How I Steambend (Now With Photos!)

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 13th, 2006, 3:22 am #1

Somebody was asking about steambending. I am certainly no expert on the subject, but I have been doing quite a bit of it, and I hope this helps...

Jim I. (Scorpion King) told me how to make this simple steam tube, and gave me lots of help and encouragement on the "how to". He also took me to his secret black locust spot twice to cut as much wood as we could carry away. Thanks, Jim!

Although we cut only the straightest, cleanest wood we could find, almost all of it bent and twisted while drying - necessitating a lot of steam bending... We probably could have somehow avoided all the wood bending, but then I would not have learned about all this...

If you want to heat up the whole stave, and get a fairly thick piece (up to 2" by 2" ) hot enough to become plastic, you need to make a steam tube. You could probably make one cheaper, but this one works well, and all the pieces are available at Home Slomo (My pet name for Home Depot - the Land Where Time Loses All Meaning and Where Mountains Erode and Stars Die While I Stand In Line).


Start with the base, which will sit on the pot of boiling water. It is a roof flashing, found in the Roofing section.




While you are there, pick up a flexible coupler (My ducting is 5"). It is the piece at top center of this photo, covered in aluminum tape and bending about 90 degrees. You can get by with one small roll of aluminum tape (but it is useful stuff, and the big roll is a better deal). You can see the joints where it bends under the tape. The cover is messy from crisco - which is one of the things I experimented with to seal my staves for a moisture barrier when steaming.




Go to the hot water heater department, and get a length of double insulated pipe a little longer than the staves you plan to steam. They only come in 5' sections where I am, but you can get a coupler and add another length. Go too long, and cut it down with tin snips later, if needed. The single insulated is one third the price, but allows a lot of heat to escape. The double insulated piece is about 15$, and gives you 3-5 degrees more heat (by my thermometer). I tried both, and I would suggest you don't even bother with the single insulated! The outside of the double insulated still gets hot enough when steaming you need gloves to touch it, so you could probably wrap it with something (heat resistant) to increase efficiency further.
I took the flexible coupler, and used a screw gun to shoot short dry wall screws through it to attach it to the base and tube; and then wrapped the whole attachment with aluminum tape to hold it together and keep the steam in. I made it so the tube angle slightly up (rather than perfectly horizontal), so the water would run back into the pot as it condensed.
Here is a side view, with two staves being steamed on one end only.




Here is a view down the tube from the back. The rocks keep the the tube on the pot.




Here is a view down the tube from the opening. The chair is a crude stand for the tube. A simple tripod of rejected staves would probably suffice.




Side view of the tin foil at the tube opening. Sorry I didn't put something black behind it so you could see the steam pouring out. The tin foil is not to seal the steam in, just slow down the heat escape. The steam must flow past the stave, delivering heat. I leave at least a 1"-2" opening around the wood. By the way, if you have a sufficient heat source (see below), the steam coming out will be HOT. You want leather gloves when pulling a stave out or adjusting the tin foil, and you definitely don't want to put your face down by the hole (trust me, I checked out that idea for you already).




Here is a coupler and a 2' section of pipe, if you need to extend your steam tube. The coupler can be taped on the shorter section, and a screw tightens down on the other side, so you can remove it fairly easy for steaming shorter staves, or steaming just one end.




Here is my tube with the extension and a typical length black locust stave (typical for me) for scale. The stave is around 76"-80". Note the coupler is single insulated, and puts out quite a bit more heat than the tubes it it connecting. I will probably wrap it with a wet towel when in use.




Ok, now for the most important part: The heat source. I went to Walmart and got a "fish fryer" for about 30$-35$. I should have got the turkey fryer for another 15$-20$, since it came with a much bigger pot. The pot I have I have to refill every 40-45 minutes. I use a timer so I don't forget and melt the pot, burn the stave, cause a massive fire in our dry, dry desert. You want to steam for about 1 1/2 hours, so a bigger pot would be really nice... The propane tank is about 20$ at Costco (empty), and good for about 3 sessions. It is definitely more economical to do as many staves as you can fit in your tube at once (About 4-6 in a 5" tube, depending on size and how bent they are. More if they are thinner, less if they are thick or really doglegged or reflexed). This kit also came with a thermometer. I get 210-212 degrees putting it in the open end of the tube. The hose is for refilling the pot - by far the fastest and most convenient method. It only slows down the boiling for a few minutes.



