Silicone Vs Plastic Resin Molds: Which One to Use

Mar 19, 2021

Plastic resin molds and silicone molds are working perfectly with a variety of resins

Plastic resin molds and silicone molds are the two primary molds we use to casting our crafts or jewelry items. Both of these resins are working with different types and qualities, and molds. However, getting to know the differences between both polishes is essential.

It is because each process carries its limitations. Information, hence, about these limitations eventually helps us in getting the desired results that we want. To know which one of the resins is best for our usage, let us discuss each separately.

plastic resin molds

How to Use Plastic Resin Molds

Plastic resin molds are the first resin that we are going to discuss. Before going into the details, taking care of the plastic resin is pertinent. It is because it helps them in maintaining the firm shape and design. There are a few suggestions for keeping the plastic resin in perfect condition. It includes:

  • The foremost step while using the plastic resin is taking care of its molds. In a stage of demolding, one must remove any plastic pieces. Which otherwise will become hard and remain there forever.
  • After using the Plastic resin molds, one must maintain a good habit of cleaning and washing the mold with suitable detergents and warm water. It will help in removing stains or colorants. For drying, dry cloth is a perfect choice to remove fuzzies.
  • The mold may show a warp upon getting exposed to direct heat or sunlight for a longer span of time.
  • The nature of the resin that we use in mold also appears destructive. Although the plastic material is sturdy, however, it may leave scratches. It is the reason that the use of a pointed or sharp object is prohibited. It includes any pointed object like pin, needle, or nail that will cause scratches.
  • The use of mold release material is beneficial in this regard. Mold release is the material that helps in easing the resin extraction and helps in prolonging the mold’s life. The extraction of resin from mold demands twisting as well as pulling while demolding. Which eventually results in reducing its strength.

Tips for Silicone Resin Molds

Just like Plastic resin molds, silicone resin molds also require tips for casting. Silicon resin molds are famous for throwing jewelry and crafts. The task may look intimidating.

However, it requires a lot guiding especially for beginners. There are some tips that a beginner must keep in mind. It includes:

The Use of Gloves while Handling Resins

In silicone resin mold, one must wear gloves while handling the silicon mold and in times of pouring. It helps in keeping you safe from hot resin, as well as it prevents from leaving fingerprints. Otherwise, fingerprints leave the marks behind in the final casting. It is very crucial when handling the glossier casting. It is because, for glossy casting, the chances of fingerprints are more apparent.

Cleanliness Is Close to Godliness

Keeping the mold clean for getting the best craft is the initial condition. 

A speck of dust or any leftover material inside the cavity may appear in the final casting and stay in the original piece.

Leveling the Position of Your Molds

Leveling the table for silicon resin molds is as essential as for Plastic resin molds. It means that casting the resin in the mold on an uneven surface may result in defective crafts. Even if one has the perfect mold material and resin quality, the final product will still appear inadequate. For this reason, hence, it is recommended to use a bubble level to check the status of the table surface.

Filling the Mold to An Exact Level

Overfilling the silicon resin molds results in overflowing the resin. It eventually results in creating a defective shape of your craft. For this reason, hence, to fill the second resin, one must for the factors like:

  • It is advisable to use resin at the gel stage.
  • One must add the next layer before the demolding step.

What should I use; Plastic Resin Molds or Silicon resin Mold?

Choosing the suitable material between Plastic resin molds or silicone resin molds is of utmost importance. However, both are useful depending upon the applications. However, these points will help you realize what is best for you.

Plastic Resin Molds

The Plastic resin molds are reusable plastic. They contain a polyethylene sheet. That is why the molds are flexible.


Plastic resin moldings are usually inexpensive and cost up to $10. Most of them are even under $5. Therefore, a damaged mold doesn’t make much impact.

Easy to Handle

Working and creating crafts with plastic molds are real fun. Demolding and handling are much easier as compared to silicone resin molds.

Less Shiny and Bright

Using Plastic resin molds, less likely to result in shiny and bright casting. It demands recoating the resin once we remove it from the mold. It eventually requires the addition of extra resin or gloss finish.

Scratchable Material

As we know that the plastic resin molds are pretty much flexible; for this reason hence, they are much softer than silicone resin molds. It ultimately results in scratching the surface as well. For this reason, therefore, if you use a pin or a toothpick for demolding, this will leave a considerable gouge. It happens most of the time when one is not so careful.

Difficult to DIY the Plastic Resin Molds

The one most potential disadvantage of Plastic resin molds is that you cannot DIY. It is because the method demands a plastic sheet that forms a vacuum around a template. Therefore, to do all this stuff, it eventually requires a specialized type of machines and equipment.

Silicone Resin Molds

The silicone resin molds comprise two parts of silicone. It makes these mold more reliable than that of the plastic. These molds can last up to several years based upon the conditions in which you use them.

Flexibility is the Key

The silicone resin molds are very much flexible. It is the reason that they are highly adaptive to complex castings. The demolding process of silicon resins is much easier than the plastic molds.

DIY Molds

Everyone can use the customized form of silicon resin molds. It is because you can purchase two parts silicon and mold anything. It helps you assume that you have a perfect model.

Shiner and Brighter

The castings that come out of these silicone resin molds always appear to be shinier and brighter. This brightness is considerable when we compare it with plastic resin molds.


Due to the quality, reliability, durability, and brightness, silicon resin mold, definitely expensive than Plastic resin molds. The price difference between plastic molds and silicone molds is two to three times.

Extra Care for Silicone Molds

Plastics are rigid material. It is also flexible than silicon. However, silicon molds require extra care while handling the resin. The cleanliness of silicone molds is very crucial. Furthermore, one must store the molds in cool and dry places.

Pressure Casting

Pressure Casting is vital for the Silicon moldings to avoid causing bubbles in the casting.

For More Information, Contact Us Today!

plastic resin molds