products contain only alternating veneers while others have layers of mdf inside. For a small project in which structural soundness and appearance are critical to you, the best bet is "baltic birch" or alternatively "finish birch" plywood. This product has multiple consistent layers, very few voids and the cut edges actually look nice. It also is more expensive by far than MDF and tends to be bought in smaller sheets. A step down would be the kind of "birch" plywood often found at big box stores. This stuff varies greatly in quality and some is fairly awful although the outer skin (of birch) looks ok. The big box plywood also tends to like to warp badly into a potato chip shape - something true baltic birch plywood does not do. The side benefit of the baltic birth is that it cuts and shapes very nicely and the dust produced isn't as bad (or toxic) as the stuff from MDF.

Last of all, think carefully about how you are constructing the cabinet with respect to fasteners, glue, etc. MDF is essentially a consistent material while plywood behaves differently to fasteners depending on whether you are screwing or nailing through the face or the edges (not so good).

Hope that is helpful and not too basic.

[ugleymatt]

Hope that is helpful and not too basic.

Thank you so much for taking the time, and it wasnt too basic at all!!

i hadnt considered the fixings and the implcations of the actual construction, so thats something to look into so thats super helpful

[RobodocX]

My pleasure.

If you are looking for a slick, easy and cheap way to construct plywood or mdf cabinets without visible fasteners, one way to go is pocket holes. You can buy a pocket hole jig at a woodworking store or on amazon for maybe $25 that will allow you to hide all the fasteners and will work well with both types of sheet goods (first attachment). You will need a drill but otherwise everything comes in the kit. Very technically easy, moderately strong and slick. If you are using particle board (for some reason, maybe because it comes in pre-laminate covered sheets) you can use "conformat" screws to hold everything together (second attachment photo), countersink your screwheads and cover them with covers. Not as slick but less initial investment.

[ugleymatt]

Oh that does look neat. Will have a look into that. thank you!

[ugleymatt]

My pleasure.

If you are looking for a slick, easy and cheap way to construct plywood or mdf cabinets without visible fasteners, one way to go is pocket holes. You can buy a pocket hole jig at a woodworking store or on amazon for maybe $25 that will allow you to hide all the fasteners and will work well with both types of sheet goods (first attachment). You will need a drill but otherwise everything comes in the kit. Very technically easy, moderately strong and slick. If you are using particle board (for some reason, maybe because it comes in pre-laminate covered sheets) you can use "conformat" screws to hold everything together (second attachment photo), countersink your screwheads and cover them with covers. Not as slick but less initial investment.

Stupid question, if i use the pocket jig with the 12mm ply, surely only a very small part of the screw would be going into the wood. Would that mean that in order to use pocket holes you need a thicket material to screw into?

[RobodocX]

You can adjust the amount of penetration into the face side of the sheet using the adjustable collar on the drill bit with these jigs. You are always going to be limited in depth of screw penetration by the thickness of the material. Perhaps you are thinking that you can butt joint two pieces of plywood and screw from the face side into the "end grain edge" (its not really end grain, I know) which would allow you to penetrate as deep as you want. The problem with that strategy is that the edge of a plywood panel isn't a reliable place to drive screws into since the plys of the panel can separate. As it turns out this isn't very strong, although its stronger if you use top quality birch plywood. The pocket hole approach bypasses this issue by anchoring the tip of the screw across the plys so even though the penetration is less the strength is greater. Bottom line, it shouldn't be a problem for good quality 12 mm material for something like a bartop cabinet, I suspect.

Now if you chose to use MDF, you could use the strategy of driving screws through the face and into the edge of a butt joint. Not super strong actually with 12mm MDF. However, you will have exposed fastener heads unless you recess them and plug them or countersink them and fill over them. More work. The pocket hole approach gives you hidden fasteners and similar strength.

If you are really looking for a bulletproof cabinet construction, you can add dowels, dominos or even biscuits which align the panels and increase the glue surface. For 12mm material, small biscuits are probably the best option but this requires using either a biscuit jointer (you have to have one) or a router with a biscuit cutting bit (painful - just say no).

Rick

[ugleymatt]

Once again, thank you so much. once i start my build i will put a post in the project area and no doubt be asking more questions.

Looking at the overall look i am after, i want to add t-molding and i would be limited if i used 12mm so i am considering using 18mm (3/4 inch) for the sides and the 12mm for all other parts. I was going to follow these plans http://holbrooktech.weebly.com/pi-arcade-101.html where he uses glue and brad nails for the bracing parts. Though i want to have plexi on the control panel so i need to consider reducing the height to allow that to still fit nicely.

Now i am thinking that if i use the 12mm for the horizontal, and the 18mm for the sides, would the pocket holes be quicker, easier?

Would you recommend still gluing as well?

[RobodocX]

Sure.

No problem using the pocket holes to connect parts of different thicknesses. Just need to adjust the depth of drilling using the stop collar. If your side panels are thicker, the pocket hole screws will have more strength. I generally still add glue for situations where I don't intend to be breaking down the cabinet in the future. You could do either and be fine. If you use no glue you might want to make sure that you use enough pocket holes but it shouldn't be a problem. It's probably obvious but you want all the pocket holes on the INSIDE (lol), so they are hidden.... They do make plugs to fill the holes if you need them on the exterior but I'd stay away from that option if you can.

Keep in mind that pocket hole jigs come in a wide range of sizes and features. For a project like this, you can easily get away with the cheapest option - which essentially can do everything the larger jigs can do. There is one on Amazon for under $20. https://www.amazon.com/Kreg-MKJKIT-Mini-Jig-Kit/dp/B00065WPP2/ref=sr_1_5?s=power-hand-tools&ie=UTF8&qid=1485545619&sr=1-5&keywords=pocket+hole+jig.

T-moulding is available in 1/2 inch diameters as well as 3/4". See: https://www.amazon.com/Foot-Smooth-Black-T-Molding-Arcade/dp/B00L1QK0S4.
Of course, if you are after a thicker look then 3/4" should be fine and appears to be the standard for these bartops.

You will want to use a thinner (i.e. 1/2" board) for the control panel if you are going to be adding plexiglass to the top. Some problems can arise with control installation if the boards total thickness is greater than 3/4".

Good luck on the project! Don't hesitate to ask any questions and make sure to show us how it goes.

Rick

[ugleymatt]

Great advice. Think I'm def going for plywood, it's not that much more but it's lighter.

Plus if I wax the wood I could g do a steam punk theme


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