An option available to you along with welding is a product known as aluminum brazing rod.

When aluminum is heated to melting point, an oxide forms which prevents bonding. In a welding environment, a flux or enclosing gas is used to prevent the oxide. The aluminum brazing rod works in a different manner, but reacting with the aluminum and forming a different compound which does not oxidize in the same manner.

I've used this product to braze two 25 mm square tubes mitered at a corner. It is surprisingly strong and fairly easy to use. The rod also flows well into the joint. One must necessarily clean thoroughly the area to be bonded, but that's good practice with all joining technology.

I suspect that you would use a large number of these rods as they are consumed quickly. I used four rods to complete the above noted joint, which had an effective perimeter of 100 mm. Perhaps some of the flowing metal entered the tubing and dripped away, but what remained sealed nicely the angle.

An internet search shows many retailers provide the product, as well as the usual online sources. Prices vary from two rods for five dollars (US) to seven for US$18 (not much better).

Photo from Northern Tool web listing.

An option available to you along with welding is a product known as aluminum brazing rod.

When aluminum is heated to melting point, an oxide forms which prevents bonding. In a welding environment, a flux or enclosing gas is used to prevent the oxide. The aluminum brazing rod works in a different manner, by reacting with the aluminum and forming a different compound which does not oxidize in the same manner.

I've used this product to braze two 25 mm square tubes mitered at a corner. It is fairly easy to use and surprisingly strong. The rod also flows well into the joint. One must necessarily clean thoroughly the area to be bonded, but that's good practice with all joining technology.

I suspect that you would use a large number of these rods as they are consumed quickly. I used four rods to complete the above noted joint, which had an effective perimeter of 100 mm. Perhaps some of the flowing metal entered the tubing and dripped away, but what remained sealed nicely the angle.

An internet search shows many retailers provide the product, as well as the usual online sources. Prices vary from two rods for five dollars (US) to seven for US$18 (not much better).

Photo from Northern Tool web listing.