How to stop RTV going off in the tin ?

It's a chemical reaction so putting in the 'fridge or freezer will slow it down - it may have a lower storage temperature limit though so read the literature

AWEM

I just happened to be reading the notes from Tiranti on RTV at the weekend and in them they suggested that the shelf life could be extended to about a year using refrigeration. I don't have the book to hand right now, but I think I remember the words "may" and "might" being used, so twelve months might be an optimistic maximum shelf life.

Jim.

What is this 'RTV' in a tin? The only RTV I know of is Room Temperature Vulcanising silicone sealant, eg the stuff you might put round a bath or sink, comes in a gun cartridge. Are we talking about the same stuff?

Tim

There is another type that comes as two parts and sets on mixing. That's the stuff that Tiranti supply in several varieties. The bath seal type takes ages to set in a mould but is available in smaller cheaper quantities. Just needs lots of patience!

Henry

Thanks to all for the answers. I will try the next lot in the fridge.

Mike

Are you saying the bath seal type be used as a casting medium as well as the Tiranti stuff ? That would be a whole lot easier from my pov as I would be able to pop out and buy small amounts as and when required instead of ordering it by the tin over the internet. Can you suggest brand names suitable for white metal casting for me ?

Thanks,

Mike

Just make sure no-one mistakes it for mayonnaise - it would add a whole new meaning to the expression "my lips are sealed"

Regards, Tony

the stuff you want is called high modulus silicone sealant ..

this stuff is like rubber ...a 6 inch piece of it can be stretched to

the hi mod also sets within hours .

be careful what you buy ...some have mastic mixed in with the silicone ...

seams that Dow corning is the stuff to avoid at all costs and is the dearest and is most likely to have mastic mixed in with it . .

plumbers merchants ...builders supplies sell the high mod ...

best price on a tube would be =A31

all the best.markj

So all Dow Corning products are s**te then?

You'd better let all their industrial customers who have used their products for decades know how bad they are. Not that they'll believe you - because I certainly don't.

Did I say :- all Dow corning is s**te

Have you come here just to argue ..would you rather him go down a long road of mistakes?

All i did is give advice ..to help him avoid making the same mistake Ive made a few times

Every time I've bought Dow corning silicone, I've ended up with some inferior product that is half mastic half silicone and don't set up ...what ever it says on the tube..........if its says silicone it should be 100 percent silicone ..and should not have to pay =A34 plus for inferior crap

Seams silicone is like DVD players ..the less you pay the better it is ....thats what Ive found.

and don't comment on these news groups if you're not prepared to give out your email address ...a comment is not valid coming from a nobody at nobody dot com.

Any more comments by you, to me shall be ignored .

all the best.markj

In article , mark writes

Mark,

Can't agree with this point. I, like many others, have found that posting on usenet using a genuine e-mail address results in a lot of spam. Genuine participants are of course always willing to give their e-mail in a form not harvestable by robots.

David

You may note that I have never hidden my identity or munged my email address when posting in any group or forum.

OTOH, I run a very well configured mail server...

Mark Rand RTFM

I had to munge my email address, as I was swamped with spam. In fact, I changed service providers as well!

Steve R.

Not exactly but it was implied from your posting specifically "Dow corning is the stuff to avoid at all costs"

Your experience differs wildly from thousands of other users, £4 is hardly a premium price, Dow Corning supply products costing ten times that price for just 100ml.

Your experience differs wildly from thousands of other users.

Sad, very sad. The comments were not intended for you, you've quite obviously made up your mind and nothing, not even the truth will change it.

Ditto.

Perhaps for this application (which needs a 100% silicone, without mastic) commonly available dow corning "silicone", which *does* contain mastic, is the least suitable, despite being most expensive?

My experience is in using the moulded silicone as the finished object. I use it to make bow bumpers for model racing yachts. There seems to be a wide variation in setting time and Dow Corning was good when I used it. Typically I buy what's available easily and cheaply and Dow's is more expensive. Not that I get through a lot. Don't know how it stands up to molten white metal but for a few bob I guess it's worth a try.

Henry address is spam resistant - just remove the bait from the trap!

I have some Dow Corning Silastic 3120 IIRC 2 part silicon rubber suitable for casting the likes of pewter (Britania metal these days) and it seems to keep well, I haven't used it for a couple of years but the last time I did it worked well and was about 4 years old then. IIRC the beneficial additions making it more heat resistant are the addition of iron oxide, rust, which gives it the characteristic brown colour and heat dispersion so helping it to cope with the high temps, that's what I was told. While pewter is beyond it rated temp range it still works well but has a reduced lifetime, not a problem for the low number of castings I do. I got mine from "Industrial silicones and lubricants ltd", I had to by more and I didn't know about Tiranti at the time. IIRC Tiranti sell smaller quantities at higher costs so it's a balance regarding how much you actually need.

I signed up on google groups using my (former) employers email. (I had some work related questions at the time) seems I dont get *any* spam from usenet at all.....

Dave