Looks like there is a good if big bow in there.
If it was me this is what I would do (others may do different).
Shape is on the back and belly using good sharp rasps ands files so it looks like a bow, giving it whatever profile you like. Make sure the tapers are good and even. Give it a fine finish with fine sanp paper or a very fine file.
Put temporary nocks on.
Use a long tiller string, accurate scales and pulley to pull no more than brace height and no more than final desired draw weight. Adjust as necessary to get a good even bend with somewhat stiff tips. I like to use a bowyers edge for this. A simple scraper is also good, used with the fine file. After each wood removal pull at least 20 times to exercise the bow and see what effect the wood removal has had. Keep a very close eye out for hinges and very stiff sections. At this stage don't worry about the draw weight, just go for good braced shape.
The bow will probably be way over the weight you want and trying to floor tillering it will feel like leaning against a tree, hence use of a long tillering string.
As soon as you feel the basic shape is about right put on a good thick and non-stretch tillering string. Non-stretch is very important as it is quite painfull when your monster bow and stretchy string traps your hand.
Pull the bow on the tiller a few inches 20 times or so and check the draw weight. This may be quite high. I once had an Ipe/Hickory bow pulling 120lbs at 3 inches (a little too much reflex!).
You now have two choices.
Finish the monster bow to the draw weight it wants to be.
Do a fairly large amount of wood removal, a lot of pulling until the bow pulls what you want at your draw length.
I have found that an Ipe bow like this can increase in reflex as you remove wood from the belly and the weight will stay high with a tendancy to develop hinges as parts of the bow do come to weight. Small amounts of wood removal can make a big difference so you may find yourself chasing hinges after hinges until eventually they even out, hopefully somewhere near your desired draw weight with a good shape, but maybe at 15 inches!
Now I like to go carefull, trying for an even amount of removal or each limb, and even off each side, exercising a lot each inch of increased draw, never pulling over the final draw weight. This is the stage at which you can bring the string over a little to the side you will shoot from. If the bow is made symetrically you can decide which way is up at the end and pretend the string lays off a little on purpose. I would be using the finse files and scraper, keeping the bow looking almost polished and ready to use as this help me go careful. Some may say this is too careful but I like to pull 50 times per inch. For me at least, it takes this kind of repetition for me to be able to see the effect of the wood removal. Sometimes it will take a fair amount of this to get the weight you want and the shape you want at the draw length you have got to. The frustrating thing is that you then need to pull it a little more, have to take off some more wood, pull it lots more times to get it to once again pull the final weight you want with the tiller shape you want but an inch further towards the draw length you want.
Now is the time you could get fed up and rush things and suddenly find you have a hinged underweight bow, or a broken bow.
From bitter experience I go slow and eventually find I have a bow that is about what I was after.
One big lesson I have learnt with Ipe is that a little wood makes a lot of bow, so very little less wood can make a much weaker bow. Changes can be sudden and unexpected to keep checking the variables.
Have fun making this one. Hope it works out good,
Mark in England
