Adhesive for new plaster cornice and ceiling roses

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Re: Adhesive for new plaster cornice and ceiling roses

Post by wobs » Sun 9th May, 2021 12:17 pm

Excellent job there Craig. The guys I got in to do ours do a great job, but their mitres were just as good as yours.

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Re: Adhesive for new plaster cornice and ceiling roses

Post by Gothichome » Sun 9th May, 2021 1:46 pm

Craig89 wrote:
Sun 9th May, 2021 6:44 am
Thanks Ron for the hints and tips. A bit of light googling suggested that the curing time of plaster of paris can be retarded by adding very small amounts of acid (lemon juice, vinegar, baking powder).

I experimented with baking powder and mixed 1/2 teaspoon in with 250ml of plaster. I was very surprised at how much this helped. It stayed wet when mixed for about 15mins and also didn't turn to stone as soon as it was applied to the cornice. I was able to do about 3 feet at a time as opposed to 6 inches. It also really helped when filling the mitres as it's possible to shave and shape it as it's drying. The addition of the baking powder doesn't appear to have had and negative effects on the plaster, it still sets up good and hard.

A worthwhile tip that could help others in the future

Craig, glad it worked out, a nice tip on the baking powder trick, I will give it a try next time I have the plaster out.

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