Primitive Archer
Main Discussion Area => Bows => Topic started by: LivingElemental on June 28, 2012, 06:05:27 am
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Starting to make my first non-board bow, and I'm interested (while somewhat reluctant) in recurving the tips.
My wife, I'm sure, won't allow steaming a bow in the house, and I'm too poor to buy some form of outdoor apparatus.
Does anyone have an idea of how to cheaply heat a bow to warping capacity without pissing off the Mrs., or running the risk of scalding or scorching a small passing child (I have 4 of the little things)?
Also,
1. I'm curious if there's any standard as to the degree of bend to put into the tips for a first attempt?
2. Static or working?
3. Back before or afterward, and if before, how do wood glue and linen hold up under steam or heat treating?
I split this persimmon tree back in January to dry. 1/2 was riddled with black rotten wood, and half of the other half split too thin around the wrong side of a knot to be usable, so I only get 1 shot with this tree. I don't want to screw it up.
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Well if you can't do it inside you could do it on a camp stove out side,pan of water and alumna foil to cover,one tip at a time, I would steam Persimmon,Osage I use dry heat. Probably steam for 45 minutes or and hour and be ready to bend quick as it comes off the steam. Do it before you back it and be sure it is floor tillered before you start,I like working recurves but either will do,just leave a little thicker if you want static. I see you are in TN. you could just make your way over to TwinOaks and do it there. ;) :) :)
Pappy
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Wait till the missus goes out and then steam over the hob, its what i do ;)
It should be safe enough providing you support everything. I just use an old pan and make a tinfoil hat and pop it over the pan to trap the heat in.
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;)
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What they don't know can't hurt them....and is it really any different to boiling some veg??
As far as angle then as sharp as you dare and also keep them short to keep the weight down. As for the profile narrow and deep is much better than wide and thin the flipside being the narrower you go the greater the chance of instabilty.
Here's how I do recurves.
Work the stave tips down to 1/2 inch - 5/8 ths thickness. Making sure the belly side is worked to one growth ring (this step can be the difference between sucess and failure). When you do this you don't need to use a steel strap to stop belly fibers lifting, unless you are doing super sharp recurves.
Leave the tips at least 1 1/2 inches wide. At this width it is highly unlikely to end up with any unwanted sideways bend.
Steam for 45 mins and then gradually start to induce the bend. I use a big c clamp set into a recess on my form (so it can't move) or you can rig a rope tourniquet style. Then every 5 mins increase the bend until you get to where you want to be.
Leave in the form for a day. Then do the other one.
This method always works for me and with a 1.5mm steel strap i've made 85 degs bends.
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GREEN WOOD STEAM, DRY WOOD DRY HEAT.
A little been go's along way most people over been there first ones. Make a caul from a 2x6 use a torch. Go out side. Keep it on low flame and at least a foot and a half away. Heat slowwwwww'ly the slower the better.Rub down with cooking oil as you go.
Have your bow clamped down to the caul and a clamp on the tip. CRANK DOWN AS YOU HEAT THE PLACE WHERE YOU WANT THE BEEN. Again go slow NO NOT scorce. AT THAT DISTANCE YOU'LL HEAT NOT ONLY THE AREA OF THE BEEN BUT ON EACH SIDE ALSO. But let me say persimmon not the best wood to heat.
Go static on your first couple bows. It's really had to been the limbs and tiller them the same with working recurves.
But let me say heat destorys more bows than anything else. If I was you I'd build a few straight end stave bows before I'd worry agout heating at all. It's not hard to build a bow with out heat. And starting out theres many other things you need to master first.
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This is all incredibly helpful. I hadn't thought at all about the belly being affected by the bend. Much appreciated, everyone.
I'll post pictures as I go along.
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try using and a campstove and a big pot for the steam. just fill the pot with water set the part of the limb that you want steemed on top cover with tin foil then turn the stove on
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I do all of my bending with a heat gun set on high.Secure the bow (vice, clamp, whatever). Get a wet rag , and dampen the wood. Start heating until the water evaporates. Repeat two or three times , while applying slight pressure. Keep the gun about 1/2" or so away from the bow . Don't change the colour of the wood ,as that will be heat treating and will actually make it less flexible . I sometimes just bend it over the rounded edge of my work bench or i will make a wrench with the exaggerated profile I'm shooting for (there is always some spring back when you bend wood). The wrench is just a piece of hardwood with a notch long enough to hold the bow tip with a curved section that runs along the back of the bow to shape the curve.If you've never done it before, try it on a scrap piece of wood 3/8" - 1/2" thick x 3/4" wide with straight grain.If you have any pieces off the actual wood you are using, try them first as it will give you a good idea as to what you can get away with.After I get the shape I'm looking for, I heat treat it just enough to change the colour.This seems to "set" the bend .If you heat it too much, you can collapse the cells and weaken the wood. You will be amazed the first time you bend wood . It just all of a sudden bends under slight pressure when it hits the magic temperature . Good luck.
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Has anyone ever tried using a hair dryer in combination with oiling the bow up, or is that a stupid question?
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I'd be surprised if you could get the necessary heat from a hair dryer. Even if you could, it would take a long time for that heat to penetrate to the core. Heat guns are cheap, you should be able to find one for under twenty dollars no problem. If you plan on using dry heat, heat gun is the way to go. But if you have a kitchen, you already have everything you need to steam it. Just be sneaky about it >:D
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Has anyone ever tried using a hair dryer in combination with oiling the bow up, or is that a stupid question?
Hair dryer? and you are worried about the missus catching you use the hob? :)
Pretty sure my better havles hair dryer cost a lot more than my heat gun.
Make sure to get a heat gun with a good warranty rather than an expensive one. That way you just return it "still in warrenty" when it goes pop ,, ,and it will with lengthy heat treats trust me.
IF you buy a more expensive one it will probably last just longer than the warranty period period and your outa luck ;)
and yes i am banned from all local hardware shops.
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Sounds good. Thanks for the advice.
Now if it'll only stop being 112° outside, i can get started without my skin melting off my bones.
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I bet a fella could make a solar steam oven that would work great in this weather?
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Good post from Lostarrow, he describes the feeling of the wood suddenly going just right. I steamed the the tips on one bow by having a brick tied to the other end, after about 10 minutes the brick just started slowly pulling it down. you don't need much force once it starts to go.
First time you will be thinking "this doesn't work... this doesn't work...this doesn't work Oh! It works ;D "
Plywood is also good for making bending jigs too as you don'y need to worry about the grain. A few pieces of 1/2" or 1" ply can be glued & nailed/screwed ro make big blocks for jigs/cauls/whatever.
Del
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Cut the tip width wise as deep as you want the tip to re-curve. It should look like the bell and back are two different pieces of wood. Slide in there another this slice of wood ( any type will do but preferable a harder more dense wood ) of the same thickness as the cut you have made. Cover this insert with glue, insert and then clamp the works over a form ( mine is a 2x4 ) in the shape of the re-curve. Once the glue cures you have a no heat needed, no worries re-curve that can look nice with color contrast of the core wood insert you made. I will do demo if you want. Helps to have a band saw or scroll saw.
My first tips I got real hot with a heat gun and bent them over my steel toe boot by hand until cool. That was 3 years ago, I still shoot that bow. You can use the charcoal grill if you want also while doing some steaks....