Some simple carpentry questions

I need to make a protective carrying case for something fragile. The dimensions will be 10" x 10" x 34".

I have some 1/4" composite board I am going to use to build the box. I understand that it’s best to put square wood reinforcements along the inside corners to hold it together. (I also plan to put some fancy brass corner pieces on the outside.)

Here’s my questions: I have left myself a couple inches margin all around. (the actual measurements of the object are 8x8x32.) What size should the inside reinforcement pieces be? Like, one inch square?

Also, should I use finishing nails or small screws? I plan to use wood glue as well.

Last, I want to cover the box with exotic fabric. Should I attach it (spray adhesive) before I put the box together, or after?

Thanks a lot, fellow Dopers. It’s for my son’s birthday present. :slight_smile:

Quack, I just realized that one-inch square will not work with two inches’ clearance all around … duh. The object is round, btw. Help?

If the object you are carrying does not weigh much, one inch should be fine with glue and screws (Always screws where aesthetics is not an issue). Not sure what you mean by composite ie plywood or something like mdf?

Plywood is much better than mdf (medium density fiberboard) for this application. Mdf is generally not made to be structural. Even covered, if mdf gets wet it swells and falls apart. I would cover it after it is assembled. The weight is the crucial thing re construction material without having more information. 1/4 inch mdf is not very strong. Mdf is used a lot for countertops, etc and is always covered by a solid surface material like laminate.

Klaatu! Barada nikto! hee hee hee

Yes! It is “MDF.” It says so on the tag. What the case will be made to hold is a tall hookah pipe, cobalt blue glass with an elaborate white metal filigree overlay. It’s gorgeous, but not particularly heavy. (at least, not without the water:cool:)

It’s nearly three feet tall, and there’s just no way he’s going to get it home on public transit without it being kind of a pain – at the very least. Because of its design, there are several natural weak points. Hopefully, the spray adhesive should provide somewhat of a barrier to moisture externally. Thanks to your advice, I will be sure and coat it with something inside as well.

Anyway, I hold the same opinion – when in doubt, screws.

What about the internal square strips down the length of the corners?

Thanks so much for your help.

The thickness of the internal framing needs to be big enough that the screws won’t go right through it - apart from that, if you’re going to glue it, it probably doesn’t matter.

If this is to be a briefcase-style box, the easiest way to make it is probably:

[ul]
[li]Make two identical rectangular frames[/li][li]Make four little ‘legs’ to attach these two frames together at the corners, to form a cuboid frame[/li][li]Clad the whole thing with MDF or thin ply (now you’ve got a box you can’t open)[/li][li]Cut it in half with a decent handsaw (now you’ve got two halves that mate perfectly)[/li][li]Add beading to reinforce the inside of the cut edges, especially the hinge side[/li][li]Fit hinges and other hardware.[/li][/ul]

Yeah, build a cage/crate around the gift with the 1x1s then cover with the mdf. Paint the mdf before putting it on the crate. There are many ways to build the crate frame. Make two identical rectangles using the 1x1s then use four 1x1s to attach the rectangles to each other at the corners to make the crate. That is just one of many ways to do it. For simplicity, don’t try cut 45 degree corners, use butt joints. To get to 10x10 using 1x1s, make 2 pieces 8 inches and 2 pieces 10 inches. However, dimensional lumber is measured wet, before it is dried, so the 1x1 isn’t really 1 inch, more like 3/4 inches, so then to get 10x10 the pieces are 8 and 1/2 inches instead of 8 inches. You’ll see. Good Luck!

And what mangetout said. You could also just leave the top open and use rags as padding.

Do this. Use plywood, not MDF.

+1 on using ply. The difference in strength and resilience is enormous. MDF will simply crush into powder, and will tear like cardboard.

In addition to the trick of making a box and cutting it in half - if you add the beading needed to reeiforce the halves to the base frame before adding the cladding, then ensure that the cut runs half way through the beading you will ensure a perfect mate between the halves. You will of course need a piece of double width wood for this, since you will be bisecting it.

Crap. I already bought, measured ("-- twice. cut once.") and marked the MDF. But it was only twelve bucks.

Frankly, part of the problem was that I was at Home Depot, which at my location seems chronically understaffed. So I picked out the board on my own; I chose it because it was thin and in a fairly convenient size already. You see, I went down there on my bike (I don’t drive), naively thinking I might find something already cut; even one foot by whatever would be something I could get home on my bike though I might have to walk it. Unfortunately, by the time I found out that the guy who cuts stuff for you was not there & wouldn’t be back for days, I had already gotten smudges on the board from carrying it around, looking for an employee in the lumber department. Duh.

