US1720356A - Coating material for metal molds - Google Patents

Description

'7 Ste '1 of ribs -,.1Accor 'sulating the molten I the thepastewillnot @mamw a' i Quintana am leptenber This invention relates 'to 'a compound'for invention "having F coating metal molds, iny special utility when applied to molds used in ld dlsad or lead antimony storage bat,-'

gn, r 1 nsiderable difliculty is, encountered in casting storage battery grids because of the filmy, intricate nature of the grids and the fact that the grids are formed of material which lts at a low temperature and, thereto 00 cal quickly. Imorder that fore, ten

may rfect, it is, of course,

acast essential hat it. be completely filled out, but

. since a is composed of a great number 'ceedingly em in cross'section, to obtain a perfect grid the moltenlead must flow through all the minor interstices or small rib forming passa ew'ays and must reach the 3 parts of the mol cavity most remote from the pouring point before the metal eongeals or has any considerable tendency to congeal.

ly, it has been customary to apy to the aces of both parts of the mold a ating which has the double mold and revent' to the mo d. Pow ered soa no is commonly employed for th1s""purpose, and in e a ve substances has been entirely satisfactory, and in fact each has distinct disadvantages. For example, when either soapstone or lamp black is employed,

35 ,the room or building in which the casting is donebecomes permeated with the soapstone 4 powder or with' t since both substances is applied or if 7 it is not applied'evenly the grid is likely to be mined as the molten metal flowing through the mold cavity gathers up the dust or powder reducing cracks or other flaws which render grid u'nsuitablefor use. Additionally, the use of soapstone has the the of. the

" stone it has the very serious disadvantage of 3: I leaving the surfaceof the grid so smooth that Y mmp yw zeeer 5s d aw considerable length and ex- I function of inmetalwfrom the metal the grid from sticking- '1 shaman, ems, .as'sienoszro mun s'roiaaca ;;--:m-rraar comm, or cmvmn, omo, a-coaronarrougor was'r menus.

*' {sgcoarme ron loans,

to sand blast'or otherwise'roughen the grids so that the paste would roperly adhere to the different parts thereog 7 The objects of the present invention are to provide a coating 'material or compound which is inherently clea in the respect that it does not permeate t e atmosphere surrounding the mold which is more durable than the coating materials heretofore used in the sense that when applied to the faces of the mold a great'many castings can be made before it is necessary to recoat the mold -wh1ch can be readily and easily applied;

ing it possible to obtain a very efiective bond between the "grid and the paste which is adapted to be applied to it; and which very efi'ectively'insulates'the mold from the molten metal solthat'good grids and other castings may beiobtamed without liability of the occurrence of so-c'alled powder cracks resulting from the use of soapstone and possibly other materials.

Theabove and other objects are attained by my invention which may be here briefly summarized as consisting in a compound havthe characteristics and composed of the :ingredients' which will be described in the some instances lam black has'been employed *ffiyification and set forth in the appended ms. 1 i v but neither of .Heretofore, the most refractory materials have employed, butI depart radically from this practice by the selection of a coatingsmaterial vor an ingredient thereof which I lieve imparts the insulating propert :which' under. ordinary circumstances wouid be readily consumed or carbonized by the 'molten metal. I have found that certain finely ground v table rodu gLs, when em ployed withpa suitable bin or and when applied in the right manner, answer fments very e ectively and produce far better results than anything employed hereto ,fore, particularly in the production of lead storage battery While my experi- M with v degrees of succem and eflicienc'y, II find that a coating substance or compound 'of iinelyl divided with a insults.

which gives the grid a granular surface makthe requrre- "ments and extensive tests indicate that varivegetable products may be employed to disadvantage that itiintlsglsligalied zlfltgr -laeac casting o ration an a mu 1 p6 On the other hand al o though'lamp black is more durable than soapbinder; water-glass uces the best "f com and, 'I use about equal volumes of this solution and Y enough to pass tEough a 100 meshscreen finely divided cork which is preferably fine although the cork could still be finer. I

This mixture isapplied to a heated moldby means of a spray gun. When the spray is a plied to the faces of the mold, the water in t e solution is immediately vaporize W1 the result that the finely divided cork adheres strongly to the-mold faces. This result is secured by rapidly movin the spray gun over the faces of the mold, t e coating operation being accomplished very quickly and without any difliculty and the coating being thus evenly and thoroughly applied.

I find that contrary to what might be expected this coating is very durable and when once applied will last through far more casting operations than any prior coating material of which I am aware. Not only do the finely divided cork particles adhere strongly to the faces of the mold but they resist the; tendency of the molten metal to burn orcarbonize them. This may or may not be due to the fact that the finely divided cork .particles are surrounded and possibly permeated with the binder which in itself is capable of withstanding without much deterioration the heat of the molten lead, or

rather lead antimony alloy. I might state also that this doating is very cleanly and makes an exceedingly good insulator, in fact it issuperior both in its insulating qualities and in the prevention of adherence of the molten metal to the metal mold,

the orm of lig' nid filass or sodium silicate has proven to ave a e desired characteristics and practically none of the disadvam tages of prior coating materials, I do not desire to be confined to these particular ingredients but aim in my claims to cover all modifications which do 'not involve a departure from the spirit and scope of my invention.

Having thus described my invention, I claim:

1. A coating material for metal molds consisting of a solution containing water-glass and finely divided cork.

2. A coating material for metal molds consisting of a solution containing water glass and a finely divided vegetable substance of a woody nature.

I In testimony whereof, I hereunto afiix my signature.

ALFRED R. WILLARD.