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.

[Michelle Silva]

Hi ericjf7,
You might want to try to contact one of the major national billboard companies and see if you can find a local warehouse to get some for free,that is what I did. Unfortunately, the back and forth calls to connect w/ the person held me up a little longer, but it was worth it. Instead of paying for them, plus shipping from the billboard tarp supplier. The standard size seems to be 14' x 28'..Unfortunately, I thought about this after I bought the same thing that FA uses (Dura-skrim) for $400! Now trying to return that stuff...another benefit to the used billboards is that it has done most of it's offgassing and doesn't smell nearly as bad as new stuff!
~Michelle

ericjf7 said:

Lo Earl, I realize that I may have opened up a sore point, and that we are all interested in doing it the best possible way we can. The only answer I can give as to what I'm using is that I'm in the (intensely studying part) of the planning process, much the same as many others who have written in, thrilled with the prospect of doing this, also having a considerable background working with construction materials, and the hazards that various plastics are bringing into our lives .

I also know that I have had scrap pieces of uni-cellular material that was used to cover some large commercial swimming pools at a ski resort, some of which have had direct outside exposure to all kinds of weather for about a ten year period, this includes summer and winter. This is a closed cell material, bright blue in colour, fairly sealed on both surfaces (smooth), and does not appear to be breaking down in any way, very tough material - this is what I am looking for, and thought (know) it was in some of the videos, used as raft material. In waiting for the Auquatic Eco-Systems catalogue, was hoping it would be in there, but don't see it in the electronic version.

While I have the address of the (Minnesota) supplier for billboard tarps, I would be very interested in your feedback on this material, as the most likely scenario with my (planned) system will be (80' long) media beds in trenches with prefab concrete slabs ( 16"x48"x2") making the sides, and a liner, or all concrete, yet to be decided, as I won't get to the site to actually build till later in the year - so far it is only what can be gleaned from the computer. So far I own a tremendous debt of gratitude to all who have contributed to the incredible body of information that is out there, and to the contributors on this site, and am only trying to add my little bit. To this end I can't help but feel that any discussions around the materials used are ultimately very important, particularly as we are striving to produce good food.

[ericjf7]

Thanks Michelle, Do you know if and how these tarps can be joined and sealed effectively - the beauty of the (Minnesota) supplier is that they have dimensions into the hundreds of feet, to make them one piece. While the paint on the back side is no doubt of the highest quality, I'll be digging the ditches into some excellent soil, not contaminated before in any way. The paint would be against the subsoil underneath, and the concrete on the sides, however this (paint factor) may lead me to consider concrete for all of it. I also have someone trying to convince me to use these (billboard tarps) for roofing membrane over the fish areas, in which case the painted side would be down, and any deterioration over time would end up in the tanks, which leads me more towards using regular galvanized or something similar for the roof. The place I'm looking to do this is in Central America, and I haven't seen too many billboards in the area, as a matter of fact, can't remember any.

[Michelle Silva]

I believe you would still have to seal the concrete. I don't have any problems or concerns about the "paint" on the billboards anymore, they do not look like they are on the surface of the vinyl. My neighbor is also in the sign business and he said he the inks used are getting more and more environmentally friendly (legally they have to be for the workers sake as well).

I haven't had to join them, but I have heard of people having leaking issues with joining liners. There is some type of sealer at HD that I was looking at that comes in a caulk type tube, but don't know for sure if it would work...my tanks are only 40'..could you work your tanks around the dimensions of the liners? I think it's kind of nice to be able to get around them too, but I don' t know what your set up is.
Good luck with it...Where in Central America?
Michelle
ericjf7 said:

Thanks Michelle, Do you know if and how these tarps can be joined and sealed effectively - the beauty of the (Minnesota) supplier is that they have dimensions into the hundreds of feet, to make them one piece. While the paint on the back side is no doubt of the highest quality, I'll be digging the ditches into some excellent soil, not contaminated before in any way. The paint would be against the subsoil underneath, and the concrete on the sides, however this (paint factor) may lead me to consider concrete for all of it. I also have someone trying to convince me to use these (billboard tarps) for roofing membrane over the fish areas, in which case the painted side would be down, and any deterioration over time would end up in the tanks, which leads me more towards using regular galvanized or something similar for the roof. The place I'm looking to do this is in Central America, and I haven't seen too many billboards in the area, as a matter of fact, can't remember any.

