Mould Resistant Silicone

[breezer]

fair point

try this with this

please ignorethe fact the second one contains slightly less, as it costs more

 

[bod-one]

The pricing of these materials will depend upon a number of factors not least the supplier and the marketing strategy. The Screwfix brand can only trade on it's price wheras Unibond has a prime name.

Never confuse a silicone with an acrylic, acrylics are overpaintable but no good for bathrooms. Silicone is water (and paint) repellent, highly flexible, bonds to most anything and stable. A cheap grade may well be silicone but can also contain extending (cheapening) fillers which harm all of the good properties above. I'd avoid the cheapest materials but don't pay over the odds. You pays your money...

 

[ChrisR]

Some "silicones" and also some of the "technology beyond silicone" products are paintable.
bod-one do you know what's the difference in the constituents in the different grades of "silicone"?

 

[bod-one]

I don't trust a lot of new stuff such as water based primers or gloss - give me smelly oil based paints any day. To get overpaintable silicone you lose some of the most precious properties of silicone ie that nothing sticks to it is good! Generally silicone is for bathrooms/showers/kitchens not usually used with paints, use acrylics for frame/gap sealing where paints are used. Of course the manufacturers will try any 'new' idea to help sales, whether or not it is actually better.


I did check up on a few things and my previous message was pretty near to the mark ie
- Big brands earn big bucks (but higher price doesn't always guarantee better product)
- Be wary of cheap own labels e.g DIy shed labels - they buy by price, some grades can be artifically extended with white spirit made cheaper but evaporates over time leaving a shrunk harder seal that will not cope with any movement!! That said, some own labels may also be the very materials commanding 5-100% more in other brands!!
- Best bet is to avoid DIY sheds, they do not really play for good materials and repeat business, on the other hand buy brands from builders merchants who need plumbers to keep coming back.

Everbuild, Vallance (own by Bostik), Bond-it, Adshead Ratcliffe, Wurth are all good brands. Unibond are owned by Henkel who also own Solvite, Elch and Loctite are also good but you tend to pay a premium

 

[ChrisR]

to get overpaintable silicone you lose some of the most precious properties of silicone ie that nothing sticks to it

...but that's the one I refered to as having lasted getting on for 20 years and still looking like new.

Evo-stick is another make which is OK.