This DIY Anaerobic chamber is considered a fully functional piece of Bio Art, As a statement from the Maker DIY community to the large Institutions that have a tendency to withhold knowledge. It was designed and built to grow cultures of Geobacter Sulfurreducens bacteria, to do research and experimentation on my other Bio Art project: a Microbial Fuel Cell project called "BactElecTric".
It is important to state the fact that this is piece of equipment intended to be used in a Bio Safety Level 1 lab environment.
Also, it was conceived to keep a low oxygen level atmosphere inside of the chamber, it is constantly pumped with inert gas such as Nitrogen or Argon.
It is NOT(repeat...not) intended to keep organisms from going outside of the chamber, it is intended to keep a desired atmosphere inside, with positive pressure.
It is NOT air tight, the positive pressure and small leaks keeps outside air from going in.
This is a functional piece of biology lab equipment, it was welcomed inside GENSPACE, the first community Biolab, based in Brooklyn, New York.
Step 1: Chamber Parts Breakdown
1- Big plastic container (36 gal), as clear as possible, as big and square as you can find.
2- Gas intake
3- Relief valve
4- Double hatch system (two plastic food containers)
5- Double gasket with metal reinforcements
6- Pressure gauge
7- Rubber arms (flex tube) and gloves
8- C clamps
9- Insulation foam + silicon + duct tape
More detailed material list and building procedures ahead.
Step 2: Materials Used
Step 3: Footers
I suggest using half inch screws.
I used 1/16 inch rubber to make small gaskets, reinforced with Lexel.
(!!!note on the Lexel: It takes very....very long to dry (curate), bu is is 1000x better than silicon!!!)
Step 4: Closing the Lid
The corners are a little tricky but with patience and a good x-acto knife, the insulating foam works.
You can use as many C-clamps as needed.
The idea is to NOT close the lid permanently, so that the chamber can be opened for cleaning, maintenance, modifications or any other need, without loosing integrity.
(You can also get a big sheet of 1/8" rubber and tailor a nice big gasket...)
Step 5: In Goes the Gas
I used quick release valves so that you could change hose, or gas type without compromising the integrity of the chamber and to be able to be stand alone in case the hose (or gas tank) needs to be removed or exchanged.
On the inside of the chamber, the valve has a brass connector to screw a barb to connect a hose (you can find size adapters), this is if you need to sparge (blow bubbles) a liquid medium (as it was my case) with a certain gas.
I used a power drill, starting with a small diameter bit, incrementing the size bit by bit. It is important that you insert the drill while its moving at high speed (do not start the drill while touching the plastic). I also used fabric tape to help support the plastic.
Remember to clamp a piece of wood on the inside and the whole chamber to a corner of a table, so that you can drill properly.
Latter on I used the Dremel, using a pointy polishing stone to make the first hole, and then, using the Dremel and a sanding paper tip, to make the whole to the desired size.
To help seal the hole properly and make it air tight, I used a gromit.
finally, I caulked some Lexel around the brass valves, inside and outside. (remember to let it dry for a very long time)
!!!!! IMPORTANT !!!!!
To prepare your oxygen free (almost) atmospherey
To sequestrate the oxygen of the normal atmosphere, I used "food preserving tablets" they are used to preserve dry food for extended periods of time.
I got them on line and you can easily calculate how many you need for your chamber size. I just put them in a corner of the chamber in a way that they did not interrupt my work... and later on i got them out of the chamber through the double hatch mechanism.
Step 6: Just in Case, Pressure Relief Valve
As mentioned before, this time I used a Dremel to make the hole. I recommend this technique over the power drill, to work with plastic containers.
The same finishing touches of the gas intake valve where made to this pressure relief valve.
I decided to put both valves on the same corner of the chamber, so that I would not have another corner used up and could not place elements in it.
Step 7: Accordion Arms
Funny thing is... they worked!!!
Make sure you make a prototype of your arm size and distance between arm holes, before you get to work on the chamber.
Also, be sure to use enough accordion tubing, to reach the inside of the double hatch while you are working.
The best way to make the big holes for the arms is with the Dremel, as explained before. (not a plastic cutter as I first did)
Since the accordion tube, had a spiral structure, it did not seal very nicely against the edges of the holes on the plastic wall of the container. To deal with this, i used expanding sealing foam... and a lot of Lexel.
It worked ;)
Step 8: Rubber Gloves
Because of the spiral structure of the accordion tube, A LOT of patience and time was needed to seal the union of the gloves and the accordion hose. I cut and tailored pieces of gorilla tape independently as I worked, so that they made a "scale mail" pattern, like scales on a fish of armor.
Additional support was provided by zip ties...and the gloves own rubber.
This elements have been optimized with liquid rubber spray, to strengthen their structure.
During lab work, it is strongly advised that you use your lab gloves while using the chamber, your hands sweat a lot, and getting them out of the chamber's gloves can be tricky.
Step 9: Double Hatch Ensemble
This dual hatch system was designed so that minimize loss of atmosphere while working, and provide a way to get elements needed into and out of the chamber at any given time. (without having to open the whole chamber and loosing all your atmosphere)
Be very careful making your holes. For this I made templates made of masonite, so that every hole drilled was on the same spot.
You'll see on the next step, this is very important to make the dual gasket system for the dual hatches.
Step 10: Hatch Gaskets
The wholes on the metal frames where drilled with a Drill Press. The metal frames where made so that screws could be used to really tight the sandwich of layers that this step dealt with, without compromising the integrity of the plastic containers. In other words, this was done so that the plastic didn't crack when you tight the screws as it is needed for the air tight sealing of this large square hole on the chamber.
Everything was done using the same templates that where made at the beginning of the double hatch process.
For everything to come together correctly, you have to use clamps, to make all the layers be tight and pressed against each other.
layers (in order of appearance):
metal, plastic container 1, rubber, plastic wall of main chamber, rubber, plastic container 2, metal
The finishing touch was to caulk Lexel on the outside edge, and Silicon on the inside. I only used silicon because the caulking gun was too big to be used on the inside of the chamber
If you can TIG weld your metal frame so that it is one solid piece, it is best, I want to do it for my next chamber :)
Step 11: Horiozontal Surface for the Hatch
Since the walls of the main chamber are tapered, the double hatch is inclined downward towards the inside of the chamber. There is also prominent edges because of the gaskets.
I did the pieces with plexi, on a laser cutter, but they can be made by hand. They three pieces were glued using "weld-on" and the notches on the middle were made,by hand, very carefully, with the Dremel.
Step 12: Pressure Gauge
The finishing touch was made with silicon...inside and outside
The only comment is that I want to replace this gauge with another one with a smaller scale, up to a 100 is enough.
The pressure relief valve works at 70 psi.