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Brahm Thexton
02-21-2007, 03:17 PM
Hello,

A really quick question.... How hot does your steam box get? My steam box gets hot enough for bending the red cedar planks im using but i just stuck a meat thermometer in the top end of my box and the temp was a lot cooler than i expected... Anyways, just curious.

Thanks,
Brahm

Robmill0605
02-21-2007, 03:28 PM
With this setup I'm about 212 degrees with full stem going using a meat therm. in the top of the box;
Here is my set up

[img]http://s55.photobucket.com/albums/g148/robmill54/?action=view&current=P20403099.jpg

Robmill0605
02-21-2007, 03:30 PM
Hmmm, still having trouble posting a picture, not sure why.

http://s55.photobucket.com/albums/g148/robmill54/?action=view&current=P20403099.jpg

prestonbriggs
02-21-2007, 04:00 PM
Generally, I see 211 to 211.5
Lower temps indicate a problem (duh!), like running out of propane or too much water going in or the boiler running dry.

Preston

http://www.clcombat.info/Images/Haven/ready.jpg
http://www.clcombat.info/Images/Haven/working.jpg

http://www.clcombat.info/Images/Haven/hot.jpg

Brahm Thexton
02-21-2007, 04:36 PM
Hey Guys,

Ya, thats the temp. I'm at too... I guess i thought it'd be higher for some reason. Anyways, it works so im happy!

Robmill0605
02-21-2007, 04:42 PM
test....

<img scr=http://s55.photobucket.com/albums/g148/robmill54/?action=view&current=P20403099.jpg>

Robmill0605
02-21-2007, 04:44 PM
What am I doing wrong trying to post a picture ?
anyone???
Thanks!

Don Z.
02-21-2007, 04:45 PM
Hmmm...
http://i55.photobucket.com/albums/g148/robmill54/P20403099.jpg

I blame photobucket...

The Bigfella
02-21-2007, 07:54 PM
Wow - pretty boxes you guys have got there. Mine is just a length of poly plumbing pipe wrapped in Armaflex (which I already had) - but it is almost 20' long.

http://www.imagestation.com/picture/sraid101/p02c6ebbf8912b3337f3925357d0e4e7c/f9dff0a3.jpg

No idea of temp - but if you check out the ice on the propane bottle, you'll note that we sure were using it fast:

http://www.imagestation.com/picture/sraid101/p2d9f0043aeb1c0aa3384a9df0c427418/f9dff088.jpg

Ron Carter
02-22-2007, 07:18 AM
Water boils at 212F at standard pressure of one atmosphere. The temperature will remain there unless the pressure is increased or as noted above the water supply fails. Dry heat is not recommended for bending.

Bruce Hooke
02-22-2007, 09:26 AM
To expand a bit on what Ron said, to get steam hotter than 212F or 100C you have to pressurize it. This is a bad idea for a couple of reasons. First off, it does not make the wood easier to bend (or so I've read), and pressurized steam is dangerous stuff. I'm told that a jet of steam will cut off your finger easier than a bandsaw will.

Bruce Hooke
02-22-2007, 09:33 AM
test....

<img scr=http://s55.photobucket.com/albums/g148/robmill54/?action=view&current=P20403099.jpg>

You are posting the URL for the page your picture is on, not for the picture itself. You need the actual URL for the image. Once you have the Photobucket page open, right click on the image (or control click on a Mac (I think)) and select properties. This should bring up a dialog box with the URL for the actual photograph, which you can copy and paste. Then either use the insert photo button on the forum http://www.woodenboatvb.com/vbulletin/upload/images/editor/insertimage.gif or put in front of the photograph URL and at the end of the URL (with no spaces anywhere). Here is the result.

http://i55.photobucket.com/albums/g148/robmill54/P20403099.jpg

Thorne
02-22-2007, 09:45 AM
First - don't attach photos. Most web forums don't allow it, and space
limitations are the main reason why.

Second - Instead of attaching them to a thread, post the pics on the web
somewhere. You have a free website area with any paid ISP's email account,
or use www.picturetrail.com or other free hosting service. Once posted on
the web, right-click the image to copy the URL (web address). Always test
first by pasting the image URL into the window of a web browser and see if
the image displays.

