Epoxy Mixing Ratio Chart for Wood Projects: Quick Guide
For wood projects, the epoxy mixing ratio chart is fairly simple: follow the manufacturer’s ratio exactly, which is often 1:1, 2:1, or 3:1 by volume or weight as specified. If you miss the ratio, the epoxy can stay tacky, lose strength, and waste a pour or repair. Bad math burns time, wood, and finish work. This guide gives a practical ratio chart, batch-size conversions, and quick checks for tabletops, void fills, river pours, and sticky-cure troubleshooting.
This guide is part of our Wood glue essentials: types, uses, and cure times series.
What epoxy mixing ratio means for wood projects
An epoxy mixing ratio is the Part A to Part B proportion printed on the product technical data sheet. Part A is the resin, Part B is the hardener, and the two can have different densities. That is why the label must tell you whether the ratio is by weight or by volume before you measure anything.
Part A and Part B in shop terms
Think of resin as the base material and hardener as the curing partner. A 2:1 ratio means two parts resin to one part hardener. For a 3 gal batch at 2:1, that splits into 2.00 gal Part A and 1.00 gal Part B.
Why the technical data sheet decides the ratio
The technical data sheet is the source of the exact mix ratio. Jeff Mack Supply says resin and hardener need to be mixed to the exact technical-sheet ratio. One product may call for 2:1 by volume, while another with a similar use may call for a different weight ratio.
Why weight and volume are different measurements
Volume measures space in the cup. Weight measures mass on a scale. Volume ratio and weight ratio are not the same for a given product, because resin and hardener often have different specific gravity. A 2:1 volume system can become roughly 100:42 by weight if densities differ.
According to resin-pro.co.uk — 1:1 mixing is described as simple equal-parts mixing for beginners.
Which ratio should you use for a wood project?
Use the ratio that matches the product and the job. For woodworking, 1:1 is often the simplest equal-parts mix, 2:1 is common for general casting and repair work, 100:55 is used for precision work by weight, and 4:1 is presented for very deep pours up to 10cm. The chart below ties ratio choice to task.
Best-fit ratios for surface coats, void fills, and repairs
Surface coats and bar tops usually want a controlled, thin mix that wets the wood well. Void fill and edge repair often need more open time and enough body to stay put. Deep pours need lower heat buildup and strict batch control, because the exothermic reaction rises fast in a thick mass.
| Project type | Typical ratio | Why it fits | Shop note |
|---|---|---|---|
| Surface coats for tabletops and bars | 1:1 or 2:1, if the TDS says so | Simple mixing and fast layout work | Best for thin floods and seal coats |
| Void fill and edge repair | 2:1 or 100:55, product-dependent | Good balance of flow and working time | Scrape sides and bottom of the cup |
| River table pours and deeper fills | 4:1 where the product is designed for deep pours | Helps control heat in thicker sections | Watch batch depth and pot life closely |
| Small repair batches | 1:1 for simple systems | Easy to measure in tiny amounts | Good for knot fill and corner patches |
When a 1:1 mix makes sense
1:1 works well when the product is designed for equal parts and the job is simple. It is easy to measure, which helps beginners avoid ratio drift. That said, 1:1 is not a universal fix. The label still decides the exact mix.
When a 2:1, 4:1, or 100:55 mix is the better match
Use 2:1 when the technical sheet calls for it and the project needs a broad, common-use formulation. Use 100:55 when the product is specified by weight and the manufacturer wants tighter control. Use 4:1 when the system is built for deeper pours and lower heat rise.
How to convert epoxy ratios into shop measurements
Converting a ratio into ounces, milliliters, or grams is straightforward once the ratio basis is known. For weight ratios, use a digital scale. For volume ratios, use marked cups or graduated containers. Do not swap the two methods unless the technical data sheet says they are equivalent for that product.
Converting 1:1, 2:1, 4:1, and 100:55 into ounces
For an 8 fl oz batch, a 1:1 mix gives equal parts of about 4 fl oz each. A 2:1 ratio gives roughly two-thirds resin and one-third hardener by volume. A 4:1 ratio gives 6.4 fl oz resin and 1.6 fl oz hardener. A 100:55 mix by weight generally needs a scale rather than cup marks.
