MOTHER EARTH NEWS readers share their observations about welding facts and safety precautions from two recent welding articles.
industrial welding and a class in farm welding for local
farmers and ranchers. Prior to my present job, I worked six
years as a welder and welding technician. I’m also a member
of the American Welding Society. I think, therefore, that
I’m qualified to comment on welding facts in regards to two articles in MOTHER EARTH NEWS NO. 31: “Homestead Welding” by John Wells and “How to Make Money
With a Welding Route” by Henry L. Farr.
I was glad to note the two authors’ enthusiasm for their
subject . . . but, while the articles gave some useful
information, they also contained errors which could be
dangerous (or at least make the job more difficult than it
need be).
Although Mr. Farr does an excellent job of pointing out the
need for welding repair services and the business potential
for qualified persons, he apparently lacks a thorough
knowledge of the trade. (He puts his foot in his mouth, for
instance, when he calls brazing rod “copper rod”.) He also
tells of cutting a hot water tank an the wrong direction,
and of misunderstanding other simple directions. A person
who welds for income ought to know his work well enough not
to make such basic mistake at the expense of the public.
As an instructor, I must disagree with the same author’s
remarks on the process of learning to weld. For example, he
says, “It’s necessary to study and practice for many hours
to get the right flames …” In two years of teaching
I haven’t seen anyone take more than a few minutes to do
so. It’s after you get the right flame that the
difficulty and hard work begin.
Elsewhere, Mr. Farr calls welding “easy” and “quickly
learned'”. The truth is that this craft — like many
others — is easy to do but hard to do well.
Welding is beautiful work. It takes concentration, manual
dexterity, rhythm, and understanding. The laws of the
universe that govern the behavior of metal are written in a
skilled workman’s mind and body, so that he instinctively
does the right thing at the right instant.
A welder worthy of the name is a person of integrity, who
bears in mind that poor work can result in loss of property
and life. Imagine the breaking of a band repair on a
boiler, trailer hitch, or moving piece of machinery! A good
weld shows real love and concern for one’s fellow human
beings. This occupation can, in fact, be a way of giving
your energies to build a better world. Although its
techniques have been perfected as part of an industrial
society, there’s no reason why they can’t be a constructive
tool in a lifestyle based on agriculture.
We do need more welders — as Mr. Farr pointed
out — but they should be good craftsmen who have spent
a few years studying under. an experienced person before
going out on their own. The best way I know to learn
welding as a trade is through one of our country’s
many vocational schools . . . or, if you can’t go that
route, in a shop where you can be trained on the job.
I must now comment on some of the statements in John Wells’
article. First, on pages 39 – 40: ” . . . the oxygen valve is
then pressed to produce a blast of gas which literally
blows away the molten metal.” This is not how the cutting
process works. When steel is red hot, it oxidizes at a very
rapid rate. The precisely directed blast of oxygen from the
cutting torch “burns” the steel in its path, leaving a cut
that can be smoother and cleaner than one made by a saw.
On page 40: “Welding is carried out at various pressures
according to the work to be done. For steel 1/8 inch to 3/8 inch
thick usually run the acetylene to the hose at about 7 to
10 psi (pounds per square inch). The oxygen is held at
about 25 to sir psi, since an oxygen-acetylene ratio of
between three to one and five to one is the general rule.”
This description confuses welding (a process of joining two
pieces of metal) and cutting, which are done with totally
different torches. In welding, the oxygen-acetylene ratio
with a neutral flame is one to one. In oxyacetylene
cutting, the ratio of consumption depends on the tip size
and the thickness of metal being cut and may vary from
three to one to ten to one,
In either technique, the pressure setting depends on the
size of the tip (the removable portion of the torch closest
to the flame) and on its manufacturer. To find the correct
tip size and pressure setting for a given job, consult the
instruction manual for your equipment. If you don’t have
one, write the maker (such guides are usually sent free on
request).
In the next paragraph — after telling how to set the
pressure — the author says: “Then open the valves on
the gas containers until the regulators’ tank pressure
gauges register ‘medium’.” This is not a recommended
procedure and could be very dangerous. The acetylene or
fuel container valve should be opened one-quarter to
one-half turn . . . so that if the hose breaks or any
emergency arises, the gas can be shut off with one quick
movement.
