How to make decorative paperweights in polyester casting resin

1. The different types of objects one can make:

Polyester casting resin can be used for the manufacturing of many objects. The paperweight idea can also be extended to include paper holders, statues, animals, gemstones, jewellery and figurines.

2. Method for making paperweights:

2.1 Make your masters with gypsum (coated with a urethane varnish for smoothness) or buy them ready-made and arrange them inside a watertight wooden box, like in the pictures below. The masters are then sealed with glue at the bottom, so that the moulding agent (liquid silicone or liquid polyurethane) cannot flow in underneath.

2.2 Pouring the liquid silicone into the pre-made moulding boxes, after adding the prescribed hardening catalyst and mixing it thoroughly:

Extensive tests have revealed that the use of silicone is sufficient in cases when one single pour of casting resin is required. However, a second and third pour may sometimes be required. The first pour must gel to a jelly stiffness, when you must then insert your object onto it. The second pour then takes place to cover the object (encapsulate). When the second pour has gelled, you can do the final pour for the base in a pigmented colour resin. The problem with silicone is that a gap appears between the gelled resin and the silicone wall, which has the effect that the pigmented colour overflows down into the cavities, covering the areas, which you want to end up with in clear transparent form. So, when more than one pour is required, we rather use cheap plastic containers, which can be purchased from chain stores, as shown in the picture below. In any case, liquid silicone and liquid polyurethane are very expensive.

2.3 Catalyst of 1% by volume at room temperatures of 20 to 25 degrees Celsius, is normally mixed with the polyester casting resin to agitate it for chemical heat curing. The quantity of catalyst can vary as room temperature, volume and pigment can influence the curing time. It is preferable to vibrate the resin so that most of the air bubbles created during the mixing process, can escape. Air bubbles also escape naturally during the curing process, but then you may end up with 3-4 small air bubbles of 1-3mm in 10% of end products.

Polyester resin shrinks when it changes from a gel state to a hardened state. It is therefore important to remember that the final pour of pigmented resin, must go in after the lower layer has started to gel, but still early enough to gel itself before the lower layer gets hard.

2.4 Pour the agitated polyester casting resin into your moulds, which must be arranged on a water levelled surface, as displayed in the picture below. Curing time to workable drying takes 12 to 24 hours, depending on weather temperature. No release agent is needed if the mould is sufficiently high in density and smoothness. For easy removal of the final product, the sides of the mould must have a slight gradient.

2.5 Here is a snapshot of some of the final products with a pigmented white base on the underside and transparent polyester casting resin on the sides and top:

2.6 Here is another colourful example of what you can make and capture inside a clear casting:

2.7 Other material which may be used for a mould is for instance stainless steel. You can have a full stainless steel plate indented by hydraulic hammer, full of moulds to your specification and size, mounted on a levelled steel frame.

3. Possible paperweight uses and markets:

- business cards: scanned, shrinked and cemented into casting
- corporate gifts: logo and contact details cemented into casting
- token or medallion awards: token or medallion cemented into casting
- event commemoration/celebration handouts or sales: any logo, image or details cemented into casting
- benefits: use as paperweight, permanent, durable, always available on someone's desk

Here is another idea to get you stimulated. It is well-known that hundreds of tourists are daily pouring into the seaside town of Hermanus in the Western Cape, for whale spotting. They are also visiting several gift shops on the lookout for a token. You can for instance supply these stores with paperweights, which have a small plastic whale in the casting, with a titled inscription of "Hermanus - South Africa", to take back with them to their foreign countries, to forever commemorate the event.

4. Economic viability of paperweights:

The cost of the final product can vary between R10 to R20 South African Rand (ZAR) per item, depending on the size and the type of mould. The current retail selling price for a 75 mm diameter x 25mm thick circular casting is between R80 to R100 per item. The wholesale price can then vary between R40 to R60. If you work on a average cost of R15.00 and a average selling price of R50, the gross profit before income tax and distribution cost then comes to R35.00 per item. The table below reflects the profitability according to different sales volumes:

Sales volume per time period	Profit per time period at R35 per item
10	R350
100	R3 500
1 000	R35 000
10 000	R350 000
100 000	R3 500 000

If you can find a big enough market to switch to mass production, you can always go into a joint venture, without capital outlay, with a manufacturing facility, who can produce these items by plastic injection moulding, or some similar high volume methods. This also serves as an example of how a small home business can possibly grow into a big time business, with the right idea and some luck.

5. Video demonstrations of polyester resin castings:

Here are a few video demonstrations of how to do polyester resin castings for different decorative objects.

5.1 Polyester resin rings:

5.2 Polyester resin gemstones part 1:

5.3 Polyester resin gemstones part 2:

5.4 Polyester resin jewellery casting part 1:

5.5 Polyester resin jewellery casting part 2:

5.6 Polyester resin jewellery casting part 3:

5.7 Polyester resin bracelet casting:

Buy some of our paperweights here.

Back to home page - Back to Career Builders Articles