Reef Central Online Community

Home Forum Here you can view your subscribed threads, work with private messages and edit your profile and preferences View New Posts View Today's Posts

Find other members Frequently Asked Questions Search Reefkeeping ...an online magazine for marine aquarists Support our sponsors and mention Reef Central

Go Back   Reef Central Online Community > General Interest Forums > New to the Hobby
Register Blogs FAQ Calendar Mark Forums Read

Notices

User Tag List

Reply
Thread Tools
Old 10/11/2016, 01:08 AM   #1
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Need help on double glass sheet for reef tank

I am in the process of building a new tank 5'X24"X20" using 12mmm glass with eurobrace( top and bottom).
Here on my remote island,Mauritius, I cannot find 12mmm ultra clear glass for the front pane. The only thickness available is 8mm . I really want to have it ultra clear in front.
Can I use just 8mm in front and the other panes 12mm?
Secondly is it possible to use 2 X 8mm clear glass glued together in front??
By glued I mean siliconed on the inside edges to hold both panes together....
Greatly need your advice before going ahead


patmos is offline   Reply With Quote
Old 10/11/2016, 03:40 AM   #2
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
I would NOT use 8mm glass on a 5'x20" pane of glass. And I don't think siliconing the edges of 2 sheets will work either. I think you need to import a sheet or live with 12mm regular glass (which isn't that bad).

So tell me, how good is the snorkeling (or diving) around your island? It looks very promising based on the images I see on google earth.


__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/11/2016, 04:03 AM   #3
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Thank you Ron. Will consider your advice
As regard to snorkeling , Mauritius is a dream place, basing myself on diving videos I've seen. That's what inspired me for the reef tank. Our reef are well protected now.I myself has never done snorkeling.


patmos is offline   Reply With Quote
Old 10/20/2016, 06:52 AM   #4
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Coming back again ...I now have found 10mmm ultraclear glass.
Would it be safe to use the 10mm ultra clear for the front pane only???...leaving all other panes @ 12mm with eurobrace as described above. Merci


patmos is offline   Reply With Quote
Old 10/21/2016, 04:53 AM   #5
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
I'm no expert, I've only built 5 tanks, but I'd say you are at the ragged edge of safety. My 2 big builds are 4'x2'x14" and 2'x2'x20". Both made with 3/8th inch glass (9.5mm) and neither is euro braced. But the 4' is shallow, so low pressure and the 20" tall one is only 2' so no long length. My new CadLight tank is 5'x2'x20" with low iron glass (exactly what you want) and it is 1/2" glass (12.7mm) and euro braced at the top only.

I hope that helps a little? Good luck.


__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/21/2016, 10:35 AM   #6
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Quote:
Originally Posted by Ron Reefman View Post
I'm no expert, I've only built 5 tanks, but I'd say you are at the ragged edge of safety. My 2 big builds are 4'x2'x14" and 2'x2'x20". Both made with 3/8th inch glass (9.5mm) and neither is euro braced. But the 4' is shallow, so low pressure and the 20" tall one is only 2' so no long length. My new CadLight tank is 5'x2'x20" with low iron glass (exactly what you want) and it is 1/2" glass (12.7mm) and euro braced at the top only.

I hope that helps a little? Good luck.
Merci for the advice...
Is it that the 20" is too high?
What is safe value for appropriate pressure? for this given glass thickness
This issue is not well documented across various forums...we have to rely on experiences of others...opinions greatly vary
Is there a way to know the pressure water exerts on glass of different thicknesses for a specific tank size
If your Cadlight is same dimension as my proposed tank, so it would be good with 12mm glass....the hiccup is the front 10mm clear I want .....
still deciding on the course of action.....


patmos is offline   Reply With Quote
Old 10/21/2016, 05:04 PM   #7
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
Yes, I think the 10mm glass is the weak point, but not necessarily a fatal flaw. I'm sure there are a couple of tank building sites that offer glass thickness calculations. You may be fine with the 10mm front glass, especially with euro bracing at the top and bottom. The water in your tank is going to weigh about 1000 pounds (450 kilos). So the question is, can 10mm glass at 5 feet long hold up to 1000 pounds of pressure. I think doing a double bottom makes a big difference, but again, I'm no expert.

