Project External Glass Overflow
- Thread starter Tunjee
- Start date
Travis
10 and over club
After reading through this thread I decided that I wanted to build one of these overflows for my 75 FOWLR. I wasn't brave enough to take the plunge and start dremeling my 75 so I decided to give it a try on an extra 20H I had laying around.
<img src=http://reefcentral.com/gallery/data/500/17792126_2632.JPG>
<img src=http://reefcentral.com/gallery/data/500/17792126_2630.JPG>
Since everything was successful I now need to order my glass pieces for the overflow.
This was much easier than I had expected, but very time consuming. The first tooth took a good 45-50 minutes.
By the time I was on the third tooth I was grinding each tooth out in about 10 minutes. I used the ball tip bit to trace the outline of the tooth and start the hole. I found that tracing the outline allowed the water to pool up where you need it, which allows for less time spraying water. Then I would use the other bit to route out the tooth. Just as Tunjee says, you need to constantly plunge the bit up and down. It was pretty easy to control the bits. There were several times when the bits would run off but never really scratched the glass. I did go through 2 ball tip bits but I think that was from the beginning of the learning curve when I was pressing a bit too hard and not using enough water. I now know that if you see the bit get red you are either pressing too hard or not using enough water, most likely it is due to the former. I will post more pics as the project progresses.
Thanks Tunjee for sharing this with us. This is a cheap and easy way to do an external overflow, which are the best overflows, IMO.
<img src=http://reefcentral.com/gallery/data/500/17792126_2632.JPG>
<img src=http://reefcentral.com/gallery/data/500/17792126_2630.JPG>
Since everything was successful I now need to order my glass pieces for the overflow.
This was much easier than I had expected, but very time consuming. The first tooth took a good 45-50 minutes.
By the time I was on the third tooth I was grinding each tooth out in about 10 minutes. I used the ball tip bit to trace the outline of the tooth and start the hole. I found that tracing the outline allowed the water to pool up where you need it, which allows for less time spraying water. Then I would use the other bit to route out the tooth. Just as Tunjee says, you need to constantly plunge the bit up and down. It was pretty easy to control the bits. There were several times when the bits would run off but never really scratched the glass. I did go through 2 ball tip bits but I think that was from the beginning of the learning curve when I was pressing a bit too hard and not using enough water. I now know that if you see the bit get red you are either pressing too hard or not using enough water, most likely it is due to the former. I will post more pics as the project progresses.Thanks Tunjee for sharing this with us. This is a cheap and easy way to do an external overflow, which are the best overflows, IMO.
psyco_guy_abd
New member
Just read the whole thread for the 3rd time and was wondering if anyone had any luck cutting the back glass of a 48" tank? A few posted that they were going to try but never came back.
I am thinking of cutting a slot about 8" long and 1 or 1.5" deep near the corners and possibly reinforcing with an extra sheet of glass.
Anyone?
I am thinking of cutting a slot about 8" long and 1 or 1.5" deep near the corners and possibly reinforcing with an extra sheet of glass.
Anyone?
psyco_guy_abd
New member
Wagerja, what side of the tank did you cut? Was it a "short" side or a "long" side? I am thinking of cutting the 4' side of my 75 and want to make sure it won't weaken the glass to much. Someone posted that they cut the long side of their 90 and it cracked after being filled with water.
WAGERJA
New member
It was the short side. I highly advise you NOT to cut the long side (4') of your tank.
If you do try it on the long side, only do so on a empty tank and make two overflows (one on each edge/end, NOT one in the middle of the span) otherwise you WILL more then likely be replacing that tank and dealing with SW on the floor.
Leak Test! Leak Test! Leak Test!
Happy Grinding!
-J
Ps you can see my tank a couple pages back on this thread.
If you do try it on the long side, only do so on a empty tank and make two overflows (one on each edge/end, NOT one in the middle of the span) otherwise you WILL more then likely be replacing that tank and dealing with SW on the floor.
Leak Test! Leak Test! Leak Test!
Happy Grinding!
-J
Ps you can see my tank a couple pages back on this thread.
psyco_guy_abd
New member
Impur, did you try it? what kind of brace?
I have a standard 75 (48x18x20) and it has a brace in the top center already.
