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How to replace elastic in pajama pants

How to add elastic to an existing waistband...

Measure your waist by wrapping the cloth measuring tape around your body about two inches above your hip bones. Make sure the tape lays flat against your body.
Where the tape overlaps is your waist measurement.

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Measure the elastic to waist measurement plus one more inch to ensure room to sew.
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Mark the elastic for cutting.

Cut the elastic. Cut on the side away from your measured length.
Extra length is better than too little elastic.

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At the back of the waistband, use the seam ripper to break the threads of the waistband to create an opening.
Through the opening, pull out any ribbon or old elastic your are replacing.

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Tape the elastic to the end of a pencil or another straight object to guide the elastic.
Carefully insert the pencil and elastic into the casing through the opening you made.
Pin the back edge of the elastic to the sleep pants.

This stops the entire elastic piece from going through the waistband.
Push the entire length of the pencil into the casing un