81.3 gallon tank

Cobia302 · 08/15/2013, 10:33 AM

Cobia302 · 08/15/2013, 10:35 AM

Well the picture loaded but I had to rewrite this. lol
Hello everyone. I am new to this site but have been searching for a site to get useful information about building aquariums. I have fabricated my own 81 gallon tank out of a sheet of polycarbonate. I am I little concerned about making sure it doesn't leak. Last night I put silicone of every edge and screwed it all together and let it sit overnight. Along all the walls there is smears of silicone from where I smoothed out the excess silicone. I want to add a additional bead on every side for extra protection. I have been reading that you shouldn't put silicone over silicone but I thought if I was to cut back with a razor where the silicone has the smears from the 1st application, then I could add the second coat and it would adhere to the plexiglas and not the other silicone.
Any help I would appreciate it. I already had to take it apart and clean the edges once to apply the silicone correctly. I just don't want to go any further and take it back apart, I would rather take it apart now than later "if I am suppose to do it all in one shot."
Thanks for any advice
Cobia302

Cobia302 · 08/15/2013, 10:39 AM

Oh and any info on how to keep my back two holes sealed and to connect the hoses to them i would appreciate also. The small one is the outlet tube and the large one is the inlet tube for the water.

thegrun · 08/15/2013, 10:55 AM

I have bad news for you, silicone does not bond well to acrylic, you need to use a solvent made for bonding acrylic like Weld-On #3 or #4. Unfortunately your tank is bound to leak, if not right away, in the near future. It is going to be difficult to remove the silicone but it is important that the acrylic is completely clean to get a good bond. You will not need the screws if you bond the acrylic properly. You should also do some research on bonding techniques and the possible need for bracing at the top of the tank.

Cobia302 · 08/15/2013, 11:11 AM

Quote:

Originally Posted by thegrun

I have bad news for you, silicone does not bond well to acrylic, you need to use a solvent made for bonding acrylic like Weld-On #3 or #4. Unfortunately your tank is bound to leak, if not right away, in the near future. It is going to be difficult to remove the silicone but it is important that the acrylic is completely clean to get a good bond. You will not need the screws if you bond the acrylic properly. You should also do some research on bonding techniques and the possible need for bracing at the top of the tank.

I thought the screws would hold it together to help brace the top also. So I need to go buy some weld-on #3 or #4? Do I have to buy it online or can I go to home depot, lowes, menards, or someplace like that? I already had to take it apart once and scrape all the silicone off it and start over. No big deal, taking it apart and starting over now. I just don't want to have to a tank full of water and fish then have to take it all apart. Do u have any suggestions what to use for the inlet and outlet holes on the back? thanks

thegrun · 08/15/2013, 11:43 AM

You can check Lowe's and HD, but most likely you will need to find a local plastics supply house for the solvent. There are a few here in the local Los Angeles area, I suspect if you live in a major metropolitan area there will be a supply house near you.

Dapg8gt · 08/15/2013, 12:23 PM

What are you gonna do about all the screw holes?are the screws stainless? IMO that made weak points all over the tank.

You definitely can't use silicone on it.. You can look on YouTube on how to make an acrylic tank . Or just type that into Google . Only my opinion butThat's ok for a reptile or something, me personally would never put 678 +lbs of water to in that and feel comfortable. Good luck with that =)..

Dapg8gt · 08/15/2013, 12:25 PM

Quote:

Originally Posted by Cobia302

Oh and any info on how to keep my back two holes sealed and to connect the hoses to them i would appreciate also. The small one is the outlet tube and the large one is the inlet tube for the water.

There called bulkheads.. The are sold a lot of places.. Amazon, ebay, brs etc.. Fish stores carry them also..

I would seriously consider doing some research on tank, building, overflows etc.. It's safest to have multiple drains from the tank etc..

Cobia302 · 08/15/2013, 12:36 PM

Quote:

Originally Posted by Dapg8gt

What are you gonna do about all the screw holes?are the screws stainless? IMO that made weak points all over the tank.

You definitely can't use silicone on it.. You can look on YouTube on how to make an acrylic tank . Or just type that into Google . Only my opinion butThat's ok for a reptile or something, me personally would never put 678 +lbs of water to in that and feel comfortable. Good luck with that =)..

