Document 8ErNO4vX1355wbN9BQjmMjKB
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SrClifi?tdtTS3 1p a is t j&tSSi -STUDIES
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Prepared'by: 0.' RV Jagd
JToveaber 5* 1937*' v
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IllI ALLI3D ESS1ARCH LABCB&TCRIES Ch ic a g o , Il l in o is
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N12511
0007-SMP-000006669
h!H4CmTiaJH. 3SPQIT 'SPECIAL HOUSE PA.I3T PBIMSR STUDIES
General Statement} In continuation of our studies on the two coat house paint system.
it becomes quite evident that the advocates of this sytem have overlooked the dur ability of the primer it self when exposed to climatic influences. :
After two 2 a two coat system has usually^. wood depends upon the priming; coat* On repaint jobs^zhere a'primsr^is employed * 1 to "uniform" the surface,.. the; durability;of tne primer^is again of considerable importance for the same reason.
Practically all of the special house paint primers contain a con siderable percentage1 of bodied, oil for controlled^enetrationi |j?hqreas. with .a regular mixed paint which is reduced for priming, a liberal percentage of raw linseed oil is added. This abundance of raw oil is available for penetration as the character of the wood will permit.
The question arises, docs the use of a special primer of slight penetration protect the wood as well as the conventional first coat reduction, using only raw oil? The principal claims made are their superior performance on woods which are difficult to paint satisfactorily from the standpoint of dur ability. Coniferous woods, such as Southern Yellow Pine, Douglas Pir and Calif ornia Pine would fall in this classification.
It was therefore considered desirable to determine how typical primers would wear on flat grain Southern Yellow Pir.e, as this is a type of wood which has a tendency to crack when exposed to the weather. A comparison was made
0007-SWP-000006670
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1 l;ttween the primers of controlled penetration and the conventional first coat re daction of a mixed paint using raw oil.
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-ayplicatipn; This series comprised 9 members, of which 5 were experimental and
4 representing competitive house paint primers (Devoe's, Eollhide, Titanium Pig ments Recommendation MW-4ol, and Mocrwhite (Benjamin Moore). The primers were applied as-one coat work on flat grain Southern Yei|gg:vPine;; six"inth clapboard"
siding. The ; Ihite (Titanium Dioxide ^^) ;nas"jdshd;^s- a;riide pn each panel -
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and reduced-according to the label directions;^The panels were exposedvertical^A^^^ '--
south on-June 2,:-1937 `for- a period1 ofi 20'weeksf'ati ^tSe,|Saerwnr7illiams'l!xp6sure;',:-' J''' i ; ^ '
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COMPOSITION OF PRIIIEBS COMPETITIVE '
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Dsvoe1 s Under-
coater
Uallhide lx. Primer
sJhite
Zinc
Lead Zinc Mag.
Lead Titanox Sal- Titanium Sul- Qx- Sil- Cel-
Garb.
3. chide Dioxide nhate ide icate ite
3&$ 37$
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25$
7$ 2.7$ 50$ Iff
Mica
T.P. Cos. KT?-401
Beccmmendat ion
38*
371
25$
Koorwhite Ex.
4 primer
No Analysis Given
INZTTFU-riOEAL DETELCPHU^S
Acme Balanced Ex. Primer
lihite Lead Garb.
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Lowe Bros.Ex.Prim. 60$
Titanox B.
Zinc Fulchide
9$
Titauium Dicxide
10$.
Lead Sulohate
Zinc Oxidia
Mag* Sillcate
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3_0_'bA.
Celitc
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0007-SWP-000006671
Special Primer for Y. Pine
BBTETOTIOffia.
^lite
zinc
Lfead Titamox Sal-
garb. _ B. -paids
Titanium Dioxide
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lead
Sag. ,
Sol- Zinc Sill- Cel-.
abate Oxide cate ite
Mica
9$
Si
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Sherwin-Williams Experimental #1
Sherwin-Williams Experimental #2.
SWP White (lex 471)34!$ ;
Exposure Results:
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10$ - ; r- -- $ -fc
16$ Z%i- 10$
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These exposures have passed through a complete; summer` and are how;
approaching the critical part of the exposure cycle. The priming coats have '
weathered sufficiently so that the following comments can he made .The protective
value or integrity of the primer is rated in direct comparison to the guide that
was painted on each panel. SEP Toite was used as a guide and reduced according
to label directions for priming.
The failure as to -checking and cracking appears to be the least on
the Acne experimental and the special development for yellow pine, but from the
standpoint of the guide, the Acme primer is definitely better. The Devoe and
MW-Uoi both show a slight improvement over the guide in this respect. The special
primer for yellow pine, Tallhide and the two Sherwin-Williams experimentals show V
the same degree of cracking as their guides. The Lowe Bros, development and
Moorwhite primers are cracking more than the guide and are the poorest primers of this set.
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A decided difference in chalking is noticed between the various ' printers. . The 17allhide and Koorshite primers ere chalking sli^itly and are very similar to the guide. The Devoe, Acne, MTT-401, and Sherwin-Willisns* Special De velopment are all showing moderate chalking characteristics. The Lowe Bros., Regular Sherwin-~ill iams Sxperinental, end the primer for yellow pine are chalk ing badly with rapid erosion.
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. The opacity of all the primers is; definitely, better, then the guide
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,CS1P Shite- priming coat), with the exception of Tallhide' end Koorwhite. The
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Wallhiae primer is slightly better than the guide1 and'Hoorwhite-is, not equal in
opacity.
Conclusion; From our observations of these exposures, it appears that there
is little or no improvement in dnrability obtained by the use of the exterior primers over the conventional first coat reduction for priming of new wood. The exposure results obtained on exterior primers indicate that c definite improvement will have to be made before a two coat system will be obtained which approaches the satisfactory performance of a three coat system self-primed.
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0007 -SWP-000006673