laying glass in winter .. heating questions

I found a post on here from 2005 that answered some of my questions but need further input

I'm wanting to lay fiberglass this winter with Polyester/Vinylester and MEK .. and was trying to figure out how to do this in the cold .. I know I need 68-80 air temp to mix and lay the glass .. can I let the inside temp cool into the 50s after the glass sets ( Hardens ) say 4 -5 hrs.. then just maintain that temp for 24-48 hrs until completely cure. and can I use electric space heaters to keep temp up ? instead of propane blower heater.

I did another boat of mine a couple yrs ago but it was later in spring .. temps in 70s-80s .. somehow I always manage to find my bargain boats in winter lol

 

If you've done it before, you must know that that the curing process only needs to be started, so at that stage you need a heat source. Once the polymer chain reaction has started, enough heat is generated. This does not apply for a single repair layer and not if you work in a windy place.
I've done a lot of grp work recently, even near freezing point; I found the moisture more problematic than the temperature, so I first warmed up the area I was going to repair or modify.

 

Thank you .. thats what Id hoped for .. but didnt want to have to do it over

 

I heated my "shop" (an over-sized, one-car garage) with an old electric furnace. Cost me fifty bucks, and heated the workspace immediately!

 

I have set both polyester and epoxy in under 10C inside a double garage with a 2kW electric heater. I had to move the heater around to get the whole surface to set.

Without the heater the reaction just seemed to stop. I was not prepared to leave this set up over night and next morning the surface was still tacky if it had not set the night before.

With epoxy you can get low temperature hardener but this still requires + 12C to start reaction.

If you cannot heat the whole area it is a slow process. It took me a day to do a layup. Probably better to do multiple layers in close sequence so there is good bonding and heat retention to save time.

Rick W.