Document YrdB08Q5aOGyodzN3RznG7wky

Cros-s-----I-n- dex House Paint House Paint Primer Gloss II c I M,CC: B, Davis,, Lab. P. B, Evans, Lab, , S. Graves, Lab, K. 'C, Lamport, Lab. PU W. LaBerge, Lab. Intaea "INDEXED* Marshall Laboratory March 4, 1952 Mr 11*33 MEMORANDUM REPORT M-433 GLOSS VARIATIONS OP NEW HI GLOSS OUTSIDE WHITE . ' Recently, in preparation for a Trade Sales meeting at Philadelphia exhibit panels of the New HI Gloss Outside White (301-892) were prepared. These exhibit panels were prepared according to label directions. The new #40 Outside White vfas applied over the regular'house primer 34?-"3i7y and also over-`itself reduced with one quart of raw linseed oil to the gallon. The panels when dried .showed spotty gloss, that Is, these were patches on the panels that were flat or-nearly so.' This peculiar spotty gloss was worse on the panel where the primer was the new#40 reduced with linseed oil. , To. investigate this uneven gloss, panel tests were conducted by the Marshall Laboratory. In these tests, the primers were applied at three different spreading rates, then the topcoat applied at two spreading rates on each board, SUMMARY? Three factors hove been found to'influence the gloss level and the uniformity of gloss; 1, A thin topcoat produces lower' gloss and more gloss variation, 2, The type of primer influences the' gloss,' The gloss. Is highest vihen 301-892 is used as primer without addition of oil in the first coat, ; . 3, The spreading rate of the primer.has little effect on gloss when 301-892 is self-primed. The House. Primer, 3^7 -817 > is more sensitive to differences in spreading ratey the gloss is lowest over thin coats of 347-817. As a practical conclusion, 347~8l7 House Primer is deficient in holdout as compared with self priming* Improvement Is desirable. N35439 2- ' ~ The spotty gloss or the exhibit panel is the result of uneven application;, with low gloss where .the topcoat is thin. ACTION PROPOSED; Uniformity of gloss was one of the properties reported in the extensive field trial of 301-892. Since the reports were consistently favorable, no action on 301-892 appears necessary. Improvement of the 'holdout of 3^7*817 Nili.be'. suggested as ,an objective Under polOftt, thfe. hob.se ypairit. support proiecty DETAILS: . The three primers, 347-817, 301-892 reduced (4/l 8-853), and 301-892 unreduced were applied at three spreading rates to duplicate clapboards1 `BOO & 750 sq. ft ,/galioti. The topcoat, 301-892, was applied at two different spreading rate's, 500 and 750 sq. 'ft./gallon, to each board-* The primer was four days old before the topcoat was applied. After the topcoat bad dried for 24 hours, each section of each board was rated visually for gloss arid uniformity. Further gloss measurements were made after 48 hour .cry, using the 60 Priofcovolt gloss meter. There were eight gloss measure*-' wants taken from each section of each board, that is eight from the side where the topcoat was applied at 500 sq. fio/galiou, and 8 from the side where it is 750 -Q* ft ./gallon. The values in Table I, are the average 60*'gloss of . two boards .at a given spreading rate. . The standard deviation hast been calculated , and the results have been tested statisti cally. Three variations have an effect, that is satisticaXXy significant: 1/ Topcoat spreading rate 2. Primers 3. - Primer spreading rate for 347*8.17 only* there is no significant variation of gloss with spreading rate of the primer for the .self-priced.systems. 'The'values in Table II ..are the range of gloss among light readings .at different placed for one paint system, on a single panel. . This is a measure of the spottiness_.or variability of gloss independent of board-to-board variation or large differences in spreading rate. The values, in the table-are the average range for two boards, 'A complete analysis of variance has been calculated for these fdlues. The only, significant effect comes from the topcoat- spreading rate. This means that the gloss is more variable with a tbin.topcoat than with a. thick one. DUP030003339 ... O. Notebook Reference; 3832 p, l8l~.l8&, 3^30 p* 6lr69 MARSHALL LABORATORY W. F, SINGLETON /( '. / C H. A. SHELLEM ^/. //, C-.Cfc--- WFSiHAS ? tmb DUP030003340 60 GLOSS OS' TWO GOAT SfSTEMS OH HEW 'WOOD Primer Primer Spreading Hate sq.ft./gal. 347-81T 450 600 750 301-892 reduced 450 600 . *750 301-892 450 600 .-A 750 Topcoat Spreading Rate 500 sq.ft./ 750 sq. ft./ gallon gallon 78$ , 6?$ 66 55 . 66 57 64 63' 68 63 69 64 73 70 76 69 75 69 Each' value In the table is the average of two determinations. Standard deviation of a single' determination* 4.3$ (18 degrees of freedom) DUP030003341 TABLE IX RANGE OP GLOSS ON A SINGLE PANEL Primer Primer Spreading Rate sq.ft./gal. 347*817 301-892 reduced 450 600 750 450 600 750 301-892 450 600 750 Topcoat Spreading Rate 500 Sq.ft./ 750 sq. ft./ gallon gallon 12 27 16 26.5 11 24.5 17.5 13.5 11.5 26 18.5 20.5 17 9.5 16.5 22.5 20 18^5 Each value in the table is the average of two determinations, standard deviation of a singie determinations 6,2 (18 degrees of freedom) DUP03'