Silicone not drying.

[MattM3]

I used RTV108 I purchased from my local Grainger The first tube I purchased was completely hardened through. The second tube I received was half hardened, but I managed to use it with my baffles. It's been over two weeks and the silicone is still a bit sticky to a point where I can remove it with my finger. The glass baffles are holding in place, but at this point I don't really know what's going on.

This can't possibly be normal. Maybe I got a bad tube of silicone? Do you think it is safe for me to fill my sump with water?

Thanks

 

[hilgert]

I wouldn't trust it. I think to be safe you need to disassemble what you did, clean it thoroughly, and start over with good silicone.

If the silicone is not good out of the tube then there is no reason to expect it to be good after application, unless you know a good Harry Potter curing spell. If the tube was/is bad I'd take it back for an exchange (tell them it still has not cured...maybe they know a good curing spell).

 

[Tom39]

I never heard of this before but I guess it is possible. I think it is safe to say that you bought some bad stuff. I would start over if I were you and not risk it.

 

[MattM3]

This sounds insane to me. I spent hours gluing all of this in, and would literally take like 10 hours to take it all apart and get the glue off. The glass alone cost about 80$. I'm so mad right now. I wonder if there is any action I can take against Grainger.

 

[mcgyvr]

YOU should have never used it in the first place..
Take action against yourself..

Shouldn't take more than an hour or so.. Its only 1 tube.. get out the razor blade and go to town.

 

[MattM3]

How was I supposed to know the tube was bad?

 

[hilgert]

This sounds insane to me. I spent hours gluing all of this in, and would literally take like 10 hours to take it all apart and get the glue off. The glass alone cost about 80$. I'm so mad right now. I wonder if there is any action I can take against Grainger.

Agree with mcgyvr...should only take an hour or so with a razor blade.

How was I supposed to know the tube was bad?

Well, once you figure out it was not a good tube, then take it back...don't keep going. Silicone should easily (almost TOO easily in fact...) "ooze" out of the tube.

Personally, while I used to be a fan of putting in glass baffles into a off-the-shelf glass tank, I know just make my own sumps with acrylic. If you are not handy with that it's usually no hard to find someone in the hobby that can do it, or find an acrylic supplier/shop (these would typically advertise themselves as plastics supply shops) that can build you a box to your exact dimensions. Or, depending on what you need, just by a prebuilt sump online.

 

[supra400hptt]

I've had that problem with old black silicone. When it's old it looks kind of lumpy and grainy. Won't harden correctly. You'll have to redo.

 

[MattM3]

I've never actually removed Silicone, so if it's not so hard to do I will give it a swing. This make me feel a lot better about doing it thanks.

 

[ca1ore]

If it is not cured/hardened then it should not be that hard to remove - though a bit messy. Remove as much as you can with a razor blade, then clean up any residue with acetone. Silicone should skin pretty rapidly (an hour or two) and then fully cure in 24-48 hours. Just don't put in on too thick.

 

[MattM3]

Does anybody know where to look for the expiration date on a bottle of RTV108? I can't seem to find it anywhere. Thanks.

 

[hilgert]

http://www.reefcentral.com/forums/showthread.php?t=2154774

http://reefcentral.com/forums/showpost.php?p=19906581&postcount=23

 

[MattM3]

Perfect. Thank you.

 

[uncleof6]

If it is not cured/hardened then it should not be that hard to remove - though a bit messy. Remove as much as you can with a razor blade, then clean up any residue with acetone. Silicone should skin pretty rapidly (an hour or two) and then fully cure in 24-48 hours. Just don't put in on too thick.

RTV100 series (and similar structural adhesives) skin in 5 - 7 minutes (the process starts.) Further tooling is a recipe for disaster after the first ~ 5 minutes or so.

These silicones take at least a week to fully cure, not 24 - 48 hrs. In the case of RTV100 series, that is 7 days for a 1/4" bead, (from the product documentation,) making most aquarium applications a multi-week curing process.

Silicone has a set shelf life, usually 2 years. However, they have specific storage requirements, and these requirements are seldom met once the product leaves the manufacturing facility. This severely reduces the shelf life. So generally, if it is a year old, chuck it; if it is expired, don't buy it. Grainger has storefronts all over the place. Whenever possible, though it may be inconvenient, walk in the door to purchase silicone—don't buy it online.

Cleaning up silicone, cured or not, is not a fairly easy task. It all has to be gone, making the final cleaning a matter of acetone (or MEK better,) steel wool and elbow grease.

 

[TropTrea]

Grainger? Several places I worked at used them as prefered suppier. But I was disapointed by what they sent me on many ocassions. The hardened tubes should have been a first lue that they were either long expired old stock or that they were subject to excessive heat.

On jub I hated was when someone turned off the cooling on an injection silicone molding machine and no one caught it untill it was too late. Complete dissassembly and soaking all the parts overnight in the MEK solution. Then the next day playing with picks and scrapers to get everything clean.

You should not have that much of a problem cleaning it though as it never hardened for you. and you do not have moving parts with small orfices for the material to flow through in a calibrated way. You should be able to clean up the verflow in under an hour.

 

[MattM3]

Silicone I was using was roughly 4 years old. :X

 

[TropTrea]

Silicone I was using was roughly 4 years old. :X

Some types could still be good but they would need to have been refigerated for that long. Usualy they are good for a year or two max from the mfg date. But again different kinds have different shelf lives. And I'n not familuar with yours.

 

[uncleof6]

Where did you get the 4 year old tube? I would be all over them saying ***... RTV100 series has a drop dead date two years from manufacture, in ideal storage conditions, so it was probably dead after the first year.

 

[TropTrea]

Where did you get the 4 year old tube? I would be all over them saying ***... RTV100 series has a drop dead date two years from manufacture, in ideal storage conditions, so it was probably dead after the first year.

I think he bought it mail order or internet order. Yes from some sources not to mntion names you have to check what you got. When the shops I worked for used to order thousands of dollars a week from them there seemed to be big return shipments every week to them for issues like this as well as getting the wrong stuff.

I rememner once when they we ordered two 55 gallon drums one of hardner and one of resin and got two barrels oif resin. We returned a barel on resin and three weeks later got a barrel of hardner for a different mixture. It took over two monts to get the right stuff that had not gone past the expiration date. I doubt they check the exiration datyes on there shelves.

Now this is for a corperation ordering from them which nation wide probably spends 1/4 million a year with them. Will they give the same service to an individual that orders only a couple hundred dollars from them a year?

 

[uncleof6]

Yeah there are some "no name mentioned" that will sell you expired silicone, even over the counter. Happens quite often in fact. That is why the date codes were posted, so folks would be forearmed.