[ericjf7]

Near Rivas, Nicaragua, in which area there are many people living at subsistence levels, including my immediate neighbours, which leaves questions of how to extend this technology to people who cannot afford a bag of cement, or a pump to lift water, let alone pay for the electricity, even though this could lead to food selfsufficiency where it matters most, ie poor people. Electricity itself presents another problem in that sometimes (yesterday) power is off for up to eight hours at a time, frequently, and for various and any reasons. The price of power is also an item, meaning the system design is that much more important - do you have any idea if air pumps are a good way to move a fair bit of water if close attention is paid to differences in elevations between tanks and beds?

[Michelle Silva]

Hi Eric,
Yes, understand the concerns. When I learn more and understand this more I would love to help others to grow their own food. Could you get cinderblock cheaply or something else locally that can be salvaged or repurposed to make the tanks? I found some cinderblock on Craig's list, that someone was giving away, then had to but the rest.
I'm sorry, I'm not sure about the air pump question...maybe someone else knows that. I'm still fairly new at this.
~Michelle

ericjf7 said:

Near Rivas, Nicaragua, in which area there are many people living at subsistence levels, including my immediate neighbours, which leaves questions of how to extend this technology to people who cannot afford a bag of cement, or a pump to lift water, let alone pay for the electricity, even though this could lead to food selfsufficiency where it matters most, ie poor people. Electricity itself presents another problem in that sometimes (yesterday) power is off for up to eight hours at a time, frequently, and for various and any reasons. The price of power is also an item, meaning the system design is that much more important - do you have any idea if air pumps are a good way to move a fair bit of water if close attention is paid to differences in elevations between tanks and beds?

[Earl ward]

No sore point just interested on what other people are using. As far as the billboard tarps being connected, here is a site for used tarps they have many sizes and are connected together, as far as the DBB mine has been out side for the summer unpainted and is as blue as the day I bought it, not used as a raft just insulating the tank, it will be cover when I get the time.. I use a media based system with ebb and flow, use the billboard tarps as a liner for the media beds built with 2x12 lumber. Here is the link
http://www.billboardtarps.com/

ericjf7 said:

Lo Earl, I realize that I may have opened up a sore point, and that we are all interested in doing it the best possible way we can. The only answer I can give as to what I'm using is that I'm in the (intensely studying part) of the planning process, much the same as many others who have written in, thrilled with the prospect of doing this, also having a considerable background working with construction materials, and the hazards that various plastics are bringing into our lives .

I also know that I have had scrap pieces of uni-cellular material that was used to cover some large commercial swimming pools at a ski resort, some of which have had direct outside exposure to all kinds of weather for about a ten year period, this includes summer and winter. This is a closed cell material, bright blue in colour, fairly sealed on both surfaces (smooth), and does not appear to be breaking down in any way, very tough material - this is what I am looking for, and thought (know) it was in some of the videos, used as raft material. In waiting for the Auquatic Eco-Systems catalogue, was hoping it would be in there, but don't see it in the electronic version.

While I have the address of the (Minnesota) supplier for billboard tarps, I would be very interested in your feedback on this material, as the most likely scenario with my (planned) system will be (80' long) media beds in trenches with prefab concrete slabs ( 16"x48"x2") making the sides, and a liner, or all concrete, yet to be decided, as I won't get to the site to actually build till later in the year - so far it is only what can be gleaned from the computer. So far I own a tremendous debt of gratitude to all who have contributed to the incredible body of information that is out there, and to the contributors on this site, and am only trying to add my little bit. To this end I can't help but feel that any discussions around the materials used are ultimately very important, particularly as we are striving to produce good food.

[TCLynx]

I don't know about the billboard material but I've been told that durra skrim can be heat welded and that they recommend welding it using a hot air welder instead of a wedge welder.

One note. The Durra Skrim obviously can get the organic certification (at least Friendlies did it.) If using the old billboard material, that might pose an issue to commercial organic certification since one might not know exactly what was used on a used billboard.

For private purposes, I figure the billboard material is probably no worse than many of the other things we use so it's better to use it than let it be thrown away.

