Adding hand hole to plastic water tank

[Scooter21]

I want to set up a mixing station with 2 plastic tanks. I don't have a lot of space in my chosen location. The tanks I picked out don't have any large holes for getting my floats inside. I also need a hole to add salt. Id like to cut a 2 or 3 inch hole but I don't know what fitting to use to be able to cap it off. Anyone know of what fitting I could use?

 

[lapin]

I would try to find someplace that has used 55 gallon plastic drums or 250 gallon plastic totes.
They have big caps.

 

[Scooter21]

I would try to find someplace that has used 55 gallon plastic drums or 250 gallon plastic totes.
They have big caps.

I only have a 36 gallon tank. The spot I'm building this entire setup is all of about 2' x 2'. I'm looking at about 20 gallon tanks

 

[lapin]

You only need the cap. They will prob give you one for free. Should be big enough to plug your hand hole in your small water tank

 

[Cell]

Cheap bulkhead with an end cap?

 

[BeanAnimal]

You did not provide the top dimensions. You don't need a tight fitting cap. Cut the hole the desired size. Build a simple cap with few locator pins in it using PVC Sheet, Polycarbonate sheet, acrylic sheet, HDPE cutting board cut to size or even wood with polyurethane or epoxy. You can order the aforementioned plastic products from numerous places already cut into discs.

 

[Pistondog]

I want to set up a mixing station with 2 plastic tanks. I don't have a lot of space in my chosen location. The tanks I picked out don't have any large holes for getting my floats inside. I also need a hole to add salt. Id like to cut a 2 or 3 inch hole but I don't know what fitting to use to be able to cap it off. Anyone know of what fitting I could use?

I have this exact tank for awcs. Used a hole saw for cutting the access hole.
Placed a small pump inside and snake the cord out the hole. If necessary, cover the hole with a flat piece of plastic to minimize evaporation. I never did, but used the water within a couple of weeks.

 

[Scooter21]

You only need the cap. They will prob give you one for free. Should be big enough to plug your hand hole in your small water tank

Who would give me a cap? What cap? The plastic tank doesn't come with a hole, so I'm not sure who would provide a cap

 

[Scooter21]

Cheap bulkhead with an end cap?

There would be no way to get the locking nut on the inside of the tank as the nut is bigger than the hole

 

[Scooter21]

You did not provide the top dimensions. You don't need a tight fitting cap. Cut the hole the desired size. Build a simple cap with few locator pins in it using PVC Sheet, Polycarbonate sheet, acrylic sheet, HDPE cutting board cut to size or even wood with polyurethane or epoxy. You can order the aforementioned plastic products from numerous places already cut into discs.

I suppose I could do this. I was hoping to find something a little more solid

 

[The_Paradox]

Go to a kayak store and look in the bulkhead section. Lots of sea kayaks have 5-10” watertight bulkheads.

Something like this.

 

[BeanAnimal]

I suppose I could do this. I was hoping to find something a little more solid

I don't know what for, but up to you.

 

[lapin]

The tanks I picked out don't have any large holes for getting my floats inside. I also need a hole to add salt. Id like to cut a 2 or 3 inch hole but I don't know what fitting to use to be able to cap it off.

You will cut a hole in the top for salt and to stick your hand in. So why is everyone thinking it needs to be water tight. Am i missing something?
Why wont a cap for a 55 gallon drum or the kayak hole cap work ?
Here are 3 caps
2 for coffee beverage cups and 1 from my 15 gallon water barrel.

 

[Scooter21]

Go to a kayak store and look in the bulkhead section. Lots of sea kayaks have 5-10” watertight bulkheads.

Something like this.

That does look pretty good. I think I'm going to go with this flange I found and then some stainless nuts and bolts and a piece of silicone rubber for a gasket

Valterra T1008 Flanged Valve Fitting - 3" Male Thread https://a.co/d/efvQmYV

 

[lapin]

SS will rust over time with salt exposure

 

[Scooter21]

You will cut a hole in the top for salt and to stick your hand in. So why is everyone thinking it needs to be water tight. Am i missing something?

It doesn't need to be completely water tight but the first suggestions were essentially cut a hole and then cover it when not in use. I'd be more worried about something falling into the tank than water escaping. It's going to be on a shelf with other stuff stored on the shelf and a part of the utility area that constantly has people walking by.

 

[Scooter21]

SS will rust over time with salt exposure

Maybe I should go for some kind of plastic bolts then?

 

[The_Paradox]

Maybe I should go for some kind of plastic bolts then?

You can just use silicone or marine grade stainless. The amount of corrosion they will see is not going to affect anything. I would go larger than 3” though. 7”+ makes filling a lot easier and if you ever need to you can reach in and wipe down inside.

 

[BeanAnimal]

It doesn't need to be completely water tight but the first suggestions were essentially cut a hole and then cover it when not in use.

it does not need to be water tight at all. Yes, cut a hole and cover it when not in use. A simple DIY cap made of any of the materials that I indicated would work. Locator pins or a flange (second smaller diameter piece attached) would prevent if from moving around. You don't need a gasket.

The Kayak bulkhead would work easily too and is inexpensive, but maybe a PITA to open and close, I dunno.

Don't overthink this...

 

[Troylee]

These work great.