Well the material was free and I wanted to make a big tank. So what if I used the proper glue do you think that it still wouldn't hold?

Dapg8gt · 08/15/2013, 03:26 PM

Quote:

Originally Posted by Cobia302

Well the material was free and I wanted to make a big tank. So what if I used the proper glue do you think that it still wouldn't hold?

That i could not tell you.. With the seams the way you have them and the shape I'm guessing it would have to be exact. with the cement it's not a gap filler it literally welds it together so I really couldn't tell you.. If you are going to rock it I would second the other response as to put a rim around it or attempt to euro brace it and use the proper acrylic cement..

There's a thread on here with a professional tank builder giving, advice I would post this thread there if I were you.. He would be able to give you reasons why it's safe or not safe.. I've only built sumps and I am by far not a professional.. I know I have never seen any acrylic tank that was screwed together fwiw..

Water is a unforgiving element and to have that explode in your house would be disastrous. Cost a ton more money than buying another tank..

I will try to find that thread for you to go through and post in and link it back..
http://www.reefcentral.com/forums/sh...questions+here

Cobia302 · 08/15/2013, 03:35 PM

Quote:

Originally Posted by Dapg8gt

That i could not tell you.. With the seams the way you have them and the shape I'm guessing it would have to be exact. with the cement it's not a gap filler it literally welds it together so I really couldn't tell you.. If you are going to rock it I would second the other response as to put a rim around it or attempt to euro brace it and use the proper acrylic cement..

There's a thread on here with a professional tank builder giving, advice I would post this thread there if I were you.. He would be able to give you reasons why it's safe or not safe.. I've only built sumps and I am by far not a professional.. I know I have never seen any acrylic tank that was screwed together fwiw..

Water is a unforgiving element and to have that explode in your house would be disastrous. Cost a ton more money than buying another tank..

I will try to find that thread for you to go through and post in and link it back..
http://www.reefcentral.com/forums/sh...questions+here

thank you

Brianmil7516 · 08/15/2013, 06:32 PM

you may be able to salvage it.. it would require cutting the acrylic to remove the screw holes then apply correct bonding to the new edges..

the top would require additional bracing if it is totally open.. can't tell from the picture.. and generally flow-wise you want your drain "pipe" to be bigger than your return "pipe" from what i see and drom what you described.. if you are using 1" PVC for the big hole and 3/4" PVC for the little hole.. you will have 330GPH draining from your tank into a sump and 660 GPH returning to the tank... at some point your sump will run dry...

other than that...i love the design.. it is a unique shape.. you could get some interesting flows in that shape with strategically placed power heads...

Cobia302 · 08/16/2013, 05:42 PM

Quote:

Originally Posted by Brianmil7516

you may be able to salvage it.. it would require cutting the acrylic to remove the screw holes then apply correct bonding to the new edges..

the top would require additional bracing if it is totally open.. can't tell from the picture.. and generally flow-wise you want your drain "pipe" to be bigger than your return "pipe" from what i see and drom what you described.. if you are using 1" PVC for the big hole and 3/4" PVC for the little hole.. you will have 330GPH draining from your tank into a sump and 660 GPH returning to the tank... at some point your sump will run dry...

other than that...i love the design.. it is a unique shape.. you could get some interesting flows in that shape with strategically placed power heads...

I am running it for a aquaponics system. I have ball valves on the inlet line and outlet line to control the amount of flow to and from tank to pots. I regulated it to have constant flow. The big hole is the return hole and the small hole is the pump out. Thanks for the props of design.

Griznock · 08/16/2013, 08:11 PM

http://www.youtube.com/watch?v=da78xmuwTHo

this guy has several videos on welding acrylic tanks very informative.

Cobia302 · 08/17/2013, 12:47 PM

Quote:

Originally Posted by Griznock

http://www.youtube.com/watch?v=da78xmuwTHo

this guy has several videos on welding acrylic tanks very informative.

