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 Posted 4/4/2016 7:14:14 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hello everyone,
Finished MIG welding up slat mounts and then welded units into plasma water table. Next I cut the 18 steel slats that are used to support work material and allow plasma cutting jet a clear direction into the water tank. I estimate about 15-hours left to complete this tool. When I look at the potential of the CNC plasma cutting table I believe the 100 or so hours I will have spent on acquiring the ability to computer control the plasma cutting of steel and practically every other metal will be worth the investment of time. A CNC table can also cut composites, acrylics, other plastics, wood, and even be used to computer control MIG welding. I expect to save 2000 or more build hours on my Tumbler by using my CNC plasma cutting water table. vertigo
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| Posted 4/11/2016 7:23:00 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hello everyone,
Assembled gantry components. Drilled and tapped gantry mounts. Mounted gantry related assemblies. Installed central CNC cross axis. Trued and squared gantry and related assemblies. Easier said than done. Took 3-hours to get it done exactly right. Less than 10-hours work left. Still need to install machine torch mount, linked cable tracking, arc height controller, set up an independent computer, and install Miller machine plasma torch, and also a 150 gallon air compressor. Miller plasma torch uses approximate 10 SCF per minute. Tired of working on this tool. Useful as I expect it to be. Ready to get back to work on my Tumbler. vertigo
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| Posted 4/15/2016 1:43:28 PM |
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Junior Member
Last Login: 9/7/2017 6:36:06 PM
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| looks great so far man. I myself want to try and build a batmobile but need to learn how to weld first
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| Posted 4/15/2016 8:45:47 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hey kafreitas,
Thanks for the kind words. Here is a reprint of a post a couple of years back on how to get started in welding.
vertigo
I already had my welding skills so I didn’t have to spend time on learning them in preparation to weld my Tumbler chassis/frame. While reading old forum postings I noticed some people writing about wanting to, or trying to, acquire welding skills. Several of my friends and many others I know acquired their welding skills from one book. WELDER’s HANDBOOK by Richard Finch ISBN: 978-1-55788-513-5 I bought a recent copy in the welding section at Home Depot a while back. With practice they became proficient in welding and most never read another book on welding. They simply refined what they learned from this book with the accumulation of practice. GAS, ARC, MIG, TIG, Plasma cutting. Most started with ARC and many have stayed with ARC. It takes about an hour to strike arcs effectively and about 20-hours to be able to effectively lay beads and butt weld metal joints together. Functional proficiency with the ARC welder takes about 100-hours. Many today believe you need a MIG for good welding. If you’re waiting to weld and trying to save your money for a MIG you are wasting build time. MIGs relevant advantages over ARC are increased weld speed, cleaner welding, and easier welding of sheet metal. Other than these, MIG has no other significant advantages over ARC. ARC however has several over MIG. ARC is cheap. Used Lincoln 230 amp welders sell for 100-150.oo and new for 300-350.oo. ARC with a 6011-1/8th inch rod can weld dirty, rusty, and oily metal and do it in damp high winds. Most every relevant welding task can be done with ARC. I am not downing MIG. I have an excellent Miller MIG welder. However, I am planning to do the welding on my Tumbler with a used Lincoln 225 amp welder that I bought for 130.oo. Action walks and BS talks. It’s my way to encourage those wanting to acquire relevant welding skills. Seventy percent of poor PRECISION welding project outcomes result from TOO MUCH HEAT/TOO MANY AMPS, TOO FEW TACK WELDS or TACKING IN WRONG LOCATION ORDER WITHOUT CONSIDERATION OF WELD METAL DRAWING EFFECTS, and NOT ALLOWING WELDS TO COOL BELOW 500 DEGREES before applying a second weld over the previous well. I just let mine cool down enough to touch with the hand. By the way when I say PRECISION WELDING I’m talking about welding projects that you want to build with accuracy, very square corners, and degree accurate angles, as well a high strength welds with no weld porosity or degradation of internal metallurgy. Vertigo
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| Posted 4/16/2016 8:18:27 PM |
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Supreme Being
Last Login: 4/6/2024 5:28:59 PM
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| Lots of valuable information here Vert. You are giving me even more of a direction looking at your log. I think the Tumbler and DoJ have a lot in common.
