Sealant compatible with Polypropylene

[Gents]

Hi All, I recently fitted a Maxxair extractor, and it seems that the Silkaflex I used, whilst sticking to the roof , has not adhered , quite so well to the extractor shaft, where it enters the roof. I am getting a very small amount of water ingress, when it rains hard.
I believe the shaft is Polypropylene , does anyone know of a good sealant that will adhere to both the metal and the Polprop?
I would be grateful.
Regards
Gents

 

[Otter Spotter]

Hi All, I recently fitted a Maxxair extractor, and it seems that the Silkaflex I used, whilst sticking to the roof , has not adhered , quite so well to the extractor shaft, where it enters the roof. I am getting a very small amount of water ingress, when it rains hard.
I believe the shaft is Polypropylene , does anyone know of a good sealant that will adhere to both the metal and the Polprop?
I would be grateful.
Regards
Gents

Which one did you use? I believe it should be sikaflex 522, but I could be wrong

 

[L' Hobo]

Hi All, I recently fitted a Maxxair extractor, and it seems that the Silkaflex I used, whilst sticking to the roof , has not adhered , quite so well to the extractor shaft, where it enters the roof. I am getting a very small amount of water ingress, when it rains hard.
I believe the shaft is Polypropylene , does anyone know of a good sealant that will adhere to both the metal and the Polprop?
I would be grateful.
Regards
Gents

Is it possible that you didn't completely clean BOTH surfaces, easy to overlook on a new product?

For further info on Sikaflex, just put it in the search, (top blue band on right) and you will find it covered for sure.

 

[eurajohn]

Don't think the Sikaflex adhesives most people use for sticking / gluing are suitable when looking to make a reliable seal for vents etc. should really use a non setting sealant such as SikaLastomer710.
It can be a bit messy to use if not used to its characteristics but when familiar with it is brilliant.

 

[Jev88]

W4 mastic on a roll for roof vents/hatches for me has worked well.

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[Gents]

Thanks for your reply, I’m pretty sure it was 521, it was only after using it that I realised there was others. Unfortunately I have thrown the empty cartridge.

Which one did you use? I believe it should be sikaflex 522, but I could be wrong

 

[Gents]

W4 mastic on a roll for roof vents/hatches for me has worked well.

Thanks for your input. May have to resort to that. Fortunately it is the absolute minimum, of ingress, and it lands in the shower tray, so not a disaster. At least, not yet!

 

[eurajohn]

The Sika 710 I suggested earlier is better (in my opinion) than the mastic strip, the mastic strip tends to be quite stiff whereas the 710 is butyl and is gunned on in the same way as the adhesive you have used, it does have the added advantage of being far easier to remove if it should ever be needed to.

 

[Gents]

Is it possible that you didn't completely clean BOTH surfaces, easy to overlook on a new product?

For further info on Sikaflex, just put it in the search, (top blue band on right) and you will find it covered for sure.

Will look at that also, thankyou. I am usually very diligent, but it appears, not this time. Still, having cut 11 openings through the van outer, for various things, some large, some small, I & this being the first problem, I can’t complain.