So I'm at the very beginning
 

I'm about an hour in on time I've spent on my new Victor type oxy/acetylene torch. I'm using a #1 tip on 5lbs pressure.



I coat my test coupons edges in flux, and the 1100(I think this is correct #) filler rod. I scrub the surfaces with a stainless brush and use a deburring tool on the edges.


I'm trying to get the two pieces to join with the flux. My flame is neutral with a very small bright tip. Would a 1" long blue flame be better?



I'm at the point where I can produce a spot on the sheet turn shiny into a puddle but notice that I can't see this if I've coated the surface in flux.


Is it okay to just use flux on the rod and not the sheet? How doe one start the formation of the bead? I'm noticing that the filler rod has a tendency to pool up on the surface and not join with either plate. Tomorrow I'm going to try welding on a brick not on a steel welding table.



So I'm wondering how I should approach this- how is the filler applied- is the filler only melted by the heat of the plates when pressed onto the surface, or is the filler melted down along the edge with the flame?


I'm really excited to get into this because I've always wanted to do it for years. Actually getting a bead to form will be a great byproduct!


c

I'm behind where you are Craig at this point having not yet picked up the torch for ali (very soon as I have a whole body to weld) and there are many Gods of O/A aluminium welding who frequent the forum here.

Certainly one of the main issues you sound to be having is that the steel welding table is sucking the heat out of your weld. Even with the searing heat of my Tig torch, I wouldn't be able to butt weld two coupons flat on the table.

From posts I've read, you need to be using pretty large coupons and certainly things need to be up in the air to avoid the quench.

Get them up in the air somehow (I'v'e used bits of alloy angle before to elevate parts for welding) and give it another try.

The correct glasses are also required to cut the orange flare from the flux.

I like gas welding- that doesn't mean I'm great at it. Maybe this will help.

You didn't mention what glasses or lens you are using. Kent's TM2000 lens is not cheap, but it is indispensable to be able to see the puddle. All color gradient is eliminated. It will simply show white for heat and the puddle as glossy or shiny when it melts/forms. Welding thin aluminum is such a razors edge type of balancing act that you need whatever advantage you can get. That lens is one of those advantages. I use mine when gas welding steel as well. It's money very well spent.

For aluminum, you need to flux all parts that are tangent to the puddle, not just the rod.

Air is an insulator, not a conductor. I love the story about the camper who slept on the ground one night and woke up half frozen the next morning. He realized he had been trying to heat the entire earth with his body.... Welding is the same thing- that steel table will suck the heat out of your welding project in the same way. Get some air or brick between the part and the table.

If you melt the rod into the joint (not cool, wrong method, unprofessional, poor weld, etc, etc) and then try to heat the lumpy mess into a smooth puddle, it will overheat and either fall through or boil/bubble/effervess and make a bad porous weld. Fail, fail, fail. Don't do it. It is the wrong way to braze, too.

The filler rod needs to be very close to the flame and the puddle so it is almost as hot as the base metal in order to liquify instantly as you dip it into the weld puddle. This simultaneously cools the puddle so it doesn't drop through and fills the puddle so the weld seam is not undercut. The temperature of the puddle is manipulated by the flame of the torch, rate of progress and the dipping of the filler rod.

Welding thin aluminum requires establishing your puddle and moving forward very quickly- if not very, very quickly- using the filler rod to keep the temp of the puddle just melted enough to push forward. For a short bead, it will be over before you know it. It's nothing like crawling along welding steel. Don't know the actual numbers , but it's probably at least 4x or 5x faster in aluminum than steel. You're really moving. Practice, practice, practice.

Hang around and an expert or few may add to the thread.

Craig, you want flat square edge, so that you butting 2 square edges against each other, with no gap. If you deburr, use a flat file parallel to the material. I would use 3lbs of pressure and specialized lenses to see through the orange flare. I also tack using a hotter flame because, I want the puddle to start quickly so I don't burn away all the flux. I adjust the flame to slightly carburizing and lower for welding.

Research O/A welding aluminum here on the forum, there's plenty info here.

For the very new beginner, some cheap easy informative helpful reading:
https://www.tinmantech.com/products/...as-welding.php
.... or some educational viewing:

https://www.tinmantech.com/products/...g-aluminum.php

Trial and error is also great fun .... :):)

Thanks to all for your replies.



c