@ARTICLE{Mashingaidze_M.M._Curing_2019,
 author={Mashingaidze, M.M.},
 volume={vol. 19},
 number={No 4},
 journal={Archives of Foundry Engineering},
 pages={117-123},
 howpublished={online},
 year={2019},
 publisher={The Katowice Branch of the Polish Academy of Sciences},
 abstract={The study evaluated the curing properties of natural silica sand moulded with 1% by weight Furotec 132 resin binder catalysed by Furocure CH Fast acid and Furocure CH Slow acid. Physical properties of this sand included an AFS number of 47.35, 4.40 % clay, 0 % magnetic components, 0.13 % moisture, and 64.5 % of the size distribution spread over three consecutive sieves (150 – 600 μm). The sand was washed repeatedly to remove all the clay and oven dried. 2 kg washed sand samples were mulled with pre-determined weights of either catalyst to give 30 %, 50 % and 70 % by weight of 20 g Furotec 132 resin which was added last. Furotec 132 resin + Furocure CH Slow acid catalyst system gives longer bench lives and strip times but the maximum compressive strength in excess of 5000 N/cm2 is attained after more than 8.5 hours curing time irrespective of the weight % of catalyst added relative to the resin. On that basis, exceeding 30 weight % Furocure CH Slow acid catalyst when sand moulding with Furotec 132 resin has neither technical nor economic justification. In comparison, the Furotec 132 resin + Furocure CH Fast acid catalyst system was only capable of producing mould specimens with maximum compressive strength above 5000 N/cm2 at 30 weight % catalyst addition rate. At 50 and 70 weight % catalyst addition rates, the mulled sand rapidly turned dark green then bluish with a significant spike in temperature to about 40 oC, far exceeding the optimum curing temperature of Furotec 132. This high temperature accelerates the curing rate but with a very low degree of resin curing which explains the low compressive strength. In fact the sand grains fail to bond and have a dry, crumbly texture implying dehydration. Thus, not more than 30 weight % Furocure CH Fast acid catalyst should be used in sand moulding.},
 type={Article},
 title={Curing Properties of Furotec 132 Resin-Bonded Foundry Sand},
 URL={http://www.journals.pan.pl/Content/113156/PDF/AFE%204_2019_20.pdf},
 doi={10.24425/afe.2019.129641},
 keywords={Curing properties, Foundry sand, Furotec 132 resin, Furocure CH acid catalyst, Curing temperature},
}