First thick heat bend . . . working up the nerve.

[Prarie Bowyer]

OK so I saw this documentary on the ELB put out by the History channel where the host conjectures with a historian that many ELB's were actually recurved at the tips and commissions just such a bow.  I'm trying to build a similar bow.

On the show they boil the wood.  I have no giant pot to boil water in.  I have heat gun.  I know some guys use the dry heat and oil the wood to prevent burning.  I saw an article here where a static recurve was made by pre tapering the wood then gluing bent laminations to the belly to bring it back up in thickness.  I've also seen the full thickness get heat bent. 

I want to add a bamboo backing to the "Lyptus" wood I'm working with.  I'm afraid that If I use the oil route I'll make glue up a pain.  I've also seen videos of guys that made a steam oven.  I'm considering this but I haven't figured out how to switch from heat gun to steam captured in the oven.  I have seen these ovens made in foam or in plastic pipe.

My bends are not 90* deep bends.  <90* over a 9"-10" long radius.  I also have some twist and warp when I sawed the piece of wood from the board which needs to be fixed.

So I guess I'm looking for input that will create the best probability for overall sauces with a heat gun.  I'll need to make the bend.  Then add the backing and belly pieces if I pre-thin the ends further. 

I'm doubting that it will be as easy as head wood with a heat gun, back out side radius with something to prevent lifting a fiber, bend gently around form, clamp and let cool over night.

[Marz5]

OK so I saw this documentary on the ELB put out by the History channel where the host conjectures with a historian that many ELB's were actually recurved at the tips and commissions just such a bow.

here is a discussion about that show (if it isn't, he came to the same "conclusion")
http://www.primitivearcher.com/smf/index.php/topic,27089.0.html

--Mark R

edit: flipping the tips should help in the fps area

[Stingray45]

Hey Prarie,

I don't if you want to spend the money or not but you can get a pot for pretty cheap. The wife would not allow me to use our stock pot at home and I complied not thinking I would enjoy eating soup made in it after I boiled some osage in there. So I went to Target and found a big stock pot for like $16 I believe it was. I can put enough water in it to boil at least 9" or more if you have it at an angle and I just boil the water out on the burner of my gas grill. You could probably get smaller ones cheaper but I wanted to grab the biggest one they had and I didnt think the price was that bad for the size. I also got it because I've had some trouble with spliters lifting when heat bending, even when I've covered with metal. But if you do the full thickness you might be able to remove most of that wood when cooled if it doesn't crack the whole way through.

~Barry

[Primitive1]

I've made some serious contraptions for heat bending but I always seem to come back to dry heat...I don't use oil, I use a heat gun and just get as close as I can to my bow dimensions (allowing some generous 'whoops' room) and slowly apply pressure...this way, I'm not having to guess if I'm overheating, heating too long, damaging the wood etc...I just start heating slowly (low setting), keep the heat gun moving and then start applying some pressure with the clamp(s)...the wood starts to move when it's ready.  I know, it sounds and to me is the most simple of the methods, but it continues to work with the least amount of cost/pain/mess/fuel associated with steam, boiling etc...my two cents worth.  I've had splinters raise up in the past with all the different methods...that's why I keep the bow dimensions generous...plan for it and you won't be dissapointed.  Cheers, P1.

[Prarie Bowyer]

Thanks for the help guys.  What I decided to do was this.  Basicaly I will be folloowing what 4est Tracker did in his osage buildalong "static recurve" only not as deep.  His actualy seem to go 90*.  I pretapered the wood and saved several offcuts that are tapered.  I'll prebend them all and laminate them togeather.

Just need to make adjustments to my forms.  Of to the shop now. 

[soy]

Best of luck...keep us posted on your results 

[mikekeswick]

The simplest way to do this would be to make a form and simply glue the bow up into the shape you want.
Remember that for a recurve to store more energy it has to have a fair amount of bend to it eg. the string must touch the belly below the nocks. Therefore it has to be a heavier tip than a straight bow needs. As the limb is being asked to store more energy it would have to be made wider and thinner than a straight bow to end up with the same set. Which in turn means the limb is heavier.
It's swings and roundabout when you start comparing recurves to straight bows, you gain something here only to lose it there....
I've found the best way to increase energy storage on ELB's is to make them reflexed along their length.

[Prarie Bowyer]

Thanks,

I'm looking for a bow that shoots and looks like the recurved ones in illuminations.  I was thinking about the gaining to loose scenario.  I would imagine that the Legolas Lothlorien bow, while looking cool would not be that great a shooter with those giant heavy limb laminations up there.

[Prarie Bowyer]

Still struggling to get my form working and efficient.  I could have cut a nice one but I HAD to use scrap from another project.  I bent some scrap and it's not bending smooth.  I deepend the form also.

someone sent me a link to photos on how they bend with tinfoil and a heat gun and now I can't find it.  The buildalong I wanted to follow claimed that the wood was bent dry and with out oil.  My scrap got a bit toasty and bent in kinks.  No splinters though.  I wonder about soaking in water.  Warpping in foil.  Then using the heat gun to heat up with out burning and getting a bit of deep heat penetration?

thanks,
PB

[Prarie Bowyer]

OH, I saw a video where small pieces are soaked in water the microwaved and quickley bent.  Wont work for me because while I can and do micrwave wood . . .  I'd have to run the marathon to my shop.  But I bet soaking in hot water then wrapping in foil and heat guning would work the same.

[zdogk9]

Get a wall paper steamer, and a length of 3" ABS pipe. cap one end of the pipe. drill a couple of holes to push dowels through for a rack so your bending stock does not sit on the bottom of the pipe. put your bending stock in the pipe,  run a length of hose from the steamer to the open end of the pipe stuff a rag in the opening and pour the steam to it. caution! experiment with a piece of stock of the aprox. dimensions first, this will give you an idea of how long you'll need to steam before you go on to your bow.  for 1/2' thick white oak I'll steam for aprox 15 minutes for 1/4" maybe five. This is for kayak ribs, and deck beams. use an old leather belt as a backing strip when you're bending, it'll save a lot of grief.

[Prarie Bowyer]

Ok, Well, So .... "Lyptus" is not "dry heat bend friendly".  Following the thread by 4est Trecker didn't work out so well.  I have one tip of the blank bent and it's mostly superglue.  I hope I didn't glue the clamps to it.  I hope  my belly laminations hold it togeather.  Actualy I'm considering scrapping the idea of bending the other laminations and just cutting a curve and gluing up. 

Never again.  Well maybe later when I get money and time to build an actual steam oven.  And I'll never do an ELB with flipped tips again.  At least not in that kind of wood.  I might try from a semi damp stave of some other oily more flexible wood.  Lyptus is starting to seem a bit brittle.  I'm wondering if it's even a good bow wood at all.