Epoxy batch splitter

Why split a pour into batches

Large pours are often mixed in more than one bucket. The bucket may be too small, the mixing drill may not reach the corners of a big container, or the data sheet may limit how much you should mix at once. Mixed epoxy also heats up while it waits: West System explains that the reaction gives off heat and that a larger mass in a container heats more (West System).

Equal batches keep the arithmetic simple and make each batch behave the same way. The splitter works out how many batches you need and exactly how much Part A and Part B goes into each.

Formula and assumptions

n = ⌈ V_total ÷ V_{max batch} ⌉    batch = V_total ÷ n

A per batch = batch × a ÷ (a + b)    B per batch = batch × b ÷ (a + b)

• V_total is the mixed volume from the river table, mold or flood coat calculator.
• V_{max batch} is the largest batch you are willing to mix. Use the smaller of your bucket’s working capacity and any mixing limit on the data sheet. If a product in our database publishes a maximum mix or pour size, the splitter shows it next to the result.
• a : b is the published mix ratio by volume. For batches measured on a scale, use the mix ratio converter on one batch.
• Batches are equal rather than “full buckets plus a small last one”. A tiny last batch is easy to mis-measure.

Worked example

A river table needs 3 gal of a 2:1 (A:B by volume) resin. Your mixing bucket handles 1 gal comfortably.

1. Batches: 3 ÷ 1 = 3, so 3 batches of 1 gal.
2. Each batch: Part A = 1 × 2/3 = 0.667 gal (85.3 fl oz, 2.52 L); Part B = 0.333 gal (42.7 fl oz, 1.26 L).
3. Totals: 2 gal of Part A and 1 gal of Part B.

With a 1.25 gal limit instead, 3 ÷ 1.25 = 2.4 rounds up to 3 batches again, still 1 gal each. The splitter always evens out the batches.

Mixing each batch

• Dispense Part A and Part B accurately for every batch; West System’s mixing instructions stress accurate metering and thorough mixing, scraping the sides and bottom of the container (West System).
• Mix and pour one batch at a time rather than mixing all batches first and leaving them to wait.
• For layered pours, each layer is its own set of batches. Plan layers first with the layer planner.