Looking at extending the height of my new tank, thoughts?

[Markpd]

For those who don't know, I recently bought a 2nd hand 7ft tank for my boys. They recently declanned a 2nd time , so I'm having to permanently split them in their tank and they now have 1/2 of a ~4ft/120cm tank each (not ideal), hence getting the ~7ft/206cm tank (which will also be divided, and ultimately I'll be selling the 4ft tank).

Anyway, the 7ft tank was advertised as 20"/51cm high (same as my 4 footer) and 18"/46cm wide (2"/5cm less than my 4ftr), but it isn't! It's just under 18"/46cm high and 16.5"/42cm wide! (so 3.5"/9cm narrower!!), and I might not be able to get the platform in it!  Although the ebayer offered me another tank for free in recompense, it's too much time and trouble to get and swap.

I can't doing anything (realistically) about the width, but I can extend the height (which I was thinking of doing for my 4ftr anyway, so they can have deeper bedding and not kick it out the tank! ).

My plan is to have a 6"/15cm high perspex screen to sit on top of the edge of the tank (so yes it'll have to be precisely made), this screen will be made in 2 halves (for easy of transportation and removal). Each screen will be the shape of a rectangle measuring (roughly speaking for ease of description) 6"/15cm high, 18"/45cm wide and 3.5ft/107cm long, and sit directly on top of the edges of the tank.

To secure the extension screens to the tank (to stop it sliding off etc), I have 2 ideas, and I'm not sure which to use atm.

1. On 3 sides of the screens screw on lugs on the outside and protruding downwards (made from perspex, say 2"/5cm square), for the 4th direction I could either clip the 2 screens together or screw wooden battens to the inside of the outer ends (wooden, because it can be safely chewed). I would also have to put a wooden batten across the middle of the tank to protect the inner edges of the screens.

2. Make 2 wooden rectangle frames that sit inside the tank edges on the ledges, and then the perspex screens could just sit on the outside of them on the tank edges. Or I could screw the wooden frames to the perspex screens.

From the point of view of how much work I'd have to do I prefer option 1, but, for it not to leak bedding the edges of the tank and perspex would have to be nearly perfect aligned .... Although these edges won't be submerged in bedding (planned bedding depth is ~12"/30cm), it would need to be at least mostly bedding leak proof for when they kick the bedding up, or manage to pile it up to the tank edge.

Re option 2, if I screw the frames to the screens then that would be a far better seal and prevent any bedding leaking between the edges of the tank and screens, and the frame and screens. But it would be a lot more work! Perhaps I could bond the frames to the screens? (with aquarium grade silicone sealant). But I don't know how well silicone would bond to wood?? Anyone know?

Btw I'm thinking of having the perspex screens being made locally at a plastics fabricator, so it's accurate and cleanly finished off (and saving me time). But I've no idea on the cost of that yet! I'll be getting a quote soon, if it's too much, a friend of mine said he will help me DIY it.

I'll be making mesh lids to go on top of the screens (raised lids if the screens don't give enough clearance for the wheels).

Any other thoughts? (solutions or problems! ).

[edit] I thought I remember reading about a year ago that a tank shouldn't be taller than it is wide for air circulation reasons, but I don't recall their being any solid info behind that claim, and I can't find where I read that in the 1st place now either!

[edit 2] A 3rd suggestion by a friend is to use I/H aluminium channel/beam, a great idea as I can then just slot the perspex boxes into the frames on the cage! . Now to see if I can actually get some for a sensible price....

Summary of cage size (LxWxH) ~206 x 42 x 45cm (1cm thick glass).

[LilyandDaisy]

Would it be better to make the height extension out of mesh (so a topper basically) because realistically, you aren't going to have bedding in the top 6"? Storm's tank is about 18" tall (shorter than I'd like) but with the cage on top of one half I find I can get a good amount of bedding in, and I don't get any kicked out either. I also don't get any bedding kicked out of Lily and Daisy's tank which also has a mesh topper. I even managed to use the top of a hamster cage for Storm's topper rather than DIYing something.

This is Storm's tank. I could have the bedding a lot higher than it is in the photo but it was taken after cleaning it out and I think I ran out of bedding.



I read on some Dutch gerbil websites about a particular height to width ratio they use for building enclosures. IF it's too tall for the ratio they put a ventilation grill in the back. But I wouldn't think it matters too much when we're talking about 6".

I don't think silicone bonds to wood at all. If I were going with the perspex idea I would probably make square wooden posts for the corners and glue + screw (both for extra strength) the perspex to them. I glued metal corner profiles to wooden posts for Lily and Daisy's tank and they bonded very well so I think silicone would be ok. I'll have to check which glue I used but it was a solvent type, so make sure it's not in any areas where the gerbils could chew and let it cure before putting the gerbils in the tank. If you have the perspex custom cut they can often drill holes in it for you as well so you don't risk shattering it. I think you can also buy acrylic square rods so you might even be able to use that instead of wooden posts.

[Markpd]

Sorry for the belated reply, don't seem to have much spare time atm! (e.g Corked lined and plasticoted the new 12" tictac wheel past 2 evenings, and partly made a new platform Saturday afternoon).

Anyway, no I can't make it out of mesh, even with 8" of tank height over the bedding my boys manage to kick out some bedding over the top! Perhaps my boys are more energetic diggers than your girls?
I see your girls platform is at the end of the opening, this will stop them kicking up the bedding high, and out, as it does at one end of my boys tank.

