Subject:
Patching aluminum
Dennis wrote:
I have an old ChrisRomer aluminum hull that I have repowered from
twin to
single engine and have had a lot of problems patching the old
holes in the
bottom. I have had advice from overlapping patches to holes in
aluminum cannot
be repaired. I am hoping you can give me some sound advice. The
hull is 5086
and I am patching with the same. The hull has small amounts of
corrosion. I am
using a mig welder with 5356 wire. It seems to me that during
the weld I get
small holes in the weld that leak when I do an air test. What
do you think?
Thanks Dennis
Organization:
Walke Point Marine Consultants
It is possible to repair aluminum hulls. Can you provide more
details of the
repair. What is the thickness of the hull. What is the amps and voltage
that you
are trying to weld at. What is your gas flow. How big is the holes
to be
repaired. Your main problem may be the cleanliness of the material
being welded.
Have you tried GTAW instead. Please provide me with some more
info. I also can be
reached at (757) 426-1405.
Larry
Dennis wrote:
Thanks for your help. My welder only has numbers on the power
from 1 to 6 and
wire speed from 0 to 100. I have been using 5 and 70. Gas flow
of 35. The
patches are around 4"x8" with the largest 8"x12". I don't know
what GTAW
welding is. I think that it must be dirty because as I
am welding the sound
changes at times and it will start to crackle and I have seen
the weld just
split with some on both sides of the joint and nothing in the
middle. I clean
with a ss brush and have also used acid. Dennis
Dennis
Walke Point Marine Consultants wrote:
GTAW = tig. What is the thickness of the material that you are welding.
Are you
using a lap weld joint or an open root joint. If you are using open
root try
using a ceramic backing strip, this will hold the shielding gas. Are
you taking
measures to prevent loss of shielding gas. An argon mix provides a
greater
cleaning action/ hotter arc.
lenny
Dennis wrote:
> Lenny, The aluminum is .190. What is a ceramic backing strip? I am
doing a
> butt weld. Tacking on one side then welding the other side but only
about
> three inches at a time trying to keep it cool. Then using a saw back
chipping
> the other side and welding there. How wide should the weld be or
how high. I
> am using 035 wire. Since I am working outside maybe the shielding
gas is the
> problem. Working inside the boat I didn't think I was getting any
wind. Is
> black soot normal and can you reweld over it without cleaning
it off?
> Dennis
Walke Point Marine Consultants wrote:
I think we have found the problem. The loss of shielding gas results
in a black
sooty weld. Take precautions to block the wind from blowing the shielding
gas
away. It is necessary to remove the soot, it will make welding more
difficult and
contaminate the weld. Ceramic backing can be purchased from a welding
supply
store, it is a series of ceramic tiles held in place by a metallic
heat resistance
tape. The weld should be fairly flat, if the weld crown is 1/8" above
the base
metal it is satisfactory. Good Luck
lenny
return to Walke
Point Marine Consultants, Inc.
