Which sealant for internal uPVC windows

[danlightbulb]

Picking the right sealant is an area I often find a real hassle. There's so many different types and it's not clear always which one is best for which application.

I used a supposedly anti mould frame sealant internally on my bedroom windows when I decorated it a couple years ago. I thought that would be the right product.

It went black though. I've just finished stripping it all off. It also shrunk and cracked. The bits that didn't go black have gone yellowish instead.

There's silicone of various types, a newer polymer based product, frame sealants, caulks (maybe the same thing).

I used DOW 796 low modulus neutral cure silicone to recently seal up external door frame which needed doing.

Can't find out whether that's external only or can be used internally as well. Although I thought I'd looked for anti mould, 796 doesn't seem to be anti mould.

Does anyone know which sealant to use for uPVC internal windows (corners, trim, and sealing to window ledge), that won't go black, yellow, or shrink please?

 

[dlockers]

I use plumbers gold where it matters. I tried BT1 once and it was horrible stuff.

 

[DJMK4]

I just used the same sealant on my window frames that I used around the bath. White dowsil 785 I think . Has mold protection

No idea if it is the wrong one. It does a good job around my bath though

 

[danlightbulb]

I use plumbers gold where it matters. I tried BT1 once and it was horrible stuff.

Thanks not heard of that one before. It's a hybrid polymer with anti mould additive and states upto 20% flexibility. Doesn't specifically say suitable for uPVC, have you used it on uPVC before?

I just used the same sealant on my window frames that I used around the bath. White dowsil 785 I think . Has mold protection

No idea if it is the wrong one. It does a good job around my bath though

Thanks o was looking at 785 earlier there seems to be 2 versions, 785 and 785n, I think the n means neutral cure (won't stink).