Made a reed that seems pretty spiffy … balanced easily enough, 2 cotaves nice… trouble is back D is, well “weak”: hard to describe, but it really is only in tune with WAY less pressure than other notes…
help?
thanks-
dave Jones
I will remain “thin-lipped” on this one. 
djm
There could be a leak along the sides of the reed. Try rubbing a small amount of bees wax on the sides.
What kind of chanter was it made for?
thin lipped… ugh… that has been my problem: I make them too weak… too wide too, which is probably why I have to wrap the bridle so far up…
'twas made for a BC Childress ‘D’ chanter…
Same problem has been reported in France for Hevia chanter; both octaves in tune, but back D weak, quite unstable, needing lower pressure. french cane tried, Medir cane, more or less sanding, etc. And no solution.
Did you read (reed) what they write on their site?
http://www.arhpa.com/ingles/flash/index.htm
Best
I wasn’t aware that a weak chanter reed was somehow a fault of the chanter… ???
I have reeds that play in it nicely… I’m sure it’s not the chanter. I am a beginner reed maker… Just wondering what feature of the reed workmanship (or lack thereof!) results in this effect.
Since you mentioned Hevia, I tried to go look at their site but couldnt get past a neverending flash session…
… nice one. 
I would agree with checking the sides for leaks and sealing with beeswax (I melt in a little olive oil to make it softer. Something you can try for thin lips is to gently rub the reed a few times across some fine grit sandpaper. I pinch the lips together with my fingers and use light pressure against the sandpaper. You may need to run the paper gently between the lips to clean up any nubs.YMMV
John
There is another cause for weak gurglin back D. The little pockets at staple sides (Alain Froment theory).
Nicolas
The bridle shouldn’t be any further up than the “V” or “U” scrape. It has been my experience as a beginning reedmaker to make sure the reed is airtight at the sides. To check this you could..
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Carefully put your index finger and block the aperture of the reed(lips) and suck gently. If there is air then your leaking at the sides.
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Don’t wrap any further than 3mm above the staple eye inside the cane reed. Doing so, will cause a horrid shreik and cause the reed to intonate at a different frequency; less than desired.
or 3. Make sure the thread or hemp is waxed with beeswax or a mix between cobbler’s wax and fiddle rosin (heated) to seal the seat and staple.
I hope this helps you out, I know it worked for me..minus a few hundred profanity words.
I’m hardly any sort of expert on this, but if it’s that variety of back D that bends down when you put the pressure on, then I believe there is a cure.
I was advised by someone far more knowledgeable in these things to carefully chop a ‘spider’s leg’ thickness off the end. That has the effect of thickening the lips again and it will almost certainly be enough to cure it. It worked for me on a reed, although it was a reasonably substantial ‘spider’s leg’ that did the trick! Too much and you’ve just altered the tuning between the octaves, so go easy.
I’m rapidly coming to the conclusion that the famous ‘21 years’ was to learn to make good reeds! The piping’s a doddle after that!
But it can be - there’s no rule. My bridle is a full cm above the binding and thus at least 5mm above the ‘V’ - it had no leaks, just a weak back D, no leaks (the Froment Theory that primola sent makes good sense and may be the cause of my weak D), and now, with the bridle up high, it’s the best reed I’ve had in 12 years of piping. Brian Howard told me that moving the bridle up high and then squeezing it in is a good cure for weak D and also flat 2nd octaves - it has something to do with decreasing the internal volume of the reed.
So don’t be afraid to move the bridle up high. It’s the outcome that’s important.
Cheers,
DavidG
Of course, that every reed behaves in it’s own particular manner. I do not doubt for a second that raising the bridle higher than normal could be a cure for this particular reed, but it would save a chance from breaking it accidentally at least.
I guess the best pointers were given, so good luck with it anyways.
upiper71