# DIY Optiwhite tank build



## Dogtemple

Hi

Ive been lurking for a while, doing lots of reading for the past few months.

Im at a point with my diy build where its worth showing to people now and if anyone would be interested, i hope it would be people on here   

My plan is to build an optiwhite cube type tank for my first planted aquarium.  i have a couple biorbs (dont shoot me!) with guppies in.   but they got me in to this fish keeping thing, the planted aquarium will be taking it to the next level.

so ive been planning the tank for a while and everything else to go with it.  ive got into the engineering side of this quite heavily and made some gear to try and get a finish which i hope will be as high as possible.   ADA tanks are the aim here, minimal silicon seams etc.   

this is what i have so far







it's in a state of being partially done and ready to build with.   using an old table I bolted down on the left a jig with a wooden plate, which to that i clamp the glass to.   I used some soft wood so when clamping, the wood would compress before the glass, saving any potential disasters.  

so the glass is clamped to the wood, i then lay a seam of silicon and lower the glass down and press it firmly.  this gives the right amount of gap without the glass going any further and pressing it too much.

it can then be left to set for how ever long i want and the glass wont move.   the pic below shows how it holds above the base sheet of glass.






i made the wood on the right hand side of the top pic to clamp to the table and then clamp to the set pieces of glass - this allows them to be dead firm and can use the lowering jig on the next side of glass.   The right angle bits of orange perspex are just there to do a similar job from the inside should they be needed, held with double sided suction cups.    the old lamp is there to light the workspace, its yet to be wired up...


I am just trying to keep everything as firm and rigid as possible with perfect right angles.  it appeals to me more than the method of sticking the edges up with masking tape and holding it that way.


This is where its starting to take shape, lots of ideas and this is what i settled on.

im using pilkington optiwhite glass for the sides and pilkington dark glass for the base.  it is 4mm.   this first tank is 50x50x40.   i know this height is risky on 4mm glass but i want to see how far i can push the first build.  i got hold of a big stack of glass so have plenty to play with.  the next few i expect will be safer sizes, around 30cm high.  although i am in 2 minds about trimming the glass down to 50x50x30, i think the shallowness and depth could look pretty cool.

any input/constructive criticism i am certainly open to it!   even support, so far everyone ive spoken to about this has made     :?    faces at me, apart from a few people that get it, so would be nice to see some enthusiastic comments on this!

cheers!

Andy


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## cheebs

Welcome to the forum Andy.   

No funny faces from me! (well not intentionally anyway  ) I commend your effort. Ive fancied having a go at a DIY tank for a while, shame I don't have the time at the moment. There are a few tank builders here, you should get some helpful tips   

Good Luck, I'll be watching with interest.


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## Radik

Niice, always like DIY stuff, for the starters where u get those tools + glass cut to size and at what cost?


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## foxfish

Your jig is inventive but it only allows one joint at a time?
If so, you would then have to join fresh silicone to cured silicone?


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## Dogtemple

foxfish said:
			
		

> Your jig is inventive but it only allows one joint at a time?
> If so, you would then have to join fresh silicone to cured silicone?




yeah good point, got to admit i hadnt considered that.   is that a big problem?


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## foxfish

To be honest I dont know if that would be a problem but, I build my tanks in a complete jig that allows all the joints to be bonded at the same time.
This method does require quite a few clamps & a lot of organisation, I also use masking tape to get a neat finish on all the interior corners.


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## Dogtemple

Radik said:
			
		

> Niice, always like DIY stuff, for the starters where u get those tools + glass cut to size and at what cost?



well the tools, i just bought them from srewfix/b&q, the spirit level, hand clamps etc, all around £6 each.  the lowering jig part i had to modify something else to make that but it only cost me £5.   the wood clamps, i had the wood already, spoke to a kitchen fitter about what i was doing and he let me use his chop saw to cut the wood accurately.   the perspex, got that done at a local plastics shop, a4 sheet cut in half and bent at a right angle, £5.  suction cups were a few quid on ebay.

money wise its not cost much at all its the time ive spent on it i suppose.

i took the glass to a local glazers, thats been the most costly part - they cut it, arrissed the edges and straight polished the top 4 edges, came to around £18.    the cost on polishing all 20 edges came out to an awful lot, so im looking into doing that myself, and maybe cutting the glass myself too.


