Epoxy

William_H

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Yes the difference is in the viscosity. Epoxy glue may be natrally thick. A thixotropic agent added.(amnother name I think) While any epoxy for brushing or rolling ona large area must be very viscous (runny)
A thick epoxy may be thinned by thinners (but not very successfully) and a thin epoxy may be thickened with a filler like micro balloons. ( usually OK) All this is of course not advised and to do the job properly you buy the correct epoxy but if you are doing a little non critical job or are just plain rough as guts like me you might want to try using what you have.
Now own up what have you got in mind? will
 

oldsaltoz

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G'day Ross,

You may find that an epoxy clue has fibres rather or spheres mixed with it, if these are not of the closed cell variety then using them below the waterline will be a disaster.

Epoxy resin mixed with Microfibres makes a very strong glue, but it's hard work to sand off any excess.

When microballoons are added it's considered to be a filler rather than adhesive and is very easy to sand.

Only use closed cell fillers if applying below the waterline.

You can thin epoxy resin with Metho to give better penetration into timber.

Avagoodweekend........
 

cliff

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[ QUOTE ]
Yes the difference is in the viscosity. Epoxy glue may be natrally thick. A thixotropic agent added.(amnother name I think) While any epoxy for brushing or rolling ona large area must be very viscous (runny)
A thick epoxy may be thinned by thinners (but not very successfully) and a thin epoxy may be thickened with a filler like micro balloons. ( usually OK) All this is of course not advised and to do the job properly you buy the correct epoxy but if you are doing a little non critical job or are just plain rough as guts like me you might want to try using what you have.
Now own up what have you got in mind? will

[/ QUOTE ]Thixotropic
The behaviour of non-newtonian fluids generally depends on mixing time, because the structural alterations need a few minutes or more to become visible. A fluid is considered as thixotropic when its viscosity decreases over time, as long as it is reversible.

thixotropic.gif


This type of flow behaviour is typical of paints that experience a reduction in viscosity when shaken, stirred, or otherwise mechanically disturbed (i.e. brushing or rolling), but that recover their original rheology in time, eventually reaching their original viscosity. It allows the paint to remain stable (antisettling action) in a gel state in the container without compromising ease of application.
Thickeners with this behaviour are rare on the market. Some time-dependant associative thickeners (for emulsion paints) or organowax (for solvent based paints) can be viewed as thixotropic agents.

High viscosity as in molasses=> very viscous => NOT runny
Low viscosity as in water => Not very viscous => runny

Adding solvents to epoxy is a "no-no" as when the resin sets and the molecules crosslink and the solvent evaporates one is left with a "sponge" of epoxy with very poor mechanical properties.
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winchservicing

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OK! So if it's the same "stuff", is it ok to use the 2 pack epoxy glue (self-mixing tube stuff) to repair redundent deck holes when fitting new winches to the deck. Maybe add filler too?

Reason I ask is, that the epoxy (west system with filler) needs a higher temp to go off, but the 2 pack glue states that it will cure in 5 degrees. This would make life so much easier!

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Cliff.
 

snowleopard

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[ QUOTE ]
epoxy (west system with filler) needs a higher temp to go off, but the 2 pack glue states that it will cure in 5 degrees. This would make life so much easier!

[/ QUOTE ]
west epoxy comes in 3 standard speeds, fast, slow and tropical (very slow). obviously you need the fast for cold conditions. for small jobs you can apply moderate heat by e.g. making a polythene tent and heating with a hair dryer.

while polyester may be speeded up by using more catalyst, you can't adjust the mixture with epoxy.
 
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