View Full Version : good pressure for steaming
just wondering what is a good working pressure for steam bending 1.5x2.5 white oak
05-19-2002, 12:19 AM
You don't need to measure pressure in a simple steam box. You want some of the steam to escape, through some small holes or a cap or lid that doesn't fit tightly. Otherwise the back pressure will block the flow of steam to the box. Green oak of those dimensions should steam for about one to one and a half hours.
[ 05-19-2002, 01:21 AM: Message edited by: Bayboat ]
05-19-2002, 05:53 AM
Listen to Bayboat's advice.You arn't trying to pressure cook the stuff.Make sure the steam can circulate freely around the frames and steam for the right length of time.Keep a test piece in the box so you can pull it out and try a bend.A few extra frames also doesn't hurt to allow for breakage.Once you get into the rythm of the job things go along well.
All the best;Earl
05-19-2002, 09:49 AM
I'll go one one further. Make SURE it leaks! Pressurised steam is dangerous. There's a reason it requires an engineering license to run a steam plant. You can run your hand through a live flame with no damage if you do it fast enough. Do that with "live" steam and you'll lose your hand...
05-19-2002, 01:10 PM
My steam Jenny puts out 350 degree steam @ 60 to 150 psi. Thats what the relief valve settings are. The steam tube (that holds the oak) has no pressure. It has the steamer wand in one end and a drywall bucket(with a brick in it) in the other.
05-19-2002, 05:44 PM
Do you have a whistle on that baby? :D
what i did was take a nipple from a pressure cooker lid and screwed it to the steambox w/the 15# weight that cam with the cooker. i was told a little pressure would steam faster. is this true .
or am i just wasting my time .the vent hole is about a 1/4 of an inch is this good enough.
thanks JLM :D
05-20-2002, 01:36 PM
See the photo of my Non Pressurized steamer at this thread.
[ 05-20-2002, 02:38 PM: Message edited by: Larry Exum ]
05-20-2002, 02:05 PM
The pressure serves to raise the boiling point of water, thus "hotter" steam. Hotter steam is not better steam for this application (IMHO). Our sponsor has a booklet which discusses steam generators, steambending wood, etc. Good reading.
05-20-2002, 02:10 PM
Obviously there will be something over one atmosphere pressure in a partially blocked box, but you do want less than would blow the stuffed rag out of the end of the box.
DO NOT let any appreciable pressure build up :eek:
05-20-2002, 02:46 PM
Now I'm really getting steamed...No, seriously the hot steam will suck the juices and life out of the frames.I find what I call "sloppy" steam works the best.This is one area where I believe low tech is the proper approach.You don't need any more pressure than an old can of water,a piece of hose and fire will provide.
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