I have two types of joints. In one location I have a tube within a tube to reinforce where
two tubes meet. In that area I mayl be installing an axle perpendicular to the
tubing. With chromolly I was going to drill the axle assembly into the center of
the tube. I may do something different with AL.
The other joints in the trailer are perpendicular joints where I will drill the larger tube and
insert a smaller tube into the hole perpendicular to the large tube. I want the tubing
to help me hold the welds in place since I am a beginner and do not want to risk broken
This is a low budget, but quality oriented operation. Our company doesn't want to go into
debt, so I want the most cost effective way to make quality welds in both Chromolly and AL. If not
possible, then I may use only AL since it is lighter, cheaper for materials, and easier on my
equipment. When you weld AL, is it a true weld or a solder/braze type weld? Can you truly get
nice looking welds with a Oxy/Acetylene torch? The typical welders in our typical low tech
community have never heard of welding AL with gas. Is there more information available to help me make my
I truly appreciate your feedback. It has been hard to find suppliers who are technically
oriented and willing to help. Ray
The Tinman Respondeth:
Sheeeszh, Ray. Drilling through for an axle is ok if: you machine a bushing to fit the hole,
silverbraze it into place, and then run the axle through that. Perp tubes do not do
well inserted into a drilled hole for a joint because of distortion.
We use the fishmouth method, whereby the perp tube "mouths" onto the horiz. Snips, file, or bench grinder do
the curved ends real quick. BTW, our video:
Aircraft 4130 Chromemoly Airframe Construction
covers this very type of construction perfectly, in 4hrs and 20 min. of detailed instruction. Aluminum may
be gas welded.
It may also be soldered (650F) and brazed (800F), like heat exchangers, refrigeration, torque converters,
etc. It may be arc welded, MIGwelded, and TIG welded, too. How pretty is an
aluminum gas weld? Well, bub, I'll just have to digitize yesterday's work for you to peruse.