HOW TO

GETTING IT RIGHT

Frequently Asked Questions

Where an object is too large to post cure in an oven

When you are using, say, Solid Cast 606 epoxy resin, which typically requires a post cure of four to six hours in an oven, larger objects can simply be placed under a table or some larger framework, draping over with a plastic tarp or blanket.

Creating a rusty look

To do this, dust the mould with iron powder. From there, colour the casting mix to a rusty brown colour with acrylic paint pigment. Then, pour in the casting material. Upon removing the casting, dust down, then spray diluted hydrochloric acid onto the gray iron powder surface. Lastly, let sit for 24 hours. The resulting casting will have a rusty-iron look (all over) – combining a mixture of actual rust and rusty-coloured material in some background areas.

Achieving a metal-finish look when casting

Beyond this particular look, the following method applies for any cold-cast material. In turn, optimum results are achieved by using a leafing-grade metal powder (in other words: a metal powder that transfers a full metal powder coating onto an item dipped into the powder). Very simply, use a dry brush to paint the mould surface in metal powder. Then, mix the powder into the casting material to achieve the same colour. From there, pour the casting material in. Upon removing the casting, buff the surface with a soft cloth. the overall look will be a low-sheen metal effect.

Protecting copying electronic components set within clear resin

To do this, colour the casting material with an opaque pigment.

The curing of epoxy resins

Epoxies, in particular, are very temperature sensitive. A temperature drop to 15°C (or lower) overnight will kill off cross-linking of the mixture. In turn, resins need to be consistently kept at 20°C (or more) for the entire cure period. Uncured epoxy resins may respond to later application of extra heat, but some may never revive and, in turn, will remain sticky. If this happens, you can wash off with warm, soapy water, dust it with talc or apply more resin mix to bond the sticky surface.

Why does a part become difficult to remove from a mould

This typically indicates that the mould has reached the end of its life, so to speak, particularly where small pieces are starting to tear away. In turn, the casting life of a particular mould varies depending on the number of casts that have been made from it, the type of casting material, as well as the overall complexity of the object and, in turn, the mould, itself.

Eliminating bubbles when pouring out silicone or casting materials

Generally speaking a vacuum pump is your best bet. Beyond this, there are several steps you can take to reduce the likelihood of bubbles. Firstly, mix materials in a steady figure-8 manner, ensuring that you mix the material on the mixing container sides. In turn, avoid lifting the material on the mixing container sides (and avoid lifting the mixing stick up and down). Then, pour the mixture out by pouring close to the work (and from one point). Slowly lift the mixing vessel to about 40cm above the work, and be sure to pour in a very thin stream (this will ensure that any air bubbles present are torn open as the material pours). In particular, avoid lacing the material over the work as this captures air. Keep pouring from one point, letting the mixture flow out evenly over the work like a slow wave.

Pattern shapes that aren’t suitable for moulding

The key thing is undercuts. The object shouldn’t be so complex that your mould halves (or multiple sections) can’t be withdrawn without excessive undercuts – a ‘tree’, for example, is to delicate to be able to practically cast.

Embedding organic objects in epoxy resin

Generally speaking, you need to allow adequate time to dry an organic object, just to ensure it’s thoroughly dry and devoid of moisture. In turn, not doing this will mean that it could decay and rot within the resin once the exothermic reaction takes place. The other consideration to take into account is that moisture will inhibit the resin cure.

Bubbles forming when embedding an object

It’s possible that air could have been present in the object you’ve embedded. In turn, warmth generated when the resin is setting causes the entrapped air to expand and, subsequently, create bubbles in the resin. A dried insect, for example, can still hold air in its body. Here, once the resin has been exothermic, the air will draw out. your best bet is to pre-seal the object with a thin coating of resin first. From there, let it fully dry, then embed the object.

Frequently Asked Questions

Epoxy Resins

Use (up to) 5% of methylated spirits as a thin film coating. You can also thin the epoxy resin by warming the it slightly. However, this will shorten the resin’s pot life.

The best rule of thumb is to double the weight of fibreglass fabric per square meter. The resulting amount is how much epoxy resin is required per square meter.

To do this, your best bet is to burn off the dried epoxy resin (and in the safest possible manner).

The short answer, whether sealed or opened, epoxy resin can be safely stored for 2-3 years. If you find part A or B cloudy, white or sugary, this is simply due to it being stored in cold conditions. To restore the resin to an even, clear colour, place the can in hot water or place by the heater, allowing to return to room temperature before using again. With epoxy hardeners, if there is a large air space left in the container, thickening may occur, which, unfortunately, will make the product unusable. The best rule of thumb is to store at around 20°C and keep off things like cold concrete floors.

Simply buff with a jewellery-polishing compound.