Thanks for the info. I have been doing some more research about poly-carbonate and it is way stronger that acrylic acrylic snaps,cracks, and shatters. Poly-carbonate just bends it doesn't break very easilily. I watched the videos. Very helpful. thanks u

08/15/2013, 10:33 AM	#1
Cobia302 Registered Member Join Date: Aug 2013 Posts: 18	81.3 gallon tank

08/15/2013, 12:23 PM	#7
Dapg8gt Registered Member Join Date: Dec 2011 Location: Pacifica Posts: 3,741	What are you gonna do about all the screw holes?are the screws stainless? IMO that made weak points all over the tank. You definitely can't use silicone on it.. You can look on YouTube on how to make an acrylic tank . Or just type that into Google . Only my opinion butThat's ok for a reptile or something, me personally would never put 678 +lbs of water to in that and feel comfortable. Good luck with that =).. __________________ 15 years in the hobby yet still learning every day. 280g radium lit sps flat living in my garage rent free. Current Tank Info: 105g SPS dominant euro braced powered by 4 ecotech pumps and lit by an ATI powermodule controlled by a reef angel =).

08/15/2013, 10:35 AM	#2
Cobia302 Registered Member Join Date: Aug 2013 Posts: 18	Well the picture loaded but I had to rewrite this. lol Hello everyone. I am new to this site but have been searching for a site to get useful information about building aquariums. I have fabricated my own 81 gallon tank out of a sheet of polycarbonate. I am I little concerned about making sure it doesn't leak. Last night I put silicone of every edge and screwed it all together and let it sit overnight. Along all the walls there is smears of silicone from where I smoothed out the excess silicone. I want to add a additional bead on every side for extra protection. I have been reading that you shouldn't put silicone over silicone but I thought if I was to cut back with a razor where the silicone has the smears from the 1st application, then I could add the second coat and it would adhere to the plexiglas and not the other silicone. Any help I would appreciate it. I already had to take it apart and clean the edges once to apply the silicone correctly. I just don't want to go any further and take it back apart, I would rather take it apart now than later "if I am suppose to do it all in one shot." Thanks for any advice Cobia302

08/15/2013, 10:39 AM	#3
Cobia302 Registered Member Join Date: Aug 2013 Posts: 18	Oh and any info on how to keep my back two holes sealed and to connect the hoses to them i would appreciate also. The small one is the outlet tube and the large one is the inlet tube for the water.

08/15/2013, 10:55 AM	#4
thegrun Registered Member Join Date: Dec 2008 Location: Garden Grove, Ca Posts: 17,023	I have bad news for you, silicone does not bond well to acrylic, you need to use a solvent made for bonding acrylic like Weld-On #3 or #4. Unfortunately your tank is bound to leak, if not right away, in the near future. It is going to be difficult to remove the silicone but it is important that the acrylic is completely clean to get a good bond. You will not need the screws if you bond the acrylic properly. You should also do some research on bonding techniques and the possible need for bracing at the top of the tank.

08/15/2013, 11:43 AM	#6
thegrun Registered Member Join Date: Dec 2008 Location: Garden Grove, Ca Posts: 17,023	You can check Lowe's and HD, but most likely you will need to find a local plastics supply house for the solvent. There are a few here in the local Los Angeles area, I suspect if you live in a major metropolitan area there will be a supply house near you.

08/15/2013, 06:32 PM	#12
Brianmil7516 Registered Member Join Date: Sep 2009 Location: Cheektowaga, NY Posts: 36	you may be able to salvage it.. it would require cutting the acrylic to remove the screw holes then apply correct bonding to the new edges.. the top would require additional bracing if it is totally open.. can't tell from the picture.. and generally flow-wise you want your drain "pipe" to be bigger than your return "pipe" from what i see and drom what you described.. if you are using 1" PVC for the big hole and 3/4" PVC for the little hole.. you will have 330GPH draining from your tank into a sump and 660 GPH returning to the tank... at some point your sump will run dry... other than that...i love the design.. it is a unique shape.. you could get some interesting flows in that shape with strategically placed power heads...

08/16/2013, 08:11 PM	#14
Griznock Registered Member Join Date: Jun 2013 Location: Tulsa,Oklahoma Posts: 121	http://www.youtube.com/watch?v=da78xmuwTHo this guy has several videos on welding acrylic tanks very informative.