Converting the same ratios into milliliters
For a 250 mL batch, a 1:1 mix splits into equal parts of about 125 mL each. A 2:1 volume mix splits into about 167 mL resin and 83 mL hardener. A 4:1 volume mix splits into 200 mL resin and 50 mL hardener. Use the ratio basis printed on the product, not a guess from another brand.
Converting the same ratios into grams with a digital scale
A digital scale is the preferred tool for weight ratios because it reads directly in grams and avoids meniscus errors, cup reading errors, and partial-fill guessing. For 100:55 by weight, the parts are measured by mass, not by eye. That is the cleanest path when the technical sheet calls for a weight ratio.
How specific gravity changes the math
Specific gravity affects the relationship between what fits in a cup and what weighs on a scale. Resin and hardener may not weigh the same for the same volume, so a labeled volume ratio can convert to a different weight ratio. That is why a 2:1 volume system can become roughly 100:42 by weight if densities differ.
| Ratio | Basis | Example split in ounces | Example split in milliliters | Measurement method |
|---|---|---|---|---|
| 1:1 | Volume or weight, as specified | 4 oz + 4 oz in an 8 oz batch | 125 mL + 125 mL in a 250 mL batch | Cup or scale |
| 2:1 | Volume or weight, as specified | 5.33 oz + 2.67 oz in an 8 oz batch | 167 mL + 83 mL in a 250 mL batch | Cup or scale |
| 4:1 | Volume or weight, as specified | 6.4 oz + 1.6 oz in an 8 oz batch | 200 mL + 50 mL in a 250 mL batch | Cup or scale |
| 100:55 | Weight | 100 g + 55 g | Use the scale-converted value from the TDS | Digital scale |
How to mix epoxy so the ratio is correct in the cup
Measure the components before mixing, and use the product’s ratio basis exactly. Pour Part A and Part B into a clean mixing container, then mix thoroughly, scraping the sides and bottom. A double-bucket method gives a cleaner blend when the job matters and the batch is too important to risk a lazy stir.
Measuring before you pour
- Read the technical data sheet for the ratio basis.
- Pick a clean cup or a digital scale.
- Measure Part A first, then Part B to the exact ratio.
- Mix until the liquid looks uniform.
- Transfer to a second cup and mix again for better blending.
Why contaminated cups can ruin a batch
Old cured flakes, dust, sawdust, solvent residue, or moisture in the cup can interfere with cure and clarity. A mixing container should be clean and dry. If the cup held something else earlier, treat it as suspect and replace it.
Printable epoxy mix worksheet for wood projects
Use this worksheet as a bench chart for batch planning. The values below are ready to print and annotate, but they still depend on the product technical data sheet. If the ratio is by weight, use grams on a digital scale. If it is by volume, use the cup values.
| Batch size | 1:1 total split | 2:1 total split | 4:1 total split | 100:55 total split |
|---|---|---|---|---|
| 4 oz / 125 mL / 113 g total | 2 oz + 2 oz; 62.5 mL + 62.5 mL; 56.5 g + 56.5 g | 2.67 oz + 1.33 oz; 83 mL + 42 mL; 75.3 g + 37.7 g | 3.2 oz + 0.8 oz; 100 mL + 25 mL; 90.4 g + 22.6 g | 100 g + 55 g scaled down proportionally |
| 8 oz / 250 mL / 227 g total | 4 oz + 4 oz; 125 mL + 125 mL; 113.5 g + 113.5 g | 5.33 oz + 2.67 oz; 167 mL + 83 mL; 151.3 g + 75.7 g | 6.4 oz + 1.6 oz; 200 mL + 50 mL; 181.6 g + 45.4 g | 100 g + 55 g scaled up as needed |
| 16 oz / 500 mL / 454 g total | 8 oz + 8 oz; 250 mL + 250 mL; 227 g + 227 g | 10.67 oz + 5.33 oz; 333 mL + 167 mL; 302.6 g + 151.4 g | 12.8 oz + 3.2 oz; 400 mL + 100 mL; 363.2 g + 90.8 g | 100 g + 55 g repeated in larger multiples |
| 32 oz / 1000 mL / 908 g total | 16 oz + 16 oz; 500 mL + 500 mL; 454 g + 454 g | 21.33 oz + 10.67 oz; 667 mL + 333 mL; 605.2 g + 302.8 g | 25.6 oz + 6.4 oz; 800 mL + 200 mL; 726.4 g + 181.6 g | 100 g + 55 g repeated in larger multiples |
Quick notes: Keep batch depth low for large mixes. Large batches can trigger an exothermic reaction, which may overheat the cup, shorten pot life, and increase the risk of boiling or distortion in deeper pours. For river table pours, smaller lifts are safer than one deep mass.
