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Poly & Esther meet Ben tonite
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MessagePosté le: Ven 30 Avr - 13:14 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

olivier a écrit:
François a écrit:


I like Polynite too Okay Very Happy


hats off
Already registered : http://www.teufelberger.com/en/products/bootstauwerk/fse-robline/segelmache…

Alors ça sera la Rapite


Citation:
Si on voulait vraiment en avoir le coeur net il faudrait faire un plan d'expérience rigoureux avec les même matériaux de départ, les mêmes moules..etc...

C'est ce que je compte bien faire...en fait, c'est ce que je suis en train de faire. Un nouvel échantillon avec la même résine que pour les premiers échantillons est en cours de polymérisation Wink
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MessagePosté le: Ven 30 Avr - 13:14 (2010)    Sujet du message: Publicité

PublicitéSupprimer les publicités ?
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MessagePosté le: Ven 30 Avr - 16:13 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

Hi guys,

I have just made new samples of "Rapite" (powdered bentonite in first type of polyester).
A rough estimation of density tells ca. 1,5.
That's rather reassuring, no Question

As soon as it will be completely set, I'll send it for measurements.

hats off
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MessagePosté le: Sam 1 Mai - 13:25 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

Since I wanted to be completely sure regarding the second type of polyester resin I had, I made a sample out of it and measured it's density: 1,154 Exclamation
Hope this helps bow


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MessagePosté le: Mar 4 Mai - 15:40 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

François a écrit:
Hi guys,

I have just made new samples of "Rapite" (powdered bentonite in first type of polyester).
A rough estimation of density tells ca. 1,5.
That's rather reassuring, no Question

As soon as it will be completely set, I'll send it for measurements.

hats off
It's on its way to you Wink

hats off
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MessagePosté le: Jeu 6 Mai - 13:20 (2010)    Sujet du message: status quo Répondre en citant

I have just received the sample, and run it.

status quo, we are back to our old readings!:

damping factor = 0.391 (average of 4 determinations) density 1.61 g/cc (1610 kg/m3)

this looks like the original resin, very nearly the same readings. Please don't get sidetracked by the value not being exactly the same, readings very rarely are. My conclusion is that bentonite and a specific isophthalic polyester resin combine to make a product that has excellent damping factor values. It does not look as though the size of the bentonite particles affect the damping factor. It is apparent that a polyester resin filled with bentonite has a better damping factor than the resin alone, and that lead filings add to the damping factor figure, but is not as good as bentonite.

Now we have to identify the resin recipe (this may be difficult) and quantify the resin/bentonite mix.


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MessagePosté le: Jeu 6 Mai - 13:29 (2010)    Sujet du message: Re: status quo Répondre en citant

Bryan a écrit:
I have jut received the sample, and run it.

status quo, we are back to our old readings!:

damping factor = 0.391 (average of 4 determinations) density 1.61 g/cc (1610 kg/m3)

Perfect Okay
In a way, this is better as it makes the mix with granulated bentonite a real user friendly product: to ground the bentonite was kind of PITA, go figure if this had to be done for a whole plinth whew Wink



Citation:
Now we have to identify the resin recipe (this may be difficult) and quantify the resin/bentonite mix.

There is a member who in his job can do spectral analysis, that could help knowing the product, no Question

Now, re the mix ratio, that's easy: untill there is too much bentonite Very Happy


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MessagePosté le: Jeu 6 Mai - 14:22 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

well, one thing this has uncovered is that there is an issue with the exact kind of resin, and we need to be specific if others are to carry out this kind of work.

Can you ask the resin supplier what is in their mix, (without asking them for trade secrets). The resin is described as isophthalic, this means it uses either isophthalic acid or its anhydride (a kind of dehydrated form). This reacts with polyols (organic chemical with many OH, or alcohol groups). There may also be other chemicals, such as styrene present.

I have bought some isophthalic resin from a UK supplier, who has a forum, but I cannot get onto it. It is very important we know what is in the different resin mixes.

Analysis may be possible on the raw materials, but not the resin, once reacted. The initiator is methyl ethyl ketone peroxide. You can ask your friend what kind of equipment he has that maybe useful.

