Josh—
Here is some useful info on the addition of urea in general, and for this task in particular.
If you want to make hot hide glue that stays liquid at room temperature, you can add urea that amounts to 30% of the weight of the dry glue you used to make the batch. That might be the way to go if you want to keep your current process. Less might work, too (like 20%). I just read somewhere that Old Brown Glue uses urea that amounts to 30% of the weight of the dry glue, so that’s what I use to make my own liquid hide glue.
I have found that adding 10% gives me several minutes of pre-gel time, and that is enough for me to clamp just about anything. That is what I used here. I like 10% because I have not been able to tell any strength difference or other differences in the glue, other than having more pre-gel working time.
For this specific task, I keep the water to glue ratio on the low end. I like a 1.8 water to 1.0 dry glue ratio, because runny glue is hard to work with for this job.
I use a very small artist’s brush for this task, rather than the larger brushes I use for most glue-ups.
I glue 2-3 inches at a time. I start with the waist, then work out in both directions. I gently tug the binding away from the guitar, slip the wet brush into the channel, and spread the glue. As I apply the bands, I’m always leaving about an inch of glued binding without a band on it. I apply the bands the way you see people rope a guitar; around the waist, then each bout is treated like a circle for a few bands (wrapping to the opposite side of that bout), then go end to end with the largest bands.
When the edge is fully wrapped (half a top or back at a time), heat the edge with a heat gun on the low setting, just enough to melt the squeeze out. Be careful with the heat! You can go too far.
I hope this helps. Let me know if you need more info.
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