I'm a bit surprised Uncleof6 hasn't weighed into this thread. He is much more knowledgeable about this than me... and probably WAY more conservative on the side of safety. You might want to send him a PM and get him involved.


__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/21/2016, 10:50 PM   #8
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Quote:
Originally Posted by Ron Reefman View Post
Yes, I think the 10mm glass is the weak point, but not necessarily a fatal flaw. I'm sure there are a couple of tank building sites that offer glass thickness calculations. You may be fine with the 10mm front glass, especially with euro bracing at the top and bottom. The water in your tank is going to weigh about 1000 pounds (450 kilos). So the question is, can 10mm glass at 5 feet long hold up to 1000 pounds of pressure. I think doing a double bottom makes a big difference, but again, I'm no expert.

I'm a bit surprised Uncleof6 hasn't weighed into this thread. He is much more knowledgeable about this than me... and probably WAY more conservative on the side of safety. You might want to send him a PM and get him involved.
Thank you for the insight in the matter
I tried to pm Uncleof6 yesterday but the forum's rule did not allow me to.....I should be more than 10 posts to do so.


patmos is offline   Reply With Quote
Old 10/22/2016, 02:16 AM   #9
uncleof6
Registered Member
 
uncleof6's Avatar
 
Join Date: Jul 2004
Location: AWOL
Posts: 12,013
Quote:
Originally Posted by Ron Reefman View Post
Yes, I think the 10mm glass is the weak point, but not necessarily a fatal flaw. I'm sure there are a couple of tank building sites that offer glass thickness calculations. You may be fine with the 10mm front glass, especially with euro bracing at the top and bottom. The water in your tank is going to weigh about 1000 pounds (450 kilos). So the question is, can 10mm glass at 5 feet long hold up to 1000 pounds of pressure. I think doing a double bottom makes a big difference, but again, I'm no expert.

I'm a bit surprised Uncleof6 hasn't weighed into this thread. He is much more knowledgeable about this than me... and probably WAY more conservative on the side of safety. You might want to send him a PM and get him involved.
I don't usually check what is going on out here; and yes I am a bit on the conservative side when it comes to safety. To give it some perspective:

It would be nice if, when running the algorithm, it would come up "even" and say 9mm, 10mm, 12mm, 15mm depending (standard glass thickneses.) More often than not, it falls inbetween. It becomes a question of how far from the lower or higher thickness does it fall, and then after that is the question of the experience of the builder.

Very experienced, go down, but then someone with sufficient experience won't usually be asking about glass thickness; and if little to no experience go up. Manufacturers will invariably go down and then some; and custom builders will go up or down, depending on things like shipping. With custom builders and manufacturers, the consumer can usually "rest easy" because the liability is on the builder, not them, provided they follow the builders recommendations concerning stands etc.

We have two safety factor points: 3.8 for a full metal rim (manufacturers excluded) and 7.6 for a rimless tank. For a tank with additional bracing: 7.6 SF less 1 standard thickness down, will usually be safe. The bottom of the tank needs to be dealt with as a rimless tank would be. Of course nothing ever comes out even... so invariably we are always inbetween...

On the pressure: call it 125 gallons with a weight of 1072lbs. The stand carries the load. (or the bottom glass panel with a full floated bottom, and the stand.) The pressure at a depth of 20" is 15.442psi. Does not seem like much, but it will push the side glass out (14.8psi will push the glass out; atmospheric pressure is 14.7psi at sea level) and if the glass is not thick enough, the seams will pop. So glass thickness is about reducing the outward deflection as much as possible. So sometimes it is a judgement call based on how much tolerance for deflection the builder has.

You have an interest in tank building, so this is offered for consideration.


__________________
"Things should be made as simple as possible, but not simpler." (oft attributed to Einstein; most likely paraphrasing by Roger Sessions; compactly articulates the principle of Occam's Razor)

Current Tank Info: 325 6' wide Reef
uncleof6 is offline   Reply With Quote
Old 10/22/2016, 03:13 AM   #10
uncleof6
Registered Member
 
uncleof6's Avatar
 
Join Date: Jul 2004
Location: AWOL
Posts: 12,013
Quote:
Originally Posted by patmos View Post
Thank you for the insight in the matter
I tried to pm Uncleof6 yesterday but the forum's rule did not allow me to.....I should be more than 10 posts to do so.
The tank you want to build clearly calls for 12mm glass, with additional top and bottom bracing. A rimless tank of the same dimensions calls for 15mm glass, (minimum side thickness of ~14mm,) with a 19mm bottom panel. (minimum bottom thickness of ~ 18mm.)

