Backyard Aquaponics
A place to discuss aquaponics

I just did some reading and apparently 3M make a structural acrylic adhesive that is designed for HDPE and other plastics, so it might be worth looking into.

I've never used them but supposedly they are designed to be strong enough to compete with poly welding, so it might be worth trying (although I think what you have done would most likely be sufficient Sophia)

3M Scotch-Weld Structural Plastic Adhesive DP-8005
http://solutions.3m.com.au/3MContentRet ... =ImageFile

3M Scotch-Weld Structural Plastic Adhesive DP-8010
http://solutions.3m.com.au/3MContentRet ... =ImageFile

Thanks Azira!

I'm struggling to find somewhere that sells the 3M Scotch Weld adhesive... The only place I found sold it in 5kg cartons for $300!

The sun is supposed to come out tomorrow so I will fill up the tank a little and test its watertightness.

I've been wracking my brain trying to think how to make a base to support the inverted rainwater tank top.

Originally I was going to remove bricks to make a depression in the floor of the shed - but it turns out the bricks are cemented together.

So I was thinking of buying a kids paddle pool like the one below, sitting the tank in it and then packing sand into all the crevices created by the conical nature of the tank before filling the tank with water.

What does everyone think? Would this work? (Kind of excited about the fun element this base will add to the tank too!

The diameter of the tank is 1.4 - the diameter of the pool is 1.5

The depth of the pool is 25cm

I'd be worried about it's durability long term. It might work out to be best to just chip out the bricks (although not as fun!)

Crap. What if I sacrifice 20cm of the FT and cut a ring that can fit around the base, bolt it to the bricks, fill it with sand?

I have been doing some maths and I think I have to chop my ST IBCs as my pit is not deep enough and with a 50cm growbed on top the total height above ground level still comes to a whopping, way too high 127cm! I would have to build a step so I could garden!

If I have 4 Growbeds that are 50cm deep and capable of holding max 250litres of water (after media is added - 250L represents 40% of their total holding power) then I only need the two STs to hold 1,000 liters minimum right?

Each IBC bladder is 100cm high, if I slice each ST so they are max 60cm tall that will drop the height of the GBs to a much more manageable 85cm off the natural ground level more or less.

Two IBC STs 60cm high will hold 714L of water each... Surely this is ample volume?

..
And there is another one. 800.. and I know that it sticks to a hdpe.. about $30 a small tube
I know because I have used it for years, sticking seals into washing machines.. hdpe tubs
But.. what does the PDS say about its safety.. ie chemicals that might leach into the water..
Its one thing for use in a washing machine and another for a large quantity in a fish tank....

You can reasonably think that I went through this whole process.. proof being similar questions in posts... but I decided that welding was the chemically safest. Solution...!

You can try some of those Scotch Products but the uncertainty of toxic chemicals, becomes far more serious than IF it will stick..
..
.

[quote="SydneyChick].....Originally I was going to remove bricks to make a depression in the floor of the shed - but it turns out the bricks are cemented together....]
Have you determined what is under the bricks?
Do you have an angle grinder and diamond blade..
Do you have a big hammer..

Normally a reasonable paving job would start with wackered road-base, which should be able to be removed..

You DON'T cement Pavers atop concrete..

I was thinking the same thing BuiDoi. If the silicone seal fails I'm going to haul this puppy out to the plastic welder in Merrylands.

I'm starting to think this half of the tank is more trouble than it is worth! Anyone want it? Lol!

For $20 I can get an IBC that doesn't need a special frame built for it. True that its rectangular and not circular - but at least it would leave enough room in my small shed to walk around and check for leaks etc.

Just thought of an alternative use for the kids wading pool - FT cover! Just flip it upside down!

I'm in on this late, sorry. I've had fantastic results using butyl tape sandwiched between two solid frames. In my plastics fabricating experience HDPE is about as tough to deal with as any plastic. While butyl tape doesn't actually stick to the polyethylene either, it never dries. so by using it between two frames that are bolted it'll last for a very long time. Butyl tape is used to seal portholes in boats and ships. Normally it is between fiberglass and a metal strip, but I found that it also works between two hard plastics strips just as well. You need to be vary careful tightening the bolts and do it in a pattern like tightening lugs on a wheel. Then cover the bolts with an fish safe sealant.
http://www.seabreeze.com.au/forums/Sailing/General/Butyl-mastic-in-Australia/
FYI it is cheap here, don't know about there.

Well yesterday I popped the empty steel cages of the sump tanks into the hole to get an idea of how it is all going to look and fit together.

It's still waaaay too high unless I decide To cut down the sump tanks or make the grow beds shorter.

Now I would rather cut down the sump tanks than the grow beds since filtration is the more important element.

However, hubby does have one good point: If I leave the sump tanks whole, that gives us the flexibility to add more grow beds and/or fish tanks down the line without having to build another sump.

As two whole IBCs gives us almost 2,000 Litres of sump tank and our current Growbeds only carry roughly 1,000 Litres of water if I can somehow rig it so we keep the sump tanks uncut we have enough sump to theoretically almost double our number of Growbeds.

Long story short I am back to digging today to see if I can make the pit for the sumps any deeper.

OMG I hate digging! I really need a friend with a mini loader or a trencher



You can see as things stand, if we keep the sump tanks whole the top would be at waist level - then with a 50cm deep grow bed on top it is just not practical. Ideally I would like to make the sump hole 50cmdeeper but I'll have to see how hard the digging is now we have hit clay.

The clay was so hard and dry when digging the holes for my first system's buried 4500l FT and 2000ST, that I had to use a pick- the mattock just bounced off it!

Ok Gunagulla! Officially making me feel like a weakling complaining about all theis digging!

How did you dispose of all the soil you dug up?

I just mostly moved it sideways a metre or 2 to make a larger flat area at the end of the greenhouse. I think there are pics in the first page or 2 here: viewtopic.php?f=18&t=16345

Take the bases off the cages and it should save you a tiny bit of digging. If the clay is really hard, cover it with a bit of water and let it soak in, then you should be able to scrape it off with the shovel. If I was close by I'd help you dig, it's always easier with company!

Thanks Azira! My friends are lovely but I think it would be a hard sell to convince them to come over and help me dig a hole.

I attacked it again this morning. Made it about 20cm deeper. Not much but it is something. Horrible job working/slipping/sliding in wet white clay but it was fairly soft and easy to dig.

Getting rid of the soil dug up is now the problem - I think this is going to limit me more than anything else.

If my neighbour won't take it the current plan is to mound it up against the IBCs and raise the natural ground level.