Cold weather glassing
Cold weather glassing
I just finished sanding the hull of my Ranger and I'm ready to put the fiberglass on. I'm a little concerned about the overnight temps. It's starting to fall below freezing up here in northern MN and I'm working in an unheated garage. I'm using US Composites resin with the medium hardener. Any pitfalls I should look out for. Will the lower temps allow me to put on the three coats of resin, over three nights, without sanding between?
Not directly answering your question, but maybe atent set up with light bulbs like I describe here would be useful?
Testing to see how the epoxy behaves at those lower temps will help. Some epoxies absorb water at low temps, or will blush, which can result in problems with adhesion later on, and the epoxy may not cure clear (milky appearance). I used an epoxy that claimed 10C working temps... it cured OK at 15C, but did turn milky with a poor chemical bond with the next epoxy layer.
Heating the garage will help... check the recommended temp range for that epoxy.
A chemical bond most likely will not result between three layers of epoxy applied over three nights, you'll have to sand between applications for a mechanical bond. Uncured epoxy can be toxic, so you'll have to have breathing protection, and maybe wait longer so that the epoxy hardens enough to sand.
Usually the indicator for a good chemical bond is to apply the next coat of epoxy when the first begins to cure, and is still tacky. It'll stick to a toothpick and touching the surface with a cotton swab will leave fibers stcking to the semi-hardened epoxy. Waiting several hours between coats should allow you to do this in one day, at the proper temps.
Good luck, and play it safe!
Heating the garage will help... check the recommended temp range for that epoxy.
A chemical bond most likely will not result between three layers of epoxy applied over three nights, you'll have to sand between applications for a mechanical bond. Uncured epoxy can be toxic, so you'll have to have breathing protection, and maybe wait longer so that the epoxy hardens enough to sand.
Usually the indicator for a good chemical bond is to apply the next coat of epoxy when the first begins to cure, and is still tacky. It'll stick to a toothpick and touching the surface with a cotton swab will leave fibers stcking to the semi-hardened epoxy. Waiting several hours between coats should allow you to do this in one day, at the proper temps.
Good luck, and play it safe!