Steam bending wood.

[Packard]

I’ve been interested in steam bending wood for a while now. 

I see that both Wagner and Earlex, the spray painting equipment companies make steam generators for about $75.00.

Add some plastic pipe and hoses, about $125.00 to $150.00 to get started. 

Anyone here have any experience with it?  With these steam generators?  I have watched some videos and the actual process seems pretty straightforward.  A blending jig to make the shape you want, lots of clamps and the steam equipment. 

It would seem that this works out best when you are making more than one piece of each shape.  The real works goes into the bending jig.

https://www.google.com/search?q=steam+generator+for+steam+bending&client=firefox-b-1-m&ei=ksooY8faD96KptQPvKO_wAM&ved=0ahUKEwjH6_jn0qH6AhVehYkEHbzRDzgQ4dUDCA0&uact=5&oq=steam+generator+for+steam+bending&gs_lcp=Cgdnd3Mtd2l6EAMyBQgAEKIEMgcIABAeEKIEMgcIABAeEKIEOgoIABBHENYEELADOgYIABAeEAc6BQgAEIYDOgUIABCABDoFCAAQkQI6BAgAEA06CAgAEB4QCBAHOgYIABAeEAg6CAgAEB4QCBANOgQIIRAKSgQIQRgASgQIRhgAUMsLWNFcYKBvaAJwAXgAgAHRBIgB0jqSAQwyLjMzLjMuMS4yLjGYAQCgAQHIAQjAAQE&sclient=gws-wiz

 

[ChuckM]

If you aren't in a hurry to buy, I'm picking up my Earlex ($69.5 US) this week or next, and will give it a try the week after.

[attachimg=1]
https://www.leevalley.com/en-us/shop/tools/power-tools/110936-earlex-steam-generator?item=03K0315

 

[Michael Kellough]

Just back from the internet, both the Wagner and Earlex units are the same except for what you connect to the far end of the hose. If you buy the Wagner to get the two steam paddles you can also order the brass fitting that comes with the Earlex.

The steam generator was the very first product Earlex made a few decade ago. Wagner bought Earlex in 2013.

 

[woodbutcherbower]

The Gothic arches on the kitchen dresser in my recent 'Member Projects' post were steam-bent using a home-made steaming box and the water/steam tank from an Earlex wallpaper stripping kit which comes with a gallon tank and a 1" steam hose. I'll dig out a few pictures and post them soon. I've also used the same rig to bend 3/4" thick oak baseboard through a 90-degree curve, plus numerous curved and arched window and door frames. 

For some major-league steam-bending, check out the fabulous YT videos made by Engels Coach Shop. Put 'Engels Coach Shop Steam Bending' into the search box. You'll thank me for it  [smile]

Kevin

 

[Packard]

Further reading shows that you are not supposed to use kiln dried lumber.  I don’t know where you would find green white oak (or even red oak), two of the species that are supposed to be amenable to steam bending.

 

[ChuckM]

I think kiln dried lumber can be used, but it takes much longer in the steaming:
https://www.rockler.com/learn/bending-wood-part-iii-steam-bending

 

[Packard]

When I was a kid, we used to soak the Thanksgiving turkey wishbone in vinegar overnight.

Then when the leftovers got served I would “discover” the wishbone for the second time. When my brother and sister would make a wish and pulled, they found that the bone was as flexible as rubber.  You could pull it apart, but you could not crack the bone.

I was wondering if vinegar would do the same to wood (and apparently it does).
https://www.google.com/search?q=vinegar soak to bend wood&ie=utf-8&oe=utf-8&client=firefox-b-1-m

 

[Peter Kelly]

Further reading shows that you are not supposed to use kiln dried lumber.  I don’t know where you would find green white oak (or even red oak), two of the species that are supposed to be amenable to steam bending.

https://ghentwoodproducts.com
Check their price list but call to confirm availability before making the trek.

 

[Packard]

Thanks for that information.  They are about 62 miles from my house.  My GPS says about 1 hr. 18 min. (Or about 6 - 7 gallons of gas.  It’s near Hudson, NY, a nice day trip.

I will put them in my Rolodex (figuratively speaking).

 

[woodbutcherbower]

I've been steam-bending kiln-dried redwood, oak, walnut and iroko since forever. It's perfectly OK to do as long as the section you're bending is as close-grained and perfect as possible, and is also 100% free from splits, knots, shakes or any unusual, uneven patterns in the grain. You need to double (or preferably triple) the tank time - which for me has always been one hour of steaming for every 10mm of material thickness. I absolutely wouldn't recommend using green timber for any type of decorative joinery. Once it starts to dry out, it will contract and move like you wouldn't believe.