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## Dogtemple

foxfish said:
			
		

> To be honest I dont know if that would be a problem but, I build my tanks in a complete jig that allows all the joints to be bonded at the same time.
> This method does require quite a few clamps & a lot of organisation, I also use masking tape to get a neat finish on all the interior corners.




ok cool, thanks for that, thats one of those things i just didnt consider but can see how it makes a difference.

ive just had a good look at it and can see a way around it.   doing it as is currently, then using the wood clamps to hold the glass then move the jig around to the next side, clamp with wood, move to next side etc.

would require something like fixing a bolt to the table on each side of the tank then holding the jig down with a wing nut for quick assembly/reassembly.     that could work but would be a bit of a faff!

im going to test some new silicon on dried silicon, see if it adheres or not.


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## foxfish

The easy way is to make a box out of plywood ( or MDF) with screwed edges & fit all the glass inside with clamps then unscrew the box a few days later.
You need to make the box so the glass can be clamped to the top edge & allow 2mm (or whatever) for silicone.
Once all the glass in in place I run a bead over all the joins & then run your finger around to ensure the silicone has filled the gap. I then remove the masking tape & do another run over with a silicone rounding tool (available from tiling outlets)
However this sounds easier that it is as timing is important so that the silicone does not have time to skin over.
If you are using 10 0r 12 mm glass I make a very different jig but the box method is good for smallish tanks.


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## Aquadream

Hi Dogtemple. I believe I can also give you some tips since.
A few right angle clamps will do the trick. You have to remember not to press the glass panels too much to each other, because if the silicone layer is too thin on this size aquarium when you fill it with water the silicone will make ugly bubbles between the glass panels. It may even fall apart. It is a good idea to leave a gap of at least 0.5mm in this case that will be filled with silicone. The best silicone I have found by direct comparison of few brands is Dow Corning 881.
For the corners I use a polished tea spoon handle or anything that can give me small radius, to get accurate equal finish. I could post some pictures if you would like to see the look of the work.


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## Dogtemple

thanks guys, yeah pictures are always good!

i have a grout tool for getting the silicon rounded nicely.   ive done some test strips and the glass holds very well, even across the whole edge, no bubbles and appears to be a very strong bond.


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## hinch

trick from a plumber friend to give nicely rounded silicon 

spit on your finger tip and wipe along the siliconed edge while its still wet / fresh.


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## Dogtemple

did a little test with the silicon, fresh silicon applied to 2 day old dried silicon - and it adheres perfectly as though there was no join.    couldnt pull it apart at all, so doing one seam at a time shouldnt cause any problems, i just have to make sure the new/old joins match up fully.


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## Dogtemple

grabbed these today, £2 for the pair!   cant go wrong, old tools are awesome!






theyre right angle clamps, should hold the top corners together brilliantly and they have a cut out at the corner so wont be getting in the way of the silicon whilst it dries.


one other thing i just found, i have a canister filter sitting out of the way, about 2 months ago i filled it with tap water and dumped some ammonia in and forgot about it.   just tested the water out of curiosity and theres no trace of ammonia or nitrite just a whole load of nitrate!   pretty pleased with that!   the other tanks ive cycled have been hard work, i guess because i was tending them so much.    

i shall keep a closer eye on the levels now but it looks ready to use with this new tank.


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## Dogtemple

sorry for the lack of updates on this, but this is where i am up to now.

here are some of the few in between photos i have











didnt do many in progress due to the whole drama of the silicone drying so quickly.

but anyway, learnt some things which i didnt expect, such as the tiniest wrong angle can throw it off massively and the last piece of glass was harder than expected.

so anyways, its done now, only one tiny leak which appeared in the corner of the last bit of glass put in.  plugged it up and filled again, success! 














Its holding water and there is only a small amount of bowing in the glass which was expected.

managed to keep the seams as minimal as possible so they are barely visible, only on the edges of the glass and not covering the inside corners at all.

as it stands with the water in it, i can see where its stressed most but it doesnt appear to be giving at all.  so far it looks to be very strong, more so than expected.  even so i am still tentative.    its 50x50x40cm - that equals to 100litres, thats a lot of water to drop in a flat...    i have a day off work tomorrow so will put it out on the balcony and fill it up to leave out all day and put some stress on the sides, just to see how it fares.



sooo, the next part is to build a stand, obelisk/ada style will be the way forward.   will be enlisting my dad for this when i go back to theirs next time.  he built one for a big tank we had when i was a kid and is an engineer so will be obsessing over the science, which is nice


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## GillesF

Looks great!

