epoxy used by dmcleish?

This is my first post, so let me start by saying congratulations on a job well done. This site is rich with information.

I'm making some daytime running lights using white LEDs to be used for enduro motorcycle racing. I noticed that dmcleish used an epoxy to fill a reflector (http://dmcleish.com/arcAAA-candle/index.html). The result looks really clear with no visible imperfections. Is this a special clear epoxy? Do any of you have some tips on how to produce really clean results?

Thanks in advance,
GWO

Try looking for LOCTITE epoxy. They have a few types. I use the one which dries up fast >5minutes and it's clear when done. When the expoxy is set you can use very mild sandpaper to sand it down then polish it. I am not sure what you can use to polish epoxy though. Loctite is quite thin when it's newly mixed, then thicken, then slowly harden. So you might be able to get away without even sanding it if you did it right. If you don't it's a real mess to clean up.

Hello and welcome GWO,

In the mod you have cited, I used Ultra-Glo which I know is available from the Tap Plastics chain. It is a very water clear epoxy that seems to have an index of refraction very close to the epoxy used in the LED envelopes. I have found that you DO want to use this epoxy in above 60 degree ambient for the bubbles to be free to flow to the surface. Many epoxies have an endothermic reaction when curing and bubbles will form as a result. These epoxies are not good for potting or creating lenses because of the trapped air (gas?) bubbles. Ultra-Glo is the best and clearest epoxy I have come across but there are likely other casting resins which will work as well.

Once cured, most of the harder epoxies can be sanded and polished. Final sanding with fine grit wet and dry paper (wet) followed with rubbing and polishing compounds can be very effective.

Good luck with your project and please share your results and findings.

- Don

Wow good stuff to make lens!

Thanks Don! That's exactly what I'm after.

BTW, this site is trouble for anyone who likes gadgets. I started off with a practical application of white LEDs. But now...
* I've made two homemade LED lights
* Purchased a Turtlelite, Inova X5T, Infinity Ultra-G
* Am waiting on a batch of Nichia Incadescent Whites and some step-up IC's
* And modified (tore up) numerous household flashlights

I might be hooked. You think? /ubbthreads/images/graemlins/ooo.gif

- GWO

GWO,

You're welcome and I think you have been infected! /ubbthreads/images/graemlins/smile.gif

nukiez,

You my friend are obviously trouble! /ubbthreads/images/graemlins/tongue.gif
Yes, with some mold release in a parabolic reflector and negative plug of a ball in the base, you could cast your own collimator! Dang ther is never enough time! Perhaps I should start with a reflector that was recently freed up from a P61 LA.............

- Don

Sorry to borrow the thread. I have drilled a 5mm diameter hole of 30mm deep in a piece of acrylic and inserted a 3mm LED into the hole. Right now, I need to seal off the remaining void. I have tried different brands of two part epoxy adhesives but they are too viscous and do not flow easily and many bubbles are created and are almost impossible to remove. Are there any casting resin or is the Ultra-Glo able to flow easily to fill up the void completely without trapping any air bubbles? Please help me because I have wasted some money and don't want to buy the wrong product for the job again. Thanks.

doesn't ultra glow yellow when exposed to UV light from the sun. I thought its only for indoor use.

Most epoxies degrade to UV and yes, I would expect the UltraGlo to yellow with extended exposure to sunlight. I don't leave any of my lights out in the sun as a rule. The epoxy used for the LED envelopes will also degrade over time due to moisture and UV. The company who makes UltraGlo has another product with better UV inhibitors in it and I bought some. Unfortunately, my experience was that it was more prone to exothermic bubbles being trapped within.

- Don