10mm gives a safety factor of 3.96, which is really low for a tank without a rim, even with the top bracing. 8mm is really out of the question. (SF 2.53.)

I understand you want ultra clear glass (low iron glass; starphire,) but with the dimensions you want it is pretty much out of the question, unless you import it in 12mm. Side by side, the difference is remarkable; but stand alone, you won't notice the difference.


__________________
"Things should be made as simple as possible, but not simpler." (oft attributed to Einstein; most likely paraphrasing by Roger Sessions; compactly articulates the principle of Occam's Razor)

Current Tank Info: 325 6' wide Reef
uncleof6 is offline   Reply With Quote
Old 10/22/2016, 03:37 AM   #11
uncleof6
Registered Member
 
uncleof6's Avatar
 
Join Date: Jul 2004
Location: AWOL
Posts: 12,013
Quote:
Originally Posted by Ron Reefman View Post
I would NOT use 8mm glass on a 5'x20" pane of glass. And I don't think siliconing the edges of 2 sheets will work either. I think you need to import a sheet or live with 12mm regular glass (which isn't that bad).

So tell me, how good is the snorkeling (or diving) around your island? It looks very promising based on the images I see on google earth.
In a word: incredible. With a semi-closed rebreather or hybrid, (nitrox) and a trimix rig, (if you don't mind the added expense and risk) you could spend the rest of your life diving in the area, and not get tired of it. IIRC, there are 20 or so wrecks to explore as well...


__________________
"Things should be made as simple as possible, but not simpler." (oft attributed to Einstein; most likely paraphrasing by Roger Sessions; compactly articulates the principle of Occam's Razor)

Current Tank Info: 325 6' wide Reef
uncleof6 is offline   Reply With Quote
Old 10/22/2016, 04:14 AM   #12
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Thank you Uncleof6 and Ron for taking time to give me such precious advice . I would go for the normal 12mm glass all around.
One more question :Can I do the bottom pane with same 12mm braced??? Or should I go thicker for it?
Merci again...Please come to Mauritius for some diving........


patmos is offline   Reply With Quote
Old 10/22/2016, 03:01 PM   #13
uncleof6
Registered Member
 
uncleof6's Avatar
 
Join Date: Jul 2004
Location: AWOL
Posts: 12,013
You can use a 12mm bottom panel, so long as the bottom panel is fully supported by the stand. You will want to install a ~3" strips of glass around the inside of the tank, at the bottom, siliconed to the bottom and the sides, as in this tank from GlassCages.



I strongly recommend that you get some 6mm glass (or 9mm) and practice using silicone to build tanks, before you attempting the larger tank build. It will give you some experience, and some notion of the techniques you need to use. In other words, build a sump, and get it to hold water first...


__________________
"Things should be made as simple as possible, but not simpler." (oft attributed to Einstein; most likely paraphrasing by Roger Sessions; compactly articulates the principle of Occam's Razor)

Current Tank Info: 325 6' wide Reef
uncleof6 is offline   Reply With Quote
Old 10/23/2016, 05:41 AM   #14
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
Do you have corner or frame making clamps and/or clamps big enough to hold the sides together? You can see them in the photo of my 50g refugium build. You may notice the small white blocks in the bottom corners of my build. If you do the inside euro brace at the bottom first, you won't need the block like I used to help line things up. Also, do a dry fit before you try the real assembly. Use good adhesive silicone (I used black RTV silicone) and don't skimp when laying the silicone bead down. You can spend days scraping excess silicone out of the tank after it is cured, but you can't add more silicone into the joins after it's assembled and you find bubbles or air pockets. And don't squeeze all the silicone out of the joints when you are clamping it together.

Is that enough things to think about? And uncleof6 is dead right, build a small practice tank and then build a sump before you try to build the DT. Practice, practice, practice!

Good luck.




