This guide is for those wanting to build an ebb and flow table, although the concepts could also be used for making other types of waterproof boxes.
Why would you even want to? Well, it can be a little bit cheaper, and you can make them any color, not just black and white. Biggest reason though is that you can make them any size. You also end up with straighter walls, which are good if your using nursery trays.
Step 1: Build the shell out of wood or concrete:
http://i43.tinypic.com/301k6tc.jpg
Keep in mind, water weights ~8lbs/gallon (2lbs/liter) Take the time to figure out how much water you'll need by finding the volume (length x width x height), then converting you're volume to liters / gallons with Google (ie: Google search "XXX cubic in to gallons" )
The easiest way to fuck up an ebb and flow table, besides leaks, is to have the middle of the table sag -- this gives you a high water level in the middle and a low water level on the ends. If you are building a table, use 3x4 landscaping timbers on their side, or even 4x4 landscaping posts. A cheaper, easier, solution, is just to set the table on 10-20 5 gallon buckets.
I'd also recommend 3/4" plywood over 1/2".
DON'T USE PRESSURE TREATED ANYTHING
Pressure treated is used for water resistance, but not to be sealed / painted
Step 2: Caulk / tape the OUTSIDE seems, if needed
Don't do the inside seems. This step isn't to waterproof the box, it's to keep the epoxy from running out of the box while you are coating
Step 3: Tape the corners and epoxy
http://i41.tinypic.com/15x1v21.jpg
There are a few ways you can coat your table - straight epoxy, straight fiberglass resin, epoxy of fiberglass, ect.
Fiberglass is cheaper, but personally I prefer just using Smooth-On's Smooth Cast 300 or 322. What is cool is that you can buy Epoxy dye (So-strong) from Smooth-On, in cast you want to make your table non-white. The tints don't work with fiberglass (fiberglass changes the color)
Fiberglass is nice because it's cheaper and has a longer working / drying time, and seems to have a slightly higher viscosity. It sucks because you can't color it - it's clear, and changes the color of tints.
Start by taping the inner seems with drywall mesh tape:
http://www.amazon.com/MARSHALLTOWN-Premier-MT07-300-Foot-Drywall/dp/B001RJ716Y
If you are using smooth on epoxy, the mixing ratio is 1:1. If you are using 3m Epoxy, you basically have to fucking guess, because the hardener to epoxy ratio is given as "10 *DROPS* per fluid ounce".
Mix it, pour it in the table, and use a paintbrush (a DISPOSABLE one) to coat the sides and tape.
Now, fiberglass is pretty simple to work with - you have lots of time, and you can add a second coat so long as the first coat hasn't hardened (if you let the first coat harden, you need to rough sand it before applying a second coat)
Smooth Cast can be a bitch if you don't understand it. Basically, it stays fluid for ~10 minutes, then turns rock-hard and completely white in like 5 seconds. This means you need to coat fast and not be fucking with it when it hardens. It also means that you can't spend 8 minutes stirring - but you need to get it 100% mixed or you'll have spots that just won't harden.
Whatever route you go, I'd recommend a test tray to get a feel for what you'll be doing.
Step 4: Install the bulkhead valves
Just buy a Botanicare Bulkhead Kit and use a hole saw for your holes. You shouldn't have to waterproof around it, since there will be a rubber O ring on top of the epoxy. Remember to keep a lid if you put the res under the table - otherwise condensation can form on the bottom of the table and cause the non-epoxied side to warp / swell. You might just want to paint the outside, especially if you used OSB.
Why would you even want to? Well, it can be a little bit cheaper, and you can make them any color, not just black and white. Biggest reason though is that you can make them any size. You also end up with straighter walls, which are good if your using nursery trays.
Step 1: Build the shell out of wood or concrete:
http://i43.tinypic.com/301k6tc.jpg
Keep in mind, water weights ~8lbs/gallon (2lbs/liter) Take the time to figure out how much water you'll need by finding the volume (length x width x height), then converting you're volume to liters / gallons with Google (ie: Google search "XXX cubic in to gallons" )
The easiest way to fuck up an ebb and flow table, besides leaks, is to have the middle of the table sag -- this gives you a high water level in the middle and a low water level on the ends. If you are building a table, use 3x4 landscaping timbers on their side, or even 4x4 landscaping posts. A cheaper, easier, solution, is just to set the table on 10-20 5 gallon buckets.
I'd also recommend 3/4" plywood over 1/2".
DON'T USE PRESSURE TREATED ANYTHING
Pressure treated is used for water resistance, but not to be sealed / painted
Step 2: Caulk / tape the OUTSIDE seems, if needed
Don't do the inside seems. This step isn't to waterproof the box, it's to keep the epoxy from running out of the box while you are coating
Step 3: Tape the corners and epoxy
http://i41.tinypic.com/15x1v21.jpg
There are a few ways you can coat your table - straight epoxy, straight fiberglass resin, epoxy of fiberglass, ect.
Fiberglass is cheaper, but personally I prefer just using Smooth-On's Smooth Cast 300 or 322. What is cool is that you can buy Epoxy dye (So-strong) from Smooth-On, in cast you want to make your table non-white. The tints don't work with fiberglass (fiberglass changes the color)
Fiberglass is nice because it's cheaper and has a longer working / drying time, and seems to have a slightly higher viscosity. It sucks because you can't color it - it's clear, and changes the color of tints.
Start by taping the inner seems with drywall mesh tape:
http://www.amazon.com/MARSHALLTOWN-Premier-MT07-300-Foot-Drywall/dp/B001RJ716Y
If you are using smooth on epoxy, the mixing ratio is 1:1. If you are using 3m Epoxy, you basically have to fucking guess, because the hardener to epoxy ratio is given as "10 *DROPS* per fluid ounce".
Mix it, pour it in the table, and use a paintbrush (a DISPOSABLE one) to coat the sides and tape.
Now, fiberglass is pretty simple to work with - you have lots of time, and you can add a second coat so long as the first coat hasn't hardened (if you let the first coat harden, you need to rough sand it before applying a second coat)
Smooth Cast can be a bitch if you don't understand it. Basically, it stays fluid for ~10 minutes, then turns rock-hard and completely white in like 5 seconds. This means you need to coat fast and not be fucking with it when it hardens. It also means that you can't spend 8 minutes stirring - but you need to get it 100% mixed or you'll have spots that just won't harden.
Whatever route you go, I'd recommend a test tray to get a feel for what you'll be doing.
Step 4: Install the bulkhead valves
Just buy a Botanicare Bulkhead Kit and use a hole saw for your holes. You shouldn't have to waterproof around it, since there will be a rubber O ring on top of the epoxy. Remember to keep a lid if you put the res under the table - otherwise condensation can form on the bottom of the table and cause the non-epoxied side to warp / swell. You might just want to paint the outside, especially if you used OSB.