Wood bed rail split

[Travis]

I have a wood bed rail that started splitting down the middle. I have glue and clamps, but I'm not sure on a good technique to get the glue very deep without prying it open even more. Ideas?

[getsorted]

At hobby stores, you can buy glue syringes to get the glue deep into tiny cracks. But just putting in a bead of glue and pushing it in with a skewer or coffee stirrer works, too.

[ChpBstrd]

Most wood glue is water-based, right? So in theory you could thin it.

I'd be more inclined to shove the glue deep in the crack with one-ply cardboard, such as a paper towel tube. You still might want to wedge the crack open a bit before sandwiching the glue into it.

Also, unless the bed frame is particularly ornamental, this might be a good application for carriage bolts or brass bolts to hold that crack together.

[Uturn]

Wood glue is stronger than most wood, as long as you get good coverage. Since this crack started at a glue line between ply's, I'm going to guess there was not good glue coverage during manufacturing. 

I would pry it open a little bit, you don't want to hear cracking, and get as much glue in there as you can.  If you have a shop vac, you can try to suck the glue in.  I would also use wood screws on the inside to help hold that joint together. 

Maybe some less enthusiastic bedroom recreation until you get a new bed frame.

[Travis]

Maybe some less enthusiastic bedroom recreation until you get a new bed frame.

It's my son's. Jumping on and off the bed to cause the crack did occur to us though.

[lthenderson]

In my experience, it is near impossible to get good coverage very far down the crack. You can thin the glue and push it with various thin utensils but it won't get you much coverage.  Thinned glue soaks into the fibers too deep and doesn't bond as well as unthinned glue. You are almost always better off going ahead and splitting it all the way, applying unthinned glue generously over all the surface area and then clamping it again.

But this is not always desirable as you can break fibers at the thin part of the break and it will be noticeable. If this were my bedrail, I would probably do my best to glue the end (widest part of the crack) where it attaches to the headboard/footboard. This will help you anchor the fastener system used to connect those pieces together. Then I would cut another piece of wood and "sister" it on the inside of the rail underneath the board that holds the battens. This will strength that area where the crack is at it's narrowest and it is impossible to get glue down into without splitting it apart. Get appropriate sized screw to screw through the added board, into the bed rail and ideally into the splitting portion but without the tip of the screw coming out of the visible side that everyone sees. Your repair will then be hidden but provide strength.

[zolotiyeruki]

You've already received some good advice about how to glue it back together.  I definitely advocate for adding screws to the glue.

I'm going to guess that there's a long lag screw that passes through the head/footboard, and anchors into the bed rail?

If so, that's a pretty bad design, going into the edge of plywood like that.  I'd suggest a couple of alternatives, after repairing the split:
A) use brackets like these instead.
B) use a forstner bit to drill a couple of pockets, and then use bolts and square nuts to hold the rail to the post. See the attached screenshot for reference.
C) similar to B), but you'll use your existing screws.  Fill the pockets with dowels, then run a drill bit down the existing screw holes to make a pilot hole through the chunk of dowel.

I've used all three of these techniques, and all seem to hold up really well. 

[Travis]

You've already received some good advice about how to glue it back together.  I definitely advocate for adding screws to the glue.

I'm going to guess that there's a long lag screw that passes through the head/footboard, and anchors into the bed rail?

If so, that's a pretty bad design, going into the edge of plywood like that.  I'd suggest a couple of alternatives, after repairing the split:
A) use brackets like these instead.
B) use a forstner bit to drill a couple of pockets, and then use bolts and square nuts to hold the rail to the post. See the attached screenshot for reference.
C) similar to B), but you'll use your existing screws.  Fill the pockets with dowels, then run a drill bit down the existing screw holes to make a pilot hole through the chunk of dowel.

I've used all three of these techniques, and all seem to hold up really well.

A long screw goes from the bed post into the rail and there's a cut out a couple inches in where you add the nut. I'll see if there's room to add the exterior brackets that you linked.

The glue we had came out thicker than toothpaste and I wasn't able to get it nearly as deep into the split as I wanted. I tried a few tools to push the glue down, but most of it ended up attaching to the tool and coming back out. I'm pretty sure I'm going to drill a few screws laterally where the glue didn't reach. Any particular thickness for the screws? I have a lot to choose from.

