Epoxy and cold weather?

[squidge]

Hi i am changing a couple of seacocks and am replacing the backing ply in the process. As part of a good job i want to epoxy the ply to the hull but as its been colder that the recommended min on the tin (15deg)should i increase the amount of hardner or just leave it to go off in its own time?

thanks

 

[Lakesailor]

In my experience it won't cure properly until it's achieved that temperature.
You notice when using it for coating wood that it stays soft and has a waxy sheen to it.
You can cure it with hairdryers etc but it's a bit of a faf. Even then you need to remove the waxy deposit with scotchbrite and white spirit, which leaves you wondering "Which component of the mix is now missing?"
But in your situation where it's used as a bond between two surfaces, you're not going to know if it's really worked.
I wouldn't have thought altering the resin/hardner ratio would've done much for the integrity of the bond.

I stand to be corrected, if someone has specific knowledge.

 

[graham]

Dont alter the hardner to resin ratio. epoxy will go off quickest when mixed to the correct ratio.

Better to increase the temp with a heater if possible.if no electric avail;able try warming the tins with a thermos flask of hot water in a bowl before you start .

 

[Poignard]

A man from WEST tech support told me that if it's too cold to be comfortable in a T-shirt, then you need additional heat!

 

[tazzle]

Agree with above comments. I've got about a day's epoxying to do and have just reconciled myself to waiting for a weather window ...

 

[Malcb]

[ QUOTE ]
A man from WEST tech support told me that if it's too cold to be comfortable in a T-shirt, then you need additional heat!

[/ QUOTE ]

The figures below are taken from the West Systems site for Standard Hardener -

Pot Life At 25°C 10 to 15 minutes
Cure To Solid State At 21°C 5 to 7 hours
Cure To Maximum Strength At 21°C. 5 to 7 days
Minimum Recommended Temperature 5°C
Pumps Required (5:1 ratio) 301, 306, 309

And 5 deg C is about the temerature of a fridge, certainly not T shirt weather, although it will take a very long time to reach maximum strength.

 

[paulrossall]

I would not bother with epoxy. I just covered my marine plywood in Sikaflex which you need to use anyway to seat/seal the seacocks in. The job is as good as new 5 years on. Don't use anything other than decent quality marine ply for the backing pad. This is what most boatyards would do.

 

[macd]

Couldn't agree more. No reason at all to mess around with epoxy. Also, Sikaflex isn't easy to get off, but it's a sight easier than epoxy.

 

[snowleopard]

You absolutely must not alter the ratio of the components with epoxy as it works in a totally different way to polyester. There are 3 standard grades of epoxy - standard, slow set and tropical, you need the standard. Outdoor temperatures are too low even for the standard type but if you warm the complonents and keep heat on it for a couple of hours it will set OK. A haid dryer, small fan heater or similar will do. Don't go OTT and use a heat gun / blow torch!

As an alternative, consider Sikaflex, it's pretty effective as a glue and doesn't require a perfectly fitting joint.

 

[squidge]

Thanks all.

When i removed the old skin fittings the ply just fell away so any sealant or adhesive used inside the hull had long gone. What was worrying was the amount of rot in the ply around the fitting which was only attached to the hull buy the sealant on the outside of the hull. Still had to cut the thing off though.So when replacing the ply i would like to seal it completely. So thinking aloud the answer to my problem maybe a mixture of both. If i epoxy the ply at home in the warm and then fix it with sikaflex when i refit the fittings would this be a suitable alternative or are there pitfalls that i am unaware of?

Thanks again

 

[Robin]

I doubt Moody bothered to protect the ply when they built the boat, hence the rot. I would at least paint the pad with primer at home, then use Sikaflex but epoxy at home would work OK. Sikaflex cures with humidity so usually OK on a boat!

 

[graham]

[ QUOTE ]
If i epoxy the ply at home in the warm and then fix it with sikaflex when i refit the fittings would this be a suitable alternative or are there pitfalls that i am unaware of?


[/ QUOTE ]

Sounds like a good plan to me.Soak plenty of resin into it especially the edges ,should then last donkeys years.

 

[Boathook]

I use SP systems epoxy in cold weather. I was concerned and spoke to them quite a few years back about it. It won't reach full strength at low temp cure and can take days but for general work seems ok. I do use heaters and have stayed on board over night to keep fan heaters running and boat warm (plus me!). Biggest problem that I have found is not cleaning the work area properlyof grease, dust etc. and creating a very weak join.

 

[pampas]

A proper job "me Ansome", is to use wood Not ply(Waste of time and money) /forums/images/graemlins/grin.gif

 

[squidge]

Ah well if i ad a proper wooden yat !