Resin and Hardener mix ratio

Yeah, I know it's a chemical reaction that causes the heat, and yes, it is going to create some heat  no matter how little hardener you use.  But there is such thing as too much.  Not only will it cause warpage, but it will also cause it to become weak and brittle.  And mikedawg, I'm not trying to start an argument with you.  I just want to make sure snowdeath is getting the right information.  I don't  doubt that you use fiberglass everyday, but that doesn't mean you're using it correctly.  But don't take my word for it.  Check out http://www.rtol.net/scornell/HowTo.htm.  If that isn't enough proof for you, let me know.  I'm sure I can find at least three more links to sites that say the same thing.  Snowdeath, typically the most common volume of hardener used is about 2% of the volume of resin.  I hope that helps.

I find that the ratio used is dependent on the air temperature that you have to deal with. If your in a controlled environment ( room temperature ) and this temperature doesn't fluctuate alot, then you can mix a smaller ratio of hardener/resin. This will allow time for you to roll out the air bubbles as well as place more matting if necessary.

If the air temperature is not stable and/or is colder, then I suggest a stronger ratio of hardener to resin so that it doesn't take days for the glass to cure. As far as warping goes, as long as you do not take the mold out too soon to thicken, you shouldn't have any problems with warping. Warping occurs ( most of the time ) when you take the mold out of the car and start to thicken the project with resin/hardener mixture too hot for the project to handle. Always thicken up the project while inside the mold or the car ( if you can ).

Velocity Motors is right.  The amount of hardener used definitely depends on the ambient temperature.  But just to give you a general idea of how much to use, take a look at https://mohawkcanoes.com/fgrepair.htm.  At the bottom of the page, there are some tables that not only show mix ratios, but also have some great conversion tables for liters, quarts, ounces, drops, etc.  This is especially helpful when you determine how much hardener you need, you can add it by the teaspoon rather than having to count out a few hundred drops.