Okay I'm getting the hang of this and every try yields better results. The thing that gives me the most trouble is the back twist. Can you all share some advice?
This:
How to Build a Great Bowstring (http://www.3riversarchery.com/how-to-build-a-great-bowstring-dvd.html)
In my experience, the amount of back twist you need is totally related to how you build your string. My first ever two bundle string had no back twist and looked like two ropes. As I have progressed I have gradually increased my back twist. The last time I made strings for my bows I used 24 back twists. Just the other day it wasn't enough and I had to use a few more per bundle. Trial and error has cost me quit a lot of string material - I likely would have been better off buying the video that McDave suggested. I replace my strings once a year so I don't make very many and therefore lose some of that skill between sessions.
As you do the back twist, count the number of twists it takes to get the string straight, then do that many more back twists.
The video Dave linked to is pretty good, or so I've been told... :D
Like Roy said. When you finish your first loop, count the number of twists you need to take out to get the bundles to hang straight, then put that many back in but in the opposite direction.
Take lots of notes. There are plenty of mistakes to make, don't wasted time making the same one over and over. Write down any variable you can think of--material, strand count, color, twists in the loops, etc.
A few variables you didn't mention that definitely effect the amount of back twist needed.
1. Loop size.
Are you making the same size loop every time? Be sure you use some type of measurement, whether it be inches of loop, number of twists, etc.
2. Type of loop
Though it is only a small amount, I do put a few more back twists in a longbow loop than a recurve loop(I know that seems backwards, but with smaller loops, you will twist up more of the body of the string than with a curve loop)
3. How far are you twisting down the string?
IF I recall, Chad puts quite a few more back twists in his string than I do, but he also twists up close to 6" more of the string than I do(were talking after you finish marrying the tag ends).
If you're twisting around 8" (from top of loop to the bottom of the twist, i'd try about 15 back twists). IF you're twisting 10 or so inches, I would do around 20 backtwists.
No one will be able to tell you exactly how many back twists to put in the string. Only trial an error can tell you that. But without being consistent on the 3 things I listed above, you'll never be too consistent with the back twists.
Thanks all. Last one I had 35 backtwist and it still needed more. I find it kinda odd that all the advice I get is use between 20-30 backtwist. I understand that everyone will do it just a little different so the next I'll try more.
Let me clarify my back twists. I don't twist the string one turn at a time. I roll the string between my thumb and fore finger about an inch. That process probably twists the string 3 or 4 turns. I count how many times I do that till I see the string bundle is laying straight. Then I continue twisting the same way that many more times.