Re: csm in a blender
Quick question. If you should mix the cataylist into the resin before you add fillers. Then, how do all the commercially available "putties" work?
commercial putties like kitty hair and bondo are kinda the same...and you are correct that these will work, however, there is a big difference between will work and work according to spec. we have all seen bondo fail, and kitty hair not as much....but we have seen it fail.
the key to any sucessful mating of chemicals is in the mixing.
The polyerization process needs a catalyst just to get it started. After that it is kind of a chain reaction. That's what creates the exothermic heat. The maximum amount of heat generated (peak exotherm) is a good indication of final cure. poly and vinyleater resins have an inhibitor mixed into them to stop this process until you add MEKP to overcome it. Without this inhibitor they would polymerize all by them selves with the addition of catalyst. I don't think you could ever mix anything enough to get a bit of MEKP next to every bit of resin. Not that there is enough MEKP to do that in the first place at 1 to 1 1/2% to start with. Sure you need to mix really good but the mixing is only part of the equation relating to final cure. The chemistry of the resin is what determines the final physicals.
this is very true.....however.....
however, in testing of the final product....data found the post mixed product to be significantly weaker than the mekp first/filler later process.
the reason was that the mekp was not fully mixed with the resin.
some areas of the castings were found to have more mekp in them.....well above the 2.5% celing, while others and little or no mekp.
did the stuff cure? did it get hard yes...it did........but was it with in manufactures specs of stiffness and stregnth throughout the entire casting?......no.
in a thremolitic reaction, heat is the key.......some of the areas showed over catylisation.....this makes the area weak and brittle. (because the resin bakes)
other areas showed that little reaction occured.
translate that into a wide spread area like tabbing a transom......where the area is 2 inches thick of peanut butter, and spanned over a total of 10 feet.....
hot and cold spots will occure if the product is not evenly mixed,,,,,
does it get hard.....yes....does it cure.....yes......is it within spec.......no.