Steam Box query

What's the size of the largest wood piece that you will steam? Perhaps you can 'get by' with a piece of large diameter iron or PVC pipe?

Have a look at this! He adapted an old deep fryer to supply his steam!

More approaches: Mounted on the wall to free up the workbench!

--Winston

There have been quite a number of steam-bending articles in Fine Woodworking over the years, including some on how to build Shaker boxes. Try the local library. Most guys seem to cobble something up out of sheet steel, like old scrap galvanized duct work from hot air heating plants in homes. Seams DO NOT have to be completely steam- tight, there's no pressure involved here, after all. Most I've seen used rags around the wood staves to block in the steam. One design used an old pressure cooker on a hot plate to supply the steam. Pop rivets should be OK, sheet metal screws, too, if you keep them away from the wood surfaces. If you've got long and narrow strips, just get some round galvanized duct from the Home Despot and go from there. With the thin stock in Shaker boxes, you might just be able to soak the stock in hot water and bend it, hope you've got some test strips.

Stan

My recommendation would be to get yourself a piece of large-enough-diameter PVC pipe.

Drill holes on each side so that you can slide some short pieces of wooden dowel through to make supports for the wood you're steaming, to hold the pieces in the middle of the pipe. Drill a larger hole at the middle of the bottom to lead the steam in through a piece of hose.For a steam generator for a small job like that, a teakettle on a hot plate works just fine.

I've used a lash-up like that to steam frames for a boat I built once, so I think it'll do the job for your shaker boxes.

Tom Dacon

Forgot to mention that all you need to do to close the box off is to drape pieces of heavy cloth over the ends of the box, or maybe you could tape a piece of scrap plywood over one end. It doesn't need to be air-tight, in fact it shouldn't be, in order to let a continuous supply of steam into the box. If you tilt the box a little, condensation will drip out of one end and you can catch it in a pan.

Tom

I saw something about a boat yard producing wooden boats in the UK recently and they steamed many of the hull plank and used a couple of DIY wall paper stripper steam units for the steam source. Can't remember at the moment what they used for the steam chest.

Do you really need to steam it? Violin makers use a hot iron (called a bending iron) and pull the strip of wood for the ribs over the iron and bending it that way. You can make a bending iron from an old clothes iron. I don't have the one I made handy, but my recollection was that you can tap the hole in a steam iron with an 8-32 tap. Hold a piece of pipe of maybe 1.5" dia onto the iron with an 8-32 screw and a series of washers. Turn the iron upside down and hold its handle in a vise. This link shows a bending iron in use about half way down the page:

A second option is to make a form of the shape of the box. Clamp your strip of wood to the form and roll that over the inverted steam iron (sans pipe sticking up). When you get to the end, clamp the strip of wood in place over night. This site gives a good explanation of how to do it. As I recall, Albert Fisher who wrote the article had worked for one of the major car manufacturers as an engineer.

Third option - some violin makers say they've had success using cold bending of the wood.

RWL

Bending irons and bending pipes work fine with very thin materials, like the ones that luthiers use. I don't know the thickness of the pieces Maxwell is using but the main reason for using a bending iron is that, with experience, you can control the softening and thus the bending locally. Guitar builders, particularly, bend the side pieces a little bit at a time, holding the piece in place for a fit, putting it on the iron again, etc. But dry heat applied quickly like that doesn't penetrate thick wood very well.

When you're bending a larger area all at once, you need general heating. Steam is good because it distributes the heat evenly. For very small pieces, just use boiling water. With either steam or water, the water itself has nothing to do with it. It's the heat. Soaking too long in either, though, will lead to failure of the piece when you bend it. With thicker pieces, that usually results from compression failure on the inside of the piece.

Or get into the gas or liquid ammonia technique, which I find fascinating, but which is NOT recommended for the home shop. The ammonia has to be very concentrated and it's dangerous to handle. Also, it turns some woods a grayish color, and cherry is one of them.

A steamer for wallpaper would work really well. They are cheap at Home Depot, maybe $50. Comes with a hose from the steam box that you could just force into the correct size hole in the PVC pipe or packed in with rags to one end of the pipe.

Thanks Tom, Calif Bill, Winston, Geolane, stan and Ed! Lots of things to think about! The wallpaper steamer and PVC pipe may be the way to go, as I don't have a hotplate, and this seems the quickest approach.

Max: although I don't quite "get" your dimentional requirements, an inexpensive steambox can be made out of pink foam insulation from a building supply store. Use duct tape to hold it together. a good source of steam is a pressure cooker over a camp stove. Thread a pipe nipple into the lid and slip a piece of tubing over that. Watch your water level carefully so you dont have a meltdown.

A larger steam generator can be had using a metal gas can over a propane "turkey cooking rig". A piece of radiator hose over the inlet of the tank and into your box. I have a rig like this which feeds steam into a wooden box 12' x 5"x 12" It takes about an hour to get the box up to temp, then an hour of steam for every inch of thickness of your work.

Happy bending, Andy

Steaming some types of wood in contact or close proximity to ferrous metals can cause permanent staining of the wood. The PVC pipe may need to be in a close fitting wooden trough to support it as it may get excessively floppy when hot. Preheat the pipe till steam comes out the far end *BEFORE* inserting the wood. If possible lag the pipe, it will work a lot better with a smaller steamer.

u can find it at the nearer store at ur house..usually supermarket sell the thing u want... have a look

xoxo, aineecumi

neway, my secret to release tension is playing this game

Bend thin sheet metal by clamping it between 2x4s and hammering it. The flange will be neater if you hammer on a block of wood rather than the metal. Bend it a little at a time along the full length or else you will stretch and kink the flange. It's easier if you flange one side and leave the other flat, stronger and more steam-tight if you flange both. You could extend the flat side past the corner and fold it down after joining them if you have a thin steel backup plate that fits inside between the corner and the screws / rivets.

I would drill bolt holes in the outer sheet before bending it, then clamp the two together over a wood block and match-drill the inner sheet. You don't need much clamping pressure, just support directly under the drill bit.

You can make the bottom hold water by folding the corners instead of notching them. Mark the diagonal from the corner of the finished bottom to the corner of the sheet and lower that line while you raise the two sides, then fold the tab over against one of the walls. Try this with paper first, corners are tricky and hard to explain without pictures.

Install the side sheets inside the bottom so condensation doesn't drip out.

Jim Wilkins