I would first ensure that my bowl was clean, then after adding the water I would gently sift the powder because just tossing it all in at once could cause bubbles. Then while mixing I would mix in such a way that the spatula goes against the mixing bowl to eliminate any unmixed plaster.Then just as Yugioh said, we would set the vibrator at a low speed as too much vibration induces bubbles.
i would slowly pour the mixture on one position at the posterior region and allow it to run and eliminate bubble pockets as it flows to fill up the mould.
The water-powder ratio should be accurate- this needs to be mixed thoroughly. You must ensure that the vibrator is not set too high and pour your plaster mix from one side of the mould- making sure that the mixture flows naturally and fast enough for air not to be trapped inside.
I'd pour the mixture in small amounts on one side of the mould, allowing the plaster to flow in such a manner that air, rather than being trapped, will be forced ahead of the flowing plaster.
I agree with yugioh and Diana but I would also ensure that I add the exact amount of water as I discovered that when the mixture is too watery many tiny bubbles appear on the model. When I mix the materials I would ensure that the mixture is smooth and pour it slowly in the impression as this would decrease the amount of air pockets thus eliminating bubble . Nabeela Cassiem
After ensuring that your bowl and spatula is clean and free from any left over plaster, measure the correct water/powder ratio. Pour the water into the bowl and sift in powder slowly this ensures that no air gets trapped in the mix. Mixing can be done on a vibrator which will free all air bubble trapped inside the mix (do not whip and over vibrate mix). Once the mixture is smooth and thoroughly mixed, start pouring the mixture by putting small amounts of plaster in one side of the posterior end of the impression making sure the whole anatomical area is covered and there is no trapped air.
I agree with Laa'iqah that pouring technique is important as well as pouring from the posterior end and allowing the the plaster to gradually flow (and not tumble) to the anterior and distally to the posterior of the other side. I would add that one should pour on the posterior side one would be able to see the flow of the plaster. Also, the use of a vacuum mixer (when properly prepared and used) would be able to eliminate most, if not all, of the trapped air from one's mix.
The first thing I do is to clean the mould with water before using it, then I dry the mould te prevent the water that is still in the mould from also making bubbles. The plaster should then be slowly sifted into the water so that air does not get traped in the mix. The mixing should not consist of wipping. The mould is then placed onto the vibrator and the plaster mix must flow in slowly from one posterior corner of the mould until all the anatomical areas are filled without getting air traped that will cause bubbles in the model.
Ensuring that the frequency of the vibrations from the vibrator are not set too high. Spatulating your mixture properly and avoiding whipping also reduces bubbles. When pouring plaster into the mould, pour a little from the most posterior region, allow the Plaster to flow along the ridge and gradually keep adding plaster until the mould is filled. This is what I would do to ensure I have no bubbles on my model.
I prefer to start pouring model from the middle and let it flow till the depth of sulcus is filled with plaster.then wait for a few second and keep the mold on vibrator.after that continue to pour mold to fill it completely.
Using the correct w/p ratio, pouring the model from one side of the mould making sure the mix covers the entire ridge. And also giving it time to flow thoroughly avoiding air entrampment.
The water-powder ratio should be accurate, it should be mixed so that there are no lumps in the mixture. You must ensure that the vibrator is not set too high because too much vibration can form air bubbles. You can then start pouring the mixture so that there is a flow and no trapped air.
I would use the vibrator on a lower setting and pour small amounts of plaster into the mold. T.Israel
ReplyDeleteI would first ensure that my bowl was clean, then after adding the water I would gently sift the powder because just tossing it all in at once could cause bubbles. Then while mixing I would mix in such a way that the spatula goes against the mixing bowl to eliminate any unmixed plaster.Then just as Yugioh said, we would set the vibrator at a low speed as too much vibration induces bubbles.
ReplyDeletei would slowly pour the mixture on one position at the posterior region and allow it to run and eliminate bubble pockets as it flows to fill up the mould.
ReplyDeleteThe water-powder ratio should be accurate- this needs to be mixed thoroughly. You must ensure that the vibrator is not set too high and pour your plaster mix from one side of the mould- making sure that the mixture flows naturally and fast enough for air not to be trapped inside.
ReplyDeleteI'd pour the mixture in small amounts on one side of the mould, allowing the plaster to flow in such a manner that air, rather than being trapped, will be forced ahead of the flowing plaster.
ReplyDeleteI agree with yugioh and Diana but I would also ensure that I add the exact amount of water as I discovered that when the mixture is too watery many tiny bubbles appear on the model. When I mix the materials I would ensure that the mixture is smooth and pour it slowly in the impression as this would decrease the amount of air pockets thus eliminating bubble . Nabeela Cassiem
ReplyDeleteAfter ensuring that your bowl and spatula is clean and free from any left over plaster, measure the correct water/powder ratio. Pour the water into the bowl and sift in powder slowly this ensures that no air gets trapped in the mix. Mixing can be done on a vibrator which will free all air bubble trapped inside the mix (do not whip and over vibrate mix). Once the mixture is smooth and thoroughly mixed, start pouring the mixture by putting small amounts of plaster in one side of the posterior end of the impression making sure the whole anatomical area is covered and there is no trapped air.
ReplyDeleteI agree with Laa'iqah that pouring technique is important as well as pouring from the posterior end and allowing the the plaster to gradually flow (and not tumble) to the anterior and distally to the posterior of the other side.
ReplyDeleteI would add that one should pour on the posterior side one would be able to see the flow of the plaster.
Also, the use of a vacuum mixer (when properly prepared and used) would be able to eliminate most, if not all, of the trapped air from one's mix.
The first thing I do is to clean the mould with water before using it, then I dry the mould te prevent the water that is still in the mould from also making bubbles. The plaster should then be slowly sifted into the water so that air does not get traped in the mix. The mixing should not consist of wipping. The mould is then placed onto the vibrator and the plaster mix must flow in slowly from one posterior corner of the mould until all the anatomical areas are filled without getting air traped that will cause bubbles in the model.
ReplyDeleteEnsuring that the frequency of the vibrations from the vibrator are not set too high. Spatulating your mixture properly and avoiding whipping also reduces bubbles. When pouring plaster into the mould, pour a little from the most posterior region, allow the Plaster to flow along the ridge and gradually keep adding plaster until the mould is filled. This is what I would do to ensure I have no bubbles on my model.
ReplyDeleteI prefer to start pouring model from the middle and let it flow till the depth of sulcus is filled with plaster.then wait for a few second and keep the mold on vibrator.after that continue to pour mold to fill it completely.
ReplyDeleteUsing the correct w/p ratio, pouring the model from one side of the mould making sure the mix covers the entire ridge. And also giving it time to flow thoroughly avoiding air entrampment.
ReplyDeleteThe water-powder ratio should be accurate, it should be mixed so that there are no lumps in the mixture. You must ensure that the vibrator is not set too high because too much vibration can form air bubbles. You can then start pouring the mixture so that there is a flow and no trapped air.
ReplyDelete