Ge Silicone I - How long before it will hold something

[president89]

So, I am trying to install 5 separators in a 40G breeder. I understand before I add water I should wait 24-26 hours. Does anyone know how long the silicone will take to hold the separators without support? I want to move on to the next one! They are 3/16" thick 17.5" x 15.5(approx). I realize that acrylic and silicone don't stick to each other very well.

 

[uncleof6]

24 - 26 hours for a very small bead (1/8" - 1/4") of silicone. The amount used for baffles and other tank uses is much 'thicker' requires at least a week to fully cure to the point it can be considered safe. So it is going to be around two weeks before you get around to finding out what it is going to do with water in it. Generally, after a few days, it is cured enough for 'light' handling, but you don't want to knock it around.

I would give it a good while, before messing with it. The thinest material whether acrylic or glass, that you should be using, is 6mm (1/4",) so you are starting out behind the 8 ball.

 

[president89]

I would give it a good while, before messing with it. The thinest material whether acrylic or glass, that you should be using, is 6mm (1/4",) so you are starting out behind the 8 ball.

Oh Boy, is the concern around bowing? I think you are right to be concerned. I'm hoping that since I will have equally dimensional size chambers, that the distribution of pressure will be equal. I wish I asked before I bought the acrylic! Oh well, we'll see what happens. If it doesn't work, I'll order up some 1/4" glass sheets.

 

[billdogg]

Having built sumps using both acrylic and glass, I won't use the acrylic again. That particular sump is still up and running some 20 years later, but the acrylic has bowed (even with fairly even water pressure on both sides) and just looks ugly. The glass baffles look great (almost like I knew what I was doing?). I used GE I without issue. You can remove the brace(s) after a few hours, but as mentioned above, it needs some time to cure for full strength.

 

[president89]

alright I think I'm going to abort and go with glass.

 

[billdogg]

Call a local glass shop - the kind that does window repairs - they will have 1/4" in stock. Measure the width inside the sump and subtract about 1/8"+ call it 3/16" or so for a good fit but still have some silicone between the baffle and sides of the tank. I used scrap wood to rest the baffles on and used painters tape to hold them at the top. A plastic spoon on a dowel will get you down in there to smooth out the silicone beads.

 

[president89]

Got my 1/4" glass. Waiting for my black krylon fusion to dry. So how can I remove the old silicone from yesterday from the tank? I was doing such a messy job with it.

 

[mcgyvr]

Got my 1/4" glass. Waiting for my black krylon fusion to dry. So how can I remove the old silicone from yesterday from the tank? I was doing such a messy job with it.

razor blade

A great "trick" when working with silicone is to lay painters tape on each side of your joint as thick as you want your bead to be.. Then apply silicone. then smooth with a wet finger then just pull the painters tape off.. voila.. beautiful seams.

 

[president89]

Got it, just watched a good video on resealing a tank. I'll follow the same. I did read some threads on using hot glue to hold the panes in place. What a good tip that is! It cures in minutes, and it'll hold it nice when trying to silicone.

Everything is in. Note to the noobs. If you are trying to install seperators - two important things. 1. Make sure the compartment is wide enough for your caulking gun, or else make other arrangements. 2. Tape off the dividers BEFORE you put them in place - way easier taping dividers outside the tank. I learned #2 on the very last of 4 dividers.

This is an excellent video on silicone work - https://www.youtube.com/watch?v=XKactsdPpO8

 

[Ratpack]

So I used GE Silicone I to put the baffles in my new sump. I would like to put it in use this Sunday. That will be 8 days from the application of the silicone as I did it this past Saturday morning. It has also been sitting in the back of my SUV in the nice SC sun. Do you think it will be cured enough or should I wait longer?

 

[SeedlessOne]

24hr cure time is plenty.

Silicone will also not be tacky and will set at 30mins. I just made another sump last night and was able to remove the supports after 15 mins and start to silicone the next baffle.

 

[lFATHOMl]

I did 24 hours when I made my sump although i think it's cured before that

 

[toothybugs]

So I used GE Silicone I to put the baffles in my new sump. I would like to put it in use this Sunday. That will be 8 days from the application of the silicone as I did it this past Saturday morning. It has also been sitting in the back of my SUV in the nice SC sun. Do you think it will be cured enough or should I wait longer?

Silicone doesn't cure by heat, it cures by humidity - the vinegar you smell is the silicone curing. It reacts with water to release vinegar (acetic acid).

 

[Ratpack]

Silicone doesn't cure by heat, it cures by humidity - the vinegar you smell is the silicone curing. It reacts with water to release vinegar (acetic acid).

Well, that is something else we have plenty of here in SC. When I put the baffles in, I didn't even have to use support, they held themselves and within a few minutes, the silicone was skinned over really well. The car should have plenty of humidity in it since it hasn't moved all week. I know when I open the car, there is no vinegar smell at all. I will check it today and get an up close sniff, but if there is no smell, I should be OK right?

 

[uncleof6]

Well, that is something else we have plenty of here in SC. When I put the baffles in, I didn't even have to use support, they held themselves and within a few minutes, the silicone was skinned over really well. The car should have plenty of humidity in it since it hasn't moved all week. I know when I open the car, there is no vinegar smell at all. I will check it today and get an up close sniff, but if there is no smell, I should be OK right?

Considering it has been in there for a week+, I would assume it may be ok. That does not mean it is. How long it takes for the silicone to cure through (cures from the outside in) depends on how much you actually used.

Reiterating the cure time, the 24hrs suggested on the label is for a 1/8" bead of silicone, not the globs used to hold baffles and seams together.

Also to clarify, the cure time of silicone is relative to BOTH humidity, and temperature. The higher the temperature and humidity, the shorter the cure time.

 

[tkeracer619]

People often look surprised when you say humidity cures it.

I used to fill engine mounts with window weld (urethane) to make them solid. Lots of material there to cure and would take 2-3 weeks normally. Drop them in a bucket of water and they would be cured in a few days.

I used acrylic in my glass sump but it is 1/2". Has held up well over the years.