Is Sikaflex Still The Sealant Of Choice?

[Lightwave395]

Butyl tape, doesn't set, means the fitting can be removed in the future without destroying the GRP.

https://www.pbase.com/mainecruising/rebedding_hardware

Don't know what I did wrongly but the butyl tape around my portlights melted in 36 deg of Vendee sunshine

 

[RumPunch]

I tried 'The Dog's Bo**ox' on the boat this year and was very impressed - even cures in a damp environment

 

[V1701]

CT1 here as well, lots of different jobs, don't buy clear any more due to same issue others have mentioned...

 

[PabloPicasso]

Butyl tape, doesn't set, means the fitting can be removed in the future without destroying the GRP.

https://www.pbase.com/mainecruising/rebedding_hardware

For deck fittings use butyl tape. It never goes off and is cheap, re-useable, waterproof, and flexible. Why would anyone use anything else?

 

[coopec]

For deck fittings use butyl tape. It never goes off and is cheap, re-useable, waterproof, and flexible. Why would anyone use anything else?

I've got to mount my stanchions shortly. I planned to mount them on nylon (marlon?) pads with the idea the pads won't move but the stanchion could under load. I've noted the excellent suggestion of putting a groove around each bolt hole and filling them with Sikaflex(?).

Should I use butyl tape under the pads and stanchions?

 

[Sneaky Pete]

I’m still a big fan of Puraflex PU40. Used it for years now without any problems, and a very good price from Toolstation.

 

[peteK]

Ok for big jobs and you use most of the tube but for loads of little jobs over a long period of time butyl tape wins.

 

[coopec]

Tonight's reading.... (This looks fairly relevant?)

PU40 vs Sikaflex 291 vs Tiger Seal?

https://www.landyzone.co.uk/land-rover/pu40-vs-sikaflex-291-vs-tiger-seal.249530/

 

[lw395]

Ok for big jobs and you use most of the tube but for loads of little jobs over a long period of time butyl tape wins.

It's £5.50 or something a tube.
If you throw away half a tube twice a year, so be it.

A few of us in the yard vaguely try to have one tube on the go between us.
So we avoid starting a tube for two screwholes.
We wrap the nozzle with insulating tape and find the sealant is usually useable for months. Often have to use a new nozzle though.

But I must admit, if I don't have a tube of Poly.... on the go, and the job's not critical, I will consider making do with bathroom silicone. Which often works fine.
I've used it under fittings on my racing dinghies, and they've passed air pressure testing.

If I'm spending £££ of materials and some hours of my time, I won't skimp on a tube of sealant though. And through hulls obviously get Polyurethane sealant every time.

 

[Poignard]

Here is tip I read recently, which I haven't yet tried, for keeping the tube useable.

Let an inch or so ooze out of the nozzle when you're finished. That will set and when you next need to use it, just pull off the dried bit.

 

[eddystone]

Looked at the description for PU40 on Toolstation website - it doesn't mention waterproof?

 

[CJ13]

‘]Looked at the description for PU40 on Toolstation website - it doesn't mention waterproof?[‘

Hmm- look at the data sheet. It says ‘good resistance to sea water’.

 

[Poignard]

https://www.ct1.com/product-applications/underwater-sealant/

 

[adwuk]

I believe it all depends on whether you wish to ever remove the track or fitting in the future. If you don't, then CT1 if above the waterline or 3M 5200 if below. If you do, then Arbomast BR if above the waterline or 3M 4200 if below. At least they would be my choices.

 

[vyv_cox]

I believe it all depends on whether you wish to ever remove the track or fitting in the future. If you don't, then CT1 if above the waterline or 3M 5200 if below. If you do, then Arbomast BR if above the waterline or 3M 4200 if below. At least they would be my choices.

3M 5200 and Sikaflex 291 have almost identical specifications. I cannot speak for the 3M product but I have removed dozens of fittings sealed with Sikaflex or Puraflex. It is a myth that they adhere so strongly that they are permanent.

 

[Habebty]

CT1 here as well, lots of different jobs, don't buy clear any more due to same issue others have mentioned...

That’s a worry! I reseated my forward hatch last year with clear CT1. Best I keep an eye on it!

 

[Akestor]

For Polyurethane i use Wurth, and for silicone the Dowsil 7091! used to them and i am happy

 

[Zing]

3M 5200 and Sikaflex 291 have almost identical specifications. I cannot speak for the 3M product but I have removed dozens of fittings sealed with Sikaflex or Puraflex. It is a myth that they adhere so strongly that they are permanent.

3M 5200 is the devil’s glue. Best not use it if you plan to ever remove it. Tougher than tough stuff.

 

[roy851]

3M 5200 and Sikaflex 291 have almost identical specifications. I cannot speak for the 3M product but I have removed dozens of fittings sealed with Sikaflex or Puraflex. It is a myth that they adhere so strongly that they are permanent.

The original Sikaflex was incredible stuff, I had a 225 merc that stayed stuck to the transom with all the bolts out, just on a few blobs of Sikaflex,
however they changed from 291 to 291i to comply with European packaging standards and changed the recipe slightly and its never been the same since

my go to sealant/adhesive now is CT1