make her bigger basket better

October 8, 2007 2:01 PM

woodworkers and/or adhesive experts: Is there some way to "seal" a thin piece of cedar wood so that it won't split?

I'm making my own bicycle baskets (after giving up on finding my ideal for sale). I've already finished one, and it's awesome. Basically, it's made of a top and bottom cedar frame connected by three dowels and a bunch of cane (cane as is found in chair seats).

The top and bottom frames are made by cutting roughly-rectangular shapes from a 3/4" cedar board, then cutting out the center of the shapes, so that what's left is about 3/4" wide edge. I drill holes in this to take the dowels and the cane.

It works pretty well, though, as I expected I did get some splitting. With the holes I'm making, the wood is pretty thin, and cedar seems pretty grainy in general. I was able to glue the splits I got successfully with wood glue, but it made me wonder if I could just apply a substance to the entire frame (soaking it?) to make the whole thing less likely to split.

I did stain the frames, and seal them, but this seems more designed to prevent moisture penetrating than to augment the existing bonds between the wood fibers -- I think this latter is what I really want.

I should add that I also thought of wrapping the whole thing with cane or something similar, but as this is for a bike, I want to keep things light, if possible. And the cane I have doesn't seem that well-suited to that use.

Soaking the whole thing in wood glue occurred to me, but I'm not sure it would work, I worry about warpage, and I'm pretty sure I'd like something waterproof. Bonus if it won't interfere with staining.

I chose cedar on the advice of a wood sculptor friend; it is nice and light -- I wouldn't want anything heavier -- and the first basket is reasonably successful. I'd just like to avoid future splitting, and it would be great if I could make the frame even lighter. I'm not using the traditional thin-slice-of-wood-looped-around approach because I wanted some small degree of structural support in case of the bike falling over (with, for instance, a laptop inside). It won't protect from a major collision, but I think it's the right degree of rigidity.

I tried a Google search for [seal wood split] without success.

[Also, if there's some great way to glue the cane ends to their terminal holes, I'd love to know about that too.]

posted by amtho to sports, hobbies, & recreation (15 comments total)

Which part is splitting? It sounds like the upper and lower parts that are used to hold the dowels? Is that right?

* How thick are those part?
* When does the splitting occur? When you drill holes, when you insert dowels, when you weave the basket, or later?
* pics?
posted by RustyBrooks at 2:29 PM on October 8, 2007

Yes, it's the upper and lower parts, which hold the dowels and provide holes for the cane. These are cedar pieces, approximately 3/4" thick (both top-to-bottom and side-to-side).

The splitting doesn't seem to occur at any particular time. I'm gentle when I drill, but I'd guess it's at that time or soon after. This type of wood just seems to have certain grains/veins (not sure of the word) that are bound together weakly, if at all, and when they run all the way through a piece, the piece is prone to just fall apart.

I'll try to put up a photo after dinner (in about an hour).

Thank you!
posted by amtho at 2:39 PM on October 8, 2007

I'm pretty sure you've got a "short grain" problem. It's a little tricky to do this without illustrations, but it sounds as if you cut a picture-frame sort of shape out of a plank of solid wood. On two opposite sides of the frame, where the grain runs with the side , you have no problems. On the other two, perpendicular sides of the frame, where the grain runs across the narrow dimension, it keeps breaking. Any wood is inherently weak in areas like this because, while the fibers are strong, most of the fibers are oriented in the same general direction and the bonds between fibers are weak. Softwoods like cedar are especially weak.

No, there's nothing you soak it in or paint it with to make it significantly stronger.

Options for rebuilding it correctly include...

1) building each frame from four sticks, with appropriate corner joints (butt with nails or screws, half lap, saddle/slip joint, box joint or dovetails, depending on how fancy you want to get)

2) glue together a sandwich of an odd number of thin, wide boards, with the grain of alternating layers perpendicular to each other, effectively making homemade plywood, then cut out your frames as you did the first time

3) cut the frames from a piece of commercial plywood

email me if you need clarification.
posted by jon1270 at 2:54 PM on October 8, 2007

Plywood would probably definitely do the trick. It might look kind of weird, because you can see the alternating layers as bands of light and dark. There are a few tactics:

Cover the edges with edge-banding - which is usually strips of veneer with a heat-activated glue. This might not work well for you because it may not be totally waterproof, or stand up to beatings.

Buy high quality birch plywood - you might have to look for it someplace like a woodworking store. This stuff is very high quality and I like the way the layers look because they are uniform, void free, and there are lots of layers. It's also very stable. You could probably get away with using 1/2" thick, which would lower the weight even more. Woodworking stores often carry it in small sizes, which is nice. It is cheaper to buy full sheets if you can find it, which are usually something like 4'x4' square.
posted by RustyBrooks at 3:02 PM on October 8, 2007 [1 favorite]

Make a picture frame! (or 2). Cut (all) the sides from long grain (the grain running the length of the piece). secure the corners with a spline, making a slot in the corners and gluing in a thin strip of wood for support. I could have sworn there was an Ask MeFi on picture frame making, but all I could find was digital picture frame stuff.