[zolotiyeruki]

You've already received some good advice about how to glue it back together.  I definitely advocate for adding screws to the glue.

I'm going to guess that there's a long lag screw that passes through the head/footboard, and anchors into the bed rail?

If so, that's a pretty bad design, going into the edge of plywood like that.  I'd suggest a couple of alternatives, after repairing the split:
A) use brackets like these instead.
B) use a forstner bit to drill a couple of pockets, and then use bolts and square nuts to hold the rail to the post. See the attached screenshot for reference.
C) similar to B), but you'll use your existing screws.  Fill the pockets with dowels, then run a drill bit down the existing screw holes to make a pilot hole through the chunk of dowel.

I've used all three of these techniques, and all seem to hold up really well.

A long screw goes from the bed post into the rail and there's a cut out a couple inches in where you add the nut. I'll see if there's room to add the exterior brackets that you linked.

The glue we had came out thicker than toothpaste and I wasn't able to get it nearly as deep into the split as I wanted. I tried a few tools to push the glue down, but most of it ended up attaching to the tool and coming back out. I'm pretty sure I'm going to drill a few screws laterally where the glue didn't reach. Any particular thickness for the screws? I have a lot to choose from.

It sounds like your rails are already option B.  As for screw size, I'd just say "get the longest drywall screw that won't poke through the rail."  I think a #6 or #8 would be a standard size.

[Uturn]

drywall screws will work if that is what you have on hand, but I would always get wood screws if going to the store.  Wood screws are generally less brittle than drywall screws.  #6 or #8 5/8" , assuming the rail is 3/4"

[zolotiyeruki]

drywall screws will work if that is what you have on hand, but I would always get wood screws if going to the store.  Wood screws are generally less brittle than drywall screws.  #6 or #8 5/8" , assuming the rail is 3/4"

If the rail is only 3/4" thick, my first suggestion would be to get new rails!

[Bartlebooth]

IMHO there is not enough thickness on either side of the screw to get a good bite, especially long-term.

Wood glue would be decent IF you could get it in deep, but even then I have some skepticism that it would bond well to the already glue-impregnated wood that is in there.

A series of small bolts and nuts is the only thing that I see as guaranteed to hold up over time.  Obviously appearances are an issue with this approach.  Carriage bolts would give you a clean round head on the outside, hopefully in an attractive pattern arrangement.  Half of the nuts on the inside could be hidden below the ledge that the box spring sits on, but the half of them above that would need some special care.  Acorn nuts or close cut and file job.

[ChickenStash]

Probably not helpful now but if the glue you were using is the tube in the background of the first pic then it might not have been the right stuff for this problem. It's out of focus but that looks like loctite power grab or a similar multi-surface adhesive that has a consistency like caulk. Real wood glue would have been a better choice as it's much thinner and would have been easier to get down deep in that split.

[ChickenStash]

Also, as an alternative to screws, I'd suggest using dowels. Clamp the board tightly then drill tight holes for the dowels, slobber well with real wood glue, then tap them in. Cut and sand them flush, maybe a dab of matching stain of the looks are important. With something that thin, the dowels and glue will probably work better than screws.

[sonofsven]

Carpenter chiming in. I don't think glue is enough to hold that split at bay. I agree with the idea of screws or bolts through to a backing plate that is attached to the inside. 3/4 ply with liquid nail adhesive would be my first choice, but other materials would suffice.
If you want to get fancy you can use a plug cutter drill bit to make some plugs out of the inside of the rail (out of sight), then use the corresponding counter sink bit for the screw heads, then plug them and chisel/sand the plugs.
And tell your son he's going to go blind!

[getsorted]

This is more of a cobble than a real fix, but when I had a rail on a futon split like that, 
I reglued and then reinforced by wrapping color-matching zip ties around in two or three places along the split. The zip ties held for two years before I gave the futon to somebody else and weren't noticeable anyway.

[snic]

Yet another option, if the glued rail splits again, is to just get some lumber and make your own. It looks pretty simple.

Or put the mattress on the floor and give away the frame. Tell the kid this is what happens if you jump on the bed.