# RTV silicone for sealing?



## forteh (Feb 9, 2009)

A sudden thought struck me today...

I use RTV silicone for sealing the base gasket on my supermoto, plus a couple of other areas on the engine. Its room tempertature vulcanising (hence the RTV) and resists temperatures up to 300 degrees C or there abouts.

It isnt intended for bathroom use and as such doesnt have any fungicides or similar in it.

Can it be used for sealing vivs?
This link seems to indicate that RTV silicone is used for building aquariums and is safe to do so. Can anyone shed any light on this?

The reason for asking is that a tube of RTV silicone costs about £1.50 as opposed to £10.00 or so for a tube of 'aquarium' sealant that for all intents and purposes appears to be RTV. As stated in the link above, successful aquarium building relies on the strength of the bond and certain RTV silicones can cure too quickly, causing a weak joint; however in a screwed together wooden viv where youre only sealing the corners this isnt an issue.

Anyone got any thoughts?


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## Jim2109 (Mar 30, 2009)

the only issue is whether or not its non-toxic. i wouldnt necessarily put too much stock in whether other people have used it or not. other people didnt necessarily do their homework to check whether it was safe first.

some RTV's are non toxic, and if thats the case then theres no reason why it cant be used. i buy aquarium silicone in caulking tubes for about £12, and thats just from a local shop. ive seen it as cheap as £8 online somewhere (look for Geocel 310ml). decent RTV in a similarly sized tube is around the £6-8 mark. so the differences in price are minimal if you search around, and the aquarium stuff is guaranteed safe.

however, there are some non-toxic RTV's out there, but not all of them are. typically if they are it will say so on the packaging because its quite a big selling point. a caulking gun tube will easily seal a very large vivarium. i used one on a 4 x 3 x 2 with quite a fat bead (in hindsight it could have been much thinner) and it didnt even use half the tube. with a better sized bead it would have used a third. you could comfortably seal the edges on a 7 x 6 x 4 viv i reckon, which is pretty large!! and for £8 it barely seems worth the bother of using anything but dedicated aquarium silicone.


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## snickers (Aug 15, 2007)

> however in a screwed together wooden viv where youre only sealing the
> corners this isnt an issue.

You will get away with just putting a bead round the joints, but sealing all the cut ends as you screw the viv together will make the viv last longer. You still need the bead round the joints of course.

I've never heard of any problems with people using other types of sealant. It's just that aquarium grade sealant is guaranteed to be OK.


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## Jim2109 (Mar 30, 2009)

snickers said:


> > however in a screwed together wooden viv where youre only sealing the
> > corners this isnt an issue.
> 
> You will get away with just putting a bead round the joints, but sealing all the cut ends as you screw the viv together will make the viv last longer. You still need the bead round the joints of course.
> ...


rather than use silicone in the joins, its better to use wood glue. you shouldnt need any screws at all, wood glue is far stronger than any screw in wood. screws tend to be used just to hold the wood together whilst the glue dries, and the glue is essentially waterproof and seals the ends. the bead on the inside is then all thats required, and glue is cheaper than silicone


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