8 replies to this topic

[Barca888]

Hello i have a long 180 l tank with a small crack i wanna patch up. Other then these points if i have missed something can u please tell me.

-Rough up the surface of both the tank and patch with silicon carbide sand paper to where the silicon is gonna be attached.

-Use aquarium grade silicon

Is there anything else i should know, like attaching the silicon to the dried silicon in the tank? Would that cause problems?

Thanks peter

[Anita ozfish]

Peter, first of all how big is a 180 lt?? I am useless with literage - give me measurements LOLOL
Secondly, why do you thin that you need to "rough" up the 2 sides of the glass?? I have never heard this and have done patches without plenty of times.
Thirdly, where is the crack on the tank and how big is it?? Are you planning to put the patch on the inside or outside?

electral@bigpond.com | web | Sydney, Australia.

[Barca888]

hello anita,

The tank is around 6.7 x 1 x 1 (48 gallons) and is segregated into three quarters. The crack is in the middle and is around 15-20 cm long. It starts from the same pane of glass curves out and goes back to the same piece of glass. I have read on the net to rough up the surface of the glass with sand paper to which the silicon will be applied. With my tank im hoping to apply the patch on the inside (since it is not to large). However my friends tank which is shorter has a very large crack in the middle.

Thanks peter

[Anita ozfish]

Hi Peter,
I guess seeing the tank is only 12" high and wide it won't be a big drama.

Quote:

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The crack is in the middle

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Is that middle front, back or base?? Getting blood out of a stone here
Anyway, it doesn't matter. You need to empty and dry the tank, then prep the area and patch with metho on a rag to make sure it is spotless and doesn't have any oil on it from your fingerprints. Apply silastic to the patch piece of glass and sit it over the crack. I would allow at least an inch of patch overhang on the crack all the way around. If the crack is on the base, then sit a brick or two on it as well for 24 hours. I would guess the tank is only 6mm glass - you should make the patch glass a bit thicker as well. I would leave it for 24-48 hours before adding water again. The longer, the better I think.
Good luck

electral@bigpond.com | web | Sydney, Australia.

[Barca888]

Thx anita, the crack is on the base ;\. What is silastic?

[mrseby]

Silastic is the clue you will need to fix it with !!!

you can buy this from most Hardware stores

Make sure u buy the one that is for glass tanks and preferb clear ...that way when it dries it dries clear ..

You can also buy this in colours so be carfull

If the crack is very big its always better to cut the sheet out and put a whole new sheet of glass !!!

Sometimes if u don't know ex how to fix these cracks it is worse to patch and far better to replace ...cause after the patch... Glass can be uneven, britle and or the silastic is not done right ..it leaks and at worst tank cracks again ...etc etc etc

[Barca888]

Hi ive already patched up the tanks. I used this black stuff called "gripset 51, waterproof bitumen rubber sealent". It says it is non toxic and is approved for potable water (tanks, drinking water, ponds etc). Is this stuff safe?

Thx peter

[Anita ozfish]

Sorry Peter, never heard of that. I guess now that you have already done it, you will have to fill the tank and see if it works - good luck - keep us posted

electral@bigpond.com | web | Sydney, Australia.

[Barca888]

Well after two days of drying (recommends 18-24 hrs) i put some water in the tank just to see if it stopped the crack leaking water. It did ;\. I went to see how the stuff feels to find it easily peels away from the surface . This really annoys me as we got this stuff through my friend who is also fixing a tank (with me). I told him maybe we should venture to some hardware stores. He replied by saying it is black and is cheaper (1 dollar cheaper). Not only does this put me in a bad mood im probably gonna have to reclean the surfaces.

Now to the future. Can someone please tell me a product i should use to fix this patch? The last product i used was a bitumen compound (not even silicone). The first clue might have been the missing "glass" in the what this product adheres too.

Thanks from a not too happy Peter