More Curves & Questions

[Teresa Jones]

OK, this headboard project is about to drive me crazy. I know it is a short drive, but nevertheless!

I am down to the LAST piece of molding on the inside frame. First effort, I soaked the quarter round molding in hot water for about 1/2 hour before I tried to attach it to the panel. Just about done and CRACK. What a mess!

Do I need to let the wood soak longer? Is the temperature of the water important?

I don't know if this photo will help or not. I need help with that too, taking pictures.

Thanks,

TJ

[christopher webb]

well i can see that you are using cherry ...and well im thinking that it is of course kd??? if so then you need to let the wood soak longer than 30 mins. i would say at least for a good 45 to 1 hour time .....then see how pilable it is at that point ...cherry is very hard to bend......and just asking to be sure what is yoru degree of bend? but try soaking a little longer first.....as long as the water is good and hot...and steaming , then it is hot enough....good luck on the project

[Fred LeBail]

You didn't mention what type of wood, but try soaking in Downy Fabric softener. The longer the better, over nite.


Fred

[Teresa Jones]

Chris & Fred,

Thanks for the quick feedback. It is in fact KD Cherry that I am using for the molding pieces.

I will make another piece of the molding and let it soak longer. I'll add that Downey in there too.

Thanks,

TJ

[Chris Padilla]

You are "cold" soaking the wood, Teresa, even if it is hot water. This needs to be done for like 12-24 hours...longer is better.

If you want to steam bend, then steaming it for 30-60 minutes should work but you need to work quickly upon removal. You have less than a minute to form it to the bend.

Fun, eh? :)

[Doug Shepard]

If you're cutting the molding yourself can you change the direction of the grain w/ respect to the roundover? Somebody will correct me on the terms I'm sure, but what I'm getting at is: If for example the cherry was quartersawn, I think it would be more pliable if the bends were along the same plane as the grain lines, vs 90 degrees to the grain lines. Maybe you're already doing this.
Also, is there any way you can do kerf bending? Maybe at a shallow 45 degrees across the 90 deg corner? Or would the kerfs show where you're applying it?

[Bob Smalser]

The photo helps a lot.

For a skinny stick on the inside of the top of that frame you will have to soak the stock in water for a few days then boil it for an hour or so at the points of its worse curvature. Cut it into short pieces with scarf joints if you haven't a tank or pot large enough.

Remember the wood has to bend across it's face grain and not along it's edge or vertical grain. This is a lamination of qsawn stock...but your stock's growth rings have to look like this on the edges:

http://pic3.picturetrail.com/VOL12/1104763/6490387/82734076.jpg

For a wider piece of molding, say a piece 2 inches wide for the top of the headboard, I'm afraid there's no way you are gonna bend a ready-made stick of kilned cherry molding to fit that curve reliably. Even with a steam box. Bending stock is milled differently and airdried....and those are relatively tight bends.

Lay up several pieces of stock like you would when making a panel.....only omit any unecessary lengths of board....so it fits the top of your headboard.

Then clamp it in place on the headboard...scribe fit the headboard profile...remove and bandsaw it out to the width of molding you desire....then do the molded edges on the router or shaper.

The curved panels comprising the sides of these bookcases were made that way...there were 3 sticks of oak laid up before the outline was cut and molded fro the panel....but 2 of the 3 pieces were very short:

http://pic3.picturetrail.com/VOL12/1104763/2594265/39181107.jpg

[Richard Wolf]

Nice looking headboard. Kiln dried wood will not become pliable enough by soaking or steaming, only green and air dried lumber. Bob has the correct answer to your design, either lay up a few thin strips or cut it out on the band saw.

Richard

[christopher webb]

another idea is that if you have a good bandsaw , then you can cut some thin slices , then laminated tehm toghter, after you put them into a bend on some type of mold...use a long setting glue, then you can go back with a router and design your edge to what you want it to look like.....thin stock will bend everytime, and will look as if it were one piece that is molded that way ...either way thats about all you can do really.....good luck and thats a very nice bed whatever you decided to do

[Teresa Jones]

You guys are terrific.

