GAS or MIG welding on 4130 tube?

Just wondering what the general consensus is on the best method of
welding 4130 tube structures. Advantages / disadvantages of each
considering I will be building in an attached garage, in a residential
subdivision, and will be limited to a 110AC/ 20 amp service?

Is an off-the-shelf MIG unit like a small Lincoln or Hobart worth the
money? Anyone have any experience with these machines?

I don't have to weld anything right now, but I'm considering taking a
few classes.

Thanks,
Harry

Earlier, wright1902glider wrote:

Just wondering what the general consensus is on the best method of
welding 4130 tube structures. Advantages / disadvantages of each
considering I will be building in an attached garage, in a residential
subdivision, and will be limited to a 110AC/ 20 amp service?

Is an off-the-shelf MIG unit like a small Lincoln or Hobart worth the
money? Anyone have any experience with these machines?
...

I've got a little Hobart 125 MIG welder, and it's fabulous for zapping
together tooling, jigs, and fixtures out of cheap mild steel tubing.
Used with .030" flux core wire, it's the bees knees for making quick
and slaggy but perfectly adequate welds. I don't know what I'd do
without that machine.

Used with .024" solid core wire and shielding gas, it can make fairly
pretty looking welds on thin stock, including typical aircraft sizes of
4130 sheet and tubing. However, it takes a better touch than I have yet
developed to get welds that I'd consider to be of aircraft quality.
With the power and feed set low enough to get good control the
penetration isn't there; and when you raise the power and feed to
penetrate it's wicked hard to hold precise control.

Some day I hope to get a TIG rig for doing the fine stuff stuff, but
until then I do it with OA. What I do sometimes is tack stuff in the
jig with the Hobart, and then do the final weld with the nice little
Meco Midget I got from Tin Man Tech -- it's perfectly sized for thin
steel.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com/hp-24

Do a Google of this news group. This has been hashed out pretty well.
My take on the sum of the debate is that while there was no clear
winner, O2/Acytelene was considered to be the defacto standard with TIG
considered by some to be either ecceptable or better. MIG on the other
hand was considered to be acceptable only when used by someone with
considerable experience using MIG on thin material.

Then there is the debate on which rod is best.
====================
Leon McAtee
Braze it when you can.............

Hi Harry,

I would not recommend MIG for aircraft tubing. The problem with MIG is
that it is easy to produce a great looking weld with poor penetration
and poor strength.

If you are good at OA welding you can get good results. I toured the
Rotorway factory a few months back, and the Rotorway frames are all
OA welded.

Why do you feel that you are limited to 110V-20A service? Don't you
have a 220V dryer? If you are not in a rental, a good electrician can
run you a 220V-50A circuit to the garage for a couple hundred bucks.
When you price heavy TIG welders, you will realize that $200 is chump
change ;-)

Don W. -- New to group, but been lurking for a while. I'll post an
intro soon.

wright1902glider wrote:

Just wondering what the general consensus is on the best method of
welding 4130 tube structures. Advantages / disadvantages of each
considering I will be building in an attached garage, in a residential
subdivision, and will be limited to a 110AC/ 20 amp service?

Is an off-the-shelf MIG unit like a small Lincoln or Hobart worth the
money? Anyone have any experience with these machines?

I don't have to weld anything right now, but I'm considering taking a
few classes.

Thanks,
Harry

When you take your classes try MIG on some thin tube, I think that will
answer your question. There are some nice TIG welders out that run on
30a/220v like your clothes dryer does. But don't spend a lot of money on a
welding rig until you have had those classes. You will know what you will
need by then.

"wright1902glider" wrote in message
oups.com...
Just wondering what the general consensus is on the best method of
welding 4130 tube structures. Advantages / disadvantages of each
considering I will be building in an attached garage, in a residential
subdivision, and will be limited to a 110AC/ 20 amp service?

