LumberJocks

steaming #1: Finally get around to doing some steam bending

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Blog entry by Lazy_K posted 09-29-2014 08:34 PM 2159 reads 0 times favorited 16 comments Add to Favorites Watch
no previous part Part 1 of steaming series Part 2: Handles for bending strap »

Hi all;
So I’ve finally gotten around to doing some of the steam bending of chair parts that I mentioned I was going to do with that log.

my set up is fairly simple:
propane tank, burner + stand from a turkey deep fryer, an old 5 gal can to boil the water in and a length of pvc pipe for the steam box.

then you need a bending form of some sort

with removable pegs and wedges to lock the bent part in place while it cools.

the pvc is supported on my saw buck w/ on end up on bricks.

so after your parts have cooked a while you whip them out and push them around the form (not to fast but not really slow, if it cools it will not finish bending) , applying wedges as you go.

that is all really.
thinner parts work better with a back strap. I do not happen to have a back strap just now.
I’ll write more as the chairs progress.

-- Kai SaerPren



16 comments so far

View redryder's profile

redryder

2394 posts in 2563 days


#1 posted 09-29-2014 08:47 PM

I’m sure I could blow up my shop with that setup.
Glad to see you’ve got it under control.
Steam bending would definitely open up some new ways to work….....................

-- mike...............

View Dallas's profile

Dallas

3599 posts in 1949 days


#2 posted 09-29-2014 09:30 PM

Why the gloves? It ain’t that hot, and you’ll learn more about the temps you can use your wood at.

TOday I am making boiled peanuts in the shop using a crock pot that will go hot enough to boil.
I couldn’t stir them with a big spoon so I used a slice from a maple board I resized.

I noticed it was bending as I pushed down and stirred.

When I took it out I wrapped it around a big piece of oil well casing.

Wow, I was amazed how easy it was and I have a great piece to work with.

-- Improvise.... Adapt...... Overcome!

View Lazy_K's profile

Lazy_K

111 posts in 1652 days


#3 posted 09-30-2014 01:17 AM

ideally the core temp of the wood needs to get to @ 375 degrees Fahrenheit that is hot enough to burn your skin..thus the gloves.

-- Kai SaerPren

View waho6o9's profile (online now)

waho6o9

7171 posts in 2038 days


#4 posted 09-30-2014 04:34 AM

That’s amazing Kai, thanks for sharing.

View Lazy_K's profile

Lazy_K

111 posts in 1652 days


#5 posted 09-30-2014 11:48 AM

I forgot to add; the boiler can be any can that can hold several gallons and the heat source could be a fire of shavings and chips from making the parts to bend.

-- Kai SaerPren

View Smitty_Cabinetshop's profile

Smitty_Cabinetshop

13713 posts in 2080 days


#6 posted 09-30-2014 12:04 PM

Does the steam flow through the pvc? I don’t see a release hole at the end. Need to do this, thanks for posting.

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive --

View Dallas's profile

Dallas

3599 posts in 1949 days


#7 posted 09-30-2014 12:32 PM

Thanks Kai! I don’t know how hot mine was, but I could still hang on to it.

-- Improvise.... Adapt...... Overcome!

View Earlextech's profile

Earlextech

1159 posts in 2152 days


#8 posted 09-30-2014 01:18 PM

I have to chime in at this point.
First of all, steam burns now. IMMEDIATELY! So that’s why you should always wear gloves when steam bending.
Second, water boils at 212 degrees, at sea level. That’s when steam starts. The temp of the wood needs to be 200 degrees or more. 375 is crazy hot and totally unnecessary and extremely difficult to achieve.
Watch my video here – https://www.youtube.com/watch?v=GpIUfI8qmTg – in order to see how to do this operation safely.

-- Sam Hamory - The project is never finished until its "Finished"!

View Dallas's profile

Dallas

3599 posts in 1949 days


#9 posted 09-30-2014 04:18 PM

Earlextech, I agree. For every thousand feet of altitude the temperature needed to boil water will drop 3°F. Or at least I think that is what I learned in school.
I lived in West Yellowstone, MT once for about 3 years. That is at 8585’ altitude. You should try cooking a pot of beans or baking a cake.
I also believe that to achieve 375° with water vapor the vessel needs to be under pressure and sealed. This is why pressure cookers work.

