Large Vat construction ideas

raaden · #1 05/01/2007, 10:01 AM

As most of you know my fiberglass vats have pretty much fallen through and with that I am searching for ideas on how and what to make them out of. I will be honest and say that I am not sure that any of my ideas are any good or if there are better ideas out there so that is why I am starting this thread. I am hoping that like most of the other things we can brainstorm together and come up with a great idea.

First off the construction criteria are as follows. [list=1][*]They need to be pretty big >400g [*]They need to be constructable inside the greenhouse as the structure is mostly complete and the entranceway is ~60" wide by ~7' tall[*]They need to be able to last somewhere in the neighborhood of 3 years without significant deterioration. [*]They need to be pretty strong espcially on the sides and bottom the weight will be pretty intense (400g = 2 tons)[*]Depending on the solution they can/will be framed with lumber for the base and sides[*]Costs should be in the neighborhood of ~$.50-$.75/ gallon[/list=1]

The ideas that I have come up with are as follows:

fiberglass: have not been able to locate a reliable source that is within (or even close to) the budget
Ceramic Tile/Grout: I have questions about the grout seams holding up under the weight pressure of the tanks and the liner is relatively expensive
Wooden Frame with pool liner/pond liner: I have concerns about the liners ability to hold up under the conditions and saltwater for the needed time frame. Pond liner only comes in black and will not work for summer use.
Wooden Frame with portland cement sealer. This is a real possibility and if I resize the tanks I can get to the bottom end of the budget. The downside is the curing time before the vats are usable
Wooden Frame with epoxy and or marine paint sealant. This one is also very doable and at the bottom end of the budget, but I have concerns about the durability and leak-proofedness of this long term.

I am sure there are many other options that I am just not thinking of and this is where I hope you all can help me out. If you have any ideas or just want to weigh in on the ideas I already have please let me know.

You can also send in your ideas via this page if you don't want to post openly on the forum.

mbunaman · #2 05/01/2007, 01:45 PM

I have seen Koi Dealers make vats out of cinder blocks and then coat it with a special pond epoxy to seal the blocks and mortar. So I assume the base is concrete with the blocks built around. Something to think about.

jrodscout · #3 05/01/2007, 07:38 PM

Im going to build my tanks out of wood covered in fiberglass. the guy at my local fiberglass supply has a 900g test tank w/bulkheads in operation for 9yrs.
You can custom build any size or shape you want & apply 3layers of glass.(1 mat,1roven woven,1 mat)
Spray or roll gelcoat.
I just water tested a 48"h x 30"w x 96" long wood with epoxy design & it worked well.The major downside is a pinhole leak will eventually seperate the plywood.

raaden · #4 05/01/2007, 09:07 PM

I wasn't aware that there was a liquid pond epoxy. That looks like some good stuff. Not too expensive and depeding on how I lay out the lumber it might be within the budget.

My hesitation with doing my own fiberglass is that I have never done it and like you said a small leak or crack and the whole thing will rot away. I think if I could do the fiberglass I could make the budget price, but I am just not sure how it will turn out. I might still try it once I get the initial 3 tanks built just to see what happens.

I think at this point I have to calculate the lumber costs for a fully framed vat and see what I have left.

A.T.T.R · #5 05/01/2007, 09:20 PM

dig ahole and put in pondliner?

build a brickor concreat block box and put pond liner in it ( maybe push some dirt onto the side for more support)

laverda · #6 05/01/2007, 10:48 PM

I would think a boat builder in your area could buld fiberglass vats fairly inexpensively. Then you could have them built with a lip built in to hold the egg crate in place and add strength.

raaden · #7 05/02/2007, 08:31 AM

Last night I looked up some fiberglass supply places and just to buy the supplies needed to build a fiberglass and wood box would run in the $4-500 range. Apparently fiberglass supplies have gone up quite a bit in the last 18 months from what I have heard. I may still give it a try on some of the expansion tanks, but I will have to find another solution for the initial set (3) of tanks.

The issue I have with the sheet pondliner is the fold and crevices that will be difficult to clean and keep from being detritus and muck traps. The liquid pond liner seems to be a great bet right now. I will be contacting a few of the companies to see what sort of volume discounts I can get and more information on the product and whether it will suit my needs.