The burner set up. Mine puts out about 50,000 BTUs (about the least of what this type will do). It should sound like a small jet engine while heating. So far nothing smaller has worked well for me. I have heard a double camp stove will work, but I think those only put out about 30,000-35,000 BTUs, so I don't know.




Closeup of the actual burner.




Before you steam your wood, you may have to seal it. I absolutely have to seal my Black Locust with two coats of spar varnish, or it will crack. Dean Torges recommends Shellac, and I can see why- I have some cracks that got filled with spar varnish and I don't know how to clean them out to put glue in them. Shellac could be dissolved out with alcohol, I believe. I have steamed BL, juniper, ash (a lighter species), one piece of osage, and something I think is elm ("Dammit Jim, I'm a photographer, not a botanist...". That's a Star Trek reference, not an outburst at Scorpion or anybody else). I have used Titebond II and crisco as well. Crisco is very messy, and not as effective as varnish, but is cheaper and will work so-so. Titebond II costs as much as spar varnish, is effective with only one coat, makes your BL look like osage until you scrape it off - and there is the trouble with that. The glue is harder to remove than the varnish.
Sealing is not my idea! Dean Torges recommends it, and Tim Baker warned me that steaming dries out your wood, and can do so excessively. This seems counter intuitive, as the steam is moist; but believe me! Steaming will remove moisture from your stave! Beware!
Black Locust and Osage definitely need sealing. Juniper does pretty well (at least in that department) so far. I leave a thick layer of cambium on, so that probably protects it. The ash doesn't seem to need it; but the pieces I did may not have been completely dry.

Ok, now you steam your wood. I go about 1 1/2 hours for a piece 1 1/2"-2" thick/wide. Don't let the pot run out of water! Your wood should be plastic and bend easily. If not, you need more heat, more time, or both.
Thinner pieces can be done over a stove top, kind of like the photo below. I put the international "No" symbol over the photo because I tried this with this powerful burner, and the heat wrapped around the pot and scorched the stave outside the pot, even though it didn't feel hot to my hand when I checked it. You may have that trouble with a gas stove, too. I have an electric stove, and the heating element is smaller than the pot. This method is good for steaming in recurves on thinner pieces of wood, I am told. I have heard that if you steam one side, you need to steam the other. I have also been told on thicker pieces (that are not floor bending yet) that this is not necessary. Sorry, I have no proof either way.




Now for bending! The simplest method, and one that has been fairly effective in a majority of staves for me, is simply to use the fork of a tree. I bend it a little past where it needs to end up, and work the various bends out (or reflexes in, as the case may be).



My friend Jim (who we have to thank for all this knowledge), has had phenomenal success using just a vise. This method gives a little better control, and allows you to remove twist - by using a pipe wrench (protect the bow's back with a piece of wood taped over the wrenches serrated jaw). You can move the stave back and forth in the vise to tackle tighter bends, if necessary. A string layed on the back can give you a road map... Between these two methods, I have had good results with most of my BL staves, and the Osage stave, as well as all the ash staves and the elm(?) stave. No success whatsoever with juniper...





And now for a series of photos of methods I have tried for clamping troublesome Black Locust staves, and juniper staves. If a stave doesn't want to stay where I put it the first time, I end up leaving it clamped in some sort of jig overnight, and I take it past where I want it to end up. Not very far with most Black Locust- but so far with juniper that sometimes I break it (even though plastic). Even then, it often creeps back... If I go too far, a little (careful) heat with a heat gun will let it start to creep back towards the other way. I wrap it with a cold wet rag as it approaches straight (and pray). Note that this factor means that you have to do all your corrections in one shot- if you resteam it to try again, it will go back to its original shape, and you will lose the original correction.


