At CeraLab, we believe that effective formulation begins with deep understanding. As part of our hands-on training programme, we often return to foundational exercises that allow formulators to build insight from the ground up. This study is part of a broader training series focused on the development of a high-performing carnauba-based car wax. Our goal here is not just to develop a working formula, but to teach the methodology behind balancing solvent, hard wax, and soft wax components.
Why Start Here?
Through both industrial experience and existing formulations, it’s widely known that a balance of around 70% solvent to 30% wax offers a good compromise between ease of application, hardness, and dry time for solvent-based waxes. By combining one hard wax and one soft wax, we can investigate how their ratios influence the feel, performance, and finish of the final product.
In this exercise, we selected carnauba wax as our hard wax due to its high gloss and durability, and paraffin wax as our soft wax for its ease of application and smooth spreading characteristics. However, other options were also considered, and may be explored in future training exercises:
| Wax Type | Wax Name | Characteristics |
|---|---|---|
| Hard | Carnauba | High melting point, high gloss, durable |
| Hard | Montan Wax | Very hard, strong detergent resistance |
| Hard | Candelilla Wax | Slightly softer than carnauba, good gloss |
| Hard | Rice Bran Wax | Hard and brittle, natural origin |
| Soft | Paraffin Wax | Soft, smooth feel, cost-effective |
| Soft | Beeswax | Tacky, slow-drying, natural origin |
| Soft | Microcrystalline | Flexible, cohesive, prevents cracking |
| Soft | Rapeseed Wax | Soft, plant-based, semi-crystalline |
| Soft | Olive Wax | Soft texture, lower melting point, natural origin |
| Soft | Sunflower Wax | Soft, high oil retention, sustainable origin |
Method
Each batch was prepared as a 50g sample, with 70% of the blend (35g) being odourless kerosene. The remaining 30% (15g) consisted of varying ratios of paraffin and carnauba wax. All waxes were melted using a bain-marie and then mixed with the solvent at ~70°C before pouring into tins to cool.
We prepared four batches:
| Batch | Paraffin Wax (g) | Carnauba Wax (g) | Odourless Kerosene (g) |
| A | 10 | 5 | 35 |
| B | 7.5 | 7.5 | 35 |
| C | 5 | 10 | 35 |
| D | 3 | 12 | 35 |
We like to make up multiple batches at a time with this type of testing. A roasting tray was filled with water and a cupcake tray placed on top to produce a 6 celled double boiler on a hotplate.
Our test panels are made from 600mm x 600mm acrylic panels painted with various colours of car paint. For this test we selected the black one to show up the haziness we were expecting once the product was dry and split it into four areas.
Evaluation Criteria
We scored each batch on the following criteria:
- Hardness (1 = too soft, 10 = too hard; 5 = ideal balance)
- Ease of sponge application (10 = very easy, 1 very difficult)
- Dry time to haze (minutes) tested with the Finger swipe test each minute until a clear streak is removed
- Buffing/removal using a clean microfiber cloth after 10 minutes
Results Summary
| Batch | Hardness | Application Ease | Dry Time (min) | Buffing/Removal | Blend Ratio |
| A | 6.5 | 8 | ~8 | Slightly sticky | 10:5 |
| B | 7.5 | 7.5 | ~8 | Very easy | 7.5:7.5 |
| C | 8 | 7 | ~8 | Acceptable | 5:10 |
| D | 9 | 7 | ~10 | Very difficult | 3:12 |
Visual Analysis
To better visualize the trends, we plotted the results across the four batches. As carnauba content increased, so did hardness, but at the cost of workability and ease of removal. Batch B emerged as the best compromise between hardness, gloss, and user experience.
- Hardness increased linearly with carnauba ratio.
- Ease of application was best in softer waxes.
- Dry time was similar for batches A to C, but longer in D.
- Buffing was optimal in Batch B; Batch D was notably poor.
Conclusions and Recommendations
Batch B, with a 1:1 blend of paraffin and carnauba wax, provided the most balanced performance. It applied smoothly, dried within a reasonable time, and buffed to a high-gloss finish without difficulty.
In the following session, we’ll investigate how different solvents influence the drying behaviour, buffing ease, and application characteristics of our wax formulation. Using the Batch B blend as a base, we will prepare twelve 25 g samples, each incorporating either a low or high level of one of six solvents: D40, D60, Isopar M, cyclopentasiloxane, D-limonene, and heptane. This focused matrix will allow us to assess performance trade-offs while maintaining a consistent 70:30 solvent-to-wax ratio.