Third - once posted on the web, try this procedure while logged in to this
Forum:

1. Click the "User CP" link in the browser window in the top left of the
menu bar.
2. Click the "Edit Options" link about 1/4 of the way down the left column.
3. In the "Misc Options" at the bottom of the next page, select "Enhanced
Interface" from the pulldown list.
4. Once this interface has been selected, in any "Reply" window you can
click the "insert photo" icon --> a little yellow square icon with the stamp
in the upper right corner, the mountains in the lower center.
5. Once the little dialog box titled "Please enter the URL of your image"
comes up, paste the URL of the photo in the field.

If unsure of the procedure, test first by pasting the image URL into the
window of a web browser.

http://us2.pixagogo.com/S5k3%21ZCYnkO41BWzsawvS4WlZdgz9zehXcl6bqm9lRlHc6S-FUvUlGxBEcf7w8-taOwIpEsDflX17JQdBwTxxrpA__/1.jpg

Rational Root
02-22-2007, 10:52 AM
You cannot normally increase the temperature of WATER above 212F/100C without increasing pressure, it will simply convert to steam.

Since the steam is coming off of boiling water, it will be at 212F/100C.

However, if you had some heat source directed at the steam itself, eg run the steam through copper pipes, and spiral the pipes through a burners flame, you can increase the temperature of the steam without needing to pressurise it.

If you have a sealed vessel, and you increase the temperature, then the pressure will increase (Boyle's law)

To generate hotter steam, I believe that the EASIEST way would be to super heat water. This water must be under pressure to allow it to superheat. The steam that comes off that water will be hotter than 212F/100C, and then the steam would be under pressure. But it is not true to say that steam hotter than 212F/100C must be under more than 1 ATM pressure.


To expand a bit on what Ron said, to get steam hotter than 212F or 100C you have to pressurize it. This is a bad idea for a couple of reasons. First off, it does not make the wood easier to bend (or so I've read), and pressurized steam is dangerous stuff. I'm told that a jet of steam will cut off your finger easier than a bandsaw will.

Bruce Hooke
02-22-2007, 11:11 AM
Good points Rational Root. I should have said that you cannot get water to boil at higher than 212F without putting it under pressure. That said, I stand by the point that IT IS A REALLY BAD IDEA TO GET INVOLVED IN SUPERHEATING STEAM FOR STEAMING WOOD!!!

dmede
02-22-2007, 01:16 PM
Good points Rational Root. I should have said that you cannot get water to boil at higher than 212F without putting it under pressure. That said, I stand by the point that IT IS A REALLY BAD IDEA TO GET INVOLVED IN SUPERHEATING STEAM FOR STEAMING WOOD!!!

You can get a small increase in boiling point temp by just adding salt. Might take it to 218*F (does that effect the temp of the steam?). But you're right, superheated steam is not only dangerous, but unnecessary for bending boat wood ;)

waters'l
02-22-2007, 02:15 PM
I don't know that having hotter steam would be such a bad idea. If you used a pressure valve to get the water to a higher pressure and thus hotter temperature, the steam wouldn't have to be under pressure to be hot. It would seem that hotter steam would make the wood easier to bend. Plus, cut your finger off steam would have be at 5-6atm to have enough force to do that kind of damage. But, caution is probably a good idea since 100C steam seems to work.

Bruce Hooke
02-22-2007, 02:22 PM
I don't have time to dig it out, but I believe it is R. Bruce Hoadley's book Understanding Wood that this issue is directly addressed and where tests are cited that demonstrated that superheating the steam did not do anything to improve the bendability of the wood and, IIRC, may actually have made the wood more brittle.

As to safety, I will concede that just mildly pressurizing the steam would be unlikely to create a finger-slicing jet of steam, but it certainly increases the risk of getting a serious burn. Steam is invisible, so it can be hard to tell where it is and avoid it. Fortunately, if it becomes visible fairly quickly when it hits cool air. This factor would be reduced if the steam was hotter than 212F (100C) and the resulting burn would be worse.

Don Z.
02-22-2007, 02:26 PM
(or control click on a Mac (I think)) and select properties. This should bring up a dialog box with the URL for the actual photograph, which you can copy and paste.


On the Mac (that's how I got his photo to post) when you control click, there is an option for "Copy image address". You can use that instead of trying to find the correct property.

You can also click and drag the image to the dialog box, and that will drop the URL instead of the image itself. Either way, it's easy...

Robmill0605
02-22-2007, 02:33 PM
Thanks everyone, I'll get the picture thing yet. Still learning this computer thing.
What great people you all are here.
Thanks again.