Is that a divider? Or just a reflection of the wall?


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## Dogtemple

thanks!  its just a reflection on the base of the tank 

ive had it full for a week now and no leaks, i think its safe to go and use now


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## Dogtemple

ok, big old thread dredge...   this thread is just for the tank build bit but I'm documenting the entire build here Everything DIY build

so I built this tank in 2011, fast forward to a few months ago and its still sitting unused, for various reasons, but decided it was time to get it out and use it.

so here it is:





when I built it I built to the tallest height I could given the thickness of the glass and its safety factor of I think 4.   it was 50x50x40cm tall.

so I filled it up to check it was ok, it was bowing a fair amount, you can't see it in the photo but it was there.  no leaks but it was bowing.   years back I would have risked it but not now.






I took a razor blade to it before I had a chance to talk myself in to taking the chance.

I built it with RTV silicone and it wasn't as easy as I thought to take it apart.  good strong stuff, if anything was to have given way on this tank, it would have been the glass and not the seams.


here it is below after a trip to the local glazers to get it trimmed down.   now cut to 31cm high, which gives a good safety factor, hopefully no bow in the glass at this height and a better proportion.


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## Dogtemple

after a hell of a lot of meticulous cleaning of the glass (and more cleaning to come) I've started to build it back up again.

I've dug out the original jig I made and got cracking.   some other other parts I made to build tanks with have gone awol but I can work around it.

the jig was part of an old photo enlarger.   just has a bit of wood fixed to it, clamp the glass on and it allows you to lower it down to the silicone. 

the way I make them is to have the base glass, run a bead of silicone on one edge, lower the pane of glass to it and use a silicone edge tool to clean it up.   then do the other 3 panes the same way and then stick one side then the other.  when dried I trim the excess with a razor blade.  fill with water to test and thats pretty much it.   only downside is that it takes ages to do, I like to let it cure 24hr at least before going to the next seam.   I'm aiming for the best quality as possible though, so this is the trade off.  and I'm in no massive rush so doesn't matter.

works well doing it this way, ive made a few tanks like this although not made one for a few years.

so this evening I've done the first pane.   was pretty tense trying to run that first bead but got it done nicely enough.

the lower bead has a larger fillet of silicone than the edges as that's where the most pressure will be, as I'm trying to get as minimal as possible the edges will have a very tiny silicone fillet.

using momentive rtv silicone again.   expensive stuff but worth doing it right first time.   cost around £30 with vat and delivery so one of the most expensive aspects so far.


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## Dogtemple




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## ian_m

No Nonsense Smoothing Tools Concave Joints

Use these to get perfect silicone joints.


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## Dogtemple

ian_m said:


> No Nonsense Smoothing Tools Concave Joints
> 
> Use these to get perfect silicone joints.



Aye, I’m using similar tools. I have these ones


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## Aqua sobriquet

I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?


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## Dogtemple

Aqua sobriquet said:


> I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?



There was a very good one years ago but I can’t find it any longer. 

Just search for aquarium glass thickness calculator and something will come up. 

It’s the height that makes the most difference as it dictates the pressure.  Obviously adding in more length will have an affect but height of the tank is more of a dramatic change.


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## papa_c

Aqua sobriquet said:


> Is there a good online source that works it out for you?



I would rely on the information from other manufacturers, find a selection of retail tanks of a similar size to that you are planning and use their glass thickness as the benchmark to base your build on.


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## castle

Aqua sobriquet said:


> I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?


I shared *this* not so long ago to calculate force on front/back glass. Once you're over 45cm height, things get a bit hairy.

For the 320x80x50 (LxWxH) i'm leaning towards a stainless steel frame.


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## Dogtemple

Part 2...


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## Maf 2500

Aqua sobriquet said:


> I’ve been considering the safety of unbraced tanks and can’t help thinking it’s a combination of not only the height but also the length of the longest side on a rectangular tank? Is there a good online source that works it out for you?


This one seems pretty good for working out glass thickness (also works out weight of glass + water etc):
Aquarium Glass Thickness Calculator

Length of longest side is important but not as important as the height.

