Epoxy advice

[Ammonite]

I need to do some transom repairs with SP130 but with the temp hovering just above 5 degrees I'm not sure its a good idea (min temp advised is 5). If the temp is say 8 during the day but drops to freezing overnight and then back to 8 the next day will it continue to cure or does the overnight cold stop it in its tracks? Appreciate any advice you can give me. Thanks!

 

[Lakesailor]

The guy I buy from uses epoxy to build wooden boats. He reckons that if it hasn't cured when he comes to work in the morning they play a hairdryer over the joint for a while and raising the temp completes the curing. You don't say if you're ashore or have power.

I would be tempted to leave it until this cold snap is over.

 

[Ammonite]

Thanks for the advice. I have shore power so I'll give it a go if I run into problems, although I'm going to wait until it warms up a bit. Cheers

 

[EASLOOP]

Get hold of a copy of Gudgeon Brothers West System Epoxy manual. It is an excellent source of 'how to' information and will put you in good stead for ongoing works.
Try Googling on Gudgeon Brothers. I believe they are from Michigan - but ??
Have a nice day.

 

[Boathook]

I was told a few years ago by an SP technican that epoxy will restart curing once the temperature is up. The downside is that some strength is lost so if the repair needs full strength you will need to keep it warm. Out of date epoxy can still be used for minor area repairs etc but does loose strength with age. How much strength is lost was not quantifyable as it varies ......

 

[Rowana]

Or have a read here -

http://www.wessex-resins.com/westsystem/wspotlife.html

 

[mbay]

lakesailors advice is sound, I had a repair to do last year on my keel and waited till as late as possible in the year march, as my boat was going back in the water in april. however march last year was very cold and the temp hovered around 5 all month so i used a hairdrier to cure the epoxy it worked but its a long process, as epoxy does not cure as fast as glassfibre resin. so i would advise waiting for warmer weather if possible.

 

[Ammonite]

Thanks for all the advice. The hairdryer approach sounds like a lot of arm ache but I have got a halogen light which gives out a fair amount of heat - might give that a try

 

[bluemoongaffer]

I can't prove it but having used both West and SP, I've found that West system epoxy is more tolerant of low temperature conditions than SP - and of slightly inaccurate mixes

 

[Birdseye]

Had no probs epoxying in a new P bracket and bearers with snow on the ground. Used a fan heater.

But - if you plan to do several layers with time inbetween, going cold overnight can trigger amine blush so you may well have to clean and abrade between operations. But going the other way and putting lots of layers on in one op can even cause it to burst into flames

 

[Avocet]

In aerospace and motorsport applications, it's common to use "pre-preg" materials. These already have catalysed epoxy soaked into the fibres. When the stuff is made, they keep it in a freezer to stop the cure - which happens as soon as it warms up. Apparently, it can keep for a couple of years like this!

Unfortunately, this is in a very dry environment. I'm told (and I THINK I've remembered correctly) that the hardener for epoxies is much more willing to react with atmospheric moisture than with the resin. The problem therefore, with extended low-temperature periods is that the hardener might react with moisture in the air and then when the temperature DOES warm up, there won't be enough left to fully cure the resin. This might be qwhy some have said you don't get as strong a finished mix. As long as the surface has gone touch-dry before the temperature drops, I BELIEVE, it will be OK to cool it and re-warm it subsequently - but I'm not 100% sure of that!