Foam

[Chris Smith]

There are several choices when it comes to foam. I prefer to use Dow blue board. This is an extruded form of polystyrene. This means that the entire board is made of one continuous piece of foam. This foam of very durable and will last many years. Blue board comes in several forms and it is important to get the right one. The best is "square edge" and not the "score board". Square edge foam is a solid sheet of foam. The score board has scores top and bottom to make it easy to break. The scores are at a standard stud layout and intended for insulation in walls. The scores make it easy for contractors to break and install.

The other type of foam is EPS or expanded polystyrene which is thousands of small pellets that are expanded into a form. The EPS foam is not nearly as strong as extruded and will break down easily. Roots of aggressive plants will actually grow into the foam. I have one of these sheets in my system and it is now dedicated to mint as the roots are growing throughout the foam.

[AJ Grottke]

The little black raft in the video is the leftovers from a pack of 2" neoprene collars.   They come in a sheet and you punch em out.  The collars are used in hydroponic cloning units.  I dont think they would be any good for plant rafts.  Maybe for seedlings.

[David Hart]

Go to M Cosmo's page....look through his pictures. Look @ picture 6/100....you'll see something similar. It's been awhile...I think he ordered them overseas, it took a long time to get them and they were costly.

Josh Fagan said:

Thank you.

Anyone know what THESE rafts are?

Or These at 3:44 in the video?

[Karen Swanberg]

So, I've been asking at the closest Lowes about the Dow Blueboard. Everything that Lowes currently sells is scored. When I asked about special ordering non-scored blue board, they called DOW. According to their call to DOW, blueboard is only sold scored anymore. Even the "square edge" stuff. Anyone know differently? Has anyone found an online source for the blueboard?

[Nigel Clement]

Hi David, does that supplier ship perchance? Dow blueboard is not something you find here in Trinidad and I am currently using EPS. If I could find them online to purchase and have sheets shipped to a freight forwarder in Miami it would work well for me. My searches online proved to be difficult and finding 2" almost impossible. I had to search Lowes stores up in Maine (thicker insulation needed up there).

David Hart said:

In central FL, I've found 2" Dow for 32 $ (@ commercial suppliers)

The 2 " EPS.... @ HD is aprox 15$   ( 1 # )

Our lowe's, normally only carrys the 1 " dow

 

I'm not normally awake and posting at this time of the night/morning. Checking on my AP

system and checking if my pipes are freezing.  I moved to FL, so I could be warm..????....:-(

[Dave Love]

has anybody tried using a buoyant wood instead of foam as the raft?

[DJ Bisson Jr]

Where I live, Lowe's only carries the Dow blue board in 1/2" thick. Now Home Depot carries Owens Corning made of polystyrene, it seems similar to the Dow blue, but it is a score board.  It is only $27 for a 4' x 8' sheet 2" thick. I have not had the time to check out some local contractor supply yards, but if i can't find any more places locally then do you think the boards from HD will work . How long do you think that they would last since they are a score board? How long on average does your Dow blue last, as in crops per season? The reason for asking is because if I have to special order the Dow blue and it costs 2-3 times as much as the board from HD, then I might try the HD board first?

[Pete]

Newbie questions:

1. How thick are the rafters?  

2. No media at all or net pots with media placed in the rafters?

3. How to cut holes on foam without getting all messy?

4. What are the advantage of raft/deep water culture other than saving the cost of buying lots of media? 

Thanks for helping, I am fascinated by aquaponic and trying to learn as much as I could. 

This guy is using some sort of pre grilled interlocking green board that can be linked together.  He seems to be put them directly in some pond and grow stuff there.  Not sure how the pond water is oxygenated enough to support doing that?  Or was it because his pots sat high, mostly above water level?
 

 

The same guy, but a smaller system.  He used some sort of green raft, "UFO" disk :)
 

Again, very shallow water, gold fishes and dense planting.  Didn't see air pump or water movement?

