# UV Cure Adhesives--a question...



## hikari

Does anyone happen to know if the typical UV Cure adhesives would be activated by something like an Inova X1 UV? 

I'm aware that the X1 UV is rated at 395 nM wavelength, but I can't find ANY information from the adhesive manufacturers. The adhesives I'm thinking of are used for bonding glass to glass (or other smooth substrates). I don't know if they're acrylate based or of the "cationic" variety. The company "Duro" markets something (though I suspect it's made by someone else) and there are other generic and specialty adhesive manufacturers. They say that the adhesive can be activated by bright sunlight or a UV light source--but they don't specify what kind (wavelength) of UV lightsource.

Am I being a dumb sh*t here for worrying about it? Should I just try any old UV light and see what happens? If anyone has any experience with these kinds of adhesives, I'd be much obliged to hear your thoughts. /ubbthreads/images/graemlins/help.gif


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## xpitxbullx

The weaker the light, the longer it needs to cure. More powerful UV curing lights usually have 1, 2 or 3 minute timers on them. An X1 UV is not even be strong enought to start the curing process.

Basically, UV curing lamps need wattage per square inch...not milliwatts. Good UV curing lights go as powerful as 600W per square inch. Wavelength needed is dependent on the type of adhesive. It could be 365nm, it could be 420nm.

Some adhesives can be cured with a handheld flourescent blacklight (tube). These output WAY more ultraviolet light than any UV flashlight powered by LEDs. You can give it a try if you want, though. It just may take a while.

Jeff


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## NewBie

Check out the Loctite site, Dymax (especially these guys), Masterbond, and Epotek. 

Some UV cure adhesives will only work with shorter wavelength UV.

Anyhow, off the Dymax site:

What are your cure times?
Typically less than 30 seconds! Cure speeds for most applications range from 1 to 30 seconds upon exposure to UV light intensities of 20 to 2,000 mW/cm2.

So, a UV 5mm LED may only put out 2mW total, and up to 12 mW total for the expensive ones.

Even using a longer wavelength blacklight tube:
"Can I use a "black light" style UV light?
Yes, but you will miss out on the advantages of very fast, complete cure using DYMAX technology. "Black lights" will cure DYMAX adhesives but at a slower rate than DYMAX lamps. Typical cure times may extend from 5 to 60 seconds. "Black lights" are not suitable for applications where the resin being cured is exposed to air. Call for specific applications."

Keep in mind, a UV LED is usually even a longer wavelength than most UV blacklight tubes put out, and both are longer wavelength than most true UV lamps used for alot of curing systems.

It will depend alot on the specific UV cure system used, some you can cure with very long wavelengths, like a Dental Blue Luxeon.


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## xpitxbullx

I didn't know that some adhesives can cure that fast with such low wattage. I stand corrected.

Jeff


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## hikari

Sorry i put it in the wrong forum--wasn't quite sure where it should go.

The adhesive I was looking at said that it'd cure in typically 10-12 seconds--in direct, bright sunlight.


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## Darell

I use Dymax product, and I tack it with my UV LED. Just takes 10 seconds to secure it really well. Then I set it out in the sun, and in a few minutes we're all done. That's all I can tell you from experience. Works great, and I've done it hundreds of times with no failures.


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## McGizmo

I have been using some product from Norland Optical. It cures nicely and clear and non tacky but I believe it requires a lower wave length than the LED's put out. I have been using a Nichia (375nm) to set the adhesive and then sunlight for total cure. I have a Cree 7090 UV in an Aleph 3 head that will set this up but not as well as the Nichia. A Shark 6W as well as the 5 mm units I have tried don't do diddley. I would like to find a good adhesive that cures to a higher pass band as the Cree in the 38 mm reflector really has a nice tight concentration of light! (I can see the visible portion of the beam well over a hundred feet away on a white wall.) As stated eleswhere, the Cree UV is a cool LED!


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## kitelights

I use UV resins every day that I work for the past 15 years. The type and application that you refer to will not cure with our UV flashlights. They will cure nicely with a blacklight tube. 

Sunlight is good, but it depends on the time of day and season. There can easily be a 90% difference in the amount of UV present. It is important to get a complete cure because most of these resins have inhibitors that stop the curing process after a specific period. 

As Newbie mentioned, most require shutting off expose to air. If you're bonding glass to glass you've already accomplished that. If not, a piece of mylar or anything that doesn't have UV inhibitors built in will work (a piece of Saran wrap).

You can buy an off brand 24" UV light and fixture (dark tube) from WalMart for $10 that does a great job. 

The high intensity type that Newbie mentioned does the best job, but they are typically very expensive.

Be very carefully using UV lights - they will cause permanant damage to your eyes. You don't know it - it doesn't hurt, it doesn't make you see spots or anything like that and it doesn't show up now. But you'll pay dearly for it later.


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## McGizmo

kitelights,

Will PVA work as a barrier as it does with gelcoat and polyester laminating resins?


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## tvodrd

The (Dymax) UV sources I built into a UV-curing conveyor 10+ years ago at work have long since removed the black from the anodize I used on the parts! /ubbthreads/images/graemlins/grin.gif (The "bare" Al parts still shield everybody from the reflected UV.) Every couple years, the cable-chain with attached clips for the product have to be replaced. It has been necessary for me to personally darken Dymax's premises (In CT) 3 times over the years. I have one of the 6W UV PM6 mods, but have never bothered to see if it will cure the Dymax stuff we use at work. /ubbthreads/images/graemlins/thinking.gif

Edit: The formulation we use is semi-custom and is in a _validated_ application. There are now visable light-curing formulations available. Intensities/time, /ubbthreads/images/graemlins/icon3.gif

Larry


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