IPE blow up-What next???

[Chuck Hoopes]

Blew out the back, mid limb, at 24" (still on the long string.  68" pyramid, 1 1/8"at fade to 3/8 tip. Thickness 1/2". It had a silk backing. Looking at the fractured wood, it seemed to be very dry.  I had down heat tempering prior to the silk backing.    The stave was from a piece of 1 1/2" x 1 1/2" that I ripped down the middle.  Still have other piece, and am trying to decide what to do with it.  I thinking: 1.No heat treatment.  2.70" instead of 68.  3. fade width 7/8 instead of 1 1/8  4. parallel out 1/2 the limb and then taper to 3/8 at tips.  Of course, Iam not married to any of these dimensions-- I have never worked w/ ipe-    What to do?  What to do?  Help, Dazed and Confused.

[PV]

I've never backed anything with silk so take it for what it's worth. My few tries with heat and ipe didn't work out well.
How was the grain on the board? Grain run out can cause the bow to fail even with backing.

I would suggest backing with bamboo or hickory for a board. Your dimentions on your first attempt would work well with either of these backings.
"If you ain't breaking you ain't making"....

Good luck

[Pat B]

Ipe isn't a good candidate for heat treating. There is no reason to. It is extremely strong in compression. Also, after heat treating you have to give the bow plenty of time to rehydrate. in dry conditions maybe a week or more or in your bathroom where the humidity is higher.

[Chuck Hoopes]

PV- I considered Hick as a backing, but opted for silk because I wanted to make an "all" ipe bow-- judging from the ipe/hick bows I have seen pictured - the Hick backing winds up being just as thick as the ipe.  I have a hard time reading and making out the grain, but there does appear to be run out.
Pat-- I did not know about the rehydration thing--there was only a 2 day wait, and stave was placed over a heat register in the house those days.  I assume that the rehydrate period applies to other bow woods as well?

[Pat B]

Being too dry is death to bow woods. Hickory can stand to be(and preforms better) at about 6% m/c. Any other wood that I am familiar with will blow at that m/c.
 As I said, heat treating is to increase compression strength of weaker in compression woods like hickory, ash, elm, etc. Ipe is ectremely strong in compression so tempering is not necessary or recommended.
   If you design a hickory backed ipe bow correctly it makes an excellent combo for a fast hard hitting bow. Ipe prefers to be narrow and thicker. It you made the limbs 1" wide and backed it with 1/8" or less hickory, you can achieve a bow of weights of 45# up to 100# or more.
   With any wood, there is a specific bow design(s) that works best for that wood's properties. Making the wood fit the design isn't your best option for success...and as always, rushing the process and impatience is the route to failure and frustration.

[bowmaker07]

When PatB speaks it is wise to listen.

[PV]

Ipe can be difficult to read especially in the darker stuff that seems to make better bows.I suspect your trouble with this bow is as Pat said the wood being to dry.You've got plenty of wood left from the board to give it another go  

[Chuck Hoopes]

Ok- you guys convinced me.  Iam going wl a 70" bow w/9" stiff handle section. NO heat treat.   The "stave" is 1/2" thick-(no changing this, its a done deal already) I am thinking 1" wide for about 2/3 of the limb and taper to 3/8. I shooting for 60#. Maybe 1/2" thickness is not enough to work with to get 60# w/ 1" width. Guess Iam going to fine out. I have not cut the width yet, I do have 1 1/2" to work with.  I'd go w/ hick back if I could find some quater sawn--but this is not likely anywhere near me.  I do have some plane sawn hick, I could size for backing, and than put one layer of silk to it--or another option would be to forget the hick, and go w 2 layers of silk.  What do think?

[Pat B]

Use the hickory backing you have. When you glue it up do it in Perry reflex of about 3". That will yield a bow with 1" or so of backset out of the clamps. Don't worry about the silk backing over that. It probably isn't necessary and will only add extra physical weight.
 Taper your limb tips to 1/2 for now and reduce them after you tiller. You may need some lateral adjustments and that can be done by removing a bit of wood from one side or the other.
  Once you get the backing on you will have 5/8" thickness plus a glue line and 60# will not be a problem.

[Chuck Hoopes]

Thanks for the heads up on going 1/2" tips initially-makes sense.  Don't think I'll go w/ the perry reflex, Iam too much of newbie at this point, and I don't need any additional tillering challenges. Ive made a few oak bows,and a few hickory-- they all have some string follow, but thats never bothered me-- they're built 5-10# over desired wt anyway, and usually settle in about right after the break in. Glad to hear I can go w/ the hick. and it will give me some extra thickness to work with.  Thanks again for your help, Pat.

[Pat B]

Don't make any of this too complicated. We ain't making Swiss watches! That's what wood bow building is getting away from.IMO  
  A flat layup will make a sweet shooting longbow with just a little set. With the hickory/ipe combo you will be pleased with the results and yourself, after that first shot. Its a very good combo.