Newbie with curing questions

I just got the Form2 a couple weeks ago and have plenty of questions. I’ve already learned so much from this community - thanks! It seems like a lot of you use UV or LED curing stations, like nail salon units to cure your prints so I thought I would get one, but which is better UV or LED? And, do you still need to soak it in alcohol or does the UV/LED curing replace that step? My prints seem to remain sticky even after soaking them for a while in the alcohol bath. Thanks for any and all help on this topic!

UV is a wavelength of light, colors closer to blue/violet have a higher energy value, UV light is above that in a non-visible spectrum which has even higher energy values, that’s the part of sunlight which is damaging to your skin.
There are multiple types of lights that can emit UV light, LED are good because they are more energy efficient (don’t lose as much power to heat). The nail salon thing I have uses small fluorescent bulbs which produce more heat which is fine.

As for alcohol, the alcohol cleans the liquid resin off the print it doesn’t have anything to do with curing the print.
What I do, when a print is finished is put the print in the alcohol for 10 minutes. After that I take it to the sink and I rinse it off, then I fill one of the plastic containers with water and then I put the print in the container of water.
The water blocks oxygen from reaching the print, oxygen prevents the resin from curing so when it’s exposed to the air the outside won’t cure as well which makes it sticky. Having the print in water while it cures fixes that issue.
I put it in the UV box in the water for 30 minutes and then take it out of the water and have it in the UV box on a turntable for another 30 minutes. It also helps if you turn down the lights while you’re cleaning the print before you put it in the UV chamber, when you rinse it in the water if the lights are on then the spots where the water is will start curing and you’ll get noticeable spots on the print. If you keep the lights down until the print is submerged in water then it will cure more evenly.

UV is actually a range of wavelengths. You specifically want something as close to 405nm as possible. Not all UV lamps (be they incandescent/fluorescent or LED) are the same. I recommend LEDs. If you search the forum for posts from me, you’ll find one where I detail the construction of a LED curing “Jar”, less than $50 in parts and about 30 minutes work. As it’s made from a clear lexan container and the LEDs are on the outside facing in, you can fill it with water to water-cure if you want. I don’t bother, I just leave the parts in the jar overnight and they come out fine.

A few other folks have followed my instructions and made ones of their own. Though there are other options as well. Just be sure you’re getting 405nm lamps.

You can leave the parts in the Alcohol too long. If my prints are “rugged”, I dump them in the bucket and agitate/shake it for 2 minutes, then I move to the second bucket with cleaner Alcohol and repeat. Then I dry the print off with compressed air. Then I drop the parts in the curing jar. It should be noted this is not the process recommended by FL, but it works satisfactorily for me, and it takes much less time to get the parts in to their final cure.

Thanks Zachary and Randy, this is all very, very helpful information. I think we’ll try to make your curing station Randy.

Zachary, thanks for theinformation about the water. I’ll definitely try following your instructions.

I’m learning so much from this forum.

So I did the same thing as Randy’s jar. I got antsy and bought a glass jar from a retail store. I wish I had gotten acrylic because I later decided to add heating to it (since the FL white paper about post curing says that it is optimal to use both 405nm light and heating (upwards of 60 degC) ). So, I grabbed an IncuKit Mini for ~$50 (see ). I should have gotten acrylic because I could have cut through the lid for mounting the heater. Instead, I am currently using a cardboard lid until I fab or laser cut something better (see ). I was surprised that I could get close to 60C. Of course, I am wondering whether the heat will affect the life of the heater and even the LEDs (even though the LEDs are outside of the jar and are in an IP65 plastic). I might just heat to 50C.

The lights might create heat as well–the salon thing uses fluorescent bulbs so they create a pretty good amount of heat. LED’s are more efficient so probably not as much.

Heat accelerates failure rate. It’s an inescapable law of physics. See “Arrhenius”.

The LEDs are probably only rated for operation up to 60 to 70ºC, so if you’re heating the interior of the jar to 60ºC, the LEDs are going to be operating near their maximum rated temperature. That being said, they’ll very likely operate well above their maximum rating. You’re probably not going to get the burn life rating but you’re unlikely to live long enough to even get half the rated lifetime so it probably doesn’t matter.

I’ve measured the LED temp while running the test unit, and they don’t seem to be getting above 60C although probing the glass surface gets close to 85C. The jar is massive, but I hadn’t planned on needing it to act as a thermal reservoir.

I am using this for post curing, and it doesn’t have anything to do with the printing step so I am not sure why there is a failure rate of post curing. I have not tested the strength of my objects, but the research suggests that heat increases the strength significantly - and it does it beyond that of just using light.

Yes, you’re right. FL has a white paper on curing, and heat and UV exposure both contribute to added strength (to a point, beyond which the strength degrades a bit).

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