Primitive Archer

Main Discussion Area => Bows => Topic started by: DC on January 28, 2020, 01:25:05 pm

Title: Steam bending heat treated wood
Post by: DC on January 28, 2020, 01:25:05 pm
I may have asked this before but can't remember. I want to bend recurves in this piece of Yew but I want to heat treat it thoroughly first because it's easier to do when it's flat. Am I going to have any problems steaming and bending the heat treated wood bending?
Title: Re: Steam bending heat treated wood
Post by: bradsmith2010 on January 28, 2020, 01:41:03 pm
Might be harder to bend,,.I am just guessing
Title: Re: Steam bending heat treated wood
Post by: PatM on January 28, 2020, 01:50:39 pm
I don't like how that works.   Why not heat treat the working limb area and leave about 6 inches alone at the tips.  Steam and bend and then touch up the heat treating and give the recurves some dry heat after.
Title: Re: Steam bending heat treated wood
Post by: DC on January 28, 2020, 02:04:29 pm
Good idea Pat. I can wrap the end with tin foil while I'm treating it :D :D
Title: Re: Steam bending heat treated wood
Post by: NonBacked on January 29, 2020, 10:24:20 am
DC – If you’re planning on static recurves, will you need to heat treat the tip area?
Title: Re: Steam bending heat treated wood
Post by: DC on January 29, 2020, 11:11:59 am
DC – If you’re planning on static recurves, will you need to heat treat the tip area?
I don't think you have to depending on how well the wood you're using will hold shape with just steam. In my case it is a boo backed bow so that would hold the shape. I will heat treat the tips after I bend them though because heat treating makes the wood stronger so I can remove more.
Title: Re: Steam bending heat treated wood
Post by: maitus on January 29, 2020, 01:40:39 pm
Heat treating should also make wood lighter. Do You will heat treat already backed bow?
Title: Re: Steam bending heat treated wood
Post by: DC on January 29, 2020, 02:15:38 pm
No, I think the epoxy would let go. One of the problems with backed bows is that once the backing is on you can't /shouldn't heat it much again. It means that everything has to be right before the backing goes on.
Title: Re: Steam bending heat treated wood
Post by: Marc St Louis on January 29, 2020, 02:58:33 pm
I would not heat-treat before
Title: Re: Steam bending heat treated wood
Post by: DC on January 29, 2020, 09:39:55 pm
Can I ask why?
Title: Re: Steam bending heat treated wood
Post by: bownarra on January 30, 2020, 02:32:56 am
Nor would I. Firstly what is the point. Heat weakens wood and you are going to give the tips a double exposure.... The wood would definitely not be able to be bent as it would if it were fresh. If a recurve 'pulls out' then you simply haven't got it hot enough when you steamed it in the first place. Any recurve I've bent with steam has not moved. All this 'setting with dry heat' is a bunch of cobblers, execution and design are what matter :)
Title: Re: Steam bending heat treated wood
Post by: Stick Bender on January 30, 2020, 05:24:36 am
I did my current & previous bows very similar to what Patm sugested & have had no issues !
Title: Re: Steam bending heat treated wood
Post by: PatM on January 30, 2020, 06:44:54 am
I hope you locked in the curve with dry heat  after still. ;)
Title: Re: Steam bending heat treated wood
Post by: Marc St Louis on January 30, 2020, 08:16:29 am
Can I ask why?

My experiences with heat-treating is that it decreases the wood's elasticity in tension....I would be worried about a tension failure
Title: Re: Steam bending heat treated wood
Post by: DC on January 30, 2020, 10:51:17 am
I should have mentioned in the first post that this is a boo backed bow. Does that change anything?
Title: Re: Steam bending heat treated wood
Post by: DC on January 30, 2020, 11:24:32 am
If a recurve 'pulls out' then you simply haven't got it hot enough when you steamed it in the first place. Any recurve I've bent with steam has not moved. All this 'setting with dry heat' is a bunch of cobblers, execution and design are what matter :)

Since it's not going above 212°f you must mean time. How long do you steam, say a 1/2" tip? Are you talking about dry wood or green wood?
Title: Re: Steam bending heat treated wood
Post by: bradsmith2010 on January 30, 2020, 01:40:47 pm
DC,, I think I remember you posted how hot the wood gets with dry heat,, can you give that info,,
Im not sure steam will get the wood hot enough for some applications,,,, for example no one steam treats a belly,, I think there are some advantages to dry heating the wood to hotter temps for some applications,,  it can be overdone ,,like most things with bow making( i love this phrase) there is a point of diminishing return,, :NN
like when your bow catches on fire and burns up,,, (lol)
   dont ask me how I know these things,,maybe I just read about it,, (-S
   
Title: Re: Steam bending heat treated wood
Post by: DC on January 30, 2020, 02:27:13 pm
The wood gets as hot as you want it with dry heat but I've found the most woods that I've done start to brown around 400°f.
Title: Re: Steam bending heat treated wood
Post by: aznboi3644 on January 31, 2020, 06:36:43 pm
I don’t have much experience with dry heat but my steamed recurves on the few red oak short bows are holding fine at 45lb draw.

I boiled the tips in an electric kettle for 10 minutes then bent them.  They were very malleable after 10 minutes in boiling water and seem to hold. 
Title: Re: Steam bending heat treated wood
Post by: IrishJay on February 01, 2020, 11:51:18 am
DC,
I'm currently working on a project the required steam and glue , that I also wanted to get a heat treat on.

Here's how I I approached it (Standard disclaimer, I'm far from an expert).

I did my shaping and tip alignment corrections with steam. Then I brought the stave down to a rough floor tiller and worked out a nice flat area where the lams are going to get glued on. Then I did a nice slow, even, deep heat treat on the whole stave. Later today I'll be gluing on the lams. Since its only at a rough floor tiller now I know I'll end up tillering off most, if not all of the browning on the belly, but because the stave was only 1/2" thick at its thickest point when I toasted I'm confident that the heat treat penetrated most of the way to the back, so it should still provide a benefit.

(https://i.imgur.com/w9EHNSH.jpg)

(https://i.imgur.com/n36LswU.jpg)
Title: Re: Steam bending heat treated wood
Post by: bradsmith2010 on February 01, 2020, 01:54:36 pm
thats looking good ,, keep us posted on the results,,,
Title: Re: Steam bending heat treated wood
Post by: DC on February 01, 2020, 03:26:20 pm
DC,
I'm currently working on a project the required steam and glue , that I also wanted to get a heat treat on.

Here's how I I approached it (Standard disclaimer, I'm far from an expert).

I did my shaping and tip alignment corrections with steam. Then I brought the stave down to a rough floor tiller and worked out a nice flat area where the lams are going to get glued on. Then I did a nice slow, even, deep heat treat on the whole stave. Later today I'll be gluing on the lams. Since its only at a rough floor tiller now I know I'll end up tillering off most, if not all of the browning on the belly, but because the stave was only 1/2" thick at its thickest point when I toasted I'm confident that the heat treat penetrated most of the way to the back, so it should still provide a benefit.

(https://i.imgur.com/w9EHNSH.jpg)

(https://i.imgur.com/n36LswU.jpg)

This is how I normally do it but this time I wanted to do the heat treat with my radiant heater( I'm thinking hard about the silicone ones :D) and the limb has to be flat in order for it to work properly. That's why I wanted to do the heat treat first. I did it the way PatM suggested and left the tips untreated. I'm steaming them as I type.
Title: Re: Steam bending heat treated wood
Post by: IrishJay on February 01, 2020, 06:19:00 pm
I did my toasting on my electric range(dont tell my wife).