The liquid pond liner also got me thinking about some sort of sealer being used with the concrete to make the walls of the boxes. Marine Paint and tank sealer were the first ones to come to mind. I will be investigating this as well.

eastcoaster1 · #8 05/02/2007, 01:30 PM

One thing to keep in mind with epoxy is that it needs to be protected from UV. I've built a number of wooden boats that were covered with glass and epoxy, and unless you coat the epoxy with varnish it just won't hold up to the sun.

As far as the plywood delaminating if it gets wet....there is marine grade plywood that is made with waterproof glue. It usually goes by the name of okume.
Another benefit is that it comes in 4x8, 4x10 and 4x12 sheets - which would allow you to make longer tanks without worrying about seems.

slevesque · #9 05/02/2007, 09:12 PM

I have no idea how much it costs but someone was looking into Formica, or Arborite few weeks ago to linned a plywood tank. Acrylics approved.

jrodscout · #10 05/03/2007, 12:38 AM

The pinhole I was referring to was the plywood tank painted with sweetwater aquaculture epoxy.The corners were sealed with silicone.Fiberglass wont leak.If I've built racing sailboats here in CT if you want to talk about details pm me.
Jerred

ctenophore · #11 05/03/2007, 10:54 AM

I use fiberglass with a foam core. I am having a mold built for my next set of tanks, they will be 10'x6'x18". No word on price yet, though. My main GH is in Gainesville FL, but I am currently in Maryland building another GH. So I will be transporting tanks up the coast. I will send you a PM with my contact info in case you are interested in this size. Personally I wouldn't go with anything except fiberglass/foam. The foam is R-13 and our existing tanks have demonstrated excellent thermal performance during last winter. They are more than .50/.75/gal but IMO the only way to go.

Justin

redox · #12 05/03/2007, 04:58 PM

you need to find another fiberglass guy. There has got to be another one! look for a fiberglass tech school. The vat constuction is so easy with the right tools. You might have to pay extra for the form but its well worth it. Brian I wouldnt use anything other than fiberglass with gelcoat for the vats. .

redox · #13 05/03/2007, 05:06 PM

also any of those solvent based sealers can leach stuff even after they have cured,trust me I looked into it

I was going to make my own and found the guy that finnaly made mine. If you still want to make you own you will need marine plywood and resin and the right cloth and plenty of ventilation durring the whole nasty process

ctenophore · #14 05/04/2007, 08:07 AM

After seeing what my fiberglass guy works with and how it smells in his giant ventilated shop, I won't work with the stuff. The solvents are strong carcinogens. This is one project that is best left to somebody else, even if just for the health reasons.

raaden · #15 05/04/2007, 02:59 PM

Lots of great info on this so far.. thanx all

I can still say that fiberglass would be my first choice. I may still have to go with another option for the first batch, but I do think I will look to fiberglass after that.

As far as the UV goes I should have little to no UV exposure inside the GH as the coverings are supposed to block >80% of UV sources, then you also can figure in the water blocking most of the rest.

I have also considered many different types of coatings (Corian, Rhino Linings, Formica, polyester resins, epoxy coatings, and numerous others) and while most of them have the potential to work (Formica is the exception, and will delaminate under extreme pressure/expansion strain) they are just too expensive ($6-10 sq ft.) to consider at this point.

I have looked into a few of the "aquaculture safe" epoxy coatings and they do look promising in particular is P0nd Arm0r, flakecoat and the Sweetwater Epoxy, and all of them state that they are safe for potable water/livestock storage. I am trying to decide if that is enough though.

I will look into the fiberglass school as I think the Tech College nearby might teach that. Hearing what you all have said I will probably not try to make my own, unless I can get into a fiberglass class.

I am still going to investigate other options for the time being while I wait on responses from some.

crazzy · #16 05/04/2007, 04:59 PM

Why not try to find those (48"X48"X48") stacking heavy duty food usable square bins. Some reefers have used them in the large reef tank section as large sumps. New, they are about $300.oo for 400 gallon capacity. Easy to drill etc. Indestructable!

Meisen · #17 05/17/2007, 07:27 AM

I did a home made 400 G indoor pond back about 20 years ago.....we used 3/4" plywood with 1 X 3"s to frame it out. Instead of spending 100s on an expensive liner, we just bought one of those giant $35 poly tarpalin liners and quadrupled it up. Inside we polysealed all the wood and ran over all the seams with wood glue. No leaks for almost 10 years while it was up and total cost back then was around $100 or so. You could still probably build them for under $200.

Only thing you might want to do differently is to coat the wood that will in contact with the ground as well. Heck, you can even hedge your bet and use marine epoxy on the insides in addition to the liners. Then you have virtually no chance of getting leaks thought the epoxy does increase the cost significantly.

