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Old 04-21-2021, 08:26 PM
BTromblay BTromblay is offline
MetalShaper of the Month August 2018
Join Date: Oct 2015
Location: Mukwonago, Wi
Posts: 467


Gas welding aluminum can be the most frustrating and rewarding process to learn. For all of the different weld type processes it is 10% knowledge and 90% practice, IMO. I recommend to tack with rod first and work your way into fusion tacking and welding in time. For O/A welding i use a inner cone 3 times the material thickness for tacking, 2 times the thickness for welding. You will find the process becomes easier and slower when you use a larger test coupon, I recommend 12" x 12" piece to start with. Pre-heating the panel will help expedite the weld process and having patience is key. Pre-heat and in direct flame on the flux tends to cause the flux to melt and stay on the surface, instead of direct initial flame on the flux, causing the flux to pop off from the surface.

If you wish to tack with no filler rod, this is what I found that works for me. The panel seam needs to be tight, any gap and it will tend to melt back. Be sure that the torch is lined up down the seam and you are creating even heat to both sides. Have the filler in hand, in case it begins to open and add as needed. As you fuse tack down the panel, pull open, or push close the seam to maintain the tight joint.

Hope it helps.

Bill Tromblay

"A sign of a good machinist, is one who can fix his F$@& Ups" My mentor and friend, Gil Zietz Micro Metric Machine.
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