Can String Follow Be Fixed?

I hear this question a lot?  Most of the time the anser is "No"... But sometimes it is "Maybe". 

String follow is caused by one or more of several factors.

Natural Deflex is one.  Belly cells being crushed due to too wet of wood, bad design, bad tillering or any combination of these are some others.  Crushed bellies can also be caused by leaving a wooden bow strung too long or in really hot/humid conditions.  Also natural wear and tear can break a bow down.  The end result is a sluggish bow that generally gets assigned to a wall or pile of first bows.

But, all hope is not lost.  I have found that sometimes we can correct these things. 

Natural deflex is the easiest since it isn't really caused by damaged cells.  Simple heat bending can correct or at least mitigate this, even after tillering.

Crushed belly fibers can sometimes be fixed with heat also.  Wood that is too wet and bent will deform but not totally crush the belly cells.  Even roughly tillered or poorly designed bows can be made better.  Removing some of the crushed wood and then toasting the belly will reform the cells somewhat.  Don't expect miracles with this or any fix but it can save a bow from the wall of shame.  The first step is analyzing what went wrong and correcting it.   If you don't correct the disease, expect the symptoms to recur or probably get worse.

Here's an example of a possibly fixable bow.

This bow was a gift to me in a White Elephant exchange several years ago.  It has about 6" of string follow and has a horrible hinge in one side.  The bow was a very aggressive design.  Made from what looks like maple with a maple veneer backing, it is way too short for a full draw bow.  It is marked as 45# at 28".  It is 58" NTN and 1-3/4" wide with a pyramid design.  If I were making a 28" draw bow of maple, the minimum length would be a full 10" longer and I would have started with 2" in width.

 So I am going to toast the belly and make it a 30# or so at 24" draw.  I will have to retiller and hope for the best.

Here's the heatgun and the first caul or form I thought about using.  But then I recalled an article several years ago about toasting a belly.  The author (forgive my misremembering his name) recommends using a narrow form so that the back of the bow is not burnt by heat reflected off the caul.  I decided to cut a new caul out of a stout 2x4 I had handy.

Toasting a belly isn't like adding reflex to a stave before tillering.  I do that with a gentle touch trying not to scorch the wood.  With toasting, I am trying to change the wood (for the better I hope) by basically heating it to the melting point, or somewhere close, and deforming it back to a state that will more effectively resist compression.

Here you see I got it really hot.  I decided that since this was basically a salvage job that I would not remove the finish.  I assumed it would melt off but it held up to the heat and only the wood was toasted.

 

   This is what it looked like afterwards.

It looks like the follow is corrected but this is before retillering.  After I work the bow, some of the follow will return.  I just hope it won't be 6" and tiller will be better.

The first look on the tree is not promising.  The left (lower) limb is bending way more than the right.  Both limbs are really stiff at the handle.  I am going to rasp it about 20 times at the handle on the right and 10 times on the left. 

Here's the result.  Better but still bad.  Ten more on the left and 20 more on the right.

Better on the right but that left limb is really stiff at the handle.   The right (upper) limb is now bending more than the left which is what I want.

After a few more passes at the handle, the tiller is close enogh for me.  It is slightly positive.  In other words, the upper limb bends more than the lower limb.

It finished at 32# at 24".  I like it.

 

I drew it about 200 times and ended up with about 2" of follow.  I will probably see 1" or so more after a 1000 or so draws but at least it shoots hard.

 

Here's the first shot.  Shoot your TV :)