So hence going for perspex screen, I've been thinking on and off about doing this for my 4ftr tank to give them deeper bedding and keep all (hopefully!) of it in, but never got around to it. Now that their new tank is 2" shallower I need to do it to avoid having shallower bedding, and I want to add some extra height to allow deeper bedding.

Yea a couple of other people I've since spoken to have also said silicone won't bond to wood.

[LilyandDaisy]

None of my gerbils are very energetic diggers actually, especially Storm. Perhaps that's why I've never had a problem with bedding being kicked out. It might also be because I use 6mm mesh and my bedding (Fitch) has fairly large pieces, which can't really pass through 6mm mesh.

[Markpd]

Ah yea, that makes sense, and I (to date) have used hemp bedding which is much smaller pieces. Whilst their lids are 1/2" mesh, I have put much finer mesh (3.5mm IIRC) in the corners opposite the platform, and over the fans. Most of the bedding gets kicked out in the ctr between the fine mesh.

Btw, I've got a quote from the local company.

Hi Mark

Please find our price and delivery below:


2 of Clear Acrylic 4-sided boxes to Sketch £90.00 each + VAT

Lead time 4 - 5 days from receipt of order

Carriage These would need to be collected unless you are local to us then we can deliver in our van.


Kind regards

Kate
Aquarius Plastics

If that's a typical price I'll be DIYing it at £216 all in!

[Markpd]

Omg!

2 off Boxes as above 5mm clear perspex @ £135.00 each + vat

Collected.
We are in South Croydon.
Let me know.

Kind regards
Ian Thompson

Thompson Plastics Ltd

And from cutmyplastic.co.uk


Hi Mark,

Thank you for your email.
​
You are looking at around £125.16 for this these 8 sheets of plastic. I hope this helps and please do let me know if you require anything else. To go ahead with a quote we will need you to confirm all dimensions.
​
Thank you
Kind Regards,

Much better, but still a lot of money!
My work has some unused sheets of perspex they want to get rid of, so I'll see if they're big enough and how much they want for them, then DIY it (with help!).

[LilyandDaisy]

Custom cut acrylic can be really expensive. Have you considered making 3 sides out of plywood and just the front out of acrylic? It might be a bit dingy but cheaper.

[Markpd]

Yea some of the prices are bonkers!
I did wonder about doing that actually, I'm not keen on the idea, but I haven't ruled it out yet either.
My work only has enough perspex for one 1/2 of the tank, and I don't know the cost yet.

[Markpd]

I've had a bit of luck with the materials at least, the sheet from my work is enough to do all 4 lengths, and they gave it to me for free*!
And the spare sheet my dad has is enough to do all 4 ends (and some), and he doesn't want anything for it either

Now all I've got to figure out is, if (with help) I/we would be able to cut it straight!

*Well, I almost certainly will owe some kind of favour at some point, I don't know what of course!

[yeti218]

Cool! Cant wait to see how this comes together.

[Markpd]

Had been put on hold whilst I was sorting out docs for holiday, and on holiday.
Hopefully I can get back on it soon, once I've sorted out the nightmare problems we've been having with covid tests post holiday.

[Markpd]

Finally back onto this after sorting Covid bureaucracy end of last year, then a Hybrid vehicle assignment, then sorting out various trips in May/June along with day to day stuff, following by forgetting about it!

I still need to get rid of a load of stuff to put the cage where I want to, I did manage to sell off some old CB radios and old car stereos earlier in the year, but it's the old car mags taking up loads of space! (that reminds me, I finally had an offer for them....).

Anyway, a 3rd suggestion by a friend is to use aluminium H channel, a great idea as I can then just slot the perspex boxes into the channel frames on the cage! . Now to see if I can actually get some for a sensible price.... [edit] finding the right size turns out to be the harder part! Found quite a lot of H channel that has 9.5mm gap or much bigger, but none that are 10+ to 12mm! (remembering the glass is 10mm thick).

[Markpd]

Finally making head way with this, it has been an absolute headache to find something to slot onto 10mm glass!
As noted above H channel/I beam just isn't made at a suitable size for 10mm glass (at 8mm you'd be fine!).

I eventually stumbled across H clips (aka panel-edge clips), which in the US are commonly used to support plywood boards when used for roofing, walls and floors (the clips are actually required by regulations in some areas).
So whilst H clips are easy to find online in the US, they're nearly as rare as hens teeth here in the UK! I found a single seller on Amazon at the time (early November) who had these clips, and 2 on ebay (1 of which was the same company, KFZ). And even KFZ only had 2 packs of the 12.7mm ones I needed! (now out of stock btw).

But using these clips alone probably wouldn't secure the perspex sheets very well, so I also ordered some ally U channel. I will bond the U channel to the bottom edges of the perspex boxes (using a few short blobs of silicone sealant, no need to do the whole length I think), then the U channel slots into the H clips and the H clips sit on top of the edge of the tank. Oh, further complications, because the tank has ledges on the inside, approx 6mm down, I had to trim the inner legs of some clips down to ~5mm so that they could seat. And, because of the (small) thickness of the clips I will have to apply sticky foam tape to the channels, in between the clips.

Hmm, I may have another problem, I was going to use silicone sealant to glue the perspex sheets together, many (but not all) websites etc say silicone won't properly stick them together!.....

[iamplankton]

How about a hot glue gun? I’m not sure it’ll work but might be worth a shot?

[Markpd]

Maybe, although I don't have one. I'll look into that, and I'm going to watch a youtuber (King of DIY) doing an acrylic aquarium build