Rafts for DWC

[Michelle Silva]

As suggested, I'm adding blog post below to "forum"..still need to learn how best to use this site.Thks.

 

Can anyone advise what the difference is between using Dow blue boards and the white 2" styrofoam at Home Depot. Do the dow blue boards need to be painted? I don't know if I would ever try to be "Certified Organic" but I would want to do what is safest.. Does it make a difference? Thanks.

[Greener]

Yes, more air by the roots, but I wonder if there's a downside to this too on hot summer days.  I imagine that the air under the board will get pretty hot.  The insulation of the water is worse too, which might hurt in the winter.

 

I didn't think I could get away with having the water below the pots, even with a wick.  I figured I should keep exposed roots to a minimum, but maybe not?

 

[Michelle Silva]

I'm not liking styrofoam rafts. TC, I can understand if you didn't want to do it again,lol! I had looked for alternatives when I was setting up, and it was really holding me up, because I couldn't find anything to use instead that would be cost effective and easily available. I never painted them either. It also doesn't seem like the underside is really building up any kind of substantial slime or anything, Someone had told me that was going to happen and they would be a biofilter.

Joseph, I love the beeswax idea. Do you have a good source for large amounts of it and could you give me an idea of what you pay for it? I have the approx 15 4'x8' sheets in my raft part of the system.'

[Michelle Silva]

I just remembered there's a beekeeping association here, I might be able to get some from someone in that group. : )

[Joseph Orlando]

 

Michelle,

Anywhere from 3.00 to 4.00 a pound and a few pounds should go a long way.  Try to heat it to about 200 F so you can apply it thin.  By the way, beeswax will also help with bouyancy it's waterproof.  Your net cups will fit nice and snug too.

While your talking to the beekeepers assn. ask about getting a hive.  The bees will keep anything you're growing pollinated, and give you some nice organic honey at the end of the season, not to mention some wax for keeping up with your rafts!

 

JoeJ

Michelle Silva said:

I'm not liking styrofoam rafts. TC, I can understand if you didn't want to do it again,lol! I had looked for alternatives when I was setting up, and it was really holding me up, because I couldn't find anything to use instead that would be cost effective and easily available. I never painted them either. It also doesn't seem like the underside is really building up any kind of substantial slime or anything, Someone had told me that was going to happen and they would be a biofilter.

Joseph, I love the beeswax idea. Do you have a good source for large amounts of it and could you give me an idea of what you pay for it? I have the approx 15 4'x8' sheets in my raft part of the system.'

[Joseph Orlando]

Not me TC, I missed the post on concrete.

TCLynx said:

Cool idea Joseph.  Was it you or some one else recommended using wax to seal concrete as well.

 

As to using the hdpe to support plants in boards above the raft tanks that actually has an added benefit too, it provides more air contact with the water so the amount of air you will need to bubble into the raft tanks may be reduced.  And I've found using wicks in the net pots can free you from the need to have the water touch the bottoms of the pots as well.

[Michelle Silva]

Thanks, I found some online sources, but had no idea of the quantity needed. I had thought about hives a while ago. a friend of mine made a whole bunch and was too busy with other projects to get started with bees. He would lend me some if I wanted, but I'm kind of in the same place right now. I'm trying to build the buying club and have so many other commitments that I'm not sure I want to take that on right now and get all that gear, lol!

I'm noticing lots of wasps around the raft tanks lately, figuring I've got some good pollinating action going on. I think at one of the meetings they once said that the travel range for the bees in the beehives was something like 4 miles for the pollination. Don't quote me on that, it was a while back, but I think there was a member with hives that live within that distance from my house : )

[TCLynx]

I tend to like wasps around (other than when I accidentally disturb one and get stung) because they are predators and will go after things like caterpillars.

 

I don't even remember which forum had the recommendation of wax on the concrete.  I think they actually recommended paraffin and a blow torch for the concrete sealing project.  Blow torch no good around foam but the paraffin would probably work if beeswax isn't easily available.  Melting temp might be slightly different though.

