Help - LED curing flashlight (365nm)

Ken Preston

Newly Enlightened
Joined
Aug 15, 2011
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3
Location
Pasadena, MD
I am looking for a (relatively) inexpensive LED light source (200mw/cm2 @365nm) to be used for curing epoxy and/or cyano acrylate. The purpose is to use one-part UV cure on thread guide wraps on fishing rods for repair work. I've tried a fluorescent small hand held unit and it did not cure the finish. Any help or "lead" would be most appreciated. Please understand that I'm a true novice when it comes to UV curing light sources.
Thanks in advance for any help.

Ken
 
200mw/cm^2 is quite a bit of uv. The 3W ledengin LZ1 in 365nm only puts out 262-328 mW of UV in the highest binned LED. The LZ4 (5W) does 650-850 mW. The LZC does 1650mW. However none of these are inexpensive
http://www.mouser.com/ProductDetail...=sGAEpiMZZMsgllGlynFdfseFuqsHmxITN7rB/zY5cPQ=

http://www.mouser.com/ProductDetail...GAEpiMZZMsgllGlynFdfseFuqsHmxIT53xH6%2bMhMQM=

http://www.mouser.com/ProductDetail...=sGAEpiMZZMsgllGlynFdfnczgoSavbUAQauNGj8QQfs=

When I mess with NOA at home, I used a CFL black-light, and it works pretty well. Just a few seconds to gel it, and then I let the part sit under it overnight just to be sure, but thats definitely overkill, < 10 minutes should work on a thin layer on the surface (without glass on top if it blocking uv) if you are using NOA, cant comment on other adhesive.

As much as I want to make a badass curing light using an LZ4 stuffed in a P6 size host and a nice sapphire lens etc... I dont do it enough to justify doing what a $5 CFL in a $10 lamp can do all day without worrying about batteries.
 
Hi Ken, welcome to CPF.

365nm is pretty short. For some reason, I am thinking that most epoxies cure at 450nm or similar, which is a lot easier wavelength to obtain in LED than 365nm, and a LOT brighter. Most epoxies have poor transmission at 365nm, so it is likely to cure the skin, but I am not so sure about the bulk.

Since you commented that you are new to use UV sources, I will throw in a safety comment - protect your eyes. UV plays hell on your eyes, and the shorter it gets, the worse it does, because your iris will not close up to protect them, and the damaging energy is much higher.

Please buy some safety glasses made specifically to protect your eyes if you plan on doing this much. At a minimum - use some really good sunglasses and keep the kids away at 365nm. That wavelength also converts O2 to O3 (ozone), which you will quickly smell if it is really 365nm.

Which epoxy are you using ?

Take care,

Harry
 
I agree - I have and use eye protection. I'll have to start searching for CFL at 365 to see what I can come up with. I wanted this to be as portable as possible so I could do "on the spot" fishing rod repairs (missing guides / snapped fishing rods) & that's why I was thinking flashlight. For at home bench top type work I will start looking at CFL's & lamps. One problem I may find is a lamp socket that is compatable with a CFL - unless there is a medium base bulb at the proper nm. The product is produced by ASI / product # MP 53810. They sent me a sample of the 'goo'. It has the correct properties (viscosity, clarity, resistance to chemicals & is water proof when cured). After testing out other's products this one seems to be the best -- Assuming I can find the correct light source to cure it properly = LOL
 
Harry, it all depends on the epoxy😉 Like I said Norland Optical Ahesive works well at the 365nm wavelength. "within the range of 320-380 nanometers with peak sensitivity around 365nm" from their website, so I guess it varies on chemestry of the epoxy. +1 to safety, 365nm, while definitely down into the UV range is still UVA, and could certainly be a lot worse. And I think you might be mistaking 365 for 185nM or so which produces ozone. My blacklight definitely doesnt produce ozone, my xenon short arc lamp at work definitely does 😀



I think I found a french (?) datasheet for your adhesive Ken, and looking at a rough translation, it looks like you should be fine with anything from 275 upto 425, with 365 being ideal. Pretty much any commercial blacklight should work for you, even if they are a bit slow due to low output.

I used http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053 in a cheap floor standing accent fixutre. but if youre doing fishing rods, I think something like http://www.buylighting.com/F32T8BLB-Black-Light-Blue-Fluorescent-p/d26136a.htm (a 4' long T8 black light bulb) would work for you. If you get a fixture that takes 2 T8 bulbs you could just lay the rod right between them for in the shop. Or even get 2 of the fixtures and drop one on top the other as a lid, for 4 bulbs all around the fishing rod etc...


As far as portable... I'd think something like a handheld spotlight sort of lantern with one of the 400nm LZC LEDs putting out 5W of UV, hopefully the longer wavelength is offest by the much higher power, and less absorbtion by other stuff. Then add reflector/cover to put over the rod and reflect the light to the back side would be workable. Pricy but workable. A taskled hyperboost would be a suitable driver. You could probably keep the whole portable assembly under $400, which is definitely cheaper then a lot of UV curing systems.

+1 to safety again, a 40W LED is going to be eye damaging regardless of wavelength, its just hard to see this one, I'd suggest some glow in the dark paint or fluorscent paint so it it lights up when its on for a safety aspect.
 
Last edited:
CKOD =
YES! That is the French (translated) datasheet. Says same in my English version 300-400nm with optimal @365nm.
Intensité minimale 200mW/Cm²
Gamme spectrale 300 – 400 nm
Longueur d’onde optimale 365 nm

I was stumped by the 200mw/cm2 ....... If a standard 32 or 40 watt flouro will do the trick that's fantastic! - For sure I will be taking plenty of precautions with this as my eyes (at 64 yrs old) are bad enough already.
 
Nichia also makes UV LEDs that could be used to build your portable setup. Perhaps one of the custom builders, especially those who produce UV lights currently, could assist in determining the practicality of building a portable curing light with the output you require. Nichia link

Another possible source of commercial curing lights is automotive windshield repair suppliers. Try throwing "uv curing" into Amazon's search or Google. A cursory look shows at least some UV cured windshield resins are cured at 365 nm and there are reasonably priced lamps available.

Note: I do not have any relevant expertise or direct experience (my only use of UV sources was for sterilization), so if you find anything promising, be sure to do your due diligence. Safety as the prime consideration for all involved is critical.


- Syncytial.
 
I like specialty flashlights as well as anyone here ... but there are better ways to UV cure. The least expensive way to fast cure is with a UV specialty bulb, available in the MR16 "mini spot" shape: http://cgi.ebay.com/USHIO-UV-Curing...110?pt=LH_DefaultDomain_0&hash=item588ae4949e

Lots more convenient is a dental curing light: http://cgi.ebay.com/Wireless-LED-12...706?pt=LH_DefaultDomain_0&hash=item231348f4ba

If your city has a large orthodontic office, they sometimes have an old cure light sitting in their "junk storage" closet. Mine was free for asking :thumbsup:
 
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