Reef Safe Plastics

Randy Holmes-Farley · Oct 12, 2014

The concern is likely that the degradation is likely too slow if there are not bacteria present which degrade them enzymatically.

Artisan · Mar 24, 2015

I know I'm a little late on this thread, but I do a lot of printing with PLA and thought this might interest you guys. In order to smooth ABS plastic prints, people most often use acetone vapor to get a glossy finish. I tried this method on the PLA plastic that I print with, but there was no change in the surface texture. None at all. I eventually completely submerged the PLA print in acetone for roughly a week and absolutely nothing happened. It was no more pliable than before. So far I haven't been able to find much more information than this on their PLA plastic, but I will see what I can find.

Our polylactic acid (PLA) filament is the most consistent and reliable material for use in Series 1 3D printers. PLA is a corn-based biodegradable plastic and is excellent for general use printing.

cope413 · Mar 24, 2015

You need dichloromethane to smooth PLA. Unfortunately, DCM is not something you want to mess with outside of a lab. You can wet sand PLA with 220-1000 grit paper to get a smooth, shiny finish, but it takes a while.

Artisan · Mar 25, 2015

I actually get a really good finish on my prints. Down to 0.06 and PLA has a bit of a glossy finish anyway. I'm just surprised that PLA wouldn't dissolve in something so corrosive. I'd think it would last quite a long time in a tank, but then again, that is a much more complex chemistry. I'll have to see how much my 3D designer would charge to replicate some parts for me. It would be fun to make a calcium reactor head as well as some parts for a higher end protein skimmer.

Prozium · May 21, 2015

cope413 said:
You need dichloromethane to smooth PLA. Unfortunately, DCM is not something you want to mess with outside of a lab. You can wet sand PLA with 220-1000 grit paper to get a smooth, shiny finish, but it takes a while.

check this article out.
http://www.printedsolid.com/smoothpla/

Randy Holmes-Farley · May 21, 2015

Artisan said:
I actually get a really good finish on my prints. Down to 0.06 and PLA has a bit of a glossy finish anyway. I'm just surprised that PLA wouldn't dissolve in something so corrosive. I'd think it would last quite a long time in a tank, but then again, that is a much more complex chemistry. I'll have to see how much my 3D designer would charge to replicate some parts for me. It would be fun to make a calcium reactor head as well as some parts for a higher end protein skimmer.

I know this is an old question...

Depending on exactly what PLA is used, it may degrade too slowly.

It also won't be dependent on bacterial enzymes for local degradation of the pellet surface the way biopellets are, and so may be not much different than soluble organic carbon dosing (that is, not localizing the bacterial growth to the pellet surface).

Prozium · Jun 7, 2015

Hey Randy, what about graphite infused ABS? "ABS base and infused with 5% graphite powder, resulting in a very smooth and lower friction part."

I want to make a bushing for a part I'm thinking of making for my pico build, and the low friction properties would be nice.

so... is it safe?

Paul B · Jun 7, 2015

Very cool, thanks for posting. I hope to get a 3 D Printer this summer if all goes well.

Randy Holmes-Farley · Jun 7, 2015

Prozium said:
Hey Randy, what about graphite infused ABS? "ABS base and infused with 5% graphite powder, resulting in a very smooth and lower friction part."

I want to make a bushing for a part I'm thinking of making for my pico build, and the low friction properties would be nice.

so... is it safe?

The graphite is OK in the plastic. The ABS (acrylonitrile/butadiene/styrene) is OK once the unpolymerizized monomers have had a chance to degas a bit (the smell). I used an ABS refugium for a few years.

cope413 · Jun 7, 2015

Randy, what about polyester or polyether based TPEs? Any potential issues with either?

Prozium · Jun 7, 2015

Paul B said:
Very cool, thanks for posting. I hope to get a 3 D Printer this summer if all goes well.

They are a LOT of fun.

Randy Holmes-Farley said:
The graphite is OK in the plastic. The ABS (acrylonitrile/butadiene/styrene) is OK once the unpolymerizized monomers have had a chance to degas a bit (the smell). I used an ABS refugium for a few years.

Thanks for the info.

Prozium · Aug 14, 2015

Would this PET+ be OK to use? The "+" seems to be some copolyester.
here are the links to the 2 data sheets they have on it.
https://d11mzknh295tta.cloudfront.net/static/docs/MadeSolid_PET+_Technical_Data.pdf
https://d11mzknh295tta.cloudfront.net/static/docs/MSDS_PET+.pdf

I also need to know about making it water tight. For ABS I was looking in to dipping the parts in a diluted lye solution. Do I need to do the same for PETG/PET+... would lye work?
PET+ is advortized as hydrophobic, if that matters for sealing.

Unfortunately the company wasn't of any help in this. :/

Randy Holmes-Farley · Aug 16, 2015

cope413 said:
Randy, what about polyester or polyether based TPEs? Any potential issues with either?

They should be fine, although a polyester may very slowly degrade, depending on which polyester.

Randy Holmes-Farley · Aug 16, 2015

Prozium said:
Would this PET+ be OK to use? The "+" seems to be some copolyester.
here are the links to the 2 data sheets they have on it.
https://d11mzknh295tta.cloudfront.net/static/docs/MadeSolid_PET+_Technical_Data.pdf
https://d11mzknh295tta.cloudfront.net/static/docs/MSDS_PET+.pdf

I also need to know about making it water tight. For ABS I was looking in to dipping the parts in a diluted lye solution. Do I need to do the same for PETG/PET+... would lye work?
PET+ is advortized as hydrophobic, if that matters for sealing.

Unfortunately the company wasn't of any help in this. :/

Why dip it in lye?

Prozium · Aug 16, 2015

Randy Holmes-Farley said:
Why dip it in lye?

Do to the manufacturing process, it leaves very small gaps and would eventually allow water to leak. The lye solution melts the outside a little, which both smooths and seals the part. (from what I understand with ABS anyway.)

I read a suggestion about using a mineral oil and bees wax mix to seal the inside, and I also thought about epoxy coating the parts that water would touch.

Cory · Aug 16, 2015

What about great stuff insulating foam?

Randy Holmes-Farley · Aug 17, 2015

Prozium said:
Do to the manufacturing process, it leaves very small gaps and would eventually allow water to leak. The lye solution melts the outside a little, which both smooths and seals the part. (from what I understand with ABS anyway.)

I read a suggestion about using a mineral oil and bees wax mix to seal the inside, and I also thought about epoxy coating the parts that water would touch.

Do you recall where you saw that?

FWIW, I don't see how lye solution will have that effect (although I've never tried it), or that water would penetrate this very hydrophobic plastic anyway. I do see how wax would seal it, but I used an untreated ABS sump for many years with no issues that I ever detected.

Randy Holmes-Farley · Aug 17, 2015

Cory said:
What about great stuff insulating foam?

I don't know how much monomer might get into the water after curing, but I wouldn't be a fan of the reactive ingredients in it. It may be OK, but the only way to know that is from others using it without issue, not from the ingredients.