Heat treating?

[Aaron curtis]

I am going to heat treat my first bow and I am going to apply the pine sap/turpentine mixture to it.  The mixture I got is super sticky and was just wondering if it stays that sticky once it dries?  I am gonna apply it with a foam chip brush unless someone else has a better idea or trick.  Thanks

Aaron

[helmet]

I am not sure, maybe try it out on a sample piece and see how it acts.

[Pat B]

If the pitch was sticky the end product will be the same.  You can remove the volatile oils that make the pitch sticky by cooking it but you have to be very careful because it is very combustible. By using hard brittle pitch to start with you eliminate having to cook out the volatile oils because they have already evaporated leaving the pitch hard.
 As far as using it while heat treating the belly I don't know it that will remain sticky because I've only used pitch varnish using hard pitch.

[Aaron curtis]

So now I am wondering about the mixture I was going to use.  I found some old threads regarding the pine sap/ turpentine mixture but nothing that I read online got super detailed on how to make it. If it remained sticky would it really matter?  I would be reducing that anyway when I tillered it.

[Bob Barnes]

what exactly is the mixture suppose to do?

[Pat B]

Bob, Marc St Louis can explain it best. He uses this method when heat treating bows.

[Marc St Louis]

I actually don't use that mix anymore, I just use straight sap from Spruce trees.  Turpentine actually comes from conifers, Spruce, Pine, Balsam Fir and so on, and I was merely using a very small amount of it to thin old sap that has turned hard.  Spruce trees that have had a recent wound will ooze sap that has Turps in it and is pretty soft.  This is what I now prefer to use but I also use older sap that has turned hard and brittle, I just don't like it as much.  I don't use sap from Balsam Fir as it is a liquid, it has too much Turp in it.  I have used sap from Pine trees but it doesn't produce as much as Spruce trees.

When the sap is applied on the hot wood, I apply it just before I move my heat-gun away, it becomes a liquid and gets sucked into the wood as it cools.  I have heated a limb after tillering where most of the browning from heat-treating has been removed and you can clearly see that the sap has been sucked deep into the wood.  I'm sure that most here know that Varnish of old was conifer sap diluted with Turpentine so I would think that doing this does add some moisture protection.

[Bob Barnes]

cool... never heard of that before.  I guess I would have to try pine since that's what grows here.  We don't have spruce or fur.  Thanks for the explanation.

[Aaron curtis]

Thanks for the response Marc. Is there a specific spruce you prefer over others?   So when your using the fresh stuff are you just brushing it on with a cheap paint brush?

[kbear]

Aaron, I use Pine Resin dissolved in Gum Turpentine as a varnish to good effect. It takes a some time to dissolve (months even), and also takes a long time to dry once brushed on (weeks), but once dry is not sticky provides a good level of moisture protection, and is quite an attractive gloss finish.
I have previously experimented with malming. That is, impregnating the belly with the same mixture whilst heat treating for two purposes: 1. To sink and evenly distribute heat from the gun and prevent scorching 2. To increase the compression strength of wood that is prone to chrysil.
I am not really sure if the malming was effective for increasing bow performance, I have more experience to gain, but it is a nice finish.

[Marc St Louis]

There's only 2 species growing around here that produce a lot of sap, White and Red.  Black Spruce also grows around here but I've never see any appreciable amount of sap on them, same with Hemlock.  Tamarack also produces sap but in small quantities.  Once the bow cools off, the sap left on the surface of the wood is brittle not tacky regardless of whether it was soft when it was applied.  The sap that gets sucked into the wood may increase compression strength, it won't increase the elasticity of the wood