It is currently Nov 21, 2018 3:20 am 




Do you or someone you know need some help with a project?
Click here to contact the Neighborhood Action Team.



Reply to topic  [ 13 posts ]  Go to page 1, 2  Next

Previous topic | Next topic 

  Print view

Offline 
 Post subject: Steam bending wood at high altitude
Post Posted: Jul 1, 2018 9:49 am 
Active Pinecam Poster
Active Pinecam Poster
User avatar
Joined: Apr 1, 2011 7:56 am
Posts: 511
Anybody had any luck steam bending wood at 8500 ft? Just for a first cheap attempt to see whether it was even an option, my husband built a steam box out of an unused piece of plastic sewer pipe, and let 2 pieces of cedar that were only about 1/4' thick steam in there about 1.5 hours. Made absolutely no difference in whether the wood bent; it was like nothing had been done. Clamping it quickly didn't help. This wasn't green wood or even air dried, it was just home depot stuff that most likely was kiln dried, which certainly wouldn't help matters. We didn't need much of a bend on this little project, so we thought we'd try with these strips.

We wonder whether the fact that water boils at so much lower a temp up here is making a difference (steam doesn't get hot enough) and how to circumvent it if it is. He'll probably go ahead and build a wooden steam box, which will probably raise the temperature slightly, but we've seen several videos where they just used sections of rolled plastic and made bags to fit the wood piece. We also read that along with using a metal strap on the outside bend, soaking the wood for a few days before steaming could help, and one place mentioned soaking the wood in water and downy can help.

Anybody tried any of this up here and can offer any insight as to what we are obviously doing wrong? Thanks.


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 1, 2018 10:32 am 
Pinecam Hall of Fame poster!
Pinecam Hall of Fame poster!
User avatar
Joined: Dec 8, 2003 5:53 pm
Posts: 36806
Location: Riding the Bailey ghost train
Cedar may not have been your best material for bending.

_________________
Image Socialism: trickle up poverty. Why are we running out of money for social security but not welfare?


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 1, 2018 11:05 am 
Active Pinecam Poster
Active Pinecam Poster
User avatar
Joined: Apr 1, 2011 7:56 am
Posts: 511
Yeah, we didn't think cedar was our best choice, but that was what the project used, so we tried it just to see. If we had used oak, would it have likely bent at this altitude? We need such a slight arc on the cedar that we can probably do it without steam bending, but wanted to test the steam bending idea out for a future project (that would use oak).


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 1, 2018 11:32 am 
Pinecam Hall of Fame poster!
Pinecam Hall of Fame poster!
User avatar
Joined: May 3, 2002 6:41 am
Posts: 17315
Location: Pine CO at Shaffers Crossing at 8,200 feet
This may not be applicable but I bent 1 inch pvc pipe by dipping it in a boiling water bath. Being pvc pipe, I did fill it with sand first. But the dipping and letting it get as hot as the water and bending it in the water worked.

I needed a curve of 45° on the pipe so it was not "slight".


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 1, 2018 4:04 pm 
Active Pinecam Poster
Active Pinecam Poster
User avatar
Joined: Apr 1, 2011 7:56 am
Posts: 511
I think PVC would bend easier. There was a slight bend in the cedar when we took the clamps off this afternoon, but not much even noticeable. Guessing had we used a more proper wood (oak, ash) that was greener or at least not kiln dried, we'd have had better luck. However, we don't know what water boils at up here (guessing less then 200F) and that still might not be enough heat to soften the lignin in the wood (essentially the glue that holds the fibers together) which is needed to be able to bend the wood. Think we'll try soaking a better wood for a long period of time next time before steaming and steam for longer and see if we get anywhere despite reduced steam temp due to the altitude.


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 2, 2018 3:32 pm 
Posts Semi-Regularly
Posts Semi-Regularly
Joined: Dec 27, 2005 12:50 pm
Posts: 194
Location: Near Shaffers Crossing
krm18 wrote:
Anybody had any luck steam bending wood at 8500 ft?


KRM18: No experience with steam bending at all, but the boiling poing of water at 8500 ft elevation is 196*F, so his starting temp to work with is 212 - 196 = 16*F. That's not a great delta T, so I would think it would simply take a longer 'soak' at the lower temp. The major factor isn't temp, but forcing moisture into the wood (FULL DEPTH ) to softer the wood fibers.

Not knowing what he used as a steam generator, it may be that low steam volume resulted in MUCH lower temps, by the time the steam exited his 'box'. Also, were the samples supported off the bottom, for full 'surround' steam?

Finally, I have to admit I do not know the suitability of cedar for bending - if the plans called for it, and bent it, then it should be OK - otherwise try an internet search for a bit if research.

I doubt Temp was the only factor. Let us know what turns out.
Dick Thomas
Retired Engineer, and woodworker


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 2, 2018 3:36 pm 
Pinecam Hall of Fame poster!
Pinecam Hall of Fame poster!
User avatar
Joined: Dec 8, 2003 5:53 pm
Posts: 36806
Location: Riding the Bailey ghost train
Pressure might be necessary.

_________________
Image Socialism: trickle up poverty. Why are we running out of money for social security but not welfare?


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 2, 2018 5:46 pm 
Posts Semi-Regularly
Posts Semi-Regularly
Joined: Dec 27, 2005 12:50 pm
Posts: 194
Location: Near Shaffers Crossing
dieselpop1 wrote:
Pressure might be necessary.

