The following instructions are for our “Holding Hands Family Casting Kit” available on Amazon, but they’re also general instructions for anyone wanting to try their own casting.
Have these tools to hand:
- Included: White container, Chromatic Alginate, Plaster of Paris, Gloves, Paint Brush, PVA Glue, Wood Pick
- Not included: Mixing spatula, Measuring Cup, Plastic Carrier Bag / Black Bin Liner / Newspaper
1) Making the mould using Chromatic Alginate
Preparation is key. Before making the mould, practice placing hands into the supplied container. Choose your preferred hand hold position. Adults should practice holding any childrens’ hands without touching the sides. Always find a comfortable position to create the mould as you’ll need to hold your position for a few minutes. It’s recommended that fingers are connected together, not held out from others as these could break. You may want to get an additional person to help.
For best results, oil the hands with olive oil or petroleum jelly, as this will make them easier to remove from the mixture. Hair in particular can be troublesome if not oiled.
- For a typical holding hands cast we recommend 2750ml of water, at around 21° C mixed with the supplied 900g bag of Chromatic Alginate. This temperature is fairly cold, and ideal for beginners as this will set slower and give you more time. (Warmer water sets faster than cold.)
- Pour the water into the supplied container
- Mix the powder slowly into the water (not the other way round as this can cause mixing problems)
- Start mixing the solution instantly preferably with an electric hand mixer on a slow setting, or with a metal/plastic whisk
- The mixture will always be slightly lumpy – don’t worry about this as it won’t affect the end result
- As soon as it’s completely mixed (try to do this within 60/90 seconds) place the hands into the container, and move around slightly, making sure the solution has spread into all gaps
- Be careful not to touch the sides – it’s a good idea to touch the bottom, and then lift up slightly
- Keep still for approximately 2-5 minutes until the alginate has set a light grey/white colour
- Once set, slowly wriggle the fingers & hands (this where the oil helps). If anyone is wearing rings, try to ensure these have become loose from the alginate. If it’s difficult to remove from the mould, slowly wiggle a few fingers. Keep pulling all hands together slowly, and eventually you’ll hear a sucking noise which means it should become easier
2) Pouring the Plaster of Paris into the mould to create the Cast
- Rinse out the mould with water to make sure there are no loose pieces of alginate present, and pour out any remaining water
- Wearing the supplied gloves, measure out 750ml cold water into a separate plastic bowl, and empty the Plaster of Paris mixture slowly into the water (in this order), mixing steadily
- Continue mixing the plaster of paris using a spatula or whisk until the mixture is smooth (creamy consistency). Try to get rid of all lumps and most air bubbles
- Once ready, you can pour the mixture into the mould
- Steadily, pour 1/3rd of the mixture, tilting the container in a circular motion to let the plaster get into any small holes/fingertips
- Tilting again the other way, pour another 1/3rd of the mixture into the mould, repeating the circular motion
- Every so often, tap the sides to try and let any air bubbles disperse
- Keep on pouring until the mould is full and level (you may probably have some plaster left – you don’t need to use it all so this is normal).
- Once full, wait around 4 hours for the plaster to set fully, or overnight
3) Revealing & finishing your new Cast – this is the exciting bit!
- Lay a black bin liner on a worktop or table, and then turn the container upside down
- Tap all sides of the container, and try to let the mould slide out. You might have to run a thin knife around the edges first (but be very careful not to touch the cast inside!)
- With a little bit of patience and encouragement, the mould should slide out
- Slowly, peel & break apart the alginate using your fingers and a knife (again be very careful not to touch or break the cast inside). It’s best to do small chunks at a time
- When revealing the fingers, take extra care, as these are the most weakest parts of the cast
- Don’t worry if you do break any fingers off though – this sometimes happens, but you can re-attach them later with glue (once the cast is fully dry)
- Using the wooden pick, scrape out any alginate from small places, such as fingers, nails and rings
- Once you’ve peeled away all of the alginate, leave the cast for a few days (5-7 for a full holding hands cast).
- The cast may become dusty, but this normal, so just brush or blow off
- Once it’s completely dry you are ready to seal the cast using the supplied PVA glue
- Mix 1 part glue to 4 parts water, and brush all over – this protects the cast and it gives it a perfect finish ready for painting
Use cooler water for more setting time with the alginate. Don’t use warm water as this will set too quick!
Use a thermometer if you want to be accurate with the water temperature.
Prepare all your materials before starting the cast. See our recommended list above.
Give yourself plenty of space, a kitchen worktop or table is ideal.
Lay a plastic bag, bin liner, or newspapers down to protect any surfaces.
Practice your chosen hand position a few times into the container, filled with water.
Take your time. Read through these instructions once or twice before starting.
Pour the mixed plaster slowly, making sure to tilt the container from side to side in circular motions
Do not seal the cast until it has fully dried. Allow 5-7 days for a full holding hands cast.
For troublesome toddlers, bribe them with their favourite treats if they hold still for a couple of minutes 🙂
Throw any leftover mixed alginate or plaster away – don’t try and wash it down the sink!
Try a silver, gold or bronze paint to finish your cast – these colours usually look best.
Chromatic Alginate: Chromatic Alginate is completely safe for direct contact with the skin – it is the same material used for making dental impressions. Chromatic Alginate is non-toxic, non-allergenic, and made from seaweed. Do not ingest the powder however.
Plaster of Paris: Do not ingest or inhale the powder. Do not apply Plaster of Paris directly to the body as this can scald. Keep all out of reach of children. Seal any powder bags when not in use. Wash hands after use. If skin or eye irritation occurs, flush with water for 15 minutes and contact physician immediately. Avoid getting any mixed solutions on clothing. If this occurs, soak in warm water then wash with warm soapy water.