Casting kits - hints, tips and further questions

Is the mould-making material safe to use on my baby’s skin?

Yes it is safe. The alginate we use is a formula used by professional Lifecasters, it is made from seaweed and is non-toxic and safe to use on skin. We did consider using colour change alginate as this does help with judging the mixing and setting times. However, it contains essential oil of peppermint as it is intended for oral use and some skin can be sensitive to peppermint. Also the colour of the gel can stain the plaster. Although the alginate is safe to use it should not be swallowed. The main problem with swallowing the gel is the risk of choking with a small child, so please make sure you wipe your child down in between taking each cast and then again once you have finished.

The mould set too quickly.

The set time for the alginate varies slightly with the air temperature and water temperature. If you have a warm house you may like to use cold water to mix the alginate rather than room temperature water. Never use warm or hot water, as the impression material will set almost immediately. If you add slightly more water than advised, or use distilled water this will increase the set time. Be careful not to add so much water that the gel becomes runny and falls off the casting cloth.

I keep getting holes in the mould

If you experience this problem it is likely that you have not applied the Alginate in the same thickness all around the baby’s hand or foot. Try to keep ¾ of an inch of Alginate all the way around and keep lightly squeezing the Alginate while it is setting. It is possible to move the Alginate around while it is covering the baby, in order to thicken it in parts where it might be too thin. Using more Alginate than recommended will also help as this will give you more to work with, but you will then have fewer chances to cast your child. It is possible to take the mould by placing the Alginate into a plastic pot etc and dipping the Childs hand/foot into the pot. However, this will take much more Alginate (about three times as much). You then need to be careful that the baby’s hand/ foot will fit into the pot and be sure they do not touch the bottom or sides of the pot while being cast. It is much easier to cast a baby’ s foot rather than hands. Start by practicing on the feet and if necessary make a cast of both feet before moving onto the hands. Air bubbles in the finger tips are quite common and difficult to avoid; it takes practice.

How can I avoid bubbles in the plaster cast?

The hardest part of taking the mould is preventing bubbles in the finished piece. When you mix the plaster keep the stirrer under the watermark to prevent the introduction of air to the mix.Only half fill the mould to begin with and swill this around the mould, pouring any residue back into the mixing pot. Do not tap the mould, it is fine to squeeze it, but tapping will release air bubbles to the surface of the cast where they will show. When you fill the mould tip the toes so they are lower than the heel and pour like champagne. You can do the same with the hands, tipping so that the fingers are down not up. When the mould is half full you can use a cocktail stick or the end of the paintbrush to push into the fingers and toes to wriggle out any air bubbles. Be careful with the amount of wriggling you do, as you don’t want to add air to the mixture.

The plaster set before I could pour it into the mould

Only mix enough plaster to fill one mould at a time.
Don’t stir the plaster for too long. The more you stir the quicker the set time will be. You need to stir enough to get a silky mix only. Don’t delay in pouring the plaster into the moulds. If you have not over mixed then you get around 5mins working time from the plaster only.

Can I reuse the Alginate mould?

The mould cannot be reused, as you have to break it into pieces to remove the plaster from the mould.
However, we can make copies of any casts you are particularly pleased with. Copies can be made in plaster, coldcure metal or solid bronze. If you want to have copies made then please get in touch with us. The copies work best if they are taken before the cast has been painted.

Help! A toe/finger broke off

If you should be unlucky enough for this to happen don’t panic. It is most likely to have occurred because you were too rough removing the plaster from the mould, or your plaster mix had too much water in it. Keep the finger/toe and wait for the cast to completely dry. You can then re-stick the missing part on using superglue. You can then touch up the join with a little more plaster, if needed. By the time you have painted the cast and put it in a frame you won’t notice the repair.

The casts don’t fit into the frame

Using a craft knife you can flatten the bottom of the mould to fit it into the frame. Our frames are much deeper than most casting kits on the market at 50mm instead of the industry standard of 35mm. However, if your cast won’t fit in the frame you can use a craft knife or the sandpaper in the kit to reduce the height. If you need to remove a lot of the cast try a handheld cheese grater, the grater is great for removing unwanted length of plaster, then finish off with the sandpaper for a smooth finish. Instead of mounting hands by the wrist, consider mounting them on the back of the hand. This not only looks lovely, it reduces the depth of the cast thereby making it fit in the frame much better. Simply use a craft knife or cheese grater to level a small part of the back of the hand so you have a flat surface to mount on the frame. Again, finish off with the sandpaper to get a really smooth surface.

I am really pleased with my results and want to have some copies made.

Should you get results you are very proud of it is possible to have copies made rather than taking more moulds.
We are able to make copies in plaster for framing, or in coldcure bronze or solid bronze to use as freestanding pieces. These work best if we take the copies before they are painted. Simply contact us for a quote.