__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/23/2016, 08:03 AM   #15
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Thanks again for your kind advice...In fact a friend who has some experience in building fresh water tank will build the tank for me. I will follow him to get some experience. I will on pass the suggestions made by you to him...
The sump glass is already cut and it will be made first, tested and put in cabinet. It is based on Uncleof6's 48" sump plan. Then we will proceed with the big tank.Oh I've never seen people using these clamps...looks like carpenter's clamps
As for silicone we have various brands here but I've chosen Rubson clear Aquarium, a European brand. Unfortunately I cannot find black aquarium silicone here...I would have preferred the black..
will post some pics of the progress


patmos is offline   Reply With Quote
Old 10/24/2016, 04:50 AM   #16
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
Good luck.


__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/24/2016, 09:28 AM   #17
Sk8r
RC Mod
 
Sk8r's Avatar
 
Join Date: Feb 2006
Location: Spokane WA
Posts: 34,488
Blog Entries: 55
Another thing that might be helpful is laying down plastic lighting grid, the sort that you use in ceilings, on the tank bottom: this prevents 'point load' on the glass from some rocks; and also stabilizes the rock structure so it won't roll, no rockslides.


__________________
Sk8r

Salinity 1.024-6; alkalinity 8.3-9.3 on KH scale; calcium 420; magnesium 1300, temp 78-80, nitrate .2. Ammonia 0. No filters: lps tank. Alk and cal won't rise if mg is low.

Current Tank Info: 105g AquaVim wedge, chromis, royal gramma basslet, tailspot blenny, ocellaris clown, yellow watchman, chestnut turbo snails, bristleworms, couple of hermits.
Sk8r is offline   Reply With Quote
Old 10/25/2016, 08:46 AM   #18
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
Quote:
Originally Posted by Sk8r View Post
Another thing that might be helpful is laying down plastic lighting grid, the sort that you use in ceilings, on the tank bottom: this prevents 'point load' on the glass from some rocks; and also stabilizes the rock structure so it won't roll, no rockslides.
I go 1 step further. I take egg crate and mount it on short PVC pipe legs so it sits just above the sand and then put my rocks on the egg crate. I hide the edges with smaller rubble. That makes for more open sand and better water flow under the rocks. You can look in some opening and see lots of 'stuff' (sponges, feather dusters, etc.) growing under the rocks just above the sand.


__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/25/2016, 12:17 PM   #19
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Thank you both for the egg crate idea....


patmos is offline   Reply With Quote
Old 10/26/2016, 07:19 AM   #20
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
Both of these islands are 1" or more off the sand.




__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 10/26/2016, 12:11 PM   #21
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
Quote:
Originally Posted by Ron Reefman View Post
Both of these islands are 1" or more off the sand.

thank you Ron.
BTW what is your sand depth?? i understand I wont find any aragonite or so commercial sand here. I will use a mixture of different sea sand sizes...collected from the sea or remote shore.
No way to import corals here. it's banned, I'll find a way locally. I love the anemones. LPS are more abundant I think


patmos is offline   Reply With Quote
Old 10/27/2016, 03:39 AM   #22
Ron Reefman
Registered Member
 
Ron Reefman's Avatar
 
Join Date: Jul 2009
Location: Cape Coral, FL
Posts: 10,431
The sand is close to 2" over the entire bottom of the tank.

If you can collect sand off shore, I think it will be better. And it could be very interesting to just put your sand in the tank with saltwater and some water movement and give it a week or two and see what develops. I did it once with a small sample and was shocked at the amount of life that developed.

On the other hand, if you want to get the tank going with corals, it may be better to wash the sand thoroughly with fresh water. Maybe even do a water and vinegar or water and hydrogen peroxide bath for a few hours or a day and then a good freshwater bath. You don't need something from your sand causing issues with corals you may collect.


__________________
The good thing about science is that it's true whether or not you believe in it. (Neil deGrasse Tyson)
Visit my build thread http://www.reefcentral.com/forums/showthread.php?t=2593017
Ron Reefman is offline   Reply With Quote
Old 12/24/2016, 03:35 AM   #23
patmos
Registered Member
 
Join Date: Mar 2016
Location: Mauritius
Posts: 25
thank you all for your help and advice


patmos is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -6. The time now is 03:17 PM.


TapaTalk Enabled

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2021 Axivo Inc.
Use of this web site is subject to the terms and conditions described in the user agreement.
Reef CentralTM Reef Central, LLC. Copyright 1999-2014
User Alert System provided by Advanced User Tagging v3.3.0 (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.