12-06-2007, 03:07 AM
Well cattle fat is no problem.
Bitumen supposedly should be like asphalt or tar. However, from what I understand, Bitumen has a different chemical composition than the other two. Using asphalt or tar may not yield the same result not to mention that if it is stronger than we have not concluded anything.
Bark pitch? Does it mean sap? If so I think we can find some of that.
I think that the cow fat (I am only speculating here) works as the "solvent" to allow the components to mix. Sap as we know is very sticky and so is asphalt. Also when sap or asphalt dry out, they are quite hard and bind very strongly to what they are adsorbed on (it is not a typo since adsorption and absorption are completely different).
So the fat is a mixing medium and the other two are binders that act cohesively. The reason I am making the statment that the fat is a mixing medium is because bitumen and sap are not readily mixable unless heated appreciably. Fat on the other hand when heated can melt into a liquid and cause the other two to just dissolve (like sugar in water). This keeps manufacture simple because a liquid solution viscous or not can be spread easily by brush or cloth. This is possible because bitumen, sap, and the cattle fat are mostly if not all organic substances.
So having a vat of this stuff warm or hot (depending on the melting point of the substances involved especially the sap and cattle fat which can decompose into a tarry subsatnce if overheated) available for spreading would be excellent for quick and easy repairs.
I doubt you would get the same result with water as the dissolving medium.
Paolo
Paolo
Bitumen supposedly should be like asphalt or tar. However, from what I understand, Bitumen has a different chemical composition than the other two. Using asphalt or tar may not yield the same result not to mention that if it is stronger than we have not concluded anything.
Bark pitch? Does it mean sap? If so I think we can find some of that.
I think that the cow fat (I am only speculating here) works as the "solvent" to allow the components to mix. Sap as we know is very sticky and so is asphalt. Also when sap or asphalt dry out, they are quite hard and bind very strongly to what they are adsorbed on (it is not a typo since adsorption and absorption are completely different).
So the fat is a mixing medium and the other two are binders that act cohesively. The reason I am making the statment that the fat is a mixing medium is because bitumen and sap are not readily mixable unless heated appreciably. Fat on the other hand when heated can melt into a liquid and cause the other two to just dissolve (like sugar in water). This keeps manufacture simple because a liquid solution viscous or not can be spread easily by brush or cloth. This is possible because bitumen, sap, and the cattle fat are mostly if not all organic substances.
So having a vat of this stuff warm or hot (depending on the melting point of the substances involved especially the sap and cattle fat which can decompose into a tarry subsatnce if overheated) available for spreading would be excellent for quick and easy repairs.
I doubt you would get the same result with water as the dissolving medium.
Paolo
Paolo
"You have to laugh at life or else what are you going to laugh at?" (Joseph Rosen)
Paolo
Paolo
