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Blocking UV light

Posted: Fri Aug 22, 2014 10:50 pm
by jesse
You guys might want to try switching out the blue with an amber UV shield material.

http://jtechphotonics.com/?product=445n ... -shielding

I ordered some for my l-cheapo uv laser cutter mod (2 watts)

Re: Blocking UV light

Posted: Sat Aug 23, 2014 9:08 am
by brent
I feel that site is unnecessarily expensive for what you're getting in return. Does anyone know of an alternative?

Re: Blocking UV light

Posted: Sat Aug 23, 2014 9:24 am
by Mac The Knife
In the video interview that John and Steve did for some 3d printing blog, the subject of the blue window came up. They said something to the effect that it blocked UV.

Re: Blocking UV light

Posted: Sat Aug 23, 2014 11:25 am
by guanu
unless you are printing outside in the sun, I've been printing every day with the cabinet open actually, working fine... what you dont want to do is leave the resin in the dish longer than you are going to use the machine. we've left a dish of resin out under the room lights for a few days without it curing from that (tho the pigment does does seperate whcih is why you pour back what you dont use into the tub after use, and shake well before use and fill up the vat.

Guanu

Re: Blocking UV light

Posted: Sat Aug 23, 2014 11:40 am
by sgraber
If it's going to be a UV DLP kit, IMO it should follow some "best practices" so it's robust (one of them being using UV blocking acrylic). It's not so much an issue printing inside, but if a person takes this to a makerfaire and prints outside or is printing someplace lit by mercury vapor bulbs, they're going to have a bad time.

I've mentioned this to John and Guanu before, but I digress... :p

Re: Blocking UV light

Posted: Sat Aug 23, 2014 11:53 am
by brent
sgraber wrote:If it's going to be a UV DLP kit, IMO it should follow some "best practices" so it's robust (one of them being using UV blocking acrylic). It's not so much an issue printing inside, but if a person takes this to a makerfaire and prints outside or is printing someplace lit by mercury vapor bulbs, they're going to have a bad time.

I've mentioned this to John and Guanu before, but I digress... :p
Where else would you purchase UV blocking acrylic, sgraber? I'm considering blocking it out entirely with a piece of wood.

Re: Blocking UV light

Posted: Sat Aug 23, 2014 2:35 pm
by sgraber
I know Ponoko has it.

Also, I hope I don't come across negative with my comments, so I apologize if I do or did. That said, I do have a significant background in formulating UV resins for different applications (see my LinkedIn profile: https://www.linkedin.com/in/sgraber?_mSplash=1 ) so I do have a lot of experience when it comes to resin requirements and things to watch for when designing UV systems, the acrylic being one of them. To be completely transparent: I am working for MakerJuice formulating UV resins.

A couple of solutions to the blue are:

* use an acrylic with UV blockers (I believe they can be sourced in a number of colors)
* put a transparent piece of polycarbonate behind it
* use a UV absorbing film behind the blue

Shane

Re: Blocking UV light

Posted: Sat Aug 23, 2014 3:27 pm
by brent
sgraber wrote:I know Ponoko has it.

Also, I hope I don't come across negative with my comments, so I apologize if I do or did. That said, I do have a significant background in formulating UV resins for different applications (see my LinkedIn profile: https://www.linkedin.com/in/sgraber?_mSplash=1 ) so I do have a lot of experience when it comes to resin requirements and things to watch for when designing UV systems, the acrylic being one of them. To be completely transparent: I am working for MakerJuice formulating UV resins.

A couple of solutions to the blue are:

* use an acrylic with UV blockers (I believe they can be sourced in a number of colors)
* put a transparent piece of polycarbonate behind it
* use a UV absorbing film behind the blue

Shane
I know of your background and highly respect your advice, Shane. Would there big a large difference between using UV film opposed to using transparent polycarb? I've never heard of the film before and that would let me keep the blue color as well.

Re: Blocking UV light

Posted: Sat Aug 23, 2014 3:55 pm
by Mac The Knife
A clear piece of polycarbonate (Lexan) would probably be easier to source.

Re: Blocking UV light

Posted: Sun Aug 24, 2014 9:25 pm
by sgraber
I just did a quick test on the blue acrylic. At best it filters 50% of the UV that hits it. Orange or amber without UV blockers filter almost 90%, based on my data.

Re: Blocking UV light

Posted: Sun Aug 24, 2014 9:44 pm
by Mac The Knife
and clear polycarb?

Re: Blocking UV light

Posted: Sun Aug 24, 2014 9:53 pm
by sgraber
I don't have any. ;)