Clear Casting Epoxy Resin by Smooth-On

From R 292.00


  • Product name: EpoxAcast 690.
  • Clear liquid epoxy for castings that require a strong, hard finish.
  • For making jewellery, river tables and many other applications.
0.65kg (590ml)
1.30kg (1.18 litres)
6.50kg (5.91 litres)
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General points for all resin work
Resins are not simple to work with and you should not attempt resin art if you are not prepared to experience a learning curve. Start small and get to know your products and the correct methods.
Preparation and mixing are crucial for any resin project to be successful. Read and follow all instructions carefully. Only mix the quantity that you will use immediately as resins cannot be stored after mixing. The heat generated in a container of un-poured resin or in resin that is applied too thick can reach dangerously high levels. 
You need to take health precautions when working with resins so read safety and health instructions carefully. Avoid breathing fumes of this product. Use a well ventilated area at minimum but an approved respirator is recommended. Avoid all skin contact and wear safety glasses, long sleeves and rubber gloves to minimise skin contact. This product is an irritant to the eyes, skin and mucous membranes. 
EpoxAcast 690TM Clear Casting Epoxy Resin
Used to make jewellery and beads, used to create ‘river tables’ and poured into moulds to create castings. Excellent for adding pigments and colourants and for securing stones and crystals in resin art. Also suitable for electronic assembly encapsulation applications where its clear nature allows component identification. Castings cure with negligible shrinkage and are very hard and strong.
Air escapes very easily from this resin and torching is often not required.
Maximum casting thickness is 10mm per layer. Many people have done thicker layers with this resin but with thicker layers the risk exists that too much heat can be generated which can damage the resin or the moulds. 
UV Stabilised (slow to yellow compared to non-stabilised resins). Not very prone to amine blush but if this does occur take required steps to remove it. 
Not approved for food contact and not suitable for heat contact above 45 oC.
Manufactured by Smooth-On in the USA.
The ratio of Part A and Part B is 100A : 30B by weight
These are not detailed instruction. You should download and read the User Instructions as a PDF from this webpage before purchasing. A copy will also be included with your order. If you print it yourself from this web page it will be in easy to read large print. 
The most important characteristics of this resin system

UV Resistant but clear unpainted resin will yellow outdoors.

  • It does not yellow quickly but be aware that most resins, including this one, do eventually discolour somewhat, especially outdoors. 

It is not very prone to amine blush.

  • This makes it less sensitive to application conditions but amine blush can occur and the resin should not be used in cold moist conditions. 
  • If amine blush does occur (most likely in cold moist conditions) then the cured surface must be washed with soap and water then sanded and washed again before adding another resin layer.  We recommend that you read our PDF document on amine blush. 

The liquid resin has low viscosity (thin with high flow).

  • It is often poured into moulds or onto surfaces that have retaining sides e.g. river tables.
  • If glass, small stones or powder pigments ect are added they can make the resin thick enough to pour onto flat surfaces and not run. We have noticed that after adding pigments, a 15 minute wait causes the resin to thicken somewhat reducing its tendency to flow. You can see pictures of resin art made this way on flat boards. 
  • The low viscosity allows entrained air to rise up and escape easily. Torching is often not required and air is usually not a problem with this resin which is a big advantage. 

It can be applied in layers up to 9.5mm thick. 

  • Do not exceed this thickness in a single layer. Thicker layers may generate too much heat which can damage the resin or the mould. 
  • This resin is not ideal for very thin layers, use in layers over 3mm thick. Thinner layers take long to cure thus increasing the chance of amine blush. 

Long Pot Life but still fairly fast curing.

  • The long pot life allows larger quantities to be mixed and used than with short pot life resins. Pot life can be expected to be around 5 hours but it decreases in warmer conditions and for larger quantities. 
  • The relatively fast curing time has obvious benefits. Thin layers, however, cure much slower. 
  • Cure time is dependent on layer thickness. Thicker layers get hotter and thus cure faster. Expect a cure time of around 24 hours for thicker layer of about 9mm. For thinner layers below 6mm thickness the cure time will be longer, up to 48 hours. 

Castings cure with negligible shrinkage and are very hard and strong.

  • They resist moisture, solvents and dilute acids.
  • They can be machined and can be painted after the application of a suitable primer (remove all release agent before priming).
More information and videos
For more information, helpful tips and how to videos visit:

Basic safety and health information is contained in our User Instruction document which is sufficient for the casual user. The Safety Data Sheet for this product can be found in the Technical Section of this website. 

Keep out of reach of children
All our products should be kept out of reach of children under 5 years and anybody who may tend to place items or liquids in their mouths should be supervised. Even packing can become a choking hazard. 
Pack Size
Pack Size
0.65kg (590ml)
1.30kg (1.18 litres)
6.50kg (5.91 litres)

How to calculate the amount of this resin required

You must use a scale and resin mass. You cannot measure this resin by volume.

For a roughly rectangular shape multiply as follows:
Resin required in kilograms = Surface length in metres  x  Surface width in metres  x  required resin film thickness in millimetres.
For a roughly circular shape multiply as follows:
Resin required in kilograms = 3.14  x  Circle radius in metres  x  Circle radius in metres  x  required resin film thickness in millimetres.

For any other shape try and break it down into rectangles and half circles then calculate each one and add them together.

If your rectangular surface is 1.2m x 60cm and you require a film thickness of 9.5mm
Resin required in kg = 1.2m * 0.60m * 9.5mm
                                 = 6.84kg of resin
Now work out how much of Part A and how much of Part B you need to give you the total requirement of 6.845kg
Ratio for this resin is 100A to 30B
To get 6.84kg total resin:
kg Part A required = 6.84/130 * 100 = 5.26kg 
kg Part B required = 6.84/130 * 30 = 1.58kg