The oxygen container’s valve is a double seating type and
should be opened all the way, for the following reason: The
pressure in a full cylinder of oxygen is 2,200 psi at
70 degrees (as compared to about 1,600 psi in a shotgun barrel
at the moment of firing). If the tank’s orifice is not
fully open, the force of the escaping gas can bend the
valve stem and ruin the valve.
In the last paragraph on page 40, Wells advises the reader
to open first the oxygen valve and then the acetylene valve
when lighting the torch. The standard and recommended
procedure is to open arid light the acetylene and then to
open the oxygen.
On page 41, concerning the operation of the cutting torch:
“The torch is best kept at an angle of about 60 degrees to the
work, with the tip pointing in the direction of
travel.” This method may be of help if you’re using a tip
size too large for the metal being cut. With the proper tip
size, the torch is held at an angle of 90 degrees to the work.
In general, the directions for arc welding are inaccurate
and too sketchy to learn from. I’ll mention just a couple
of points with which I disagree. On page 41, in his
description of the safety helmet used in this process,
Wells says that the hood lens should be “at least a No.
12”. Actually, the shade of the lens depends on the welder
and the type of job being done. It normally varies from No.
10 to No. 12, with No. 11 most common.
Also, the chart showing rod size and amperage setting is
misleading. If you try to use an electrode 3/16 of an inch or larger
on a home welding machine, you’ll probably blow a lot of
fuses . . . because the large electrodes draw more amps
than most residences or farms are serviced for. The chart
also implies that large electrodes are needed to weld
thicker metal. This is not so. A 1/8 inch electrode can handle
almost any job that’s likely to arise, although you may
have to make several passes.
Welding is, of course, too complex a subject to be more
than touched on in a magazine article. For MOTHER’s readers
who would like to learn welding for their own purposes, I’d
recommend taking a night class at a local high school or
community college. If that’s not possible, get books from
welding equipment manufacturers. Such works are less
expensive than those from publishing houses, and their
authors are generally more in touch with practical
applications of the craft.
One good source of study material is the James F. Lincoln
Arc Welding Foundation, Cleveland, Ohio. This organization publishes Arc Welding
Instructions for the Beginner by H.A. Sosnin (a very
understandable book with explicit, clear instructions) and
Arc Welding Lessons for School and Farm Shop by
Harold L. Kugler (which contains direct applications to
farm use arid other hard-to-find information). Each of
these manuals costs $2.00.
The Union Carbide Corporation, New York, publishes two excellent books on
oxyacetylene processes: Oxy-Acetylene Welding, Brazing,
and Cutting for the Beginner ($2 .50) and
The Oxy-Acetylene Hand book ($6.75). These prices
are for individual orders and include handling and shipping
costs.
PETER ROBINSON:
I have some feedback on the article “Homestead Welding” in
MOTHER EARTH NEWS NO. 31.
(1) First, the author omitted a very important safety
consideration (and one that’s not obvious to the
inexperienced): It’s imperative to wear eye protection when
chipping the slag off a weld. The slag is a glassy material
that can come flying off at high velocity, and is also very
hot for some time after its formation. Any splinter that
flew into the eye would cause permanent damage.
(2) The valves on the cylinders containing the oxygen and
acetylene are opened slowly and all the way.
(3) Mr. Wells describes the procedure for lighting an
injector-type torch, not the more common equal pressure
torch. In the latter case one normally opens the acetylene
valve, lights the torch, and then opens and adjusts the
oxygen.
(4) A horizontal flat weld is also done with the electrode
pointing back toward the start of the work.
The above information is based on my own experience of 20
years of part-time welding, and was confirmed by two
friends, each with over 40 years’ experience as a full-time
professional welder.
(It’s interesting to note that these two
feedbacks — in an effort to “set the record
straight” — disagree with each other on a very important
point. Which is it, fellows? Do you open the
acetylene valve all the way as
recommended by Mr. Robinson or
only partway as stated by Mr.
Hill? — MOTHER.)