Only other downside I can think of is that they do take some time to make....figure probably 3-4 hours each. Perhaps you can hire some local college kids to build them in a weekend?

Oh and the folds in the liner....they shouldnt be a big issue if you wait to pull it taut as you fill it.

Meisen · #18 05/17/2007, 07:32 AM

Oh and to follow up on eastcoasters comment.....You do have to watch epoxies exposed to UV light.

there are both UV resistant epoxies and additives you can put into the mix that increase UV resistance. Using one of the waterproofing exterior epoxy paints in white would be your best bet unless you are trying for heat absorption. I think AE has a whole bunch of things along this line in stock however they are probably cheaper elsewhere. West System does a whole line of fairly straighforward products. I have had very good luck using them in a variety of applications from boat repair to exhibit fabrication.

raaden · #19 05/22/2007, 08:55 AM

Well, I finally gathered up a plan and have made the first batch of vats. They are framed up and ready to be coated. I ended up making them 8'x6'x30" and used pressure treated 2x4's 12" on center all around for bracing and 3/4" OSB for the walls. These things are built SOLID, and I am pretty sure that the entire greenhouse could collapse on top of them and they will still be there smiling at me :P. I am going to try out a couple of different things to seal them up, one is a standard epoxy and the other is a plastic rubber compound.

I looked into lots of different commercial containers and just couldn't find anything that: seemed like it would work for what I wanted, and was economical on a $/sf growing space consideration. The vats I built are going to run somewhere in the neighborhood of $250-300 and will offer ~475sf of growing space. I couldn't find anything that was even close to that number. The other big thing is that I can build all of the drains and returns and "factory" seal themdirectly with the epoxy or other coating that way there should be no seepage through any bulkheads. I can also run the airlifts on the outside of the vat in the joist runners so that I save a few sf of grow space.

I am going to stay away from fiberglass epoxy as they will have to be coated in the greenhouse, and I am afraid of what those chems will do to the plastic in the gh. I am also going to stay away from those EPDM liners as I am afraid that with all of the activity in the vats they will begin to abrade over time and the corners will eventually crack.

This is all a first run and I am sure that I will revisit this again once I have used them for a while and change many things for the second batch.

Appreciate all of the responses and will post some pics once they are all sealed up and (hopefully) holding water.

Ken668 · #20 05/22/2007, 09:42 AM

Raaden, have you looked into the Sanitred brand products? When I was researching creating vats, I was referred to them. While I didn't end up going that route, it did look like a viable option. Not sure on the pricing compared to the other products you were looking at.

http://www.sanitred.com/

storrisch · #21 05/22/2007, 12:09 PM

http://www.rcpworksmarter.com/rcp/pr...m=507_555_4242

why not just use rubbermaid stock tanks. portable, sturdy, decent pricing.

raaden · #22 05/22/2007, 12:15 PM

I did look at Sanitred, and my first inclination was to use the Rubbermaid tanks. with Sanitred the issues was that for all of the steps and prep work that had to be done I could have just gone with Fiberglassing the frames. I still have them on my list of alternatives along with a few others that I will try if the first coatings don't work.

The problem with stock tanks in general are that they only come in dark colors, and odd/round shapes. The dark colors will not work as they will suck up too much heat in the summer and reduce the upwelling light that many corals love. I may use the stock tanks in the winter to collect heat in my makeup water to help with heating, but not for the coral tanks. Another is that i would lose about 33% of my growout space if I went with round tanks instead of square.

MoCha920 · #23 05/22/2007, 05:22 PM

dont forget to use fine weeves to fiberglass these vats

Whaledriver · #24 06/09/2007, 09:45 AM

You should see if OSB works as well as marine grade plywood. I would take into consideration the strength when wet. You will have high moisture and some leaks along the way so you might look into it.

raaden · #25 06/10/2007, 04:36 PM

From what I understand OSB makes a little more sense than regular plywood, mostly becuase there is more glue, but marine plywood would be a better choice. It is also much more expensive, and I believe OSB will work pretty well. I am painting it all around and that should help as well.

I will be using a fibreglass tape (very fine weave) to seal the seams of the epoxy tank and a thick rubber/fabric tape to seal the seams of the other tank.

I should have some results of the both by the middle of next week. I should get delivery of both coatings by the middle of this week, and will set things up to work on them this coming Saturday. I will let ya know soon how things are turning out.