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| Posted 4/17/2016 7:03:40 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hey slysnake and kafreitas,
Something that may be useful to you in your future welding projects.
A particulate respirator rated for welding and grinding is essential to welding/grinding operations in any enclosed or semi-enclosed area and most of the times in outdoor locations. You might get by outdoors with a good stiff wind but never inside closed or semi-closed areas or outdoors in static air. Welding produces somewhere between 50 and 200 toxic and/or carcinogenic (Cancer causing) compounds). Grinding, somewhere between 10 and 30, depending on whats on what you are grinding. I’ve done welding/grinding without a mask a lot of times and will probably pay something for that as I get older. As an example I have attached a picture of a used mask that I used to weld for 4-hours in a semi-enclosed location; a 2-car garage with the doors open and a light breeze blowing. I placed the used mask beside a new mask. You be the judge. So, why do I use this particular mask? IT IS THE MOST EFFECTIVE MASK THAT WILL FIT UNDER MY WELDING HELMET. I found out about it a few years back from a professional industrial welder. Wish I had found it sooner. It’s made of some material that stops extremely fine particles but still allows comfortable breathing. It was developed by 3M for grinding/welding toxic materials, lead/arsenic/cadmium dusts, and protection from the Hantavirus which is carried by rodents. I usually use a mask for 8-hours of welding and maybe 16-hours for grinding. The density of the welding/grinding environment will dictate how long a mask can be used. Welding with ARC rods on dirty and/or rusty steel in confined areas may make the mask good for only a couple of hours. They cost between 10-12.oo each and to me are worth every penny. No, I am not a salesman for 3M products. Vertigo
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| Posted 4/17/2016 7:08:47 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hello everyone,
Cut some 1/8" and 3/16" 4 X 8 sheets of steel in half in preparation for cutting on plasma table. vertigo
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| Posted 4/19/2016 5:28:04 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hello everyone,
As I approach completion of my CNC steel cutting plasma table and
control booth I cannot help but feel a sense of exhilaration from
knowing I will soon be cutting the body panels and other parts for my
Tumbler. Yet, after a few thoughts of cutting raw steel into beautiful
parts one must soon turn their thinking to welding. Pleasurable as I
find welding it is not without some sense of apprehension, brought
forth from the dread of weld distortion; the non-even contraction and
warping of the welded metal parts. To me anything less than 1/8th inch
metal plate is thin and subject to very hard to control distortion.
The best welding I’ve seen done on “thin” sheet metal has usually been
done with TIG or lapped spot welding with MIG. Known in welding as the
stack of dimes or MIG like TIG welding. My Tumbler body will be
constructed from 1/8” and 3/16” plate steel. Soon as you get to 1/8th
inch you can easily control most of the weld distortion effects. But,
not without applying proper material preparations and anti-distortion
welding techniques. I’ve seen 2-inch plate steel warped several inches
out of alignment from butt welding from one side only.
What is Weld Distortion? The experts at Lincoln Welding say:
“Distortion in a weld results from the expansion and contraction of
the weld metal and adjacent base metal during the heating and cooling
cycle of the welding process. Doing all welding on one side of a part
will cause much more distortion than if the welds are alternated from
one side to the other. During this heating and cooling cycle, many
factors affect shrinkage of the metal and lead to distortion, such as
physical and mechanical properties that change as heat is applied. For
example, as the temperature of the weld area increases, yield
strength, elasticity, and thermal conductivity of the steel plate
decrease, while thermal expansion and specific heat increase. These
changes, in turn, affect heat flow and uniformity of heat
distribution.
