Conlroller

This single compqct inslrumenl is truly the "mosler-mind" of the lloore Gross-Circulqtion Kiln-ii embodies in one cqse lhese sepqrqle four-point conlrols:

Automoticolly conlrols qnd records lemperolure ( | ) ot green end of kiln, qnd (21 qt dry end of kiln, (31 oulomqticolly controls humidity, ond (4) outomoticolly conlrols roof venlilotion, conserving steqm ond fuel.

Instrument Repairs

Insfrum€nl3 lhst orc nol cccurole co3t money to operotc. Send your in3trurnanfs lo our lnslrumenl lcborotory for prompt rcpoiring and recslibrct ing. All repoir work guoronteed.

'Noil Popping' Pinned Down

Washington-Nail popping, a headache for home builders and homeowners alike, has its principal origin in the drying out and shrinkage of the wood into which the nail has been driven. This is the major conclusion of Ralph J. Johnson, director of the Construction Department and Research Institute of the National Association of Home Builders, based on tests made, and set out in the current issue of the NAHB Correlator.

Johnson said the failure of nails to stay put in drywall construction is a "problem of real concern" and a "costly item to repair." He added that although the data obtained from the various tests are at variance in some respects, these conclusions could be stated: l. Shrinkage of the stud framing members due to loss of moisture is the principal factor affecting nail popping, and the amount of pop is proportionate to the shrinkage and loss of ,:-1 ii; moisture. , '. 'l'

2. The length of nail is directly related to the amount of ::1r pop. The shorter nail will give less pop. i.::l

3. The nail diameter does not, for all practical purposes, afr, 'tt'ii or annularly ringed nails have greater holding power as the-,i,, wood dries out. ,:

5. The species of wood has little, if any, influence ori. popping.