A new and better use for a compound bow press, some photographic C-stands (multi purpose light stands), clamps, and a pipe wrench:






















Straightening and adding reflex to a troublesome Black Locust stave. The form was lying around from attempts to make a bamboo backed bow.











Note the form was not reflexed enough, so I drove some scrap wedges left from bandsawing out other bows between the form and the steamed stave. Incidentally, pieces of these wedges can be very useful when clamping irregular shaped pieces of wood (to keep the clamp jaws level and from slipping off).








Finally, some (failed) attempts to remove deflex (if not add reflex) to a promising juniper stave (This is one of the four I posted a thread about a while back):







And another attempt after that one failed:








Neither of these attempts worked, nor did a third I did not photograph, in which I really went even farther into reflex. That time it looked good, but crept back to some deflex by the end of the day. The good news is it ended up with half as much reflex, and I decided since I was going to sinew back it, I would use the sinew to pull it into reflex. The bad news is I got overenthusiastic trying to chase the back ring and pretty much ruined this stave.
Here is a photo of the best I could do removing the deflex (the back faces up):





Sal brought a very good jig to Chamberlin Ranch that you put the stave back down in and clamped it to achieve a nice reflex shape. It also had a 2x piece of wood all along one side to clamp to to straighten any doglegs. Sal used a heat gun to heat up a localized area and clamp it, moving progressively down the shaft. I believe he used crisco to protect the wood from drying out.


Here ares some uncorrected staves just to give you an idea of why I have been steam bending. From left to right: Black locust (debarked, not down to one growth ring yet), juniper (belly side), another juniper (back side, showing cambium), and the elm(?), which I did already straighten some (it was really a snake). The juniper staves are coated in Titebond II.





Same staves, side view:





Alright, now- the proof is in the pudding... So following are some results I got with these methods:


Here are two black locust staves that gave me trouble, and still need correction. The small one on the left is belly towards the camera, and the larger one is back facing right. The small one has both dog leg bends and deflex. The one on the right has been by far the most troublesome stave (other than every juniper stave I have tried) to straighten. I have gotten most of the dog leg bend out, but that lower limb is refusing to take any reflex. Back to the tube. I have probably steamed this stave at least 4 or 5 times... Now I am hitting localized areas (to avoid undoing any good work).





These black locust staves were from the inside (log center) side of bigger staves. They were extremely snakey, but since they were thin, I was able to get them fairly straight in a few sessions. These required the vise method. The one on the left is a kid's bow almost ready for a string, and the other three may either be kids bows, or english long bows (light ones). The longest is just over 78", and they are approximately 1"- 1 1/4" thick.





Same staves, profile view (Backs facing left):





Here are some black locust staves ready to be tillered, and one halfway there. The longest is around 77", and the shortest (braced) one is about 67". I will probably sinew back it to get it to my draw length (approx. 30" to the grip). Since three of these have glue on risers, now is a good time to say that if you steam the section that has a glued on riser, it will probably come off (epoxied ones have, the time I tried it... Don't ask me why I did it).





Here are three ash staves I got from the same 1/2 log Alex gave me a few months ago in Pasadena. The big one I removed some side to side bend out of. It is one of the four I posted a thread on a while back. The two small ones were from the waste when I cut out the big one. They were curved to the side nearly as much as the side profile of the braced bow in the above photograph (maybe 2/3 that much). I steam straightened them and will try and make kids bows out of them. They may require further localized heat corrections. All three dried reflexed nicely. The larger one was probably too green when I floor tillered it, and has some slight set, now. It is much stiffer after drying out. The big one is about 72" long, 2" wide at flares, and 3/4" thick just afther the fades. The others are 71 1/2" and 54". I had a similar piece explode on both sides at once on the tillering tree at about 1/2 draw (and maybe 30#), so I am going carefully. It did look like it had rotted where it broke, though(punky looking inner wood), so I hope they will be ok.