Use a butane torch and pass the flame back and forth above the surface of the resin. The moving flame can actually touch the resin without it catching on fire or burning. This should cause the air bubbles to expand and then burst. The result being a very flat surface. Another method is to very lightly spray metholated spirits over the surface, although the flame treatment is more effective.

If you find part A or B cloudy, white or sugary, this is simply due to it being stored in cold conditions. To restore the resin to an even, clear colour, place the can in hot water or place by the heater, allowing to return to room temperature before using again. With epoxy hardeners, if there is a large air space left in the container, thickening may occur, which, unfortunately, will make the product unusable. The best rule of thumb is to store at around 20°C and keep off things like cold concrete floors.

Both Acetone and Xylenes are excellent at cleaning up sticky, uncured epoxy resin, as are many general solvents. While slightly less effective, metholated spirits are much better for your health.

1 litre of epoxy resin will cover 1 square metre of area at 1mm of thickness. A safe rule of thumb is to allow around 1.2Kg of epoxy resin per square meter at a coverage of 1mm depth.

Silicone Rubber

Silicone rubber cannot be moulded over glass, glass/ceramic mixes or silicone based sealant. The silica element in silicone rubber will bond tenaciously to these materials.

Very simply, dust the mould with talc or talcum powder to assist metal flow and, in turn, increase the life of the mould.

Not really. For the best results you should brush on a layer of pre-mixed silicone rubber first – prior to any spatula application of a silicone rubber. Not taking this approach could result in air becoming trapped on the surface of the mould.

Yes – your best bet is Vaseline (petroleum jelly). It will need to be slightly warm before you brush it on.

Generally, up to around 200°C. That said, however they can tolerate much higher temperatures if it’s a one-off casting.

3D Freedom, for example, can tolerate up to around 280°C, or, again, much higher temperatures if it’s a one-off casting.

If your mould is damaged, you can use silicone glass sealant (the type of sealant used for windows).

The rule of thumb is roughly 12 months for both catalyst and rubber. Beyond this period, ageing may cause shorter pot life and silicone rubber can go ‘lumpy’. As for silicone rubber moulds, once made, dust the mould with talc and, ideally, store the pattern in the mould – this will help to retain the mould’s shape.

To stiffen up the rubber, add (up to) 25% corn flour or silica flour. Bear in mind, though, that flex and elongation will be affected. In turn, you can add (up to) 10% silicone oil to soften the rubber. As for Shore strength, you can mix a different ‘Shore strength’ after you have catalysed each silicone with its own catalyst. In turn, the ratio between ‘soft’ to ‘hard’ silicone wil determine the final Shore Rating.

If this is the case, you’ve possibly added too much catalyst. In turn, this can shorter the rubber’s pot life. Another thing to remember is that this can weaken the mould cross-link, which, in turn, also reduces the mould’s life.

A good ‘citrus orange concentrate’ solvent works very well.

It’s possible that you haven’t used enough catalyst. The other reason might be that the product is past its shelf-life. Temperature does not greatly affect the casting of conventional silicone rubbers, however high humidity which accelerate setting also shortening pot life.
Given that this is ‘water clear’, sometimes it’s difficult to tell if you’ve mixed it well enough. In turn, add a drop of POLYTEK Polycolour liquid dye to your catalyst. This will give it a distinctive tint, so that, when it’s added to the silicone rubber base, you’ll be able to tell that it’s mixed enough, as there will be no streaking left and the silicone will have a uniform, even colour.

 

These are the only type of mould that are self-demoulding. Silicone does not require a demoulding agent, but because most resin systems are aggressive for the moulds, we recommend if more than a few parts are required from the mould, extend the mould life by assisting it with the occasional application of a release agent such as POLY-EASE 2300.

Polyurethanes

To do this, buff with a jewellery-polishing compound. Alternatively, polyurethane surfaces can often be retreated by cleaning then buffing. Or, you can apply/spray another polyurethane finish.

Generally speaking (up to) around 70°C.

Generally speaking, this is around three months. Beyond this period, potential moisture absortion can cause foaming. In turn, squirting a shot of Poly Purge into the can prior to releasing can extend the shelf-life of polyurethanes that have been opened.

To do this, first, clean with warm, soapy water (or a solvent) then proceed with an enamel paint system.

Your best bet is a kerosene and oil mix. The rule of thumb is: one part oil to three parts kerosene.

To do this, use Solid Cast 305 5-minute Epoxy Glue, Solid Cast 300 Epoxy Glue or Solid Bond 390 Superglue. Firstly, though, rough up the surface with sandpaper prior to gluing. This will help you achieve optimum results.

Very simply, some flexible polyurethane rubber systems can take a few days to fully set.

