June 1941 Radio-Craft
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
A shortage of aluminum for manufacturing seems impossible given its abundance in the form of bauxite - an ore of aluminum and iron - in many places of the world. It is the third most abundant element in the Earth's crust after oxygen (20% of the atmosphere) and silicon (sand)*, and is easy to mine because it is found close to the surface. Today, aluminum is extracted and processed primarily in Australia and - no surprise - China. The U.S., as with so many areas of production, has surrendered its aluminum mining operations to offshore sources, thus exposing its critical supply to the whims of trade deals. During the early days of World War II, aluminum was being produced domestically, but enough foreign sources were being used that the danger of shipping trade routes due to German U-boats and surface ships made access to ample supplies impossible. A U.S. bureaucracy called the Raw Materials division decided how much of each resource certain industries could consume based on rationing plans. Radio-Craft magazine editor Hugo Gernsback discusses here how the radio industry might offset the shortage of aluminum with more available steel and other metals in components like variable condensers (aka capacitors).
By the Editor - Hugo Gernsback
... Defense priorities, especially in metals, portends important radio developments
Up to very recently the radio industry did not fully appreciate the tremendous Defense effort through which this country is now going. The shortage of certain materials which has taken place recently has caused a near-panic in radio manufacturing circles, because it is being realized that it will be difficult to produce as many radio sets in 1941-1942 as was the case in the preceding year.
The Raw Materials division in Washington which controls all priorities of materials, has set a figure of 30% of last year's requirements of certain important materials that established manufacturers of radio sets can use. This is particularly true of the key metal, aluminum. Thus, if a manufacturer used 100,000 lbs. of aluminum in the year preceding, he would only be allowed 30,000 lbs. for the coming year. A similar condition exists in the metal nickel which is almost unobtainable at the present time; that means that permanent magnets - in which nickel is used - for loudspeaker purposes are at the present time hardly obtainable. It appears that radio manufacturers will not be able to obtain high-grade permanent magnets for loudspeaker purposes for a long time to come.
There are two schools of manufacturers at the present time, one which feels that if everybody would cut down his production to 30%, all of the set manufacturers no doubt would be able to make money because they would have to get more money for their product and due to the fact that less sets will be sold during the coming year, all manufacturers would have to charge more for their sets. That would mean more profit for the manufacturers. The public would get better sets for the money and everybody would be satisfied - in theory. The other school, mass-production minded, will have nothing to do with a smaller production. Their arguments run somewhat as follows:
"This is America, the land that makes the impossible possible, the land where Yankee ingenuity was born. We will not allow our production to lag just for the sake of a little aluminum or nickel. We will substitute other materials for these metals and go the German Ersatz artists one better. We are not going to let these two metals stop our production one iota."
It remains to be seen which class will have the better of the argument. There is much to be said for both sides and only the future can tell exactly what will happen.
The "Ersatz"-substitution-craftsmen, will tell you that variable condensers now made exclusively with aluminum can just as well be made with steel stators and rotors. Indeed, there is nothing new about this either. One of the oldest radio parts manufacturers in the business blanked-out steel condenser blades in the early '20's. The trouble with steel plates is that they are magnetic and in the course of time, will accumulate (on account of wear and tear) small iron filings which adhere to the edges of the plates like whiskers. These are held in place due to the magnetism of the plates and after awhile such condensers tend to short-circuit. But we can still use brass, copper or phosphor-bronze. Zinc is a good material and could be used but unfortunately zinc is also on the priorities list and cannot be obtained. As far as the copper materials are concerned they seem to have the best chance.
The trouble here may be expressed in one word - weight. All of these materials are considerably heavier than aluminum. For this reason new designs must be evolved because due to the greater weight; the rotor will tend to fall back by its own weight, unless some friction method is used. On the other hand if friction is used to keep the rotor from tumbling back due to its weight, tuning becomes more difficult and will not compare with the smooth tuning methods to which we have been accustomed.
Fortunately the difficulties in the variable condenser problem cited here, are not insurmountable. It is certain that American ingenuity will overcome the trouble and perhaps emerge with something that might even conceivably replace aluminum completely, even when it can be had again. Tendency of invention and progress is, that often when an industry is put to the task, something better is evolved which replaces old methods and old materials. If an illustration is desired, we can point to plastics, now on a tremendous upswing. It is certain for instance that in due time wood in radio sets will be completely obsolete. Even today a large proportion of radio sets already are made with plastic cases and this tendency is on the increase.
Of course aluminum is used elsewhere in radio sets aside from variable condensers. There are quite a few other small parts termed "radio findings." These, however, can easily be replaced. There are also the so-called shield-cans which heretofore, on account of the desirability of achieving light weight, were made of aluminum. These will now be made of copper or brass and there is no difficulty about this.
There remains the electrolytic condenser used in many sets. Here the substitution problem is far more difficult for the reason that in an electrolytic condenser, aluminum is practically the only metal that can be used effectively. What the electrolytic manufacturers are going to do about this problem is not immediately apparent. If no substitution can be found then it means we will have to do with only 30% of electrolytics for the coming years, till the aluminum shortage has passed.
As for the permanent magnets in our loudspeakers, this is not such a very serious thing except that we may have to go back to the permanent-type magnets which were used before the nickel-iron magnets had been invented. That means larger and heavier magnets and is one thing the radio manufacturers do not cherish. Yes, we can go back to the electromagnetic type of loudspeaker which makes a permanent magnet unnecessary, but this again means using something that was discarded years ago and incidentally such loudspeakers not only cost more, but they also have been, as a rule, larger in size.
There is however, a possibility that a substitute of nickel may be found in the future. The metal tungsten has been used in permanent magnets for many years but tungsten is one of the metals difficult to obtain and it is also rather expensive; whereas nickel is much less expensive but right now unobtainable on account of Defense priority.
From all this it will be seen that a great deal of inventive ability will of necessity be required during the coming months to find substitutes for the present radio bottleneck. Personally I have no doubt that the problems can be solved and will be solved in due time, If It becomes a vital necessity to solve them.
We will probably be in for a good many radio surprises on account of all of this and it will be interesting to watch American radio receiver progress during the near future.
Posted June 28, 2019