[Chris Smith]

Dow square edge is the best foam to use. I have dow scoreboard that has been in use for two years now. It can be used just fine despite what has been said about it. It is important to make the first cut on the 4x8 sheet down the center score longways(leaving 2-2x8 sheets). Then cut the 2x8 sheets to 2x4 or into 2x2s. Cutting the score boards this way will leave 1 score in a cut down sheet instead of 3 scores (if the 4x8 sheet were cut into 2x4 down the length). If a piece of foam breaks on the score it is very easy ti repair using polyurethane sealant and a few long stainless lag bolts for support. DO NOT USE THE EPS FOAM!!!!!! The EPS foam is weak, will water log, and roots grow right through it. Most people prefer 2" foam because the 2" net pots are 2" deep allowing the bottom of the pot to sit in the water.

I have sourced blue board from White Cap building supply. They were the best price on quantity orders.
DJ Bisson Jr said:

Where I live, Lowe's only carries the Dow blue board in 1/2" thick. Now Home Depot carries Owens Corning made of polystyrene, it seems similar to the Dow blue, but it is a score board.  It is only $27 for a 4' x 8' sheet 2" thick. I have not had the time to check out some local contractor supply yards, but if i can't find any more places locally then do you think the boards from HD will work . How long do you think that they would last since they are a score board? How long on average does your Dow blue last, as in crops per season? The reason for asking is because if I have to special order the Dow blue and it costs 2-3 times as much as the board from HD, then I might try the HD board first?

[David Hart]

 

Nigel, I'm so sorry, I didn't see your post till now.

 

 Like Chris, we have been ordering from White Cap construction supply, aka.... HD Supply...which is owned by Home Depot.

I too, am using EPS, but we are having 3 pound made. It's very strong...just as strong, or maybe stronger then blue dow. Plus, it's virgin foam, no bug poisons or fire retardant,  like some foams have.

I've only been using it for a short time. So far, It doesn't get water logged like the 1 pound EPS. I know Chris has mentioned 'aggresive' roots growing right through some foams. I've only raised lettuce, bok choy, cutting celery and a few tomatoes in it, So I cant say whether it will stand up to that or not.

@ Pete....if you could make some kind of a 'hot wire', you could cut foam without making too much of a mess. If you use a hole saw, the way to make the least amount of mess is....pay some one to drill them for you, at 'their house'....

Nigel Clement said:

Hi David, does that supplier ship perchance? Dow blueboard is not something you find here in Trinidad and I am currently using EPS. If I could find them online to purchase and have sheets shipped to a freight forwarder in Miami it would work well for me. My searches online proved to be difficult and finding 2" almost impossible. I had to search Lowes stores up in Maine (thicker insulation needed up there).

David Hart said:

In central FL, I've found 2" Dow for 32 $ (@ commercial suppliers)

The 2 " EPS.... @ HD is aprox 15$   ( 1 # )

Our lowe's, normally only carrys the 1 " dow

 

I'm not normally awake and posting at this time of the night/morning. Checking on my AP

system and checking if my pipes are freezing.  I moved to FL, so I could be warm..????....:-(

[Chris Smith]

David, you refer to the EPS in different weights. Is that weight per sheet? It must be a density thing. Do you have a spec sheet on the 3 lb foam? I found a plant on Oahu that can make anything out of EPS and I was quoted very good prices on bulk orders. I'm sure that the cost would be higher for heaver foam. Even with shipping the per sheet price was about half the price as blue foam at the local big box store. The blue foam now costs $60 a sheet locally!!

[DJ Bisson Jr]

I got lucky, Lowe's can ship me the 2" x 4' x 8' Dow blue board $29 a board. Shipping for 5 boards they said was only $7.95, so i guess that's good. Thanks for the help.

[Chris Smith]

Wow that is a good price compared with what I have to pay!

DJ Bisson Jr said:

I got lucky, Lowe's can ship me the 2" x 4' x 8' Dow blue board $29 a board. Shipping for 5 boards they said was only $7.95, so i guess that's good. Thanks for the help.