At some time, you will have to weight the ingredients before mixing, to get a standard recipe.
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MessagePosté le: Jeu 6 Mai - 14:34 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

Bryan a écrit:
Can you ask the resin supplier what is in their mix, (without asking them for trade secrets). The resin is described as isophthalic, this means it uses either isophthalic acid or its anhydride (a kind of dehydrated form). This reacts with polyols (organic chemical with many OH, or alcohol groups). There may also be other chemicals, such as styrene present.

Bryan,

I have just asked him. let's wait.........

Citation:
Analysis may be possible on the raw materials, but not the resin, once reacted. The initiator is methyl ethyl ketone peroxide. You can ask your friend what kind of equipment he has that maybe useful.

I think he is rather well equipped: Ottawa University.

Citation:
At some time, you will have to weight the ingredients before mixing, to get a standard recipe.

zzzzz.....
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MessagePosté le: Jeu 6 Mai - 15:04 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

[quote="François"]
Bryan a écrit:

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At some time, you will have to weight the ingredients before mixing, to get a standard recipe.

zzzzz.....


Bryan,

I do not even think it's necessary to weight the ingredients: the figures we already have (densities of pure resin and mix, volume of samples) could be enough, with a little maths Rolling Eyes to get the ratio of resin/bentonite, no Question
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MessagePosté le: Jeu 6 Mai - 15:43 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

François a écrit:
François a écrit:
Bryan a écrit:

Citation:
At some time, you will have to weight the ingredients before mixing, to get a standard recipe.

zzzzz.....


Bryan,

I do not even think it's necessary to weight the ingredients: the figures we already have (densities of pure resin and mix, volume of samples) could be enough, with a little maths Rolling Eyes to get the ratio of resin/bentonite, no Question
maybe, but unlikely. The problem is the bentonite. As it is a powder or small particle, we can only measure the tap density, that is, put some clay in a tube, and tap the tube several times to lightly compact the powder. we can measure the volume and mass, and so tap density, but its not an exact science. And varying the particle size will change the tap density, even though the chemical structure will not have changed. Weighing gets around all those problems. Having said all that, I don't suppose it is all that critical.
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MessagePosté le: Jeu 6 Mai - 16:03 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

Bryan a écrit:
The problem is the bentonite. As it is a powder or small particle, we can only measure the tap density, that is, put some clay in a tube, and tap the tube several times to lightly compact the powder. we can measure the volume and mass, and so tap density, but its not an exact science. And varying the particle size will change the tap density, even though the chemical structure will not have changed. Weighing gets around all those problems. Having said all that, I don't suppose it is all that critical.


I have a method: to put a certain weight of bentonite in a known quantity of water......... and you have seen where I want to go, yes Question Question
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MessagePosté le: Jeu 6 Mai - 16:06 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

François a écrit:
Bryan a écrit:

The problem is the bentonite. As it is a powder or small particle, we can only measure the tap density, that is, put some clay in a tube, and tap the tube several times to lightly compact the powder. we can measure the volume and mass, and so tap density, but its not an exact science. And varying the particle size will change the tap density, even though the chemical structure will not have changed. Weighing gets around all those problems. Having said all that, I don't suppose it is all that critical.


I have a method: to put a certain weight of bentonite in a known quantity of water......... and you have seen where I want to go, yes Question Confused :
yep, but bentonite is porous, how do you know how much water it is absorbing?
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MessagePosté le: Jeu 6 Mai - 16:43 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

Adding Bento to water won't work as it goes thixotropic in water and swells out.  What's wrong with just weighing it ?
Anyway the recipe was just to add as much bentonite grain as the polyester will take the aim being to end up with no more than 1-2 mm of resin floating on top of the bento-mix when it is set in the cast.
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MessagePosté le: Jeu 6 Mai - 16:55 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

Rap a écrit:
Anyway the recipe was just to add as much bentonite grain as the polyester will take the aim being to end up with no more than 1-2 mm of resin floating on top of the bento-mix when it is set in the cast.

That is indeed what I have done and explained.........
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MessagePosté le: Jeu 6 Mai - 17:10 (2010)    Sujet du message: Poly & Esther meet Ben tonite Répondre en citant

François a écrit:
Rap a écrit:
Anyway the recipe was just to add as much bentonite grain as the polyester will take the aim being to end up with no more than 1-2 mm of resin floating on top of the bento-mix when it is set in the cast.
That is indeed what I have done and explained.........

That was much to simple, let's complicate things and fix them until they no longer work
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