Here are some more staves that have been steam corrected. From left to right: A black locust bow, tillered and ready to be finished up for a youth or lady (Still wavy, but string lines up fine), then a black locust stave that I plan on sinew backing. It is the one I charred when trying the "stove top" method when I first got my big propane burner (before I made the steam tube). You can see the char marks near the top, and about 6" above the fades. It also has longitudal cracks on the back, one of which runs off... I'll have to see how it goes. The next two are the other half of the four I posted about a while back. The juniper was kind of a shallow letter "C", and I tried to correct it many times in the handle before I finally got it fairly straight (thank God!). The osage had some limb twist above the crack on the top limb, and when I corrected it, I also matched the reflex on the other limb. The last bow is a little mulberry (fruitless - used in
landscaping ubiquitously in Southern California) bow 43 1/2" nock to nock. I straightened it and tillered it to 30# @ 21" to the grip. It took 2 1/2", set, so I belly tempered it (my first attempt) and re-reflexed it.






The same bow and staves, profile view. I plan to sinew back to the four staves on the right, pulling them into varying degrees of further reflex with the sinew.





Ok, that is it for now. I accidentally posted this before I was done- sorry about that. Now it is even longer - sorry about that, too!
Hope this helps. Those of you with more experience steam bending please jump in with your two cents.
Ken
Quote
Like
Share

Redhorse
Registered User
Redhorse
Registered User
Joined: November 15th, 2005, 2:04 pm

May 13th, 2006, 7:00 am #2

I se how you keep the pool water warm.
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 13th, 2006, 9:42 am #3

You mean "the cement pond"? Heat is not much of a problem here... I wish I could afford to replace the broken equipment that pumps and filters it - then it would not be green. I only fill it with water because the insurance company forces me to. They would rather someone drown than break a bone. Dead people don't sue, I guess.

I have been known to dunk a stave in the water to cool it quickly when I get it straight (using the forked tree method). Not a problem, because of the spar varnish.
I also soaked some staves in the "cement pond" under some rocks prior to steam bending once, when they were apparently so very dry that steaming didn't help. That turned into a fiasco, as it worked, but the staves bent even farther before I could steam them... All my other wood has steam bent very well when dry. The green wood seems to creep back much more often (though it is physically easier to bend).

Ken
Quote
Like
Share

NorthShorelongbow
Registered User
NorthShorelongbow
Registered User
Joined: November 5th, 2005, 7:49 am

May 13th, 2006, 10:07 am #4

Cool thread Ken, thanks
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 13th, 2006, 10:16 am #5

Thank you Manny. I hope some of it helps.
Ken
Quote
Like
Share

Bow bandit
Registered User
Bow bandit
Registered User
Joined: April 24th, 2006, 12:35 am

May 13th, 2006, 1:03 pm #6

yay finally ... thank you very much!

Brandon
Quote
Like
Share

Guest
Guest

May 13th, 2006, 1:57 pm #7

Nice pictorial Ken. Your steam setup is similar to what I use for boat ribs. I don't do much steaming on bow staves, simply because by the time I get around to bowbuilding whatever staves I have are already dry, and then I prefer dry heat.
Quote
Share

Thimosabv
Registered User
Thimosabv
Registered User
Joined: December 25th, 2005, 5:03 am

May 13th, 2006, 2:06 pm #8

NICE!

I like the boat trailer method. Very smart.
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 14th, 2006, 5:44 am #9

Brandon, you are welcome. Thanks, Iktom and Thimo.

Iktom, I have heard that if a stave gets too dry it is harder to steam bend; but I have only suspected it as the cause of trouble once (on a stave that had been drying in my desert climate for about 4 years). My black locust has all been drying for about a year. It seems dry, but maybe it isn't (Maybe some of the set I am getting is from the woods MC and not bad tillering).

Sal certainly made the heat gun method look easy... I will probably make a form like his for myself. By the way, I got the idea for my tillering tree from looking at Sal's...

Thimo, I had that rig lying around (!) and it was good to put it to use. However, I don't think it is as useful as Sal's form or even just the 2x4 with various blocks in place to clamp to. I would not bother making one like it; and I will probably not modify it. It was a lot more trouble to make than a wood form... That said, it worked pretty well on some staves. I forgot to mention that the pipe clamp and bar clamp are being held by the C- stands (photo light stands) to remove twist.

