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GlassCast 50 Clear Epoxy Casting Resin - 500g Kit

Clear epoxy casting resin designed for deep sections, such as river tables, up to 50mm thick.

Use clear or add tints, pigments, metallic effects or even encapsulate objects within the resin.

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Availability: More than 20 available


You must read essential safety information contained within the product datasheets before storage and use.

£14.95 (inc VAT)
Equivalent to
£29.90 /KG (inc VAT)

The Super Clear Epoxy Deep Casting Resin for River Tables and More

GlassCast 50 is a water-clear, UV resistant epoxy casting resin developed specifically to meet the demands of thick section casting - especially in contact with wood - making it the ultimate 'river table' epoxy.

Its slow-curing formulation allows it to be poured in depths of up to 50mm (25mm into wood) per layer without overheating.

GlassCast 50 has been formulated as a casting resin and not a coating resin meaning that it is water-clear even in very thick section. It doesn't, however, self-level to quite the perfectly flat, glossy finish of our GlassCast 3 coating resin and usually requires a flat and polish if a perfect finish is required on the open face.

GlassCast 50 Recommended Uses

  • River tables (any total thickness, 25mm per pour)
  • Knot/hole filling in wood (with or without pigments or effects)
  • Clear casting (larger jewellery pieces, figurines, paperweights)
  • Wood turning (bowls, pen blanks)

GlassCast 50 Advantages

  • Incredibly clear - no epoxy beats it for clarity
  • Highly UV stable - GlassCast 50 is best-in-class
  • Natural air bubble release - almost zero trapped air without degassing
  • Highly machinable - great for turning, shaping and polishing
  • 100% solids - zero shrinkage
  • No odour - VOC free

How to Use

GlassCast 50 has been developed for professional users to produce the best results possible. It is not a 'craft' product and not intended for children. Before purchase, storage or use you must read the safety and technical data. Having said that, GlassCast 50 is incredibly easy-to-use and delivers fantastic results under a wide range of conditions.

GlassCast 50 is sold as a kit which includes both the resin and hardener in their correct ratios. Take a look at our Resin Calculator to work out how much GlassCast you'll need for your project. The resin and hardener are mixed together at a ratio of two parts resin to one part hardener by volume. Because GlassCast 50 is designed for thicker castings, it needs to cure more slowly than other GlassCast resins and will take around 48hrs to cure.

GlassCast 50 is very often used for 'river tables' where the resin is poured into wood, in which case the insulating effect of the wood means that the total depth should be built-up at a maximum of 25mm per layer, allowing around 24hrs between layers. For detailed information and tips on using GlassCast to create the perfect river table, read the Resin River Table Handbook and study the GlassCast 50 technical datasheet.

Always download the Technical Datasheet from the 'Downloads' tab for full details on correct measuring, mixing and use of the product.

Getting More Creative - Pigments, Tints and Metallics

Although GlassCast 50 is often used completely clear it is also compatible with our complete range of tints, solid-colour pigments and metallic-effect powders. Many other colours and powders can be added too but be sure to conduct a test to ensure compatibility.

  • GlassCast Translucent Tinting Pigments - including neon colours!
  • GlassCast SHIMR Powders - metallic effect pigment powders
  • Epoxy Colour Pigments - solid colour pigment pastes


Un-cured Properties

Property Units Resin Hardener Combined
Appearance - Clear Liquid Clear Liquid Clear Liquid
Maximum Casting Thickness mm - - 50 (into mould)
24 (into wood)
Viscosity (25°C) mPa.s 650 - 950 180 - 300 400 - 700
Density g/cm³ 1.10 - 1.14 0.99 - 1.01 1.08 - 1.12

Working & Cure Times

Hardener Pot-Life @ 25°C Gelation Time @ 25°C 15ml 6mm Gelation Time @ 25°C 100ml Demould Time @ 25°C
GlassCast 50 75 - 95mins 10 - 12hrs 140 - 180mins 36 - 48hrs

Cured Properties

Property Units Result
Colour - Colourless
Machinability - Excellent
Density @ 25°C g/ml 1.08 - 1.12
Hardness @ 25°C Shore D/15 80 - 85
Glass Transition °C 61 - 58
Max Working temperature °C 55
Flexural strength MN/m² 90 - 102
Flexural Elastic modulus MN/m² 2900 - 3200
Maximum Strain % 4.0 - 5.5
Strain at Break % > 15
Tensile strength MN/m² 51.0 - 58.0
Elongation at break % 6 - 9

Questions Asked About GlassCast 50

Yes, GlassCast 50 can be used to cover the top of the project as well as the deeper sections. The cured surface finish of GlassCast 50 is not quite as perfect as the GlassCast 3 (which is designed specially as a 'coating resin') but for most applications you would probably be perfectly happy with the surface finish straight from the GlassCast 50 pour. If you do need absolute perfection then you can always flat and polish the surface, which is quite easily done with GlassCast 10 and 50.