 

Use a double boiler for melting wax to keep from burning it.  Probably need a burner you can set up outside by a work area to coat the foam.

[Mike Konshak]

For everyone's intellectual curiosity, I attached the material Safety Data Sheets for both the blue Dow extruded polystyrene (aka Dow Blue Board - DBB) and the pink Owens-Corning Foamular 250 XPS equivalent (BTW the OC has a higher R rating of 10 for a 2" thick board and compared to Dows R-2) which is available at Home depot for $17.27 2"x24"x96".  Note that these are 24" wide when comparing prices with the 48" wide DBB. I went to the Lowes site and although they show the Dow product they list  it as unavailable.

[Michelle Silva]

WOW! around $17 a sheet, I think when I checked it out it was around $30. That was the main reason why I went with the reg open cell 2" styrofoam. I had a friend that knew someone w/ a hydro raft system (not AP) that used it and said his rafts lasted years..maybe it's different with aquaponics. I was willing to take a chance, as this was all a huge experiment for me being that I researched and pretty much designed a hybrid system by just piecing info from many sources.

BTW, I wrote in an earlier post in this thread that the underside of the rafts weren't building any slime and I didn't think that the rafts were acting as biofilters.. I didn't realize at the time that the brown stuff is the benefical bacteria, so it is there

 

The rafts are now getting painted on the tops only and slightly around top edges.. doing it while they are wet .I don't want the beneficial stuff to dye..the paint gets absorbed, but couldn't figure out a better way (they've already been on the water for many months now), They are holding up so so, I do see little flecks of styrofoam on the side edges. They were put on the water I think it was sometime around the end of September (?)

 

[Michelle Silva]

Oh, never mind.. I just saw that it was the pink was that is at that great price..ok, thanks for posting.

Michelle Silva said:

WOW! around $17 a sheet, I think when I checked it out it was around $30. That was the main reason why I went with the reg open cell 2" styrofoam. I had a friend that knew someone w/ a hydro raft system (not AP) that used it and said his rafts lasted years..maybe it's different with aquaponics. I was willing to take a chance, as this was all a huge experiment for me being that I researched and pretty much designed a hybrid system by just piecing info from many sources.

BTW, I wrote in an earlier post in this thread that the underside of the rafts weren't building any slime and I didn't think that the rafts were acting as biofilters.. I didn't realize at the time that the brown stuff is the benefical bacteria, so it is there

 

The rafts are now getting painted on the tops only and slightly around top edges.. doing it while they are wet .I don't want the beneficial stuff to dye..the paint gets absorbed, but couldn't figure out a better way (they've already been on the water for many months now), They are holding up so so, I do see little flecks of styrofoam on the side edges. They were put on the water I think it was sometime around the end of September (?)

 

[Rebecca B]

I've been warned against pink or white polyisocyanate rigid insulation boards.  Someone knows someone who had a bad experience with the fish after making rafts from them. When I did a Google search for "polyisocyanate," I was taken to the OwensCorning Foamular 150.  150, not 250.........

[Dave Love]

Hi Michelle, 

I have similar concerns as you about env. sustainability and human toxicity of DBB and for that matter any plastic with direct exposure to UV.  Did you arrive at a suitable raft that doesn't degrade and that you feel good about?    I posted a question today to another thread about using wood as a raft to see if others have worked with it.  I'm building my system now, and would like to compare wood to DBB. 

Dave

Michelle Silva said:

HI Ernie,
Thanks for you reply..wow,how weird, I have this catalog and was just looking at this page earlier today!
I think I'm more comfortable for some reaon w/ the styrofoam than with foam. It rolls up so would think it wouldn't be easily lifted, although could work if not lifting out of the system.

ernie.j said:

Have you considered Farmtek STK#109243 cross linked HDPE foam made for floating raft lettuce systems?
http://www.esapco.com/1070/f/p074-075.swf