[Sahib Punjabi]

Sincere "Thanks" Earl. Great link :-)

Earl ward said:

No sore point just interested on what other people are using. As far as the billboard tarps being connected, here is a site for used tarps they have many sizes and are connected together, as far as the DBB mine has been out side for the summer unpainted and is as blue as the day I bought it, not used as a raft just insulating the tank, it will be cover when I get the time.. I use a media based system with ebb and flow, use the billboard tarps as a liner for the media beds built with 2x12 lumber. Here is the link
http://www.billboardtarps.com/

ericjf7 said:

Lo Earl, I realize that I may have opened up a sore point, and that we are all interested in doing it the best possible way we can. The only answer I can give as to what I'm using is that I'm in the (intensely studying part) of the planning process, much the same as many others who have written in, thrilled with the prospect of doing this, also having a considerable background working with construction materials, and the hazards that various plastics are bringing into our lives .

I also know that I have had scrap pieces of uni-cellular material that was used to cover some large commercial swimming pools at a ski resort, some of which have had direct outside exposure to all kinds of weather for about a ten year period, this includes summer and winter. This is a closed cell material, bright blue in colour, fairly sealed on both surfaces (smooth), and does not appear to be breaking down in any way, very tough material - this is what I am looking for, and thought (know) it was in some of the videos, used as raft material. In waiting for the Auquatic Eco-Systems catalogue, was hoping it would be in there, but don't see it in the electronic version.

While I have the address of the (Minnesota) supplier for billboard tarps, I would be very interested in your feedback on this material, as the most likely scenario with my (planned) system will be (80' long) media beds in trenches with prefab concrete slabs ( 16"x48"x2") making the sides, and a liner, or all concrete, yet to be decided, as I won't get to the site to actually build till later in the year - so far it is only what can be gleaned from the computer. So far I own a tremendous debt of gratitude to all who have contributed to the incredible body of information that is out there, and to the contributors on this site, and am only trying to add my little bit. To this end I can't help but feel that any discussions around the materials used are ultimately very important, particularly as we are striving to produce good food.

[Giorgio]

I'm still learning how to use this forum...I had a comment and I don;t see it anywhere.
I'm interested in the raft because I need to expand my system and I don't want to use the HD EPS boards, I know in Oahu some people are using luan plywood attached to some pvc pipes so is suspended above the water which suppose to help oxyganate the roots. I ordered some luan from HD today and will get some food grade epoxy and some pool noodles and play with the concept

[Michelle Silva]

This sounds interesting. I am just preparing rafts for my system and although started w/ the 2" EPS still would love to find an alternative. However,, I'm not understanding how suspending over the water works, especially when the plants are in the beginning stages (b/4 roots are long enough to dangle out).
I just planted some seeds today and if I expect to place them on the system at around 3 wks. I would think they wouldn't be able to wick up the water.
Also, I would think there would be less insulation, more debris in tank and the underneath sides of the EPS boards are supposed to be great biofilters..supposedly the good bacteria builds up on the under side of the rafts when they are on the water.
Michelle
Giorgio said:

I'm still learning how to use this forum...I had a comment and I don;t see it anywhere.
I'm interested in the raft because I need to expand my system and I don't want to use the HD EPS boards, I know in Oahu some people are using luan plywood attached to some pvc pipes so is suspended above the water which suppose to help oxyganate the roots. I ordered some luan from HD today and will get some food grade epoxy and some pool noodles and play with the concept

[ericjf7]

I have written AquaticEco.com to try and get information about the preformed rafts as shown on page 3 of their current e-catalog, but don't expect to get an answer until early next week. These appear to be of the thin 1/2" closed cell material specifically designed for this application. For those not familiar with this catalog, it is downloadable as a PDF from their site - it is however very comprehensive, a full 425 pages, so may take a while to download. This is the only picture of these rafts, with no further mention, or prices elsewhere in the catalog. The search continues!

[Michelle Silva]

Those rafts are very nice looking. They look similiar to something that I inquired about a few months back form a Taiwainese manufacturer (I had posted a video of them in use). I think it came out to be something like $5 a net pot!. Even if 1/2 or 1/4 that price, on a smale commercial scale would be way too cost prohibitive for me! It would be nice if these were affordable. I wonder why they don't post it as an item for sale.