Some things in life are just a fact: there will always be a tax to pay, weekends never last as long as you want, and build-up will occur on molding surfaces. While entirely preventing build-up on your mold surfaces is not a realistic goal, you can still significantly decrease the build-up on your mold surfaces by using a combination of excellent molding products and optimizing your molding and cleaning processes.

At Stoner Molding Solutions, we help molders in various industries mold more products in less time with our mold release pastes, sprays, cleaners, and sealers. We want to help you find the right solutions to your molding woes, so your molding processes are more productive and efficient. With our tips and products, you’ll have less downtime, less scrap, and fewer defects on your products. Get started today by talking to one of our experts!

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1. Use Better Mold Releases

One of the first things you want to consider when trying to decrease the build-up you experience on your molds is the mold release you use. The right mold release agent can combat many production challenges, including sticking parts, cracking, and build-up. If you’re current mold release isn’t helping you in these areas, it’s time to try something new, like a better product from Stoner Molding Solutions.

Our mold release paste waxes and sprays are designed for each industry and polymer type to improve molding efficiency and decrease build-up. For example, a leading filament winder of polyester and fiberglass tried Stoner’s TraSys® 9825 because they had issues with build-up on their mandrels. After switching to this water-based, semi-permanent release coating, they had no build-up that needed to be cleaned, increasing the number of parts they could produce.

Polyurethane Industry

Water-based releases may be suitable for the fiberglass industry, but it’s not always the right choice for polyurethane fabricators. Instead, you may need a product like Stoner’s M883 PolyOut Polyurethane Release, a solvent-based suspension for flexible molded foams.

This versatile, silicone-free release provides excellent results with in-mold coatings. The consistent, open-cell finish helps reduce build-up on the mold surface. To clean the mold, use B505 PolyOff—a polyurethane cleaning solvent that removes cured polyurethane residues, excess release, and build-up.

2. Clean the Mold Surface More Frequently

We know that cleaning more frequently sounds counter-intuitive to producing more parts in less time. However, when you do regular spot cleanings, you can reduce the frequency in which you take the mold out of production for a thorough scrubbing to eliminate the build-up. Whether your build-up is from fillers, the resin itself, release agents, or stabilizers, developing a consistent mold cleaning process is essential to prevent it.

Stoner’s citrus-based mold cleaners are perfect for in-cycle cleaning since they won’t evaporate on hot tools. They also produce little odor, making them the ideal choice for spot cleaning at operator stations. We also have an A499 Precision Mold Cleaner with an extra powerful spray stream to remove resin build-up, grease, oils, waxes, and silicone from molds, tools, and equipment.

Composites Industry

While the previously mentioned products work for many applications, we know those in the composite molding industry face very specific build-up challenges. Composite fabricators who mold with polyester or vinyl ester resins and gel coats deal with styrene monomer build-up on the mold surface. And since molds in the composite industry are often quite large, it creates a significant headache when you must take that piece out of production to remove the build-up. That’s why in-cycle cleaning of the mold surface before you observe build-up is essential.

If using semi-permanent mold release, saturate a clean, non-abrasive medium such as a white cotton rag with no seams with KantStik Mold Cleaner and wipe down the entire molding surface. Finish by buffing with a microfiber towel. The cleaning solvent blend in this mold cleaner is specifically designed to remove styrene and surface contaminants without removing the semi-permanent mold release. However, it will remove mold release paste wax, so you’ll need to reapply the paste after using KantStik Mold Cleaner.

3. Invest in the Right Mold Sealer

A clean mold prepared with a good mold release paste or spray is only part of the equation to prevent build-up. Adding the right mold sealer can also minimize the build-up you experience on your mold surfaces. While the surface of the mold may appear to be smooth to the naked eye, there is some degree of porosity on a microscopic level. Additionally, small cracks form as a mold expands and contracts throughout the thermal changes of every production cycle.

The mold release agent won’t be as effective without a proper mold sealer. The mold sealer provides a barrier between the microscopic pores of the mold and the release agent, resulting in a more effective release from the mold. The better the mold release can work on your molds, the less build-up and frustration you’ll experience.

4. Optimize Your Production Cycle

Once you have the right molding products in hand, you must ensure your production cycle isn’t causing unnecessary build-up. For example, you should read the resin or polymer manufacturer's directions to ensure your molding machine is set to the right temperature and cycle time. Too high of a temperature or too long of a molding cycle can quickly cause build-up on your tooling.

Also, examine if there are nuances between operators regarding build-up. Does it occur more on one shift or when a certain operator is working the machine? If so, there may be something that they are doing to cause the build-up. They may need to be retrained by a more experienced operator.

5. Check Other Areas of Your Molding Machine

The mold surface isn’t the only area of your molding machine that can experience build-up. For example, you may need to use your polyurethane cleaning solvent on the mixing head. The press plate may experience build-up for rubber compression molding and need cleaning. All these little spots of build-up can make your molding process less efficient, so make sure you’re checking them periodically.

Thermoplastics Industry

Gasses from certain thermoplastic polymers can also build up on the vent in the molding process. Be sure you are checking and cleaning the vent regularly to prevent build-up on this specific type of tooling. The resin or gas build-up can create appearance and sticking issues and reduce the finished piece's stability.

Need Help Finding the Right Mold Release Paste, Sealer, or Cleaner? Talk to an Expert!

Reducing or eliminating build-up on your molding machines doesn’t have to remain a mystery. You can improve your production cycles, increase output, and produce higher quality parts by using the best molding products from Stoner Molding Solutions! We have carefully formulated our mold release pastes, sprays, cleaners, and sealers to help you achieve better results and reduce downtime. If we don’t already have a solution for you, we’ll produce a custom formulation for your unique process – just call us to ask about this option!

After over 80 years in the molding business, we have learned what molders like you expect and want in your molding operations. That’s why our team of chemists, engineers, and R&D experts have taken the time to carefully formulate products for your industry, like our polyurethane cleaning solvents. We’ll be happy to look at your operations and see which products may be best for you. Get started by talking to an expert today!

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