You need to know the safety factor you are aiming for to use this tool. For a normal braced tank 2.9-3.8 is usually the accepted value but for rimless and braceless it is less clear cut, I have seen 7.6 suggested. I believe if the edges of the glass are properly polished before manufacture these values can be reduced. Other manufacturing processes may also allow the safety factor to be reduced. If you put the dimensions of rimless tanks offered by Aquariums4Life through that calculator you have to use a safety factor around 7.2 - 7.6 to get the thicknesses they use. For some ADA tanks you need to use a factor of 5. What I would use for a home built tank? I guess depends on a combination of how much care you would take building the aquarium and how risk averse you are.

For the OP's tank the calculator gives a value of 4.75 as the safety factor at the new height.



> There was a very good one years ago but I can’t find it any longer.



Yes, there was a really good aquarium glass calculator site with tons of useful knowledge in addition to the calculator itself but it disappeared about 1-2 years ago. Very annoying when useful sites disappear.


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## Aqua sobriquet

Thanks for that. I was thinking of maybe a 720 x 450 with a height of 400. 10mm glass gives a factor of 10 so that’s good?


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## Maf 2500

Aqua sobriquet said:


> Thanks for that. I was thinking of maybe a 720 x 450 with a height of 400. 10mm glass gives a factor of 10 so that’s good?


Yes, better to overbuild than under. You could very safely go to 450mm height in 10mm at that length. I have an ADA tank sitting upstairs empty that I bought second hand and never used. It is 750 x 450 x 450 in 8mm glass.


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## Dogtemple

Third section done


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## papa_c

Just a comment and I am by no means experienced in DIY tanks and thinking about when sealing sanitary ware and showers. I was under the impression all joints be made at the same time when the silicon has not cured to ensure water tightness. I always thought that it is not possible to get a proper bond between cured/skinned and fresh silicon?


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## Dogtemple

I think someone asked that originally in this thread, I never had a problem.  Silicone sticks to silicone.  And this stuff really sticks.  

This is the 5th tank I’ve made this way and all have held up.  One was used for several years without leaks.  I have no concerns with this particular silicone myself.


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## papa_c

Good to know if I ever go down the DIY route 😀


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## Jaseon

I have a little bit of experience of DIY tanks, and can tell you silicon does adhere to cured silicon no problems despite what ive heard some say on the subject.

I tend to do the same and run a bead along the glass edge and press into place. It gives that added insurance of a good seal before running the second bead along the inside of the glass. I dont let the first bead cure first though so run some masking tape inside and the apply the second bead in. You could most probably get away with not adding a second inner seal and it would not leak if it was applied evenly, but why take the chance.

This is the stuff i use. Good stuff.


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## Dogtemple

Healthy bit of “it’s gone wrong so I’ll have to redo it update”. 

When the glass was originally cut the sides were cut so it was a 50cm square and so was the base.  The edges of the base were arrissed but the edges of the side panes were ground and polished to give a bevel.   Therefore the tank is actually about 2 or 3mm smaller than 50cm whereas the base is still 50cm. 

When putting in the panes of glass I have been centralising them to the base and having them flush against the edge.  I made the mistake of doing this to the third pane of glass. 

What’s happened is that the third pane doesn’t fit flush at the vertical edges, it’s just off.  Which isn’t good enough in terms of safety and even more importantly it doesn’t look good!

So had to strip this pane out and redo it. Means loads of silicone removal again.    Reassuringly, it took at least 10 passes with a razor blade and pulling back on the glass to split the seam.  So it’s a very strong bond.  

Have attached a photo of the edges.  Hopefully this may be of use to someone should they consider building their own tank.   I totally forgot to take this in to consideration.


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## ian_m

I use this to remove sealant. Works wonderfully well. It breaks the bond between the sealant and anything it is attached to. I always use this before doing any siliconing.

No Nonsense Sealant Remover 100ml


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## Dogtemple

ian_m said:


> I use this to remove sealant. Works wonderfully well. It breaks the bond between the sealant and anything it is attached to. I always use this before doing any siliconing.
> 
> No Nonsense Sealant Remover 100ml



I have some of that but it didn't seem to want to do anything for me, maybe mine was from a dud batch?    you just slop it on, leave and try to remove?


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## Jaseon

What are you using to strip the silicon back with? i use one of these,




I use a dab of nail polish remover to take off any residue that left.


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## ian_m

Dogtemple said:


> I have some of that but it didn't seem to want to do anything for me, maybe mine was from a dud batch?    you just slop it on, leave and try to remove?


