Can you over heat with steam?

[Mo_coon-catcher]

While steaming a recurve hook on black locust this morning I got to thinking, is it possible to over steam a piece of wood? Or more along the lines of it you can get the steam too hot and damage the wood.
But the first hook was fairly successful. Only a couple of shallow splinters on each corner. I consider that a success for a sharp recurve, hopefully it stays put when i pull the clamps and that the other side goes well. I'll find out this evening when I get off work.

Kyle

[PatM]

It only gets so hot. It's duration of heat that causes potential damage.

[Dances with squirrels]

Only if you boil away all the water. I let that happen once. Cooked an osage bow well done. It was toast.

[Pat B]

Steam only get to 212deg(F) unless under pressure. The water vapor will protect the wood from scorching.

[DC]

Like the Pats says, it only gets so hot. Depending on your altitude you won't get much more than 210 degrees. I have read that if you steam too long the moisture swells the wood cells making it harder to bend. At the same time I've read that steaming dries the wood. What are you going to believe? I steam stuff 45- 60 minutes because that's how much water my steamer holds

[PEARL DRUMS]

As said the heat is what it is, over exposure can and will cause issues.

[Mo_coon-catcher]

That's what I was thinking that it couldn't get hot enough without being under pressure. I knew it could get up over 1k degrees if under lots of pressure. It wasn't anything I truly worried about but was curious on. But it's good to know. Now I wonder I pressurized and super heated steam can burn wood. Just some of the random thoughts that pop up while heating a bow.
I have had steam dry out an osage that I bent that I forgot to grease before I satarted steaming. I steam by wrapping with a wet towel and foil. So ye wood soaked up the moisture then when I removed the foil the boiling water quickly evaporated out and left lots of little drying checks every where in the bend area. I steamed for 50 minutes and with the aid of the heat gun the locust was like rubber and only raised splinters where I didn't round the corners enough.

Kyle

[OTDEAN]

I stopped steaming stuff, dry heat works well enough. 

[DC]

I've been wondering if the steam itself has anything to do with the bending or if it's just a convenient way of limiting the temperature. Maybe a little oven that peaked out at say 250-275 degrees might be a good compromise. No mess and not much danger of smoking your prized stave. No stains on the wood either.

[Pat B]

Steam prevents the wood from drying out too much. I usually use dry heat but the next recurves I build I will use steam to bend them.

[huisme]

Once I get a boil on I put anything at  or past rough stage over the pot with a wet rag cover for fifteen minutes and do the whole bend in one go. Great for recurves or heavy inner limb/grip deflex.

[Mo_coon-catcher]

I feel like the steam also give the wood a chance to be a fairly uniform temperature throughout without much chance of scorching the outside before the inside is ready to bend. For ye shallower flipped tips and lateral movements I've been using dry heat with good results. But when I've been going for near 90* bends for the hooks I've been steaming and using the heat gun to keep the wood hot while bending it around the form. So far it's worked well with minimal splintering.

Kyle

[Danzn Bar]

I feel like the steam also give the wood a chance to be a fairly uniform temperature throughout without much chance of scorching the outside before the inside is ready to bend. For ye shallower flipped tips and lateral movements I've been using dry heat with good results. But when I've been going for near 90* bends for the hooks I've been steaming and using the heat gun to keep the wood hot while bending it around the form. So far it's worked well with minimal splintering.

Kyle

Kyle,
I think your right on with your comments......I've used more dry heat than steaming but I think it's because of convenience, but whenever I make big bends I use steam.  no chance of over heating and if you steam for an hour the temp is through out the thickness for a nice consistent bend. Kyle, Well said IMO..........
DBar

[Danzn Bar]

To answer the original question "can you over heat with steam?
Answer.....No you can not.
DBar

[alcot]

I remember an old post or  build along where the bowyer steams for five minutes and no more.  Said 212 is steam temp whether its five minutes or fifty. Wood gets too hot to touch. Made sense to me and  I've tried it and it seems to work fine.