DP: I hope you meant to say 'pressure to BEND' and not presurized steam! If you used pressurized generator, the pressure in his steam box would still flash down to atmospheric at 8500 ft, chilling itself to 196*F. Pressurizing the steam box would be extremely dangerous in the hands if a novice: Pressure vessels are expensive, and pressure regulation more so. If he attempts to pressurize a PVE pipe with steam, he is asking for a steam explosion and plastic shards everywhere - extremely more serious than using PVC pipe for compressed air lines.
Even Schedule 80 threaded PVC is only good for 100 psi +/- depending on diameter, but even at 196*F that rating drops precipitously.
Bomb in the making! :fireworks: :fireworks:
I've worked with steam up to 1200 psi in a powerhouse. Very dangerous stuff.
DT


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 2, 2018 6:17 pm 
Pinecam Hall of Fame poster!
Pinecam Hall of Fame poster!
User avatar
Joined: Dec 8, 2003 5:53 pm
Posts: 36806
Location: Riding the Bailey ghost train
True. I've welded high pressure vessels. They have very thick walls.

_________________
Image Socialism: trickle up poverty. Why are we running out of money for social security but not welfare?


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 2, 2018 9:17 pm 
Posts Semi-Regularly
Posts Semi-Regularly
Joined: Jun 9, 2007 2:14 pm
Posts: 159
A friend of mine builds guitars. He bends wood all the time. I asked him for some input and here is his response.

This video shows a luthier bending sides around 15:00 in: https://www.youtube.com/watch?v=qvsDcM0HaqU
For 1/4" cedar, I would try a plumber's butane torch directed through some 3" black pipe (in a vise). You want it to be between 300-400°F, so it takes some trial and error not to scorch. Cedar is probably the hardest to bend, though. It crushes instead. Flatsawn maple would be better. Walnut works well. Oak - not so much.


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 2, 2018 10:54 pm 
Active Pinecam Poster
Active Pinecam Poster
User avatar
Joined: Apr 1, 2011 7:56 am
Posts: 511
No, no, we didn't and wouldn't use pressurized steam; that would have been just asking for trouble. While novices to steam bending, we aren't novices in general; my husband has done woodworking for more years then I can count, we are both former long time mechanics, along with years of home and rental refurbishing. We are pretty much old school, from the times where you did pretty much everything yourself.

The simple project (just a partially banded curved shelf for a specific purpose) using the cedar strips was also tweaked a bit in design just to test out two things- whether any type of simple steam bending was possible and whether we could age wood with vinegar and steel wool (the shelf part, not the cedar strips yet). The aging part worked really well, but its fairly obvious the fact that we used cedar for the strips was a real mistake (it wasn't a choice to use cedar; it was just the extra board we had laying around that would work) and it will definitely take a more professional set up for bending wood then what we threw together to even have a real chance at it next time around. We did have a jig built with clamps set up to immediately bend and clamp the wood upon removal from the steam.

There was a drain hole drilled in the tube so there wouldn't be a buildup of pressure, and the wood was supported in the tube so the steam could circulate underneath it. As Dick mentioned, there was very likely not enough volume of steam and that made the temperature even lower (and at 196F, we obviously don't have a lot of wiggle room). We used a refillable metal can with a hose running to the plastic sewer pipe at the opposite end of where the drain hole was that held the boiling water. We babysat it the whole 2 hours it was in the steam (1/2 hour just letting it warm up and 1.5 hours where it was clearly steaming and the drain hole was dripping water). Things did get hot enough to deform the sewer pipe (wasn't household PVC), so a real wooden steam box with a larger hose for more volume is probably in order for the next attempt, along with a better wood and longer steam time. Some people just use heavy plastic sheeting for their steam box.

We did go ahead and put the cedar strips on without steam bending them anymore (they didn't absolutely need to be steam bent because they were thin) but it was certainly an interesting experiment and hopefully, with some modifications, it could work next time around. We saw that some people do bend wood using the propane torch through black pipe, but it did look like it would scorch the wood and didn't particularly like the idea of flame shooting through the pipe while you are bending the wood right there. Some people bend wood with a heat gun too, which might be a little better and easier not to scorch the wood. Saw one video of a guy using a microwave to bend wood but our pieces were too long for that idea. Steam bending seemed to be the most versatile and easy to set up. If we had used something besides cedar maybe it would have worked. Thanks very much for all the input- most helpful.


Top
  Profile  
Reply with quote  
Offline 
 Post subject: Re: Steam bending wood at high altitude
Post Posted: Jul 3, 2018 7:58 am 
Posts Semi-Regularly
Posts Semi-Regularly
Joined: Dec 27, 2005 12:50 pm
Posts: 194
Location: Near Shaffers Crossing
Glad it worked out in the end. Yes, sounds like insufficient ooooomph in you steamer. I'm in process of totall rebuilding my cobbled together shop, in the 3rd car space of a 3-car garage. When I'm done I plan to get into turning & may try som bending just for fish.

There is one weak link here though: If there aren't any pictures, that shelf didn't happen . . . . :rof laughing:


Top
  Profile  
Reply with quote  
Display posts from previous:  Sort by  
Reply to topic  [ 13 posts ]  Go to page 1, 2  Next

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:

Who is online

In total there are 83 users online :: 1 registered, 0 hidden and 82 guests (based on users active over the past 60 minutes)
Most users ever online was 2823 on Mar 26, 2012 6:26 pm

Users browsing this forum: TJllirrem and 82 guests





Powered by phpBB © 2000-2012 phpBB Group

This website copyright © 1994-2018 by
Pinecam.com is a member of the Platte Canyon Area Chamber of Commerce