Best UV wavelength for detecting glue repairs on guitars?

Bimmerboy

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Looking to get another Christmas gift for the very person who I was searching flashlights for 17 years ago when I found CPF.

This time, it's for a UV light to find glue repairs on guitars. Wondering if there's a particular wavelength best suited for that.

Also looking for recommendations on said light in a 2 X AA format, preferably with high and low settings.

Thanks in advance for any info!
 

PhotonWrangler

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Looking to get another Christmas gift for the very person who I was searching flashlights for 17 years ago when I found CPF.

This time, it's for a UV light to find glue repairs on guitars. Wondering if there's a particular wavelength best suited for that.

Also looking for recommendations on said light in a 2 X AA format, preferably with high and low settings.

Thanks in advance for any info!
365nm hands down. Anything with a longer wavelength will show more visible purple and reduce the contrast of the fluoresence. Considering that the shellacs/resins might also fluoresce, you want to get as much contrast as possible.

The Fenix LD02 v2 might be a good fit. It offers both 365nm UV and warm white and can run on AAAs or lithium cells. It offers three brightness levels and runs in the $30 range.

Neat application BTW!
 
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Bimmerboy

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Neat application BTW!
Thanks for the excellent reply, PW! Definitely a neat application.

I checked out the Fenix, but I'll likely go with a dedicated UV only thing. In fact, I might go all out and get the Prometheus for the overall quality, 1 X AAA format, and especially that LG diode.
 

PhotonWrangler

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Thanks for the excellent reply, PW! Definitely a neat application.

I checked out the Fenix, but I'll likely go with a dedicated UV only thing. In fact, I might go all out and get the Prometheus for the overall quality, 1 X AAA format, and especially that LG diode.
You might consider posting some pics of the results in the "What did I use my flashlight for today" thread. That would be interesting.
 

Bimmerboy

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You might consider posting some pics of the results in the "What did I use my flashlight for today" thread. That would be interesting.
Will definitely try to do so. He most certainly has guitars with neck repairs that we'll try it on. I got him the Prometheus with what sounds like a guaranteed peak at 365.
 

alpg88

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you'll have to try and see for yourself, different glues, made by different companies, with different ingredients, may glow at different wavelengths. but in general, 365nm should be capable of lighting up many materials, clear dry glue, usually seem opaque greenish in uv light, no matter the band. regular hot glue, and uv cure resin look pretty much the same under uv.
 

Bimmerboy

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Mission accomplished! Got the Prometheus, and upon giving it to my friend at his guitar shop he showed me a few different examples of what a typical glue repair looks like under UV. They all showed up as a kinda' black-ish color. Interestingly, what showed up as an opaque green, mentioned by alpg88 above was the shellac (or nitro possibly, I have to ask again) finish on an old guitar.

Thanks for the help, guys. Happy new year as well.
 
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