Magnesite Stucco

By Mr. H. Schwartz; Ajax Stucco Co., Los Angeles.

N{arked attention has been given recently to Magnesite Stucco etc, (oxy-chloride cement) and the articles on the subject have usually been written by competitors and have beerr rather one sided and not unbiasedly instructive.

The magnesite industry (which is about 12 years old) has been making remarkable progress in the last 2 years. IJnfortunately many persons have been making oxy-chloride cement who have not had any knowledge or experience and the results have been disastrous. The nature and kind of aggregates used rvith magnesite are as important to the formation of a satisfactory oxy-chloride cement as the kind of magnesite used and t6e mannet and method of its calcination. Simply mixing magnesite with any kind of an aggregate will invariably show poor results. Magnesite is not a wonder material, it will not do the impossible. It will not produce an excellent or satisfactorj' job if the chief factor moving the person using it is cheapness and no regard is given to proper application. Magnesite is not diffelent in that respect from ordinary cement. Many a cement stucco job cracked, buckled, chipped, fell off, etc., because it was not properly applied or mixed. Assuming that magnesite is properly applied it will be found muchluperior to cement stucco and quite as permanent. Frost or heat will not affect it and the cracking will be nominal and much less than in cement stucco. The chief cause of troubles and failures of magnesite has been because, l. The stucco or other material was not properly mixed. fn order to remedy the above almost all magnesite stucco manufacturers have issued specifications foi use of their materials and the manner of their application.

2. Th.e aggregates used were not right and consequently ' did not form a correct bond.

3. It was not applied to.proper thickness.

4. The base or-fbundatiotr upon which it was laid was not strong enough or was of.a kind that should not be used.

5. 'fhe job was skinned.

6. Fire walls were not protected.

7. Cl-reap work without regard to results.

One of the chief fallacies still maintained by many peo- ple is- that the Magnesium Chloride is graddally teainea out__of the oxy-chloride cement by wetting and that eventually the magnesium chloricle is entirely le"ached out, thereby causing the material to disintergrate and fall off. Such is not the case. While it is true that the magnesium chloride.does partially leach out by constant wetting, the prc.,cess.is very slow and in the melntime the oxy-chloride cement by absorbing carbonic gas from the air gradually increases rts carbonate content and thereby replaces the loss caused. by -the leaching of the chloride. - It i4/ill be readily seen that by this process of absorption from the air thi lossis compensated and that the characteristics and strength of the oxy-chloride cement is not impaired.

Extenslve experrments were recently made by the U. S.

(Continued from Page 39)

Government and the Dow Chemical Co' the results being the work of several years' In referring to the data upon the replacement of the loss of chloride-by increase of*the carbonate content in the oxy-chloride cement the Dow Chemical Co. reports as follows:

"The outstanding feature of the data is the proof of the Eradual increase in the carbonate coincident with the loss 3f in" Magnesium Chloride rvhich is gradually leached'out of the oxy--chloride cement. The second,important {eature of this daia is, the evidence that the physical or mechanical strength of a good oxy-chloride cement, is not impaired- or damaged to any noticeable extent during this conversion of the magnesium oxy-chloride to the hydrated magnesium carbonate. These facts support the belief that magnesia stucco is a permanent building material in spite of the quasi solubility of the oxy-chloride of magnesia which is the binder. At the worst the washing out of the magnesium chloride is a very slow process and the absorption of carbonic gas and the reconversion of the magnesium should be expected to normally compensate for the loss of the chloride at any stage of the life of tfie stucco."

This investigation indicates that no fear need be held regarding the permanency of l\Iagnesia Stucco if highgrade ingredients are used in its composition and ifit is applied rvith the proper specifications.

"It is significant that the higher grades of this material are inherently permanent to the weather and are independent of any waterproofing protection."

In summarizing, I desire to state that rvith a little care on the part of the user or dealer in (a) the purchasing of a standard material (Containing a sufficient amount of magnesite and the proper aggregates), (b) following of specifications in application; and (") bearing in mind that cheapness of price alone is not sufficient to assure satisfac- tion; results of a highly gratifying nature-can It is my opinion that oxy-chloride cem€nt to make 6ven greater strides that it has, vantages and superiority.

"Enclosed find a very small check in pa very large and indispeb.,?li*:?f;.)

Foresters Give Rodents A Feast Bidden Tree Bark

Flagstaff, Arizona-Members of the Southv Experiment Station are for once gladly pro' squirrels and porcupines a feast of tender, juicybirk. This unusual hospitality is occasioned b to this station of Dr. Walter P. Taylor of the Un Biological Survey, who is intent upon a ltudlof particularly of porcupines. To assist Dr. Tay the same time to attempt to settle the much' tion of whether porcupines or squirrels are sponsible for the girdling of young trees in this area of about half an acre has been indlosed

MOULDINGS

FINISH.CASING

BASECOLUMNS

STEPPING.PANEI.s

RGH. K.D. CLEARS manner as to keep several porcupines and squi inside. seedlings, n for Dr.

EXCLUSIVE AGENTS.

Here choice provender is provided in the form saplings, and half-grown trees. It will rer Tiyloi and his assislants to determine to which blame for tree-girdling belongs.

NE\[| YARD AT ONTARIO

The Christenson yard at Ontario.

o. H.

Mr. O. H. Barr, spending a several

Luumber Company has weeks vacation in the N