My plan was to reinforce the back with a second sheet of 1/4" glass that would go the full length between the plastic trim and go to the bottom of the teeth that I want to cut for the overflow, and then do one of two things:
1 cut a single large overflow in the center of the tank about 24" long and 1" or 1.5" tall
OR
2 Cut two smaller overflows near the ends of the tank, both 12" long and 1" or 1.5" tall.
I would prefer the first option if it will be strong enough because it will be less work and a little cleaner plumbing wise.
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The second line from the top would be where my reinforcing piece of glass ends at the top of the tank
the little drawing didn't work, I'll post a better one when I get home from work
I have a standard 75 (48x18x20) and it has a brace in the top center already.
My plan was to reinforce the back with a second sheet of 1/4" glass that would go the full length between the plastic trim and go to the bottom of the teeth that I want to cut for the overflow, and then do one of two things:
1 cut a single large overflow in the center of the tank about 24" long and 1" or 1.5" tall
OR
2 Cut two smaller overflows near the ends of the tank, both 12" long and 1" or 1.5" tall.
I would prefer the first option if it will be strong enough because it will be less work and a little cleaner plumbing wise.
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|__________________________ |
The second line from the top would be where my reinforcing piece of glass ends at the top of the tank
the little drawing didn't work, I'll post a better one when I get home from work
psyco_guy_abd
New member
Ok, I guess I am going to try it and then leak test for a week or so. I called around and a new back glass will cost me about $30 so I'll test the theory and let everyone know. Any ideas what I can do with 50-70lbs of live sand for a week while my tank is full of cold fresh water in the garage?
WAGERJA
New member
Actually I does make a differenceââ"šÂ¬Ã‚¦ the middle top of the back pane is where there is the most deflection(the bottom has the botton pane to support it)ââ"šÂ¬Ã‚¦ and the most likely place to have a crack start if there is a flaw(read; the weakest part of any tank) ââ"šÂ¬Ã‚¦ I ââ"šÂ¬Ã‹Å“m not saying it canââ"šÂ¬Ã¢"žÂ¢t be done when braced properly but be careful and make sure you radius all corners. 90-degree corners are not your friend in glass that is under stressââ"šÂ¬Ã‚¦ good luck and be sure to post some pics.
-J
-J
impur
New member
I would think that any flaw anywhere in the glass would be cause for concern. But the top of the tank only has an 1/16" piece of plastic siliconed to it. I mean that plastic is so weak and flimsy i can't see how it provides any support. It broke with minimal pressure once i removed it. IMO its just to protect us from the sharp uneven edges underneath and also a place to rest a top or light.
8BALL_99
New member
The plastic is just for looks.. Call AGA and ask them they will tell you it serves no structural purpose. Its just for looks...
I see what your saying WAGERJA. But I still dont think taking a 1" or so slot out at the top of the tank weakens it much. I would do it, You have to think.. I'm sure they dont use glass that is just barely strong enough... That would be a liability issue. Most anything made that will be under preasure.. Airtanks ect... can handle more then there rated for..
I see what your saying WAGERJA. But I still dont think taking a 1" or so slot out at the top of the tank weakens it much. I would do it, You have to think.. I'm sure they dont use glass that is just barely strong enough... That would be a liability issue. Most anything made that will be under preasure.. Airtanks ect... can handle more then there rated for..
WAGERJA
New member
impur said:
Ya know ya would think that as a casual observer and in a non-modified tank your mostly right, but when you start removing material from a sensitive area of the tank structure like this, things can go wrong... some one else on this thread tried this same thing with a partly filled tank and it cracked... the flaw I was talking about is in the new cutting and a micro fracture caused by a jumping bit (or something similar) will go unnoticed until it propagates under load and then you have a failure on your hands. I'm just trying to give psyco_guy_abd fair warning...
J
FWIW I have done this mod on a large tank, hand built glass tanks and I'm suppose to be designing a power plant right now not surfing RC. :bum:
WAGERJA
New member
8BALL_99 said:
While youââ"šÂ¬Ã¢"žÂ¢re on the phone with AGA ask if they will still warranty the tank after you remove the top plastic.
8BALL_99 said:
True to a point but they are in business to make profit not build tanks like a M1A1 TANK! That being said there is a lot less over kill then you may think (its call a Safety factor in the industry).
-J
