Boxing impressions to pour up

Boxing impressions can be beneficial before pouring up casts because upon removing the impression from the cast the cast will be of ideal shape and will require minimal adjustment. Inverting impressions onto a stone base can be harmful as if the stone base is too firm it can distort the stone overlying the impression especially over unsupported areas. Also, water in the stone mix rises upwards against gravity so inverting the impression will result in a higher concentration of water at the working surface resulting in a weaker cast predisposed to chipping. Boxing allows for the impression to be poured without inverting.

Steps:

1. If it is a lower impression, the lingual area must be blocked out with a sheet of red wax. Trim a wax sheet to the approximated shape of the lingual area and seal 2-3mm from the sulcus depth with sticky wax or a hot wax knife.
2. Soften a sheet of red wax and fold over the long edge once. Cut a thin strip ~2mm wide. This will result in a strip ~3mm thick and ~2mm wide.
3. While soft, wrap this around the impression ~2-3mm from the sulcus height. Care must be taken not to apply more than light finger pressure to the impression to avoid distortion. A permanent marker can be used to mark the intended line of wax. This wax will produce a land area ~3mm wide at ~2-3mm from the sulcus depth.
4. Seal this wax onto the impression with sticky wax or by running a hot wax knife on the underside of the wax. This is necessary for adherence and to stop seepage of the stone
5. Wrap a softened red wax sheet around the impression meeting it at the strip of wax. you will probably need more than one sheet to cover the border. Seal this to the wax strip with sticky wax or a hot wax knife. The excess wax on the underside can be softened and folded over. The height of the wax needs to be at least 10mm at the thinnest portion of the cast
6. You can add 2 wax "legs" on the posterior area of the impression tray to form a stand that tripods with the handle. If this is not done you can support the posterior area of the tray with any object.
7. Mix stone and pour onto intaglio surface under vibration till the box is filled to the top

An alternative method can be done with plaster:pumice 1:1 mixture poured and the impression pushed in upside down till 2-3mm from the sulcus area. This replaces the thin strip of wax around the periphery. Boxing wax is placed around. Vaseline is placed as a separator and stone poured in.

Wait at least a few hours of the stone to set and place in hot water to soften the impression material before tray removal.