Removal Of Tank Cross Brace

funkyman

funkyman

Member
Has anyone else had any experience doing this?
I have a 120 gallon All Glass which is . There is a very wide cross brace in the middle of the tank, which effects the lighting of the tank in a big way. I realize the cross brace is needed, or it wouldn't be there.
I want to replace this wide, non transparent cross brace with two narrower transparent cross braces (one on either side). I'm thinking along the lines of a 1/4" thick, 1" to 1 1/2" wide strips. The new braces would be installed before the existing one is removed.
I'm curious as to what methods were used for the installation of the replacement braces and removal of the existing brace for anyone else who may have done this.
 
db

db

Member
I had to replace my middle brace on my aga 72 bow, but not on purpose. My halides eventually weakened it and it broke in the middle. What I did was purchase a sheet of 1/4 inch clear acrylic from HD and cut a strip as you mentioned. I then cut out the middle brace leaving about 3 inches on each side. I then drilled two holes on each side of the old brace that was left and then through the acrylic. I clamped the tank back in place and then used nylon screws and nuts to secure the brace.
 
darknes

darknes

Active Member
I would recommend that you do this only to an empty tank.
If the tank is full when you go to put the braces on, they will not be very effective. You want to install the braces before any stress is applied on the glass walls (from water pressure). This way, when you go to fill the tank, the stress is properly distributed to the braces.
 
funkyman

funkyman

Member
Emptying the tank is not an option. That's why I'm asking for other's experiences. I had already considered the stress of the tank being full, which is why I mentioned the new braces would be installed be for the old one would be removed.
 
darknes

darknes

Active Member
Gotcha.
Somehow I read right past that sentance; In which case, adding the two braces before removing the middle brace should be fine.
I have no experience with this, I just wanted to put in my 2 cents.
 
hedonic

hedonic

Member
Drain tank as much as possible, clamp in place before applying brace. Apply brace and fill back up, if your siliconing, leave clamp on for a few days
 
fishy7

fishy7

Active Member
Slide a brace on both sides of the center brace, then remove the center brace. I would also ecommend doing a large water change to take some of the pressure off the brace in general....
Not sure this will work but just a suggestion.
 
turningtim

turningtim

Active Member
Is the tank long or tall? I would think you will need at least 3/8" glass but 1/2" would be better. Don't really know if there is enough "meat" on the trim to provide holding power. I just broke a center brace on a 50 that I was using as a temp. QT tank and boy was I surprized at how much the tank bowed with out the center brace. It is only 20" T x 48" L. The glass deflected about 1/2"-3/4" of an inch.
Really tough call......
HTH
Tim
 
phixer

phixer

Active Member
Hi, cool avitar. This is almost identical to a post a few months back.
Very often there is engineering data availible which represents specific charactaristics of materials under given conditions. This wont be hard to find out, but first you have to have to know a few established non variable facts.
How far apart do you need the new braces be located? How thick is the glass and what are its dimensions?
Got an idea of how to figure this out based on information similar to a suspension bridge config that might be transferable but need more info to see if it will work. I'll try to help you by checking back at this thread.
 
phixer

phixer

Active Member
Different materials have different charictaristics and some work better than others for certain applications. For yours I believe you could use glass or plastic, but plastic is better for this type of loading. Yes I know some tanks use glass cross members but they also use plastic frames. Keep in mind that if glass bracing is used the pulling force will manifest itself at the weakest point which would be the silicone bond holding the glass braces to the sides of the aquarium not the glass itself. This will work if you use enough silicone and big enough braces.
However if your frame has been removed and there is no lip around the top edge of the tank you could make a couple of sliding braces using two thick acrylic blocks with a grove cut into each end for the glass to fit into. (similar to a sliding window pane). This material is easily obtainable from the scrap bin of most plastic suppliers. Because each brace is one peice they will be inherently stronger in this circumstance for this type of loading then two seperate pieces held together by silicone patches. The force would be applied to the plastic and the glass, not the silicone. Make sure they are wide enough so that the stress is distributed evenly across the glass and not centralized on the edge of the glass or the glass could snap off. These braces are moveable and could be slide either direction. There are many types of thermoformable plastics other than acrylic that would work also, the drawback: heat from some types of lighting will soften them if too close.
You really need to know how much defection your looking at to adequetely determine the width, thickness, depth of the notches, overhang and placement of the braces.
 
jakebtc

jakebtc

Member
Originally Posted by hedonic
Drain tank as much as possible, clamp in place before applying brace. Apply brace and fill back up, if your siliconing, leave clamp on for a few days
 
jakebtc

jakebtc

Member
Originally Posted by TurningTim
Glass tank, needs glass bracing. acrylic will not stick to glass.
not true, your not attching the brace to the glass of the tank your attaching it to the trim ring with vinyl screws and maybe silicone "1/4 in. acrylic"
if it were some other brand of tank similar to that of acrylic construction with no plastic bracing then you would want glass for sure
 
funkyman

funkyman

Member
Here is a pic of a similar tank. Mine is the same, but reef ready. The cross brace is part of the frame that goes around the top of the tank.
 
phixer

phixer

Active Member
Wouldnt it be easier just to modify your lighting? placement of that brace is critical. If your dead set on this acrylic can be drilled and taped, you could drill new holes in the plastic frame add new cross braces use nylon machine screws and washers. Might be unsightly if left uncovered but could work.
 
jakebtc

jakebtc

Member
Originally Posted by Phixer
Wouldnt it be easier just to modify your lighting? placement of that brace is critical.
it's about esthetics I had the same prob w/ my 65 aga
wouldn't have the same prob w/ a 75 though
can't see that 2 evenly spaced braces would be any weaker then one of equal strength
 
phixer

phixer

Active Member
Originally Posted by jakebtc
it's about esthetics I had the same prob w/ my 65 aga
wouldn't have the same prob w/ a 75 though
can't see that 2 evenly spaced braces would be any weaker then one of equal strength
Sure would. Check this out, what are your thoughts?
It depends where they are located and their spacing, I mean if they are evenly spaced too far from the centerline they wouldnt be helping, for example one brace centered would be stronger than two braces placed at opposite ends of the tank.
Im thinking that drilling a couple of horizontal holes on each end of the new cross braces and using nylon machine screws and flat washers might be the way to go with this. 1/4 is too thin unless its very wide, but then very succecptible to heat from the lamps. Need to know how much deflection to accurately determine cross memeber specs. Otherwise were guessing, how much pulling force does the current cross member support? How much bowing does it prevent ? knowing this will help us to determine an adequeate substitute.
I mean he could even use nylon suspension wires but would be very cheesy IMO.
 
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