Steam Bending

[John Morris]

30 minutes ago, kmealy said:

Not sure that's right.  While liquid water (without impurities) won't go above 212 at atmospheric pressure, I think steam (gaseous water) can go higher.  Isn't that like saying that ice can't get below 32 degrees?  https://van.physics.illinois.edu/ask/listing/1799#:~:text=Is it true that water,and colder than 32 degrees%3F&text=A%3A,up much hotter than that.

 

Try this one Keith

 

http://cleanboiler.org/learn-about/boiler-efficiency-improvement/steam-basics/#:~:text=When water is heated at,can exist at this pressure.

[jthornton]

13 hours ago, kmealy said:

Not sure that's right.  While liquid water (without impurities) won't go above 212 at atmospheric pressure, I think steam (gaseous water) can go higher.  Isn't that like saying that ice can't get below 32 degrees?  https://van.physics.illinois.edu/ask/listing/1799#:~:text=Is it true that water,and colder than 32 degrees%3F&text=A%3A,up much hotter than that.

 

While you can superheat water in a microwave in a totally smooth container with no nucleation sites the chance of you heating water in any vessel that has nucleation sites to above 212°F is not possible without increasing the atmospheric pressure on the water. The escaping steam cools the water as it evaporates in the same way a "swamp cooler" works in drier environments.  Also note that water boils at a lower temperature in Denver than Miami... at sea level, water boils at 212 °F. With each 500-feet increase in elevation, the boiling point of water is lowered by just under 1 °F.

 

JT

[Cal]

All this talk of steam and pressures reminded me of this railroad accident I read about.

Central Ohio in 1948...

 

 

[jthornton]

The strap showed up today and I did a bend test to see how malleable the strap was and I'm happy to report it will work great. The strap is 1.375" x 0.050" with 0.250" holes on 60mm centers... a bit odd on the center spacing but I can add more where I want them. After bending the strap around the mandrel it straightened out real easy. Thanks for the suggestion @lew

 

 

Now to out fit the strap with fittings and handles and build a new steam box.

JT

[John Morris]

20 minutes ago, jthornton said:

Now to out fit the strap with fittings and handles and build a new steam box

Hey JT, do you mind showing us your blown up steam box?

[lew]

50 minutes ago, jthornton said:

Thanks for the suggestion @lew

[jthornton]

The gaps have closed up quite a bit since the day I steamed the last parts.

 

JT

[jthornton]

So the first repair worked for the top of the steam box but that caused the bottom to explode... well not explode but it looked like it did.

 

One thing I didn't consider was the end blocks and the bottom blocks grain direction, so you can see the end blocks run side to side and the bottom blocks run for and aft.

 

JT

[John Morris]

@jthornton, ya it kinda moved on ya didn't it. Mine did the same thing and I just screwed it all back together but mine is made from 3/4" pine so it was easy to screw together to close some of the gaps, yours is made from a bit thicker boards I think?

I saw some videos of chair makers steaming their parts and their boxes leaked like a sieve, as mine does, didn't seem to effect the process at all, so I let mine expand and contract and bend and warp and do what it does and it leaks pretty good every where, but it still takes the same amount of time to steam, perhaps it may use more water though? Like yours I noticed if I had assembled some of the boards in a different direction, they would have warped in a better direction.

Thanks for showing us your blow up!

 

[John Morris]

On 12/1/2023 at 1:21 PM, jthornton said:

I'm shooting for a 1/4" thickness and 1 1/2" wide with a 2" radius on the inside of the bend.

Back to your original post here JT, you have kiln dried material you are working with, can you just find an oak tree in your area somewhere and cut a limb off, you'll have green wood to work with and problem solved completely!

Also, I just realized the thickness is quarter inch, too late to mention here since you are having so much fun with your steam adventure, but at that thickness, you could boil your kiln dried for an hour and achieve the same thing. Sorry I hadn't mentioned that earlier, but I got so wrapped up in your steaming adventure

[jthornton]

Actually all my red and white oak is air dried from trees I cut down and milled up.

 

JT