Most manufacturers recommend 5 minutes, other sources (and my experience) call for tansferring the 1st mix to a 2nd clean container (use disposable plastic beer cups) for more mixing. The right type of epoxy has a working time of 40 minutes, plenty of time.
Correct mix proportions is crucial (usually 1:1), use two platics cups side by side to evenly measure out resin & hardener then pour one into the other.
It should turn out so hard (and it can take more than 72 hrs) that it will be a big big job to sand own the radius and polish.
Do a test batch on a scrap of wood before attempting your neck. I know this is all a little too late.....
From U.S. Composites...
Beginners Notes:
This material leaves professional results when applied correctly so take your time and make sure to beware of these of the common problems we have seen encountered by first time users.
1. Always make sure that your mixing container is clean and your measuring device is accurate, this product REQUIRES that you mix at a 1 to 1 ratio by weight or volume, any variances from this can cause the epoxy to stay soft and not fully cure.
2. This product requires a THOROUGH mixing, usually between 4 to 5 minutes of solid mixing without excessive whipping of the mixture(whipping will put lots of air bubbles into the epoxy). Mixing one gallon at a time can require up to 6 to 7 minutes of mixing. Beginners should never attempt to mix more than one gallon total per batch, 2 quarts per batch is suggested until you feel comfortable with how the product works.
3. After the two components are poured together and stirring begins the mixture will turn a cloudy white color, this represents areas in which the epoxy has not fully combined. You must continue to mix until all signs of cloudiness and tiny white lines have completely disappeared (usually takes 3-4 minutes of thorough mixing).
4. Always scrape the sides of your mixing container and also the stick during those 3-4 minutes. If UNMIXED epoxy remains on the side of the container or the stick it will cause wet spots on your finished product if that UNMIXED material falls into your project......Followup: While pouring your epoxy onto the surface NEVER scrape the container to remove every last drop, because no matter how thorough you mix there will always be an unmixed drop on the side of the container that will leave a wet spot.