Reasons for Distortion
In a welded joint, these same expansion and contraction forces act on
the weld metal and on the base metal. As the weld metal solidifies and
fuses with the base metal, it is in its maximum expanded from. On
cooling, it attempts to contract to the volume it would normally
occupy at the lower temperature, but it is restrained from doing so by
the adjacent base metal. Because of this, stresses develop within the
weld and the adjacent base metal. At this point, the weld stretches
(or yields) and thins out, thus adjusting to the volume requirements
of the lower temperature. But only those stresses that exceed the
yield strength of the weld metal are relieved by this straining. By
the time the weld reaches room temperature - assuming complete
restraint of the base metal so that it cannot move - the weld will
contain locked-in tensile stresses approximately equal to the yield
strength of the metal. If the restraints (clamps that hold the
workpiece, or an opposing shrinkage force) are removed, the residual
stresses are partially relieved as they cause the base metal to move,
thus distorting the weldment.” vertigo
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| Posted 4/20/2016 6:56:14 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hello everyone,
When someone looks at doing a vehicle in flat steel plates with many
multi-angular welded relationships, like my Tumbler,
one must take a tactical and predictive stance in
planning and executing the welding where two or more plate edges meet.
Shrinkage Control - What You Can Do to Minimize Distortion
from the Lincoln welding engineering division.
To prevent or minimize weld distortion, methods must be used both in
design and during welding to overcome the effects of the heating and
cooling cycle. Shrinkage cannot be prevented, but it can be
controlled. Several ways can be used to minimize distortion caused by
shrinkage:
1. Do not over-weld
The more metal placed in a joint, the greater the shrinkage forces.
Correctly sizing a weld for the requirements of the joint not only
minimizes distortion, but also saves weld metal and time. The amount
of weld metal in a fillet weld can be minimized by the use of a flat
or slightly convex bead, and in a butt joint by proper edge
preparation and fit up. The excess weld metal in a highly convex bead
does not increase the allowable strength in code work, but it does
increase shrinkage forces. Select either a joint in which the weld
stresses balance each other or a joint requiring the least amount of
weld metal.
2. Use intermittent welding
Another way to minimize weld metal is to use intermittent rather than
continuous welds where possible. For attaching stiffeners to plate,
for example, intermittent welds can reduce the weld metal by as much
as 75 percent yet provide the needed strength.
3. Use as few weld passes as possible
Fewer passes are preferable to a greater number of passes with small
electrodes when transverse distortion could be a problem. Shrinkage
caused by each pass tends to be cumulative, thereby increasing total
shrinkage when many passes are used.
4. Place welds near the neutral axis
Distortion is minimized by providing a smaller leverage for the
shrinkage forces to pull the plates out of alignment. Both design of
the weldment and welding sequence can be used effectively to control
distortion.
5. Balance welds around the neutral axis
This practice, offsets one shrinkage force with another to effectively
minimize distortion of the weldment. Here, too, design of the assembly
and proper sequence of welding are important factors.
6. Use backstep welding
In the backstep technique, the general progression of welding may be,
say, from left to right, but each bead segment is deposited from right
to left. As each bead segment is placed, the heated edges expand,
which temporarily separates the plates. But as the heat moves out
across the plate, expansion along outer edges brings the plates back
together. This separation is most pronounced as the first bead is
laid. With successive beads, the plates expand less and less because
of the restraint of prior welds. Backstepping may not be effective in
all applications, and it cannot be used economically in automatic
welding.
7. Anticipate the shrinkage forces
Presetting parts at first glance, might make one think that this was
referring to overhead or vertical welding positions, which is not the
case, before welding can make shrinkage perform constructive work.
Several assemblies, preset in this manner, The required amount of
pre-set for shrinkage to pull the plates into alignment can be
determined from a few trial welds.
Pre-bending, pre-setting or pre-springing the parts to be welded are
examples of the use of opposing mechanical forces to counteract
distortion due to welding. The top of the weld groove - which will
contain the bulk of the weld metal - is lengthened when the plates are
preset. Thus the completed weld is slightly longer than it would be if
it had been made on the flat plate. When the clamps are released after
welding, the plates return to the flat shape, allowing the weld to
relieve its longitudinal shrinkage stresses by shortening to a
straight line. The two actions coincide, and the welded plates assume
the desired flatness.