You must trim any silicone as thin as possible, using a sharp knife first. I then wipe with IPA/meths for ensure 100% dry. Then apply remover and go for a couple of cups of tea. 

When you come back just use a non metal scraper, nylon pot scrubber etc to remove the now loose silicone "film".

Wash with water. Water deactivates the remover.

Dry, clean with IPA/meths, apply masking tape, apply silicone, smooth away with your favourite tool and/or finger soaked in Fairy liquid solution. Job done.

Soudal (at some B&Q's) also sell a silicone remover which I have used a couple of times. Similar results to Screw fix stuff.


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## Dogtemple

Jaceree said:


> What are you using to strip the silicon back with? i use one of these,
> 
> 
> 
> 
> 
> I use a dab of nail polish remover to take off any residue that left.



yes something like that, for getting paint off glass, I think it has a Stanley blade inside.   using 99% alcohol after to clean it up.


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## Dogtemple

ian_m said:


> You must trim any silicone as thin as possible, using a sharp knife first. I then wipe with IPA/meths for ensure 100% dry. Then apply remover and go for a couple of cups of tea.
> 
> When you come back just use a non metal scraper, nylon pot scrubber etc to remove the now loose silicone "film".
> 
> Wash with water. Water deactivates the remover.
> 
> Dry, clean with IPA/meths, apply masking tape, apply silicone, smooth away with your favourite tool and/or finger soaked in Fairy liquid solution. Job done.
> 
> Soudal (at some B&Q's) also sell a silicone remover which I have used a couple of times. Similar results to Screw fix stuff.



ok cool, ill give it another go.   will need to use it on the cut face to get the remains of the silicone off.   the flat surfaces are not too much of a problem


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## Dogtemple

gave the silicone remover a go, put loads on there and it worked much better, got it all cleaned off and had another go.  third pane back in place and properly aligned this time.


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## Dogtemple

All four sides are in now, just need to do the sides.   So just two more silicone sessions to do, test for leaks, trim the excess, clean it up, then it’s done.


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## Dogtemple

Sorry for the slow progress on this. It should be done by now but work sucking the life out of me like a hungry vampire has caused me to be lazy after 5 on a week day. Got a day off today and done one side edge.  Just the other side to do which I’ll hopefully do tomorrow morning.   After that the hard work is done.


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## Dogtemple

The tank is all complete and sealed up, but I’m not happy with the finish on the front panel. It could be better. It is sound and tidy but looking up close there are some tiny bubbles in the silicone. I don’t really want to compromise on the finish of this tank so I’m going to pull the front pane out, clean off all the silicone and redo it.


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## Dogtemple

No turning back…


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## Dogtemple

Redone it and got the seams bubble free this time.  Before I was laying a bead of silicone on the edge then pressing the glass together and holding with a right angle clamp.  

Tried something different this time, I clamped it up then run a bead in the seam and pressed the silicone in the gap with my finger.  By doing this i could see the bubbles and press silicone in until they came out the other side.    Once the gap is nicely filled just swipe up the seam with a grout tool and it’s a clean finish.  

In retrospect I should have done this on the whole tank but only worked it out at this stage.  It wastes slightly more silicone but it gets you a better finish. Would almost go so far as to say a perfect finish.


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## Dogtemple

Redone the last bits and now on to the leak testing.  I stick a piece of brown paper down under the tank as it shows up the water if it leaks, if it has a leak it will show up pretty much immediately.  Normally they leak in one of the bottom corners but I made a point of plugging these up. Luckily, no leaks! 

Been sitting about half an hour and I’ve given some firm taps on all the sides to see if it will give out and it’s all stayed together. Which is nice.

Most importantly there is barely any bow in the glass, this is what prompted me to strip the original build of this tank and reduce the height.   Measured about 1mm which is acceptable, I think all tanks bow by that amount.

Just need to cut off all the excess silicone and scrape off any remains.

Taken a month but I have been careful with letting every thing cure over a long enough period before moving to the next bit.   I have done tanks with this set up before over a weekend with no problems. If you leave a few hours for the silicone to set you can usually move to the next part with no issues.


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## Dogtemple

The tank is now finished.  Given the glass a clean and scraped the traces of silicone off. The excess all trimmed off and looking better for it.  The excess is quite important, should you try this yourself make sure you have excess silicone along the whole length of the seam, when you slice it off you’ll get a nice and continuous clean cut.


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