Mould care and instructions

HDPE Mould - Care and Instructions Thank you for purchasing our HDPE casting moulds, below are a few guidelines for getting the best use out of your moulds. We recommend using a suitable mould release (even if the manufacturer states it’s not required) as it not only helps with the release of your cast, avoiding having to dismantle the mould, it also protects your mould and silicone bungs and plugs from the aggressive nature of some resins, especially epoxy resins such as GlassCast. Due to its easy release and protective properties, we recommend using a vaseline mould release in both our silicone and HDPE moulds, see below for instructions on how to make an easy DIY Vaseline based mould release. Our shallower HDPE moulds (up to 25mm thick) have a silicone vacuum release bung in the centre of each cavity to aid de-moulding without the need for dismantling the mould. We also put in a silicone bung in our deeper moulds however due to increased surface area and dependent on the resin used, these may still need dismantling for de-moulding. For our cube/sphere moulds, we generally don’t put in a vacuum release bung as due to the increased surface area, a vacuum release bung is unlikely to help with de-moulding and the mould end panels will need to be unscrewed. It may be useful before disassembling your mould to mark the sections with a permanent marker so you know which parts go where to aid reassembly. When reassembling remove any excess resin first and make sure you do not over tighten the screws. This is especially important if using a power screw driver as with HDPE being very soft you can easily strip the threads. We use 3.5 mm flange head screws on all our moulds. If you do happen to strip the threads when reassembling the mould you can always replace the screws with slightly thicker 4mm screws and then 4.5mm screws if needed. This way you have multiple chances to repair your mould. We generally don’t use threaded inserts as these can also be over tightened and strip the threads and there are no 2nd or 3rd chances like there are with screws. If preheating our HDPE Moulds before casting, we would recommend preheating to a maximum temperature of 60°C (140°F) as HDPE has a very low melting point. To de-mould first remove the bung from each cavity and give the bottom of the mould a few taps with a dead blow hammer/soft mallet, or turn the mould upside down and carefully slam it onto a solid work surface. Then you can carefully blow pressurised air up through the hole or alternatively use a small punch through the hole. (Note our moulds with deeper sides may also need a couple of taps on each side of the mould to help release the cast.) To re-insert the bungs, first apply mould release for lubrication and then push them in without twisting until fully inserted. If storing your moulds for an extended period it is advised that you remove any plugs or bungs from the mould to prevent the silicone from being compressed over time. 

Silicone Moulds and Plugs - Care and Instructions Thank you for purchasing our addition/platinum cure silicone moulds/plugs. Below are a few guidelines to help maintain and extend the life of your mould. Generally silicone moulds have excellent release properties and are ideal for casting polyester, polyurethane and epoxy resins in, however, ALL silicone moulds will loose their release properties with use over time. With this in mind we would always recommend applying a suitable mould release before each casting (even if the resin manufacturer states that mould release isn’t required). There is a growing range of different resins being used for casting, some of which are more aggressive towards silicone than others, causing more wear and tear to silicone moulds, this is especially the case with epoxy resins, in particular GlassCast. For unknown reasons GlassCast seems to deteriorate silicone moulds much sooner than other resins. We’ve found that silicone mould release offers no protection to silicone moulds against the aggressive nature of GlassCast (Just like you wouldn’t use silicone mould release if casting silicone to silicone as they’ll just bond together). To date we’ve found the best mould release to protect against GlassCast is a vaseline based mould release, see below for instructions on how to make an easy DIY Vaseline based mould release. Due to its easy release and protective properties we now use this with all resins in both our silicone and HDPE moulds. Our silicone moulds can be preheated before use and you can also post cure your casts directly in the mould. Warning: although our silicone moulds will withstand temperatures of 120°C (250°F) or more, if using our “Less-Resin” moulds the HDPE Plugs will only withstand a maximum temperature of 60°C (140°F). Your mould is quite flexible and durable but take care when removing your casts to not overstretch it or nick it with any sharp edges of your cast, as once you get a nick or tear this becomes a weak point. After each use remove any resin residue from the mould with warm soapy water, any stubborn resin can be removed using a small amount of denatured alcohol or acetone on a soft cloth. Dry your mould with a paper towel and allow to dry completely before reusing. Store your mould flat to prevent it from potentially becoming deformed. Do not leave the plugs in the ends of the “Less-Resin” moulds when storing as it will stretch the holes over time. If you have purchased one of our “Less-Resin” moulds below are instructions on the correct technique to insert the plugs into the moulds. Insert a plug into one of the holes of the mould, slide your tube onto the end of the plug, insert the second plug into the opposite hole and push it into the other end of the tube. Ensure there is an even gap between the tube and each end of the mould. Apply a reasonable amount of pressure inwards on the plugs with your index fingers. Whilst maintaining pressure inwards on the plugs, place your thumbs inside the mould and pull the mould walls slightly outwards. This will ensure a snug fit of the plugs and prevent any resin seepage. Note: if you wish to cast only one blank you can temporarily fill the centre tab with a small piece of plasticine/modelling clay, or use a resin tab saved from a previous casting. Remove the plugs by twisting to break the seal, then simply pull them out with your fingers or use a small pair of pliers if needed.

DIY Vaseline Mould Release With this DIY vaseline mould release we find casts release so much easier from the mould compared to silicone mould release. Also its the only mould release that, to date, we’ve found offers considerable protection to moulds against the aggressive nature of GlassCast epoxy resin. Due to its easy release and protective properties we now use this with all resins in both our silicone and HDPE moulds. • Mix 1 part Vaseline / Petroleum Jelly in approx 10-15 parts white spirit in an air/water tight jar such as a jam jar or other suitable container. • To dissolve the Vaseline place the jar in a tub of hot (not boiling) water, don’t forget white spirit is highly flammable! Shake the jar every few minutes to help dissolve the Vaseline, it may take a little while to initially dissolve the Vaseline. • Once mixed when left a while the mixture will separate into 2 layers but all it needs is a good shake to remix it. • Apply to the mould and plugs etc with a brush, then leave the mould until the white spirit has evaporated, this leaves a thin layer of Vaseline on the mould. Blowing the mould with an air compressor aids with evaporation, especially with HDPE moulds. • We find that lubricating the bungs for the HDPE moulds by dipping them on the lid of the jar makes re-inserting them easier.