Backyard Aquaponics
A place to discuss aquaponics

I'm having trouble finding an inexpensive fish- and food-safe, waterproof finish for more than a few wood boards (30 4'x4's). Two part epoxy would cost me $1000 for the amount of boards I would like to cover. Having them sprayed like a truck bed liner with polyurea would probably be as expensive.

Bitumen paint (like what Jaymie and Axl use) is not available in the USA as far as I can tell. The only "asphalt paint" I've seen so far has no mention of food-safety, it seems to be for painting driveways.

If anyone knows of a good inexpensive but effective way of sealing a bunch of wood boards (more than 30) that would be great to hear! These would be getting AP water drained on them all the time. Not submerged but very wet.

I like the look of Durapond but can`t find any USA stockist.
Maybe this stuff ? a gallon covers 60 sqft.
Says it can be used for lining metal water tanks but no info whether its fish safe or not.
www.durabakcompany.com

Everything I have found is so expensive that I decided to stick to pond liners.

Here is a 2 part paint
website

$79.95, covers 60 square feet (1.33/Sq foot)

Then for $840 you can use a spray in foam liner, also fish safe. Covers 75 Square feet at 50 mil thick.




I have seen the city painting the inside of large water tanks with something, but I dont know what.

Dave have you considered using a wood that would hold up to the water and not need treating? Cypress can stay wet pretty much forever. It can even stay submerged.

Hey JPM, I am ignorant but learning . Cypress is a good idea, but I would have to check on the cost; it would at least have to be shipped from somewhere non-local. Any other water impervious woods besides cypress?

Have learned about turpenoid or citrus-based thinners, and linseed, tung, and mineral oils so far.

Have been thinking about wrapping in pond liner, still collecting info.

try Wattyl Estapol 7008 , I got 20L ( 10L part a + b ) for about 70 bucks , to do 2 kitchen benches , food safe from all the reading Ive done

I managed to cover about 4 square metres , with 2 coats , using about 2 litres of the stuff . Its more of a finish for the great look that it gives , almost like a glass coat ( actually , thats another product I was looking at - "Glasscoat" from the US ) but it provides an solid barrier on top of the wood

It REALLY stinks when its wet , but its completely inert when dry . Dunno if wattyl products are available in the US

If not , its a post - catalyzed laqcuer , I suppose theres other companies making the same sort of stuff

I wouldnt use minerals / turps / tung oils if the waters going to come into contact with the fish after coming into contact with the wood

Thanks for the info B, why not use tung oil?

The MSDS (material data safety sheets, just learned about those yesterday) go on for two pages with that stuff:

http://www.wattyl.com.au/Applicators/MT ... ductId=555

Edit: Having some luck googling "NSF 61 paint". NSF 61 is the regulation covering potable water tank coatings in the US.

yeah , the wattyl stuff is pretty toxic in its seperated form , but its a catalyzed lacquer , once the reaction has occurrred it dries and becomes a solid

I read up on different wood coatings when I was doing my kitchen bench , it HAD to be the best possible food-grade coating , cause Im eatin off it . im pretty confident Ive used the right thing

only problem in your case is that it may not be UV resistant over a long period of time . mines not in the sun , so it will last ages . Now just got to get a certain someone to stop draging pots and pans across my beautiful glasss-like surface

Just got a reply from Dwayne with Real Milk Paint here in Pennsylvania. He recommended using the right wood as well. He suggested black locust, and I quote:

>
The Amish say it lasts "Two years longer than stone "
<

Uh-oh, from wikipedia:
"In fact, every part of the tree, especially the bark, is considered toxic, with the exception of the flowers."

Food Safe wood finishes:

http://www.taunton.com/finewoodworking/ ... x?id=26893

Not very relevant but cool, pre-impregnated water-activated fiberglass material, NSF 61 approved.

http://www.airlog.com/FACS/FACS%20Aquawrap.htm

Thanks JP, I'm dozens of pages back of Google searching now. Read that one yesterday.

One way of preserving wood in the presence of water without negative consequences for AP seems to be citrus-based "turpenoid" as a thinner and oils like tung or linseed oil in multiple coats.

I know hemlock seems to survive a long time in water and it does well as siding. Up in Michigan we pull lots of old edge boards from the late 1800s earily 1900s out of Torch lake to use in the garden.

Here are a couple more you may want to look at.

Sani-Tred and Ames waterproofing products.
The Ames material comes in 5 gallon Buckets and you get about 100 square feet per gallon.

I know two people that are using Durabak and Herculiner for fish ponds. Both were painted over existing concrete ponds and neither has experienced any major problems.

Robert

here in Australia Cypress is toxic to fish, not sure if it is the same species in the US.

Didn't Doug Basberg use some bitumen paint for his big tanks?