You should be fine with that--it's nicer and lighter than plywood, and easier than making your own plywood.
posted by RikiTikiTavi at 4:18 PM on October 8, 2007

Thank you for the suggestions so far. The picture-frame-like construction idea is one possibility, though it sounds like more work than I'd hoped, and I like the ability to make arbitrary rounded/trapezoidal shapes (you'll see in the images below). Plywood might work, though -- even though it's heavier.

Has anyone tried reinforcing short grain with some kind of protein-based adhesive or sealant? I'm awfully interested in what happens on attempts...

Here are images, the first one on the bike for scale, the second a close up of one end of the bottom - the basket weaving part is kind of random since it's just a prototype, but I think it's promising.
posted by amtho at 5:18 PM on October 8, 2007

Very interesting. If you don't like the look or weight of plywood, you might try laminating 2 thinner pieces of cedar at 90% angles. This might be kind of difficult depending on what kind of tools you have at your disposal. At the least you're probably going to need a jointer to get two flat faces. I guess I don't think that would be my first choice.

Alternatively, you might be able to just reinforce the 2 sides that are likely to break with strips of wood that have the grain oriented the right way (running along the length). These reinforcement strips would not need to be as thick as the frame, 1/2" might be fine.

Making a "picture frame" that's oversized and square will let you cut out an arbitrary shape. It's often not a walk in the park for inexperienced woodworkers though, and the corners in picture frames can be weak unless reinforced, or unless a particular joint style that is designed for strength is used.

Good luck!
posted by RustyBrooks at 6:22 PM on October 8, 2007

Reinforcing the ends is a good idea -- I'll think about doing that; maybe I can get some extra functionality from such pieces stuck on the ends. Plywood is still a possibility, especially if I can use a thinner piece.

My tool supply is even more limited than my experience; I live in a condo and can't acquire much since there's not much storage. Maybe someday.

I've also thought about routing (with my little Dremel tool) a shallow channel around the outside perimeter of the top & bottom frames, then somehow putting a tight band around them. This would accomplish something similar to attaching a cross-piece to the ends; I'm not sure how to accomplish this, though.

Thanks!
posted by amtho at 6:34 PM on October 8, 2007

Where do you live? You might find a me-fi-er near by who can help you out. I'm in Austin, TX.
posted by RustyBrooks at 7:55 PM on October 8, 2007

(and I'd be happy to help you out)
posted by RustyBrooks at 7:55 PM on October 8, 2007

Thanks, RustyB; it happens that I'm in North Carolina, so I guess commuting to Austin's not really practical.

I'm having fun working it out, so no worries, and my wood sculptor friend (the one who recommended cedar in the first place) has offered to let me use some of his equipment, although I'm interested in whether I can do it with just what I have.
posted by amtho at 8:04 AM on October 9, 2007

Cutting a frame shape from a 3/4" solid piece of wood wastes an incredible amount of wood, doesn't it?

I'll second the idea of using plywood for the frames. You could completely wrap them in the caning material for a nice effect that would also hide the edges.
posted by srt19170 at 8:11 AM on October 9, 2007

You might be able to steam bent the the frame but that is an awfully tight radius in your corners. If you went to a 180 degree bend at each end it would be easier to use a solid piece.

Otherwise you could steam bend thin strips.

1. Source the strips. You don't have a band saw so you'll need to farm this out. Or possibly your sculpter friend has a bandsaw. Basically take your 1X material (3/4" actual) and rip it into strips 3/4" wide and ~1/8" thick. For best results you'll want to remove the resaw marks with one of
   • thickness planer
   • wide belt sander
   • hand plane
   • belt sander
2. Build a plug/form. You want the outside of your plug to match the inside shape of your frame and to be at least a bit thicker than your frame. The plug needs to incorporate a way of clamping your strips. Easiest is a hollow centre that you can use with bar/C clamps.
3. Steam the strips until they can be bent around your corner curve without cracking. Ideally enough at a time to do a single frame. Easily done with an electric kettle, a length of pvc pipe longer than your strips and a couple PVC fittings.
4. Use the strips to build up enough layers to give you the width you require. The strips are wrapped around the plug and held in place with the clamps. You need to work quickly so the strip is in place and clamped before it cools. I'd use strips slightly longer than the circumfrance of the plug and then cut them to the exact length required with a thin kerf dovetail or dozuki saw. Make sure you stagger the joints.
5. Wait until the strips have set then remove the clamps.
6. Glue the strips together using a waterproof glue, I'd use a polyurethane because it actually likes moist wood.
7. Let dry a few days before drilling. Finish with a varathane or CPES.

posted by Mitheral at 11:05 AM on October 9, 2007

Lee Valley has an excellent online booklet on steam bending. They claim a 2" bend radius for several woods.
posted by Mitheral at 11:14 AM on October 9, 2007

Wow, still getting answers - thanks, Mitheral. Steam bending sounds fun, but I may stick with cutting the solid piece. The cedar isn't too expensive; I hate to waste it, but I'm hoping to find a hamster enthusiast who'll want the scraps.
posted by amtho at 1:18 PM on October 9, 2007