[python] Re: Welding or brazing?
- From: Vi Vuong <vi_vuong@xxxxxxxxx>
- To: "python@xxxxxxxxxxxxx" <python@xxxxxxxxxxxxx>
- Date: Thu, 2 Jun 2011 18:35:25 -0700 (PDT)
George,
Good point about dry joint, probably often thicker tube / very low power
setting. I tend to burn holes more often at ~60amps with conduit tubing. When
the tube is thick enough, I prefer to use the higher power setting ~90amps.
Here is the welder I use if anybody is interested. I will add some wiki
info. http://www.harborfreight.com/90-amp-flux-wire-welder-98871.html
Here is a good reference video of a steel trike frame welded with MIG, TIG, and
brazing for different types of joints. Yes they (Greenspeed?) seem to apply
welding very effectively...
http://www.youtube.com/watch?v=jUnVeywtTXY&NR=1
greenspeed.com sticker at 1:40
http://www.youtube.com/watch?v=UMESGL0fues
TIG vs. MIG comparison @ 4:50
brazing @ 7:30-
Vi
>
>>________________________________
>From: George Durbridge <gdurbrid@xxxxxxxxxxxxxx>
>To: python@xxxxxxxxxxxxx
>Sent: Wednesday, June 1, 2011 5:30 AM
>Subject: [python] Re: Welding or brazing?
>
>On Tue, 2011-05-31 at 23:17 -0700, Vi Vuong wrote:
>> Hi Arjen,
>>
>>
>> For relatively safe welding at home/outdoor, I suggest an inexpensive
>> 110v flux-core welder (no gas needed). Buy high quality wire to
>> minimize splatter, and go easy on the trigger at lowest setting for
>> tubings. Do spot welding if needed to control the heat on very thin
>> tube.
>>
>>
>> If you have access to a shop with other methods, try them all which
>> should be strong enough for tubings, but differ in control, heat,
>> beads, and safety hazards. Here are some claims by Greenspeed:
>> The frame tubes are MIG welded. MIG beads are not as fine as TIG,
>> though the craftsmanship of the Greenspeed is exceptional. We don't
>> see many MIG welded recumbents, so we asked Ian about it, "We find
>> that MIG welding puts less heat into the tubing than TIG, and a lot
>> less than brazing, leading to less of the metal around the joint
>> losing its strength. We have also had superior performance from the
>> MIG joints over brazed joints. In addition, we find that the MIG is
>> quicker than TIG, and much faster than brazing, thus is is much better
>> suited for production work".
>> http://www.greenspeed.com.au/rdtest1.html
>
>Ian Sims knows what he is talking about, but Greenspeed use MIG welding
>with gas, not the gasless flux-core system. He is also referring to a
>production line, not one-offs. Working on a one-off, you spend so much
>more time preparing the pieces than welding them that the extra speed of
>MIG hardly matters. Greenspeed's welders are very experienced and
>competent and their welds are reliable, but for occasional welders it is
>too easy to make "dry joints" using MIG, which spits metal spaghetti
>over the joint, whether or not it melts the parent metal. The payoff for
>the extra heat put into the workpiece with TIG is that you always know
>you have melted the parent metal, as well as the rod. Ian may be wrong
>on one point: most people think that brazing does not heat chromoly
>enough to affect its strength. Although a larger area is heated, it is
>heated to red heat, well below the melting point.
>
>
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