Making my own luminescent side dots.

[Bruce Johnson]

Finding out that perfect ratio is what I am most focused on right now. For the UV resin, with my setup and materials, it is somewhere between 25% and 30%. At 25% the rods seem perfectly cured, at 30% they are getting noticeably softer, past 30% the center of the rod remains gelatinous.
For the 2 part epoxy, I am using right now, it is yet to be determined. Yesterday's batch was at 33% and it is hardened but I still need to wait another couple of days for it to be fully cured (as specified by the manufacturer). All this is keeping in mind that I use the sacrificial glow powder that is of unspecified granulometry and is opaque. After I find a ratio, I will still have to try it with the good powder and see if it translates.
I went for broke today and went directly to 50% to see if that amount is even realistic with my setup/materials. I will know more in a few days.

In your chemistry experiments, you can also try adding a little more hardener (Part B) than you are supposed to. With a high mix of powder, the hardener may be soaking into it, so there's not enough to go around to kick off the resin. That may be why you are getting a soft core at a certain mix ratio.

Also make sure you are mixing the two parts of the epoxy together well enough. That's always an issue when you are mixing up small amounts of epoxy.

 

[llmk]

In your chemistry experiments, you can also try adding a little more hardener (Part B) than you are supposed to. With a high mix of powder, the hardener may be soaking into it, so there's not enough to go around to kick off the resin. That may be why you are getting a soft core at a certain mix ratio.

Also make sure you are mixing the two parts of the epoxy together well enough. That's always an issue when you are mixing up small amounts of epoxy.

At this point, I only have a soft core with the UV cured 1 part resin (that's why I switched to the 2 parts, to see if I can improve the ratio). I think that not only the more powder I put in, the more opaque the material becomes, therefore blocking more UV rays but the powder itself absorbs part of the UV and it ends up never reaching the core of the rod, stopping the curing process. Maybe a more powerful UV lamp could solve this problem but I don't have one handy to test this theory.


When it comes to mixing, I add the hardener to the cup first, then the epoxy then I mix thoroughly for 3 minutes, scraping the wall and bottom of the cup regularly. At the end of the 3 minutes, I add the powder and mix for another couple of minutes. I measure the mass of the components, not the volume, with 0,1g precision. Can I improve on this procedure or should I just continue like so?

 

[llmk]

Today's activity: Cutting silicone "french fries" into tiny little cubes to reuse in the next molds.

 

[Bruce Johnson]

At this point, I only have a soft core with the UV cured 1 part resin (that's why I switched to the 2 parts, to see if I can improve the ratio). I think that not only the more powder I put in, the more opaque the material becomes, therefore blocking more UV rays but the powder itself absorbs part of the UV and it ends up never reaching the core of the rod, stopping the curing process. Maybe a more powerful UV lamp could solve this problem but I don't have one handy to test this theory.

If the 50% powder test fails, I will try again with more hardener. When you say a little more, are we talking like 10%, 20% maybe, more?
When it comes to mixing, I add the hardener to the cup first, then the epoxy then I mix thoroughly for 3 minutes, scraping the wall and bottom of the cup regularly. At the end of the 3 minutes, I add the powder and mix for another couple of minutes. I measure the mass of the components, not the volume, with 0,1g precision. Can I improve on this procedure or should I just continue like so?

Your mixing process sounds fine. I mentioned it because, sometimes when mixing small mounts, you only stir it for a couple of seconds. Because it seems like such a small amount. But there needs to be some time stirring. When I'm mixing small cups of West Systems, I normally stir it for a minute.

You are probably right, that there is a saturation level where adding more powder doesn't make it any brighter. Because the powder down deep gets covered and can't see the light. The solution there is to make the dot bigger in diameter and not so deep.