My first attempt at welding aluminium goes well!

Welding alumium has always been a specialised task so I thought. However I have read a few articles in the past about a system of welding aluminium that is supposed to be as easy as 1,2,3! Life never seems so easy in reality and it would be interesting to see if the claims were true. At the moment I am in the middle of refurbishing a Myford ML7 and one of the castings had a crack in it that ran through both sides. So it seemed a good time to try out the claims that Durafix make for their product.

The process involves cleaning up the part to be welded with the supplied stainless steel wire brush. Then the parts need to be brought to the temperature at which the welding rods will melt when in contact with the metal, and not the flame of the propane.

Here is where I learnt an important (and obvious now) fact that there is a considerable amount of heat required to get the metal to the 700 °plus needed. The great amount of heat is made worse by holding the parts to be welded together in the vice. As we know aluminum is a great conductor of heat so you end up heating the parts plus the iron vice!

Well when the heat was eventually reached the welding rod was rigorously rubbed in the indented V between the two parts and the rod flowed easily enough into the space. After letting the whole area (!) cool down the two pieces were inspected and there seemed to be a good weld considering the small run or weld.

Armed with this experience I moved out into the garage and decided to hold the casting to be welded in my ‘old’ B&D work bench. At least the heat transfer problem from the trial wouldn’t occur although the piece to be heated up was much bigger than the practice piece. At least I knew it would take some heating up and I was now prepared for that.

After grinding out a V shape in each side of the crack the casting was held in the workmate bench and heating started. When I thought it was getting close to temperature the flames fierceness was dropping off…..yes the gas was running out. Quickly I got my spare cylinder out only to find it also was empty. How I don’t know but it was. So I had to go and find a supplier, needless to say the first one only had empties himself! Eventually I returned home with a full cylinder but a cold casting! SO the process started again with cleaning the area to be welded being brushed hard with the supplied stainless steel brush, the heating supplied and after several minutes the rod was applied away form the flame and it ran into the V nicely. It was here that I learnt my second and important lesson, if I turned the casting over, would the weld already made drop through? Well it was too late to worry about that now and heat was again applied to get the casting up to temperature and the weld done as for the first one. When looking, the work done before was undone.

I decided that the crack, which opened slightly when heated the first time, allowed the welding rod to flow through so that was a positive but I would redo the outside edge and accept that the inside joint would have to be held the best I could. When allowed to cool the outside weld was done and the inside had also a good depth of weld but it had been about to drip. So the next time I try a repair similar to this one I will place some material over the first repair so it has no where to go, before doing the second side. I am sure that will make a neater and therefore stronger weld.

So what were my overall impressions?

1.      You need a significant source of heating if you are repairing a large part.

2.      The three steps are easy enough to remember and the kit does come with everything you need.

3.      I was considering ordering a larger amount of rods (I got 20) but they should last for a long time, as there didn’t seem to be a lot of wastage.

4.      I am happy that the casting repair was done to the instructions i.e. the rod being melted by the casting and not the flame. Therefore it should be a strong weld, as they say it is stronger than the surrounding metal.

5.      It takes longer than you think to heat the material.

Will I use it again? You bet. I think this is a serious solution to welding aluminum and I will experiment with other repairs to learn better techniques. So I think it was a success. Makes a change to find something that in the end does what it says!