Epoxy and Sikaflex cure time - from lift to launch in less than 24 hours possible?

[MagicalArmchair]

I am dropping my rudder next Thursday to swap the bearings out and launching again on Friday (there are reasons it is all quite such a rush, one of them, of course, is I want to go sailing, the other is that the yard manager is jumping ship).

The bearing housing is aluminum, and I suspect it will be pitted in places (copper antifouling got too close to it, I'll correct that) once I tidy it all up, so I will want to fill it. I would usually use WEST SYSTEM 105 system epoxy with colloidal silica, however, whilst this cures to solid in eight hours, it gets to full strength in 1 to 4 days.

I will also want to seal around the top of the rudder whilst I have it off. Jefa suggest Sikaflex, which takes 7 days to cure. Clearly too long! Even 3M 5200 Marine Adhesive Fast Cure cures in 24 hours...?

The questions then:

1. What epoxy can I safely use to fill the housing on day 1, and fit the bearings and rudder back day 2? 105 Ok for this?
2. What Sikaflex jollop can I use to seal the rudder stock onto the rudder that will cure in those 16 hours?
3. Do I just sacrifice a week of sailing and go in a week later??? This is a one off job after all...

 

[andsarkit]

Sikaflex cures with atmosheric moisture so the cure time will depend on the thickness of the seal. I have stuck instruments to the deck of a ship with a 300mm square plate and when I took it off 2 years later the Sikaflex at the centre had still not set. However the bond around the outside was plenty strong enough to survive breaking seas on the instrument.
You can get flexible epoxy that will set in a few hours. Speak to Permabond as they probably have a suitable one. Permabond
I have used these at work for a different application and was quite impressed with the performance.

 

[howardclark]

I am dropping my rudder next Thursday to swap the bearings out and launching again on Friday (there are reasons it is all quite such a rush, one of them, of course, is I want to go sailing, the other is that the yard manager is jumping ship).

The bearing housing is aluminum, and I suspect it will be pitted in places (copper antifouling got too close to it, I'll correct that) once I tidy it all up, so I will want to fill it. I would usually use WEST SYSTEM 105 system epoxy with colloidal silica, however, whilst this cures to solid in eight hours, it gets to full strength in 1 to 4 days.

I will also want to seal around the top of the rudder whilst I have it off. Jefa suggest Sikaflex, which takes 7 days to cure. Clearly too long! Even 3M 5200 Marine Adhesive Fast Cure cures in 24 hours...?

The questions then:

1. What epoxy can I safely use to fill the housing on day 1, and fit the bearings and rudder back day 2? 105 Ok for this?
2. What Sikaflex jollop can I use to seal the rudder stock onto the rudder that will cure in those 16 hours?
3. Do I just sacrifice a week of sailing and go in a week later??? This is a one off job after all...

If you use West GFlex from Wessex Resins, its designed for use with metals and a pretty quick cure - can’t see why it wouldn’t do the job

 

[westernman]

At least some epoxies (may be almost all of them), will cure underwater.

 

[ibbo]

I have used sikaflex 291i between tides fixing a stern gland before. The last bit was done as water lapped my feet.

When I checked it later, it had set under water with no discernable difference to the air set side.

Mike