Robmill0605
02-22-2007, 02:50 PM
[IMG]http://i55.photobucket.com/albums/g148/robmill54/P20500044.jpg?t=1172173696


Welll close anyway, I used foam with a slot in it to steam the ends of a 10ft plank for my project. By the way, this is NEW 5 gal gas tank, and auto radiator hose.

Rational Root
02-22-2007, 03:13 PM
I think I would tend to agree.....

It would seem to be somewhat dangerous, or at the very least, damned unforgiving.:eek:

D


Good points Rational Root. I should have said that you cannot get water to boil at higher than 212F without putting it under pressure. That said, I stand by the point that IT IS A REALLY BAD IDEA TO GET INVOLVED IN SUPERHEATING STEAM FOR STEAMING WOOD!!!

Don Z.
02-22-2007, 05:32 PM
http://i55.photobucket.com/albums/g148/robmill54/P20500044.jpg

Lose everything after the ".jpg". Not sure why it's there on the URL, but if the "[/img] goes after the "jpg", you shouldn't have any problems...

waters'l
02-22-2007, 06:30 PM
[quote=Bruce Hooke;1508710]I don't have time to dig it out, but I believe it is R. Bruce Hoadley's book Understanding Wood that this issue is directly addressed and where tests are cited that demonstrated that superheating the steam did not do anything to improve the bendability of the wood and, IIRC, may actually have made the wood more brittle.

Well, I guess it's better to keep it simple then. Where does the bendablity occur? If you didn't have to get the steam box all the way to 100C, it would make the process even easier.

Charles Burgess
02-22-2007, 09:52 PM
Water boils at 212F at standard pressure of one atmosphere. The temperature will remain there unless the pressure is increased or as noted above the water supply fails. Dry heat is not recommended for bending.

I was wondering who would say it...How hot is a steam box is like asking how hot you boil your water...LOL: if it is steam it is 212F at sea level. The box temp will be slightly lower. Other than that steaming a plank is a lot like cooking pasta.

Brahm Thexton
02-23-2007, 01:15 AM
I suppose you're right Charles.... i never really looked into it too much. I reckoned there was a lot of variables, like amount of steam produced vs. steam box volume and box insulation etc. Thanks folks for your replies...

Brahm

Ps.... I do sometimes overcook my pasta...... and i have overcooked a plank....

Charles Burgess
02-23-2007, 03:24 PM
I suppose you're right Charles.... i never really looked into it too much. I reckoned there was a lot of variables, like amount of steam produced vs. steam box volume and box insulation etc. Thanks folks for your replies...

Brahm

Ps.... I do sometimes overcook my pasta...... and i have overcooked a plank....

Unlike pasta, wood differs from batch to batch and the particular dimensions of the wood stock. This is why you need more wood than you will actually use - to test the best steam time by trial and error. You can figure using 2 to 4 planks to figure the best range of time to steam the planks (the day's tempurature and humidity figures into it as well). And you need a moaning chair to gather your thoughts...good stuff to write in your builder's journal.

The Bigfella
02-23-2007, 11:43 PM
Rule of thumb is one hour per inch thickness IIRC. Works for me

Robmill0605
02-24-2007, 08:16 AM
While we are talking about steaming, how many of you pre-soak your wood before steaming?

....
Thanks Don, I'll try that.

Robmill0605
02-24-2007, 08:21 AM
http://i55.photobucket.com/albums/g148/robmill54/NEW20GOLDEN20NUGGET20001.jpg[/URL]

test

Don Z.
02-24-2007, 09:56 PM
Close, so close... you forgot the square bracket after the first "http://i55.photobucket.com/albums/g148/robmill54/NEW20GOLDEN20NUGGET20001.jpg

Robmill0605
02-27-2007, 03:57 PM
ttp://i55.photobucket.com/albums/g148/robmill54/Scan0002_0002.jpg

Robmill0605
02-27-2007, 04:02 PM
test


http://i55.photobucket.com/albums/g148/robmill54/boatplanking6.jpg?t=1172610040

Robmill0605
02-27-2007, 04:03 PM
http://i55.photobucket.com/albums/g148/robmill54/boatplanking6.jpg?t=1172610040

Robmill0605
02-27-2007, 04:05 PM
DUHHHHHHHHHHHH>

Got it.!