Ken
Quote
Like
Share

123Sharo
Registered User
123Sharo
Registered User
Joined: May 9th, 2006, 9:07 pm

May 14th, 2006, 5:59 am #10

Thank you, Ken, an excellent lesson for new beginners! And with perfect pictures again!
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 17th, 2006, 12:22 am #11

Thank you very much Iliana! I consider myself a beginner; but if anyone can benefit from my mistakes and trials, I am happy.

I wanted to mention here a method that Tom Mills has described to me a couple of times. It is much more primitive, and sounds like a really good method, regardless.
He uses dry heat, secures the stave (in a vise?), and hangs a bucket or bag of rocks from the end he wants to move. He just hits the appropriate area with heat until the stave moves where he wants it. That way he doesn't overheat it, or use too much force (a problem I keep running into).

Really sounds like something that our distant ancestors would have done...

Ken
Quote
Like
Share

tqpotia
Registered User
tqpotia
Registered User
Joined: August 19th, 2005, 9:01 pm

May 17th, 2006, 9:51 am #12

Hi, Ken !
Thanks for this detailed guide ! I can imagine how labour you`ve involved in those pictures to share them with us. Nice tips, too !

I`d like to ask you something - why you seal the wood ? The idea is to soak the stave. The sealing may prevent this ?

I`ve tried Tom Mills`s method but it was failure - because of very bad grains in one end of the stave. It warked wonderfull on the one end and I was sure it was best way; but using the same technics on the other end - nasty splinters resulted.

So, I`d keep on using a metal strap and form.

Best regards,
Kosio
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 18th, 2006, 5:35 am #13

Is the same Kosio that we have to thank for helping inspire Iliana to make her wonderful miniature bows (see "Bonsai Bows" thread)? Good for you!

The reason I have been sealing the wood is that steaming actually dries out the wood. You would think it would be the opposite (I did before I saw for myself), as steam is made of water... The steam merely carries the heat to the wood. The wood only gets really wet if the steam condenses into water on the wood. The heat causes the wood to lose some moisture content.

I may not be describing the cause and effect correctly; so let me say more succinctly that before sealing, I was getting a lot of drying cracks in my staves after steaming - ruining some, and effectively shrinking others.

Dean Torges, in his excellent book "Hunting the Osage Bow" gives a lot of very good information on steaming wood. His opinion is that steaming dries green wood and partially rehydrates dried wood. He recommends against steaming fully dried wood, stating that he believes it degrades the wood's qualilty for a bow. I have no personal evidence, yet.
Dean is a furniture maker, and he mentions that when bending pieces dramatically for chairs, etc., that green wood works bends uneventfully, but that dried wood treated in the exact same fashion (time, temprature, shape) often cracks or crinkles, even with a metal strap.

Most of the wood I have been steaming is fairly dry. I thought it was completely dry, but upon removal of surface wood of a stave, I saw evidence of drying cracks soon after. It may be helpful to keep in mind that I live in the desert...

Kosio, we were discussing the metal strap method on a similar thread. Can you describe how much bend you are able to put in your wood by this method? Also, the general rig you are using?

I still plan on trying out Tom's method. It seems rather elegant.

Thanks!
Ken
Quote
Like
Share

tqpotia
Registered User
tqpotia
Registered User
Joined: August 19th, 2005, 9:01 pm

May 18th, 2006, 6:16 am #14

Hi, Ken, thanks for the long replay - it is very detailed. I understand everything you say but now a question arise : Why don`t you boil the wood instead of steaming it ? It seems to be the most appropriate choice. Yes, you have to wait to dry again, but no problem with you - in your dry climate.

I`m trying to make "Turkish Bow without Horn" according description of Mike Grace ( I need his address though).
It is static recurve, with ears, bent to 90 degree, with a deflex around the handle and heavily sinewed.
So, I tried to get a gentle gradual deflex by hanging 2 lb. weight (from my spine meter) and heating it with heat gun - a good one. I`ve got it on the lower limb (the wood start sloooly bend by the weight) , but using the same technique, temperature, time and weight all I got on the other limb was ... splinters, so it brokes.
So, at once - the grain of the board started to very important to me. LOL

It was pity because was my last slat of OO.

