UV resins, and lights

[Roland58 0]

AKtrap sed, "Interesting... Not exactly about the resin from above posts, but a recent experience I had was that, in my impatience to wait for my "clear cure goo light" to arrive in the mail, I attempted to use a 75-watt blacklight bulb on some Loon UV Fly Paint with no success. Nada...not even after several minutes. Ended up just drizzling it back into the bottle to continue waiting for the light."

 

Blacklight and UV light are often confused, as they both have some similar properties. A blacklight will cause certain things to fluoresce, however, they also contain some "white" light to make them visible to the human eye (blue). Mike is correct (as usual). A UV or blacklight will emit mostly UV A to cause items to fluoresce (if they have the qualities). However, it is the UV B and C that will activate a photo-initiator, especially in the 256 nm and 365 nm wavelength.

 

The makers of these UV curable resins are really ripping people off. I found a formula for making your own much less expensively:

 

* Best results yet! Excellent curing speed, great hardness and toughness:

For 100g of final resin mix (RM)
3g of Benzil
1g of Benzoilisobutylether (BIsoBE)
1g of MDEA
0.5g of EDTA or 0.1g of Hydrochinone

complete to 100g with Polyester resin.

 

The problem may come in locating some of the chemicals, but, if you can, you can make 100g of resin for about $1.60. Of course, it will have to be stored in a light tight container for long shelf life. You may have to find a chemical source on the net if you live in a town like mine!

[AKtrap 0]

Thanks for the clarity, Mike and Roland.

 

It now makes sense to me, that if each company makes a resin with a different wavelength, they can all sell us their own lights.

[Roland58 0]

@AKtrap

 

I don't think resin makers are manipulating the UV wavelength to change the frequency to which the photo-initiator will react. From what I could determine while researching this, the two frequencies I mentioned are the ideal wavelengths for activating the resin. I am still trying to find out if both frequencies would work with any resin, if not, you could be right.

[SilverCreek 0]

I found that formula 4 years ago here: http://forums.reprap.org/read.php?70,10142

 

I rejected it because I don't think that formula will cure with a UV flashlight but you should try it. BTW, the UV B designation does not appy to either 256 nm or 365 nm wavelengths.

[Roland58 0]

@Silvercreek

Thanks for the good info! Do you know which, if any, wavelength that the UV B will work on? It sounds like AKtrap may be on to something as far as making the resins respond to a particular wavelength. I guess we could simply put it in the sunshine, that should cover all options! As a disclaimer, I have not tried the formula yet, however, I have started looking for the particular chemicals locally (to little avail). I don't recall where I found the formula, it was just amongst a myriad of info on photo-initiated resins. I also read that the UV light would work on epoxies. I can't see the advantage there if they cure with the addition of an activator!

 

If I can find the chemicals, I will give it a try just for grins and let you know how it worked.

[mikechell 0]

I didn't say anything about wavelength ... and since several comparisons have been done (I like Cheech's) I don't think there's much difference (manufacturer to manufacturer) for lights or resins.

All I was stating is that the STRENGTH of the lights makes a huge difference.

[roadki11 0]

I care too much about my eyes to use a UV material. Tuffleye uses blue light instead of UV. There's a reason the medical field left UV for blue light over 50 years ago. All materials will have the tack, even supposedly "tack free" material. A little rubbing alcohol will take care of it.

[SilverCreek 0]

@Silvercreek

Thanks for the good info! Do you know which, if any, wavelength that the UV B will work on? It sounds like AKtrap may be on to something as far as making the resins respond to a particular wavelength. I guess we could simply put it in the sunshine, that should cover all options! As a disclaimer, I have not tried the formula yet, however, I have started looking for the particular chemicals locally (to little avail). I don't recall where I found the formula, it was just amongst a myriad of info on photo-initiated resins. I also read that the UV light would work on epoxies. I can't see the advantage there if they cure with the addition of an activator!

 

If I can find the chemicals, I will give it a try just for grins and let you know how it worked.

 

There are UV epoxies but you do NOT want to use them for fly tying. UV epoxies cure by an entirely different method from the UV cured fly tying resins. An UV epoxy will shadow cure.

The key reason UV epoxies are not used in fly tying is that once the proper UV light activates polymerization in UV epoxies, it continues and CANNOT be stopped. The photoinitiator in an UV epoxy creates the catalyst. The catalyst is not consumed so polymerization occurs in the areas that are not hit by light. This is shadow curing. Shadow curing is desirable when gluing electronics onto a computer board, because the UV epoxy under the computer chips will cure.

UV fly tying polymers require UV light to complete polymerization so the rate of polymerization can be controlled or stopped, but not UV epoxies. So there is a limited working time with UV epoxies. Also if you accidentally contaminate the uncured UV epoxy in the bottle or syringe or UV hits the uncured material in the container polymerization will initiate and the entire supply of epoxy will solidify.

Suppose you use a bodkin to coat a fly and the UV epoxy on the bodkin cures. There is catalyst on the bodkin. Then you touch the bodkin to your resin supply. Your entire supply of resin will eventually cure.

The UV epoxies have minimal shrinkage. So they are used in critical applications where the manufacturing process cannot accommodate the volume loss of other UV cured polymers.

Since UV epoxies cure by a different method, there is no oxygen inhibition and no tacky surface.

[williamhj 0]

I care too much about my eyes to use a UV material. Tuffleye uses blue light instead of UV. There's a reason the medical field left UV for blue light over 50 years ago. All materials will have the tack, even supposedly "tack free" material. A little rubbing alcohol will take care of it.

 

I don't use it much but did grab a pair of clear UV glasses and have them on my tying desk.

[Roland58 0]

This place is such a wealth of information! And, sorry Mike, but, you were right again......I misquoted you.

[mikechell 0]

LOL No problem. I am used to being misquoted. And I have been wrong before.

[retrocarp 0]

I don't believe you Mike.....

[mikechell 0]

[SilverCreek 0]

I don't believe both of you..... or myself...

[Roland58 0]

@Igotwood,

I can't imagine paying $20 for one of those lights!

That is truly a rip off. However, you should be able to find a switch you could adapt to make the light work. Another possibility is to find a similar light (like a cheapo from Harbor Freight, 2 in a package for $1.99) and use the switch from one of those. Post a pic of the end cap and switch, along with the inside diameter of the threaded portion. I have a number of these lights and would gladly send you a couple. If I have the correct size, I will let you know and you can pm your address to me......I will send you some.