Why is my epoxy still sticky after mixing the right ratio?
Sticky epoxy after the “right” ratio usually points to incomplete mixing, temperature problems, pot depth, or contamination rather than the ratio alone. The resin-pro page says incorrect ratios can be used to diagnose why epoxy stays tacky. If the ratio is right, the next suspects are the cup, the room, and the blend quality.
Ratio error versus incomplete mixing
If the measured ratio was off, cure failure can leave epoxy tacky or soft. Too much hardener does not speed cure; it can cause the opposite problem and leave a weak surface. If the ratio was correct, poor blending can leave unmixed resin or hardener streaks that stay gummy.
Temperature and pot depth problems
Cold shop temperatures slow cure. Deep pots hold heat differently than thin spreads, and the center can react differently from the edges. Large batches deepen the exothermic reaction and can scorch the mix or shorten working time. That is why batch size matters as much as the ratio for deep pours.
How to spot contamination in the cup
Cloudy residue, oily films, dirty stir sticks, water droplets, or softened old epoxy in the container can all interfere with cure. If the cup smells off, looks dirty, or holds cured scraps, do not trust it for a critical pour. Use a fresh container and mix again.
When the batch is beyond saving
If the epoxy remains uniformly tacky after the full cure window, or if soft zones spread across the surface, the batch may be beyond repair. Scraping and recoating can help only when the problem is on top. Deep soft cures usually need removal and a fresh, correctly measured batch.
Frequently asked questions
What epoxy mixing ratio should I use for wood projects?
Use the exact ratio on the product technical data sheet. For wood projects, common options include 1:1, 2:1, 100:55, and 4:1, but the right choice depends on the resin system and the task. Surface coats, void fill, and deep pours all have different limits.
Is epoxy mixed by weight or by volume?
Either method may be correct, but only if the technical data sheet says so. Volume ratio and weight ratio are not interchangeable for a given product, because resin and hardener can have different densities. A digital scale is the better tool whenever the ratio is listed by weight.
How do I convert a 2:1 epoxy ratio to ounces or grams?
A 2:1 ratio means two parts resin to one part hardener. If the label calls for volume, divide the total batch into three equal parts and give two to Part A and one to Part B. If it calls for weight, use the listed gram amounts on a digital scale.
What happens if I add too much hardener to epoxy?
Extra hardener does not make epoxy cure faster in a helpful way. It can upset the ratio, leading to cure failure, soft spots, or a tacky surface. The safest fix is to measure again from the technical data sheet and mix a fresh batch at the correct proportion.
Why is my epoxy still sticky after mixing the right ratio?
If the ratio was correct, look next at mixing quality, cup contamination, temperature, and pot depth. Scrape the sides and bottom, transfer to a clean cup, and keep batch size under control. Deep pours are more sensitive to heat and can cure poorly if the mass gets too large.
Can I use the same mixing ratio chart for all epoxy brands?
No. A chart is a planning aid, not a substitute for the product technical data sheet. Different brands can use different bases, different densities, and different ratio methods. Check whether the product is specified by weight or by volume before relying on any conversion chart.
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