Another common practice for balancing shrinkage forces is to position
identical weldments back to back, clamping them tightly together. The
welds are completed on both assemblies and allowed to cool before the
clamps are released. Pre-bending can be combined with this method by
inserting wedges at suitable positions between the parts before
clamping.
In heavy weldments, particularly, the rigidity of the members and
their arrangement relative to each other may provide the balancing
forces needed. If these natural balancing forces are not present, it
is necessary to use other means to counteract the shrinkage forces in
the weld metal. This can be accomplished by balancing one shrinkage
force against another or by creating an opposing force through the
fixturing. The opposing forces may be: other shrinkage forces;
restraining forces imposed by clamps, jigs, or fixtures; restraining
forces arising from the arrangement of members in the assembly; or the
force from the sag in a member due to gravity.
8. Plan the welding sequence
A well-planned welding sequence involves placing weld metal at
different points of the assembly so that, as the structure shrinks in
one place, it counteracts the shrinkage forces of welds already made.
An example of this is welding alternately on both sides of the neutral
axis in making a complete joint penetration groove weld in a butt
joint. Another example, in a fillet weld, consists of making
intermittent welds according to a planned sequence. In all these
examples, the shrinkage in weld No. 1 is balanced by the shrinkage in
weld No. 2.
Clamps, jigs, and fixtures that lock parts into a desired position and
hold them until welding is finished are probably the most widely used
means for controlling distortion in small assemblies or components. It
was mentioned earlier in this section that the restraining force
provided by clamps increases internal stresses in the weldment until
the yield point of the weld metal is reached. For typical welds on
low-carbon plate, this stress level would approximate 45,000 psi. One
might expect this stress to cause considerable movement or distortion
after the welded part is removed from the jig or clamps. This does not
occur, however, since the strain (unit contraction) from this stress
is very low compared to the amount of movement that would occur if no
restraint were used during welding.
9. Remove shrinkage forces after welding
Peening is one way to counteract the shrinkage forces of a weld bead
as it cools. Essentially, peening the bead stretches it and makes it
thinner, thus relieving (by plastic deformation) the stresses induced
by contraction as the metal cools. But this method must be used with
care. For example, a root bead should never be peened, because of the
danger of either concealing a crack or causing one. Generally, peening
is not permitted on the final pass, because of the possibility of
covering a crack and interfering with inspection, and because of the
undesirable work-hardening effect. Thus, the utility of the technique
is limited, even though there have been instances where between-pass
peening proved to be the only solution for a distortion or cracking
problem. Another method for removing shrinkage forces is by thermal
stress relieving - controlled heating of the weldment to an elevated
temperature, followed by controlled cooling. Sometimes two identical
weldments are clamped back to back, welded, and then stress-relieved
while being held in this straight condition. The residual stresses
that would tend to distort the weldments are thus minimized.
10. Minimize welding time
Since complex cycles of heating and cooling take place during welding,
and since time is required for heat transmission, the time factor
affects distortion. In general, it is desirable to finish the weld
quickly, before a large volume of surrounding metal heats up and
expands. The welding process used, type and size of electrode, welding
current, and speed of travel, thus, affect the degree of shrinkage and
distortion of a weldment. vertigo
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| Posted 4/21/2016 7:54:12 PM |
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Has NO LIFE!!
Last Login: 12/4/2023 11:08:55 PM
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Hello everyone,
Two years ago when I decided to build a Tumbler I didn't know much about automotive vehicles, but two years, more than a hundred books, and a couple thousand hours of studying the builds and techniques of people, like Big Wave Dave, Shaggy, and others on this site, and still many others on the web has given me a lot of tools and insights into building. I will forever be grateful to them all. vertigo
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