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Connecting (soldering?) aluminium sheet and pipe

Connecting (soldering?) aluminium sheet and pipe

Connecting (soldering?) aluminium sheet and pipe

Hi there,

We are designing a cooling shell (ethanol, at -25ºC / -13ºF). It consists of a pipe 10/8mm and an aluminium sheet (as thin as possible: 1 or 2 mm)

Here some pictures of the current design:

The sheet is ca. 800mm / 30inches (maximum length)

The pipe will (probably) be AW 6082, CNC bent, the sheet we can decide.

How can we connect them to have a good thermal transfer?

The problem with soldering is that the sheet will deform because of the temperature

Glue or thermal paste don't have good thermal conductivity

Maybe some clamps.

My favourite option would be soldering, adding material for a good contact. Is there any option here?


RE: Connecting (soldering?) aluminium sheet and pipe

This is often done using furnace brazing. A brazing paste is applied to fixtured parts and the whole assembly is evenly heated in a furnace. An inert atmosphere will keep the parts clean.

RE: Connecting (soldering?) aluminium sheet and pipe

The catch here is that Al is difficult to braze other than in vacuum.
With Cu this would be a piece of cake.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Connecting (soldering?) aluminium sheet and pipe

These glues could be an option, but they have poor thermal conductivity.

The furnace brazing seems promising, I'll dig into that

Unfortunately, we need to use aluminium for this project


RE: Connecting (soldering?) aluminium sheet and pipe

Those glues will be a 1000x better than a mechanical fastening system, and if you are careful and keep the fit tight so that the bond line is only a few thousandths of an inch they will add an insignificant amount of resistance to heat transfer.
It would help greatly if you could slightly flatten the tube so that it had more contact area against the plate. We used to use square tube for projects like this.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Connecting (soldering?) aluminium sheet and pipe

Was your question solved?

RE: Connecting (soldering?) aluminium sheet and pipe


Adhesive has poor thermal conductivity specifications. If the adhesive has a large cross-sectional area and it is thin, it may still be very conductive.

Is there any way to use square tubing?


RE: Connecting (soldering?) aluminium sheet and pipe

Hi there,

I'm talking to the company to see the possibilities for square section tubes. They want a lot of money for the bending tools.


RE: Connecting (soldering?) aluminium sheet and pipe

Use round tube and pull it between a pair of rolls to flatten it some (the shape is called 'double D'). In Cu square and rectangular tube is fairly common.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

RE: Connecting (soldering?) aluminium sheet and pipe

Dip brazing is your best chance of success if both the sheet and pipe are aluminum alloys. The aluminum braze filler metal melts at about 50 degrees F lower than the melting point of many aluminum alloys. With such a small temperature window, it is difficult to precisely control the temperature using methods other than dip brazing.

Best regards - Al

RE: Connecting (soldering?) aluminium sheet and pipe

I found a company (in France - I'm based in Germany) which can do it (after some negative answers)

They can do it with vacuum. It's now know how much the plate will deform, so they'll run a first test.

I'll ask them about the double D option. It sounds good.

If this vacuum doesn't work I'll check the dip brazing


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