Mantua, New Jersey
Original Site:
September 2004
E-mail: usav8or@yahoo.com
Aircraft Welding 101
or as Budd Davisson puts it, Zen and the Art of the Weld
Puddle.
Welding. YIKES !
How did I get myself into this thing ?
If
I didn't really plan on learning to weld, why then, am I doing
this ?
I've taken so long to build the Skybolt that now there is
a Radial Engine version of it. My original intent was to buy
an existing fuselage (original version of the 'bolt) that another builder got tired of working
on. That would save me from having to weld up an entire fuselage.
When I got up the gumption to start building on the Skybolt again
I discovered that there was now a Radial-engined version of
it. (I'm a sucker for the classic look
of a radial-engined biplane.) Unlike the original version
of the Skybolt, the R version hasn't been out for that long.
The only one that I know of that is being built is in Australia.
AND, that's JUST being built. It should be flying by Spring/Summer
of this year, 2007. Thus my need to either, 1. Buy the $15,000
pre-welded fuselage from Steen Aero or, 2. Buy the tools and
material for roughly $2500 and do it myself. Should I buy or should I build ?
If I decide to build/weld it's going to be
a learning experience for sure. But, hey, that's what were
doing this for, right ?
I threw the question out to the biplane forum about taking a course in welding at the local Tech School. I gave them a discription
of what the course consisted of and I was told that it isn't such a good idea. I need to know about welding thin-walled
tubing and the Tech School, from what the write up says, is teaching the basics of industrial welding. I could possibly learn
the basics there in a 15 week course, but also learn a lot of stuff that I really don't need to know. Fifteen weeks is a lot of
time to be spent learning something that you're not really going to need.
The group on the biplane forum agreed that if someone had the confidence to build a plane they could learn aircraft welding VIA,
as the military says, OJT. That's On the Job Training. They say it's not the "Black Art" that some people
claim it is. They suggested I get a few books/videos from EAA on the subject and buy a light-duty welding unit from one of the online
stores.
My question then was as to what type of welding unit I should
invest in.
There are basically two types of welding units you can use
for building your plane that are pretty easy to learn. There
are arguments on both sides as to which is better and maybe
some will say that you should use an entirely different type
of welding unit, but I'm not here to debate that topic. I'm
just jotting down these notes to pass on some basic knowledge of welding and how
to get that biplane of yours ready for it's wings.
There is the old standard, the oxy-acetylene (Oxy/Acet) set-up and then there is heliarc, better known as TIG. There is also MIG set-ups, but that is
the one that is harder to get a good weld on 4130 tubing and not practical for the novice welder.
Oxy/Acet
is how they put airplanes together since metal airplanes were
around. (It was actually discovered by two guys, Morehead
and Wilson, back in 1892 when they accidentally discovered
how to make acetylene. When they combined acetylene with oxygen
they discovered that the hottest flame temperature was 5720
degrees F. This was well above the melting point of most metals.
Soon the oxy-acetylene welding process was developed.)
That, my good man, says a lot for that style of welding. Oxy/Acet
is the least expensive way of getting into the art of welding.
The initial set-up cost (cost of the unit is between $300
and $1000 - year 2007) and the consumables are inexpensive.
TIG on the other hand is pretty expensive to get set-up initially,
($1000.00 to $3000.00.) Once you have the TIG unit the consumables, just like
the Oxy/Acet, are pretty inexpensive.
A little on the history of the TIG process. Around the time
of the BIG War, Jack Northrop wanted to
build a magnesium airframe for lighter and faster warplanes.
Spurred on by this, Russell Meredith, who was working at Northrop
Aicraft from 1939-1941, came up with TIG welding. At that time
it was called "heliarc" because it used an electric arc to
melt the material and helium gas to shield the puddle.
In the TIG welding process the electrode is not consumed in the weld. No metal is added to the weld joint unless a separate filler rod is used.
Back to my original statement... my need
to either, 1. Buy the $15,000 pre-welded fuselage from Steen
Aero or, 2. Buy the tools and material for roughly $2500.00
and do it myself. Me being the frugal person that I am, I decided
to go the $2500.00 route and learn a little something along
the way.
Times a wasting. Went to the EAA website
and got the video/welding manual combo and saved about $8.00.
I would have spent the extra for the DVD but they don't have
that as of today's date. I did a search for welding equipment
and found a nice Smith Airline Welder, one made for
the aircraft industry, on Wag-Aero for a great price. Denise
just called and the tubing for the tailfeathers is in and I
have some extra tubing at home that I can practice on. I'll
be cutting and fitting the tailfeathers at the same time I'm
learning to burn holes in 4130. Ain't it great!
A great article to read is one that was written by Budd Davisson for the "Experimenter" a few years back. I "quoted" it in my headline. "Zen and the art of the Weld Puddle. Click here to go to Budd's
airbum.com site to read the article.
This will get you started, like it did me. Now I'm off to burn a few holes into some 4130 and make a little soot fly around my shop.
when a student is ready the instructor will appear.— Zen saying
“Time in the saddle” as I say... learning to push the puddle. Click "here" to read more about my examination and experimentation in learning the art of fusing metal together.