Anyway, it doesn’t have to take much wear and tear, it just has to get him and his hookah home on BART. (electric train.) He lives right by the station, and I live maybe a third of a mile away. Yes, yes, I know – I’m sending my boy home with a hookah, ho ho. :smiley:

I was thinking actually of a three-sided box with a hinged lid, like a guitar case. Well, a square one. I guess that would be a lot less sound structurally; prone to skew and shim. But, you know, there will be a top and bottom and glue and screws. I figured as long as the latch absolutely positively stays shut (probably two of them) he should be okay.

I got these gorgeous brocade remnants, green and gold, they just happened to be just about exactly the right size with a healthy margin. Gonna put a handle on one long side adjacent to the latch(es.)

If the goal is just to get an awkward glass item home on the train, you can go to UHaul and buy a “lamp box” (12x12x40") for five bucks and some bubblewrap, and call it done. Just don’t send him home with it on a rush hour train.

Presentation cases are lovely, but what’s he going to do with a big, heavy, fabric-covered plywood box once he gets home?

I’m going to respectfully disagree with the MDF naysayers. MDF should work fine for what you want to do, especially if you seal it well. The advantage of plywood in this case is that it would likely be a bit lighter than the MDF, but I don’t think you need to abandon what you currently have.

Paint or varnish the interior surfaces before assembly, but make sure not to seal the corners where you’ll be gluing to the internal supports (glue won’t stick to varnish at all, and probably not well to paint). Instead of making the internal corner braces square, you could knock off one corner with a block plane held at a 45 degree angle to the adjoining faces (so you end up with something that looks like home plate in cross-section). That would gain a little interior space and accommodate the round object a little better.

Be sure to pre-drill the MDF for the screws, and counter-sink the heads flush using a counter-sink bit. Don’t try to just drive the screws in without pre-drilling, or you’ll ruin the MDF. The screws could actually be removed after the glue dries–the glue alone should be plenty strong to hold it together.

Mike

Do not rely on glue alone. Use glue, and some screws. Set the screws so they are just below the surface of the outside material, and calk over the dimple before painting. Be sure to sand the calking well. Actually you want to use "bondo", not calk.

Actual carpenter here. I would probably just go buy a case myself. :wink:

Use plywood; much stronger, much lighter. I recommend going to 3/8" material, it will hold a screw better. You can just use some cove moulding or corner bead (hardwood not mdf) for the corners, it has mating surface only where you need it, not impinging on the interior. Mark out and drill pilot holes. Glue, clamp and screw. Metal (or even wood) corner bead on the exterior would go a long way to make this stronger and give something to hold the head of the screws. You can actually get hardware just for case construction from places like Lee Valley Tools. I don’t know what the American equivalent is.

MDF is a great material, I use it all the time, will probably work with it today, it just is not well suited to this though.

Dimensional lumber size is the nominal size measured before kilning and planing. It isn’t smaller because it is measured when it is wet so much as because it has been planed down to its finished size which is actually standardized. A rough sawn 2x4 is pretty damn close to 2x4 inches.

Why not rely on glue alone? Except when gluing end grain, wood glue is stronger than the wood itself: http://www.elmers.com/demos/?video=1yqvlnNqcvk. If I can’t rely on the glue alone, then I’m going to have a problem with several tables I’ve built where the top is made up of narrow pieces glued together to make a wide tabletop!

You could if you have a quality set of clamps and jigs, and the skill to avoid under or over gluing, and preparing the wood properly to get tight fully butted joints, and especially if you can cut mortises and dados. But it’s easier to use a few screws. Except for fine cabinetry, gluing and screwing is very common, and generally preferred. And even in fine cabinetry it’s done where it isn’t seen.

I have no carpentry experience. The way I’ve handled similar situations is to make some sketches of what I want made. I mark the sketches with measurements, etc. I then give the sketches to a friend who does carpentry as a hobby, along with cash for material.

When my carpenter buddy needs something I’m good at, I go all out.

Agreed, that’s how I would do it too.

1/4 inch MDF is not very strong. 3/4 inch is actually quite solid, and would make a great display box, though it is very heavy in comparison to the material strength. MDF isn’t garbage material, it’s what they make good home speakers out of.

I’d probably suggest going the lamp box route for the transportation home. Then build a display box separately. The lamp box will be MUCH lighter than one made of wood, and packed with styrofoam peanuts, the hookah would be pretty safe.

I’d build a display box out of 3/4 inch MDF, glue and screw the joints (pre-drill the full length of the screw) and attach a door with a window. No internal framing, just screw right into the “end grain” of the panel. Plenty solid, no ugly framing to hide, and simple to build.