Is an off-the-shelf MIG unit like a small Lincoln or Hobart worth the
money? Anyone have any experience with these machines?

I don't have to weld anything right now, but I'm considering taking a
few classes.

Thanks,
Harry

wright1902glider wrote:
Just wondering what the general consensus is on the best method of
welding 4130 tube structures. Advantages / disadvantages of each
considering I will be building in an attached garage, in a residential
subdivision, and will be limited to a 110AC/ 20 amp service?

Is an off-the-shelf MIG unit like a small Lincoln or Hobart worth the
money? Anyone have any experience with these machines?

I don't have to weld anything right now, but I'm considering taking a
few classes.

Thanks,
Harry

The Hobart 120 (older unit) I have had for years has welded for me many
trailers up to and including 5th wheel equipment trailers at 16000 lbs
gross wt. 1 flat bed truck body to carry my track hoe, and 1 well
cleaning machine which has a 28 foot telescoping crane. I forgot to add
my Sonerai II fuselage tubing. Runs on 120 volt 20 amp circuit. welds
1/4" in 1 pass and up to 1/2" with multiple passes.
For the 4130 tubing I use .023 solid wire and c25 gas mix (25%Co2 and
75% Argon). These welders are great. YMMV

Rocky

, and 1 well cleaning machine which has a 28 foot telescoping crane.

Can you tell me more?

I have a 28 foot deep well that collects silt and crap. It is 4 foot
concrete pipe across at the top, and goes all the way down to 2 foot pipe at
the bottom. Sections have been added by hand over the years, but I use a
sludge pump on a flexdrive shaft to remove the sand and silt, and find that
returning some of the waste water under pressure from a 1/2 inch pipe stirs
up the silt and allows much faster cleanup.

Thanks,
Peter

Bushy Pete wrote:
, and 1 well cleaning machine which has a 28 foot telescoping crane.


Can you tell me more?

I have a 28 foot deep well that collects silt and crap. It is 4 foot
concrete pipe across at the top, and goes all the way down to 2 foot pipe at
the bottom. Sections have been added by hand over the years, but I use a
sludge pump on a flexdrive shaft to remove the sand and silt, and find that
returning some of the waste water under pressure from a 1/2 inch pipe stirs
up the silt and allows much faster cleanup.

Thanks,
Peter


Peter, if you will contact me directly I will tell you how the cleaning
machine works. Go back to my original post for the e-mail add
Rocky

"wright1902glider" wrote

FYI, 220v isn't an option because I don't own a house, and I don't
think my roommate would let me cut a hole in the wall of her brand-new
garage. Well, maybe, but only if it was HER welder, and not mine.

How far from the house to the garage? I have made up heavy duty 220
extension cords to plug into dryer outlets, for various reasons. g
--
Jim in NC

"Ron Webb" wrote in message
...
The standard is OA. Tig is as good or better, but more expensive, and you
still need OA for cutting, and to stress relieve the welds after they are
done.


Hi Ron.
I wouldn't say the standard is OA. That would mean there IS a standard, and
there isn't one.
The entire center wing box of the B1 is welded Titanium, and not a gas weld
to be seen.
Light alloy steel tubular structures are almost universally welded with an
electric process with the
exception of low dollar lugged bicycle frames which are brazed. Nascar Roll
Cage rules
prohibit TIG welded joints due to some history of brittle failures in what
should be a
deformable structure. Their preferred process is MIG. Very few aluminum
fabricators
use torches anymore, their preferred process is TIG. Homebuilders use OA
gear
because it is cheap to use, requires a low degree of skill to get acceptable
results, and is portable.

You might wish to go to the welding specs and do a bit of review.
The SAE and AWS do not require/recommend PWHT of 4130 welds on material less
than
1/2 inch thick. PWHT of 4130 only adds to its ability to move to somewhere
you don't want it .
Post weld heat treatment can do more harm thru distortion than any small
benefit you MIGHT
get reheating things.