Hi all,
I’m planning a project to make some ceiling and wall lights which will involve steam bending.
Hopefully you see a picture attached which is similar to what I want to do. Each branch needs a wire running through it so my plan is to make each one from two strips that have grooves routered in to them. I will steam bend them prior to placing the wire in and gluing but I have some questions.
I would like to use ash or oak, are they good options or should I consider something else?
Each section will be around 30mm x 15mm, what minimum bend radius can I expect to achieve?
I will be making the steam box and bending formers as well. The lights will be 12v LED so no safety concerns.
Thanks for any input.
kevin
Replies
Ash or oak will bend just great. But I'm unsure if it will work. If you rout a groove in a board and bend it, that groove may very well close when you bend it. You may be able to open the groove back up after. But you'll probably have to joint the faces after bending, since getting two faces to match up, with a groove in the middle, after steam bending is apt to be a little frustrating.
The lamp looks like it is made of laminations. You can build a couple of forms out of MDF or plywood and bend and glue thin pieces to make your shapes. I think laminating would give you more consistent results. You would need forms for the steam bending anyway.
As John says, the woods are good choices for bending with steam. I'd re-think your order of operations. Start by bending oversize blanks, then do your final milling and routing after they set up, and finally cover the wires with a laminate strip of the same stock. The bending will change pretty much all of the geometry of the parts.
I land with Hotdogman on this one, bent lamination is the way to go. Also, you can get to almost any radius if you combine pre-bending with steam and lamination glueup.
Thanks for all of your input, it’s given me a lot more to think about.
I will be making forms or jigs for whatever I need. I’ve got to make 3 ceiling lights and a wall light so it’s worth me investing time in the jigs.
I have a lot of tools but most are for cars so for woodworking I’ve got the typical DIY hand power tools, pillar drill, band saw and a black and decker workmate. Now you’re either laughing or cringing but I have done some good stuff this way, it just takes time and patience. If I need to buy some things for this project I can do.
My design will be simplified from the one in the picture, I will have 5 or 6 prongs and I’m prepared to have them fixed on to the body of the light rather than merged in to it. I will see how it goes on that point.
The aesthetic will be a little more rustic as well so I don’t have to achieve the crisp lines.
For my intended two pieces I had considered getting a local joiner I use to plane some lengths to size and put the groove in but if it’s all going to distort maybe I should do that bit myself and get them machined afterwards if needed.
If I use thinner pieces and laminate it would I glue all of the layers at the same time or build it up with the glue setting on each layer before adding the next?
What thickness for the layers?
I’ve done it with veneers before but if I steam bend and laminate I guess I could do 5 to 10mm layers?
I will be replacing lights like the one in this pic so whatever I do it can’t look worse.
Just bent a few ribs up for a boat and one thing I learned is it is harder than it looks! Tighter bends like that will require very good to excellent wood. Very straight grain or it breaks in the curve as you bend it.
You have to work FAST! Apparently steam bending gets the wood just to the point of bending. It doesn't take much cooling before it stiffens back up. The thinner the strip the quicker it cools.
I make kayak coamings and I find that thin strip laminations are much easier but they are slower. I can heat thin strips with a cheap heat gun and bend them around the form. No need for a steam box and it works really well
I have only done a little steam bending but would definitely laminate that design.
It is very hard to get the strips to bend round a tight radius like that after steaming and so difficult to drill a hole down the length of such a strip that you end up laminating it anyway.
You will need to experiment as to the radius - I have laminated 2mm treated pine with straight grain into a similar radius without problems.
If it were my project, I would make my form first as there is no doubt you can make it work. Then I would take some test stock and start with a 3mm/ 1/8" strip or two and see if they go in well. If they split then go thinner. If it's easy and you want a thicker lamination then try 4mm. I suspect somewhere between 3/32 and 1/8 will be the ideal thickness for that piece.
For the cable, a 12V LED will need only a very fine cable as anything over about 4W (0.3A) is probably going to need a heat sink. Woodshop Junkies did a similar sort of thing recently. https://www.youtube.com/watch?v=7yg1-vS1dF0&t=914s using a router to cut a slot. It might be possible to squeeze your wires between laminations if you go thin enough without routing though a slot is best if you can make it work. 22AWG is plenty for that application and at 0.54mm dia, really not big either though there is no reason not to use bigger wires for easier handling if you can fit them in.
If you do want to go with the steam bending, I recall the New Yankee Workshop did a hat stand which involved bent wood on a similar sort of scale to your idea. I think you can see all the episodes free now on their website (though it has been a while, and I can't recall the episode, though think it was a later one)
Check into hot pipe bending like the guitar makers use. Soaked wood heated and fixed to a form to set before glueup. Works very well.
I'm a big fan of hot pipe bending for smaller items like this. Very controllable, and once you've bent it, it normally stays in place.
Well, I’ve got some pipe, a gas torch and a welder so I can make a hot pipe rig quite easily so I can give it a go. First step is making the form.
I’m also thinking about conductive copper foils for the conductors but I need to research that a bit more first.
@bikergonebald, firstly, that is an awesome moniker!
Copper foils will conduct the current easily enough, but you may find they tear if you try to gather them into tabs that fit standard LED light fittings.
Regardless of the design, LED bulbs do not last as long as advertised. Well, some will probably last effectively for ever, but experience suggests that at least 10% of good quality brand bulbs fail at or before the usual failure point of tungsten. Averages mean that with 5 or 6 bulbs there's a decent chance that one will fail long before you have grown tired of the light fitting.
This means that using a fitting that will take regular home store bulbs is far better than something custom, unless you really like soldering. This means routing a channel for a wire is probably better than trying to use foil.
Your copper foil needs to carry 0.3A or so which is not a big ask. Foil that is 0.5mm2 will carry that easily. you would need very thin foil if it was 10mm wide. I suspect that ordinary tin foil from your kitchen would suffice, but would be hard to solder. Experiment!
Even so, I would still rout a groove...
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