As for 200°F temps, I seldom ever wear gloves for temps that low. My mom had a restaurant when I was a kid and one learned to handle hot stuff at that temp. I never got out of the habit and it soon becomes clear that the surface temp of most organic substances cools very quickly compared to the interior temperatures.

-- Improvise.... Adapt...... Overcome!

View Lazy_K's profile

Lazy_K

111 posts in 1652 days


#10 posted 10-01-2014 07:49 PM

Earlextech – I gotta disagree. just because the water is at 210 +- degrees that does not mean that the steam is. this high school chemistry (which is why I don’t understand that not everyone knows this) the steam coming off from an open pot is nearly always 50 or more degrees above the water temperature, creating back pressure by putting a lid on can bring the steam temp up another 100 degrees, steam coming out of a tea kettle’s whistle is often hotter than 400 degrees, which is why it burns instantly. the lignin in the wood doesn’t actually soften until the wood is that hot. a bigger problem in steam bending is accidentally letting the interior of the box to get to hot and dry (steam temperatures reaching 700 will do this) and scorching the wood which doesn’t happen until the wood reaches temperatures in access of 450 degrees (Fahrenheit). your blatant and incorrect self-aggrandizing advertisement tells me you have no idea of the situation.

-- Kai SaerPren

View Dallas's profile

Dallas

3599 posts in 1949 days


#11 posted 10-01-2014 08:21 PM

Hmmm, let me try this before I agree one way or another.

From what I learned in school, steam cannot heat to higher than 212° at sea level when not under pressure.
If it does, it is no longer steam, instead it becomes gasses.
In that case, you won’t be steaming your wood, you will be heating it with gasses: Hydrogen, Oxygen and Nitrogen, plus a few minor things. (Remember nitrogen makes up 93% of the air we breathe).

On another note, I have read a number of studies by wood workers that say wood doesn’t really need to be steamed, only heated in order to bend.

BTW, please don’t accuse anyone without proof or at least references. I didn’t see Earlextech as either self aggrandizing or making an advertisement.

-- Improvise.... Adapt...... Overcome!

View Earlextech's profile

Earlextech

1159 posts in 2152 days


#12 posted 10-01-2014 08:29 PM

Lazy – I’ve read your post several times now. I don’t see where you are disagreeing with me. Steam is hotter than the water it comes off. I agree. I didn’t actually say anything different. I stated that the wood needs to be 200 degrees or more. You agreed but thought that 400 degrees works better for bending. I’m fine with that. I happen to work for a company that makes a safe way to provide steam for small steam bending projects. I showed that in a video I did for them. Then I shared it with fellow LJ’s to give them and you the information that there is more than one way. Your last line baffles me. To each his own.

-- Sam Hamory - The project is never finished until its "Finished"!

View Dallas's profile

Dallas

3599 posts in 1949 days


#13 posted 10-01-2014 10:52 PM

Hmmmm, As soon as steam is given off by heated water it will start to lose temperature.

-- Improvise.... Adapt...... Overcome!

View Lazy_K's profile

Lazy_K

111 posts in 1652 days


#14 posted 10-02-2014 12:58 PM

Dallas = no, the temp of the steam coming off from the water is higher than the boiling water temp. when you put a bit of back pressure on it (like a loose lid on a pot) you generate what is known as vapor pressure inside the container which causes the steam temp to increase rapidly, the water temp does not increase.

-- Kai SaerPren

View Dallas's profile

Dallas

3599 posts in 1949 days


#15 posted 10-02-2014 05:38 PM

Actually, I forgot to ask my smart college educated friends and family about this.
I have no problem with being wrong, I just want to have scientific prrof to get my noggin around.

I’m not well educated, but I do have an 8th grade diploma.

Kai, I am really not doubting you, I just need some corroboration.

-- Improvise.... Adapt...... Overcome!

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