Regards,
Kosio
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 19th, 2006, 3:16 am #15

Kosio, that sounds like a cool bow. Hopefully on the next try!
2 lbs sounds lighter than what Tom described to me (I'm pretty sure he use more weight, but not totally sure). If so, maybe you had to get the wood too hot before it started to bend? Just a guess.
I also want to hear about the metal strap method you use, please.

There is a guy advertising osage slats on the laminated bows site, but he has not responded to my ezboard message yet. Three rivers archery also carries them. I don't know how economical it would be to have them shipped to you, but it may be worth a look. If you can't find them, I can post their website.

As far as boiling vs steaming - The short answer is I am doing what I was told to do... It works (Finally!), so I am sticking with it...
Dean Torges recommends taking wood in one direction (from green to dry), without going back and forth with moisture content. He recommends steaming vs boiling; and also says to avoid water condensing on the stave while steaming, as it can insulate it from the heat you are trying to put into it with steam.

You are right about the dry climate. So far my problem has not been getting wood dry, it has been getting it dry without it cracking... If you look at the thread I posted about the knothole, you will see I suspect drying cracks on newly exposed wood in a stave I thought was dry.
One experienced wood bowyer I talked to recommended resealing wood after every working session - every time wood was re-exposed... Have tried it but not "converted" to that method yet.
Ken
Quote
Like
Share

tqpotia
Registered User
tqpotia
Registered User
Joined: August 19th, 2005, 9:01 pm

May 22nd, 2006, 6:38 am #16

Hi, Ken - there is nothing special about metal strap. It was described in TBB. I just fix the strap to wood I want to bend with a clamp and holding both firmly, press them down to the form. Then secure them.

Regards,
Kosio
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

May 22nd, 2006, 5:44 pm #17

Thanks, Kosio. I will pull out TBB and check that out again.
Ken
Quote
Like
Share

Arko
Registered User
Arko
Registered User
Joined: September 18th, 2009, 3:50 am

October 3rd, 2009, 2:38 am #18

Can't help but to admire your engineering skills and your creativity. Great stuff!
Quote
Like
Share

toxophileken
Registered User
toxophileken
Registered User
Joined: January 15th, 2006, 4:55 am

October 6th, 2009, 7:11 pm #19

Thanks! These days I usually pick a stave that needs less heat correction, and just use a heat gun and caul. Check out the thread about that:

How to Build And Use A Simple Caul

Ken
Quote
Like
Share

Huey Tlatoani
Registered User
Huey Tlatoani
Registered User
Joined: February 22nd, 2009, 3:15 pm

October 11th, 2009, 2:48 pm #20

Ken, that is hardly paleo, but oh my goodness is it ever awesome! I have a question for you about this type of setup since you've done it-what do you think would happen if you steamed an entire rivercane stalk to make into an atlatl dart shaft? In my mind I picture being able to evenly heat the whole thing, and then maybe hang up the shaft, tied to a cross piece at the top, with a cinderblock on a cord tied to the bottom end of the shaft, and just let the snaky-ness hang itself out. Do you think this would work or is this just a (stove)pipe dream?
"(unintelligible word)...after my stay in the earth lodges of the Mandan, I decided to move on in my explorations-but not further west, I decided to take my travels up-to visit the legendary tribes of the Jupiters, those men who dwell on the moons which Galleleo had spied through his spy-glass, and forged a relationship with through the flashing of signal mirrors. My friends say that I am a fool, nay, that I am mad, but as I toil, endlessly glueing together the ailerons and mighty jets of my "thermo-nuclear pulse-rocket" I giggle inwardly to myself. Just wait, you a*******. Just you wait and see, Thomas Jefferson and captain Clarke."

-George Catlin, "the Jupiter Diaries", 1849
Quote
Like
Share