If this happens, it is often due to exposure to moisture, which in turn, causes polyurethanes to bubble and foam up. With this in mind, moisture can come from several sources (it’s possible moisture was absorbed while in storage). Or, bubbles and foaming can simply be due to the product being near the end of its shelf-life (use Polypurge to extend shelf-life). The other issue is that the mould surface might be damp. In turn, you can dry it in a low-heat oven. Other reasons could be: possible excess humidity in the air on the day that you cast the polyurethane, or, if you’ve added a polyurethane mix, the filler may have been moist. In turn, fillers can be dried out by sprinkling on a tray and heating in a low-heat oven, ensuring that you allow to return to room temperature before adding to the polyurethane mix.

Despite their flexibility, these moulds must be waxed like a resin mould.

Foam Sheets

No solvent-based paint/finishes (or superglues and polyester, MEKP) should be used. These will melt the foam. In turn, your best bet for surface coating is an acrylic waterbased paint, Solid Bond 330 Epoxy Fibreglassing Resin or Solid Cast 630 Acrylic Plaster.

Solid Cast 630 Acrylic Gypsum can be brushed, sprayed or spatulated onto Styrofoam, once set the surface can be readily sanded or machined. The final surface will be non pourous and fully waterproof.

The desntity is 30kg per cubic meter. In turn, please see the following sheet weights: 25mm x 600mm x 2.5m 1.33kg 30mm x 600mm x 2.5m 1.5kg 50mm x 600mm x 2.5m 2.31kg 75mm x 600mm x 2.5m 4.8kg 100mm x 600mm x 2.5m 5kg 165mm x 600mm x 2.5m 9kg

Always use solvent-free adhesives. A good example is Solid Bond 305 5-minute Epoxy Glue. ***Bond inboard of any joint lines when the Styrofoam has to be shaped and sanded over joint lines.***

Your best bet is a saw, craft knife or hot wire-cutter. To shape it, use a file, rasp or sandpaper.

Moulding

Here, the best rule of thumb is to fill the area (that you’re going to fill) with, say, water, sand or rice (or something similar). Then, pour this amount into a measuring container. The resulting level on the measuring container will give you the amount of liquid you will need. In turn, add an extra 10% to this amount, as this will take into account any losses that occur during during the pouring process.

The short answer is yes. That said, it mustn’t contain sulphur (please ensure you check, as most plasticines do) – this will contaminate the silicone. For optimum results, use Klean Klay

This typically indicates that the mould has reached the end of its life, so to speak, particularly where small pieces are starting to tear away. In turn, the casting life of a particular mould varies depending on the number of casts that hace been made from it, the type of casting material, as well as the overall complexity of the object and, in turn, the mould, itself.

Postage and Handling

Orders over $125 receive free shipping (Excluding WA & NT) Otherwise a flat rate of $10 applies for all orders under $125. All orders to Western Australia and the Northern Territory incur a flat rate surcharge of $15.

A $20 flat fee applies to all dangerous goods above 500ml.

ESTIMATED DELIVERY TIME Please note that delivery times are calculated from despatch date, not the date when the order was placed/processed. See a rough guide below: VIC 2-4 Business days NSW 3-6 Business days ACT 4+ Business days SA 3-6 Business days TAS 5+ Business days QLD 4+ Business days NT 5+ Business days WA 5+ Business days *Locations in remote areas may incur longer delivery times than the times listed above.

You can now get most of Solid Solutions’ products shipped to your door anywhere around the world

Casting

This is simply the impurities in the metal coming out. To discard, skim off with a spoon. This is really important, as the scum impurity will weaken a casting.

To do this, firstly, partially blend liquid colouring into the resin mix (no more than a couple of swirls). Next, pour out the mix in a swirling motion as the mould begins to fill up.

Your best bet is kerosene and oil mix. The rule of thumb is: one part oil to three parts kerosene.

Generally speaking, this is typically a sign of poor mixing. Unless both parts A and B are thoroughly mixed together, any undermixed material will not cross-link fully and, in turn, remain sticky. Mix thoroughly in a straight-sided, flat-bottomed container (using a flat ruler-shaped mixing stick), scraping around the sides and base of the container.

Generally speaking, you can store these for many years. If separation does occur, however, simply re-mix, or, if the material has dried out, add a small amount of metholated spirits.

Your best bet is to use a jewellers polishing compound, bearing in mind that a glossy mould surface will make the metal brighter. Just make sure that the original pattern is glossy before casting the low melt-metal silicone rubber.

Very simply, when pouring a hot met into a cold mould, the mould, itself, cools the metal quickly and, in turn, stops the flow, resulting in ‘partial casting’. The best rule of thumb is to preheat the mould in an oven. This, combined with dusting the mould surface with talcum powder, will assist slip and flow in the pouring process.