The piece of molding is 5/16 thick and 5/16 wide. I put it (2 pieces, just in case) in a piece of PVC with HOT water and Downey last night at 7:00pm. I was going to give it a another try this morning, but now I am glad I didn't based on your feedback.

I am going to let it soak for awhile and try it again. I am going to cut some scarf joints like Bob suggested if the second attempt fails.

Now, another question.

Does it matter if I start at one end and work towards the other or should I start in the middle and work out to the sides?

As an option, I may just pack it up and take it over to Steve Jenkins and pay him to do it for me!!!!!

Thanks a bunch,

TJ

[Carl Eyman]

One of the problems with bending wood is it is not as strong in tension as it is in compression. The outside edge of the curve is in tension, of course, and that is where the wood breaks. Now if you can force the bend to be in compression you have a much better chance. People making bentwood furniture (Mike Dunbar, for instance, fasten a piece of steel band along what will be the outside of the curve before they start the bend. This means the outide fibers can't stretch; the whole deformation has to take place by the inside compressing. Now you are not likely to have too many steel bands lying around, but a very good substitue is plastic packaging tape. I'm talking about the kind that has fiberglass reinforcement in it. You'll have to prepare this ahead of time so it is ready when your piece is hot. Cut a piece of tape some 6 or 8 inches longer than the piece of molding. Lay wooden block at the end of the tape so the length of the molding fits snuggly between the blocks. Make sure the blocks won't move. You want to make sure when you start the bend that the action is forced to the inner portion of the molding. This has worked for me in the past. Yours is an ambitious project as others have said, but this will give you a chance, I think.

[Bob Smalser]

You guys are terrific.

The piece of molding is 5/16 thick and 5/16 wide. I put it (2 pieces, just in case) in a piece of PVC with HOT water and Downey last night at 7:00pm. I was going to give it a another try this morning, but now I am glad I didn't based on your feedback.

I am going to let it soak for awhile and try it again. I am going to cut some scarf joints like Bob suggested if the second attempt fails.

Now, another question.

Does it matter if I start at one end and work towards the other or should I start in the middle and work out to the sides?


TJ

Unless your friend has proper bending stock, he'll have the exact same problems that you'll pay for solving. Pick a piece of clear stock with zero grain runout and begin soaking it. I literally stuff my bending stock under the floats of a dock.

Then your best chance for sucess is to make a steam box from a piece of 4" PVC pipe and fashon bearers or bend a long piece of window screen so the workpiece is raised off the bottom of the pipe. Set the pipe on sawhorses using blocks to it is raised a bit in the rear, plug the ends with wood, drill an escape hole in the top of the far end and an entrance hole in the bottom of the lower end. Then rent a wallpaper steamer or cobble together something that'll make you lots of billowing steam and feed it thru a hole into your entrance hole. 5/16 stock I'd give 20 minutes and try to to bend it. Shouldn't take any longer than 30 minutes max.

On your piece I'd try to bend it in place using brads to secure as I went, and I'd do it in two pieces scarfed in the center (cut the scarf joint before steaming) to better my chances of getting at least oen bend in before the stock cooled.

It's the heat in the core of the workpiece that does the bending, not the steam. Steam is merely the best way to do it without burning the piece, and works better than boiling water.

[Carl Eyman]

Look at the facia board on the forward part of the upper deck. When we were building this boat we broke any number of boards trying to bend them around the upper deck beams even though we had a good steamer. Finally, we used the method of straps and were able to get stock that didn't want to bend to do so.

[Bob Smalser]

Very nice, Carl.

But your stock was a tad bigger than 5/16", which in a double bend like on that headboard won't take a strap easily. Straps work best bending a single bend over a form, and a form large enough for that headboard molding would be a waste of material larger than a few pieces of broken stock if it can be done any other way.

But that's just my experience...if you can design a strap and form to do that double bend headboard job then by all means have at it. I think her stock is too small for a strap unless she bent 5 pieces at once....and she doesn't need 5 pieces.

[Carl Eyman]

Yes the double bend is a big difference. You are probably right. However, I learned so much from restoring that old oyster boat - all 74 feet of her - that I almost think the money and time I spent were worth it. Almost. I enjoy your boat building posts. Keep them comning.