There's a good chance that the ribbons would absorb resin and take on a 'wet' appearance that you would want to avoid. I'd suggest experimenting with this first (using some valueless ribbons if possible) but it might well be that applying PVA (glue) to the ribbons beforehand, and allowing it to fully dry, would seal the ribbon and ensure that they keep their original appearance when encapsulated in resin. This is the same technique that is used to stop photos and magazine prints from doing the same thing. Remember though, experiment first!

This usually occurs when you're doing particularly deep pours and generally when the mixing has been quite vigorous and resulted in a lot of smaller air bubble entrapment. Smaller bubbles are more difficult for the resin to release because they have less buoyancy compared to their drag (less volume as a ratio to their surface area).

To reduce the air entrapment in the first place the solution is to mix more slowly and purposefully, making ever effort you can not to 'whip' air into the resin. Also, make sure that the resin is at a starting temperature of 20°C when you mix it. If the resin is cooler then it will be thicker and more prone to air entrapment when mixing. To help to eliminate the air that does get mixed into the resin it's helpful to pour the resin a bit at a time, using a hair dryer or heat gun gently each time you add some more resin. This way the air bubbles don't need to rise as far and the affect of the heat gun can penetrate each shallower pour of resin more easily. This isn't the same as making up the depth in multiple pours (allowing the resin to cure between each pour). What I'm describing is just pouring out maybe 5mm, then gently hair-dryer, watch the bubbles pop, pour another 5mm and keep going.

The risk from deep pours (deeper than 25mm) is that the resin could exotherm (overheat) during the cure which can cause it to crack, distort and discolour. If the resin doesn't get into this overheating spiral and stays relatively cool during the cure then there is no disadvantage to deeper pours. We have one customer who regularly manages 50mm depth in a single pour by positioning big fans blowing air over the table to keep the resin temperature down.

The exact grade of abrasive you should use to key a fully cured previous pour of resin isn't too critical but you should use something reasonably coarse; we would normally use a 120 or 240 grit. And yes, worry not! The next pour of resin will fill in all the scratches and there shouldn't be any evidence that they were ever there.

Yes, you can definitely do this with GlassCast 50 but there would be a couple of things to think about when you do. When casting into a mould (including your sphere mould/container) GlassCast 50 can be used for sections up to a maximum of 50mm thick. It can be tricky to explain but what we mean by 'thickness' is the smallest of the 3 dimensions if you could measure the resin block (or the gap where the resin will be) in all 3 directions (example: width, height, depth). If the resin will be more than 50mm in length, AND width, AND depth at any point then you would need to pour the resin in layers, to avoid it over-heating whilst it cures. If - because of how much space the burl takes up - the resin wouldn't ever exceed 50mm in all 3 dimensions anywhere on the casting then you could do it in one pour.

In terms of then turning down the piece once cured, you'll have no problem. We have lots of beautiful examples of similar pieces in our gallery.

Good question. It's hard to say for sure because household clingfilm can actually be made from a number of different types of plastic and therefore have different release properties. In the past we have seen GlassCast release from some clingfilm but on other occassions it seems to have well and truly stuck. Therefore, the only firm advice we can give you would be to test a small area first in order to see if it releases from your clingfilm.

One other option to consider if you're looking for a low cost release material is brown packing tape. Packing tape/parcel tape is almost always made from polypropylene which GlassCast doesn't stick to so you're pretty safe if you cover something in brown parcel tape, rather than clingfilm.

20C is definitely the recommended working temperature but there is a bit of leeway on this. With GlassCast 50 I would suggest that 15C would be the minimum acceptable working temperature.

What you'll find when working at lower temperatures is the that the resin and hardener will both feel thicker than they normally would; this can mean that more air gets mixed in when you mix the resin and hardener together and so it becomes more important to mix carefully to avoid aerating the resin when mixing and also maybe a bit more thorough with the heat-gun or hair dryer when removing bubbles from the poured resin. The other affect you'll see in cooler conditions is that the resin will take longer to cure than we state on our datasheets/tutorials etc although other than a bit more patience, this is not normally an issue.

Just for completeness in the answer, working at temperatures much higher than 20C is more of a worry because of the risk of the resin over-heating during cure. If you do ever find yourself working at higher temperatures then you would need to reduce the maximum casting thickness from 25mm to something more modest.

GlassCast 50 is very much a rigid resin once fully cured and as such would not be considered to have any noticeable flexibility.

Small defects in the Glasscast finish can be cut/drilled out and then refilled to repair the damage. However it is essential that you thoroughly clean the area being repaired before you refill with resin to avoid any dust or dirt being trapped.

Yes you can clean the surface in that way or by using pre-made IPA wipes. Bear in mind, you will still need to key the surface with 120 grit sand paper before cleaning to ensure the best bond between the resin layers.

Yes, you should always seal your wood first before you do the main pour. This will eliminate the risk of air bubbles coming out of the wood whilst the resin cures and becoming trapped (and visible) in the cured resin. The best thing to use to seal the wood would simply be a small batch of the GlassCast resin, mixed up in the normal way and painted onto the wood (and into the knots and crevices) in advance of the main pour. In a thin coating like this, you will find that the GlassCast 50 will take quite a while to cure but it will work great and saves the need to purchase another type of resin or sealer.