Here, the best rule of thumb is to fill the area (that you’re going to fill) with, say, water, sand or rice (or something similar). Then, pour this amount into a measuring container. The resulting level on the measuring container will give you the amount of liquid you will need. In turn, add an extra 10% to this amount, as this will take into account any losses that occur during during the pouring process. To convert a volume to weight multiply by 1.2 as most resins, silicone rubbers and polyurethane weight around 1.2kg per liter.

Firstly, cast up to the level where the object is going to set, and letting the resin partially set, bearing in mind that cast epoxy resin will generally firm up within a couple of hours (you can monitor this by checking the resin and applying pressure with a needle, which is better than using your finger, as the latter will leave a fingerprint). The best rule of thumb is to cast subsequent layers of resin after the previous pour has had time to set up and come down in time from its peak exotherm point (layers should be cast within 24 hours of each other. This is to help eliminate visible joint lines between each layer of resin). Once firmed up, place the object to be embedded on top of the resin, before pouring a new resin mix to top up the mould. in turn, this technique can be used to cast multiple layers – clear or coloured – with an embedded object.

This can be caused simply by the resin heating up during the caring process. To ensure this doesn’t happen, restrict the volume of resin, or try casting in several layers.

The best bet is to, firstly, apply a thin coating of PVA adhesive, or a spray photographic fixative. From there, let it dry. Then, coat or embed the paper in resin.

It’s possible that air could have been present in the object you’ve embedded. In turn, warmth generated when the resin is setting causes the entrapped air to expand and, subsequently, create bubbles in the resin. A dried insect, for example, can still hold air in its body. Here, once the resin has been exothermic, the air will draw out. your best bet is to pre-seal the object with a thin coating of resin first. From there, let it fully dry, then embed the object.

Generally speaking, you need to allow adequate time to dry an organic object, just to ensure it’s thoroughly dry and devoid of moisture. In turn, not doing this will mean that it could decay and rot within the resin once the exothermic reaction takes place. The other consideration to take into account is that moisture will inhibit the resin cure.

The key thing is undercuts. The object shouldn’t be so complex that your mould halves (or multiple sections) can’t be withdrawn without excessive undercuts – a ‘tree’, for example, is to delicate to be able to practically cast.

Generally speaking a vacuum pump is your best bet. Beyond this, there are several steps you can take to reduce the likelihood of bubbles. Firstly, mix materials in a steady figure-8 manner, ensuring that you mix the material on the mixing container sides. In turn, avoid lifting the material on the mixing container sides (and avoid lifting the mixing stick up and down). Then, pour the mixture out by pouring close to the work (and from one point). Slowly lift the mixing vessel to about 40cm above the work, and be sure to pour in a very thin stream (this will ensure that any air bubbles present are torn open as the material pours). In particular, avoid lacing the material over the work as this captures air. Keep pouring from one point, letting the mixture flow out evenly over the work like a slow wave.

This typically indicates that the mould has reached the end of its life, so to speak, particularly where small pieces are starting to tear away. In turn, the casting life of a particular mould varies depending on the number of casts that have been made from it, the type of casting material, as well as the overall complexity of the object and, in turn, the mould, itself.

Epoxies, in particular, are very temperature sensitive. A temperature drop to 15°C (or lower) overnight will kill off cross-linking of the mixture. In turn, resins need to be consistently kept at 20°C (or more) for the entire cure period. Uncured epoxy resins may respond to later application of extra heat, but some may never revive and, in turn, will remain sticky. If this happens, you can wash off with warm, soapy water, dust it with talc or apply more resin mix to bond the sticky surface.

To do this, colour the casting material with an opaque pigment.

Beyond this particular look, the following method applies for any cold-cast material. In turn, optimum results are achieved by using a leafing-grade metal powder (in other words: a metal powder that transfers a full metal powder coating onto an item dipped into the powder). Very simply, use a dry brush to paint the mould surface in metal powder. Then, mix the powder into the casting material to achieve the same colour. From there, pour the casting material in. Upon removing the casting, buff the surface with a soft cloth. the overall look will be a low-sheen metal effect.

To do this, dust the mould with iron powder. From there, colour the casting mix to a rusty brown colour with acrylic paint pigment. Then, pour in the casting material. Upon removing the casting, dust down, then spray diluted hydrochloric acid onto the gray iron powder surface. Lastly, let sit for 24 hours. The resulting casting will have a rusty-iron look (all over) – combining a mixture of actual rust and rusty-coloured material in some background areas.

When you are using, say, Solid Cast 606 epoxy resin, which typically requires a post cure of four to six hours in an oven, larger objects can simply be placed under a table or some larger framework, draping over with a plastic tarp or blanket.