Sealer for Steam Bending?

[Green]

Prior to steam bending in the handle area for alignment, what do y'all seal the bow with?  In Gary Davis' video he suggests fully sealing a stave to be steamed with poly, but I have used Shellac the first few times doing this.  Recommendations from the more experienced?  Also, cleaning up the back of the bow after this has been done......sandpaper best so as not to thin the back?  Bow is at low brace at this point.
Thanks in advance...Rob

[PatM]

Nothing. I see no reason to.

[Eric Krewson]

Why use steam? A heat gun will get the job done in a hurry.

[Green]

Eric, I have used a heat gun on the last two staves, and my technique must stink because both bows developed cracks that compromised the limbs.  I've used heat to remove some prop twist in a limb or two with good results, but every time I try it where bending the inner third of the limbs and the handle I've not had good results.  I've used steam several times and not had any issues.  I guess it's a stick with what works scenario for now, just trying to figure out how to do it best.   

PatM.....I guess I was worried about steam driving too much moisture from the wood at once, but I suppose letting the stave rehydrate for a week or so after clamping would fix that. 

[Dances with squirrels]

I put two coats of shellac (not aerosol) on the bow's back prior to steaming.

If you're getting cracks in the wood while heating with a heat gun, there's probably too much moisture in the wood, and/or it's getting too hot or being heated unevenly.

Generally, if the wood is wet, I steam it. If it's dry I heat gun it, and I NEVER get crack/checks from doing so.

[Eric Krewson]

Another thing; I don't align the handle with heat until I have it fully shaped. I make bulbus handles with 1" thick arrow pass on one end and a similar thin place on the lower end. I only bend the thin spots because there is less wood to heat, never had one crack.

[Dances with squirrels]

I do the same Eric... same handle too :^)

[DC]

I usually prefer steam for bigger bends. Heat gun for minor corrections. When steaming, sometimes I get stains on the wood. Maybe a sealer would stop that. On the bigger bends where more wood is going to be removed the stains are not an issue.

[Ryan C]

Coat of wipe on shellac in the area that will come in contact with the steam.

[Green]

Thanks y'all!

I suppose the two coats of Shellac isn't too unusual then.  I did get stains the first time I steamed without anything and I ended up having to live with it.  Using shellac, I can take that off with sand paper on the back, and a scraper everywhere else.  The paper loads up pretty quickly, but it is pretty easy to do and take just the shellac residue off.

Dances.....you're most likely right about the moisture in the stave when I used heat gun/caul on those two.  I suspected that might have been the cause of the cracks, which is why I returned to the steam.   

When I got this particular prospect off the long string and to a low brace (5 1/2" from back of bow), the limbs were both off to one side and the string fully off the handle.   This is a pretty good amount of bend in my mind, and I feel like I need to make the correction before proceeding any further with exercising/tillering.   The handle is still in rough form as I was advised not to finish out a handle until I am at full brace and have the string tracking where I'm good with it, and then shape the handle to align with the limbs and string.