Although you could use GlassCast 50 to make a decorative ashtray problem, heat from a cigarette butt would degrade and damage the resin surface over time meaning we would not recommend it for functional use.

GlassCast 50 is ideal for larger pen blanks where it's clarity and ability to be poured up to 50mm is ideal. Once cured for a minimum of 48 hours, the pen blank will be ready to machine and turn.

HDPE is a very chemically inert low energy plastic and as such, in a similar fashion to polypropylene, nylon and PVC, resins will not stick to HDPE.

Yes, once the GlassCast has fully cured, you should be able to paint over the top no problem but it will depend on the type of paint that you're using. Cured GlassCast is essentially a plastic so you're likely to need to use a two-pack paint like a polyurethane or an acrylic to get a really good bond. We would certainly recommend 'keying' the GlassCast with abrasive paper and then testing a small area first to check the quality of the bond.

GlassCast 50 has a maximum working temperature of 55 °C which is much lower than the radiated heat given off by some fireplaces. As such we would not recommend keeping it too close to a fireplace or fire to avoid damaging the resin.

...I'm looking for clear resin for coasters and tables which can hold hot plate or mug.

The maximum working temperature for GlassCast 50 is 55°C. GlassCast 50 could be marked by hot objects such as very hot drinks (think fresh black coffee, no saucer). To improve the heat resistance of your GlassCast surface, an elevated temperature post-cure should be undertaken.

Even with the post-cure we would recommend being careful about placing down hot cups and items, ideally allowing them to cool first or use a saucer just to be on the safe side.

As long as you reseal the bottles promptly after use and store them in accordance with the datasheet, then we would expect you to still achieve the full 12 months shelf life.

Yes you can layer the resin in that way. The ideal method is to pour the second and any subsequent layers when the first layer has become firm but is still tacky. At this stage no further preparation is needed and you are likely to get an almost invisible join line.

If you need to wait until after the first layer has fully cured, then the resin will need a key with sand paper and a thorough clean before pouring the next layer.

GlassCast will stick to many surfaces including stone and concrete. Where surfaces are smooth, it is recommended to key the surface to aid maximising adhesion.

It's worth noting that if you want a resin to 'coat' materials like stone or concrete then the GlassCast 3 Coating Resin would be a better choice. GlassCast 50 is designed for very thick section casting (up to 50mm) but would require polishing on the open surface to achieve the perfect flat gloss finish of GlassCast 3.

GlassCast 50 has zero volatile content which means it doesn't really give off any fumes that you could breath in (unlike resins such as polyester which have high volatile solvent content). This means that, providing you are working in a ventilated area, a vapour mask should not be necessary.

Nonetheless, you should avoid breathing in any odour/vapour in close proximity (i.e. smelling the containers) and of course if you may make your own decision to wear a vapour mask.

GlassCast 50 has been designed from the beginning to be as UV stable as possible. No epoxy resin system is completely invulnerable to prolonged high levels of UV light but in the world of epoxies, we don't know of any resin system that is more resilient to UV (and yellowing) than our GlassCast 50. To provide some perspective, this has been tested in an accelerated UV exposure chamber (like a sunbed!) where it's spent months being bombarded with high levels of UV, after which there was very little sign of any discolouration.

Very well. GlassCast 50 was designed from the beginning to be an epoxy with the best possible UV stability. Much like the paint on your car, nothing is completely invulnerable to the effects of prolonged UV exposure but, by epoxy standards, GlassCast 50 is about as good as it gets. We have done lots of accelerated UV testing (leaving samples in intense UV exposure units) which are far stronger than normal sunlight and in months of this testing we can barely detect any discolouration. Nonetheless, we still don't recommend GlassCast (or any other clear epoxy) for permanent outdoor UV exposure.

Not exactly but it's pretty close. The actual relative density of the GlassCast 50 when mixed is 1.08 (so it's 8% off being 1kg = 1L) but for the purposes of a rough estimate of how much you'll need, we usually just treat them as the same.

GlassCast 50 has not really been developed for outdoor use and so we would not recommend it for this purpose, particularly if this would be 365 days per year in the more extreme conditions of snow/ice through to lots of exposure to strong sun. For more occasional use there would be no problem but as a permanent outdoor installation we wouldn't recommend it.

Yes GlassCast 3 can be used in this way. If you are making a river table and want a thin layer of resin right over the top of the wood as well, then using GlassCast 3 in this way over the top of the GlassCast 50 will give a smoother finish on the surface.

There are no known issues with encapsulating LED's in resin in terms of curing or using the resin. The only area of concern is ensuring the LED cluster is fully working before pouring the resin and also long term maintenance - any failed LED's would be unable to be replaced.

You can certainly use tints and pigments when working with LED's. The way the LED diffuses the light may effect how the overall piece looks.

After allowing a minimum of 48 hours curing time, the GlassCast 50 can be machined, cut, sanded and shaped no problem. Once finished you will be able to polish the resin back to a very high gloss.

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