Have you ever been confused and asking yourself: why do I always have leftover parts even if I measured a 1:1 ratio perfectly by volume and everything cured properly? You don't need to be depressed by it because It's absolutely not your fault! What matters most is not throwing them away!
Why Do You Have Leftover Resin (Part A) or Hardener (Part B) in the Bottle?
Please note that the part A and B are generally filled by weight instead of volume during production. So it's normal that you will always have leftover of either Part A or B. In fact, it doesn't matter if you measured by weight or by volume but for the best result is to follow the label says (mostly by volume).
Also, not every resin is created equal. A set of 16oz IntoResin resin measured by volume is filled with 6~7oz resin and 9~10oz hardener so they can maintan the same level. Another reason is the viscosity difference of Part A and B. The difference in viscosity results in disparity because more viscous liquid will cling to the A bottle.
💡P.S. The hardener is generally lighter than the resin part so you get more hardener than you need because it weighs less and more goes into the bottle to equal the weight of what went into A bottle.
What to Do if You Got Leftover Parts in the Bottle?
Do not throw them away! Try to leave it for when you buy more resin or hardener. Most of brands do not offer separate part A or B but IntoResin did sell them separately, check here. If you're always having leftovers of one part, I'll recommend you to choose the brands who are able to sell separate parts or your leftover just went into general waste. Keep in mind that you're not allowed to mix brands, like Brand 1 Part A mixed with Brand 2 Part B is not acceptable.
Another option(what I usually use) is to mix your leftover part with your mica powder to make pigment paste. Yeah, it sounds unbelievable, doesn't it? But it did the trick! Check more details of this article how to make your own pigment paste.
No matter you have extra resin or hardener, it does happen normally because part A and B vary based on amount or the viscosity, which depends on the brands. More impotantly,do not tosst thm away or it must be a big waste.