Also - most importantly of all - the radius of your bend former needs to be at least 10-15% smaller than the radius of the finished bend. No matter how many clamps you use whilst the timber cools and dries - it will spring back by around this amount. It's easy to push out and expand a smaller radius to fit the work, but almost impossible to make an under-bent radius tighter, as you'll be fighting against the linear solidity of the material. To start with = it's always better to go tighter than you need, at least 15%. Think of it like making a cut = you can always take a little more off, but you can't put it back on. Plus - wear gloves when you take it out of the steamer, and get it on the former, bend it around slowly but firmly, pressing it hard against the former, and get it clamped up as quickly as you possibly can. Until you're comfortable with the process and you've got your available timescales figured out -  a buddy tightening the clamps as you bend it is a great asset. It cools and starts to firm up very quickly, but don't stress or panic. If it goes badly = just put it back in the steamer, wait, and try it again.

Here's a matching pair of sash window frames I made for a Georgian rectory built in 1799. The astragal (glazing) bars were pre-machined to shape, bent through 180 degrees in one hit, then trimmed to size. The main section of the window frame was made in four pieces, with the curved section at the top, plus the two vertical jambs spliced onto it, then fixed to the sill using mortise & tenon joints. The rest of the frame consisted of various additional thinner decorative sections also bent in one piece, and fixed to the frame.

Good luck with the curves !! Pictures - or it didn't happen.
Kevin

[attachimg=1]

 

[Packard]

It dawned on me the other day, that though I have made plenty of pieces, all of them have been lines and angles. Almost no curves or radii.

I did add the “CMT TMP-1200 Flexible Template for Curved and Arched Routing” recently and have been incorporating curved pieces where it seems to fit.  Steam bending seemed like the next step. 

Thanks for or the images and replies. 

 

[Crazyraceguy]

It has been a few years, but I did quite a bit of steam bending on a big library job.
It was all kiln-dried, mostly maple but some cherry too.
I actually prefer laminate/strip bending myself, but that was not an option on this one.
The main thing I can tell you is that the positive side of the form is just as important as the negative. Those fibers need to be supported too or you will have cracking problems.
I had a few failures during this process. I had a few crack, even with careful inspection, so have extra stock on-hand.
The other was the shape. Getting the "over-corrected" form right took a couple of tries. There will be some spring-back, so you have to compensate for it. This was a fairly big radius, so some force could have been used to glue them in place, except for one thing. These pieces had to meet at a perfect, tight miter/seam. They needed to fit in their relaxed state to get the cuts right, plus there were 6 of these.
There were other items on this job too, just not as many copies to be made.
It is all holding up well, in a public library. I was just there a couple of months ago.

 

[Bob D.]

Here is a method of bending without a steam box.

 

[Crazyraceguy]

Luthiers (guitar/violin) do it with a somewhat hybrid approach. They soak the wood in water, then bend it around a heated pipe. The press it against the pipe with a thin stainless steel band. That makes the steam occur at the point of the bending and keeps their hands away at the same time. but this is done with much thinner wood.
All of the stuff I was bending was 3/4" thick and some was over 2" wide too. I just used piece of PVC plumbing tubing and an Earlx unit from the local woodworking store.

 

[Bob D.]

I like Lou's method of bending inside the bag as you can keep steaming as and after you bend.
Not necessary for all bending maybe just larger members like he was working with here.

But it is a way around not using a pipe or building a box.

 

[rst]

major steam bending...Acorn to Arabella - Journey of a Wooden Boat - Episode 92: Steaming Planks

 

[Packard]

Luthiers (guitar/violin) do it with a somewhat hybrid approach. They soak the wood in water, then bend it around a heated pipe. The press it against the pipe with a thin stainless steel band. That makes the steam occur at the point of the bending and keeps their hands away at the same time. but this is done with much thinner wood.
All of the stuff I was bending was 3/4" thick and some was over 2" wide too. I just used piece of PVC plumbing tubing and an Earlx unit from the local woodworking store.

The company I worked for before I retired manufactured the handles that went into those bending bands to Metropolitan Music in Vermont.  The handles were repurposed for those bands.  They were originally made for a manufacturer of 5 gallon popcorn tins. The customer told me how he intended to use the handles and I searched through our standard tooling and came up with the popcorn tin handles.  They only ordered 3,000 at a time, so special tooling would be too expensive.  We kept these in stock for the tin can industry.

The handles came with the rivet-friendly tin tabs.