Temporary attachment intake/exhaust pipes

[Master]

Want to temporarily attach brass intake/exhaust pipes to flanges while on the engine. After temp attachment remove everything from the engine and solder the works permanently. I'm reluctant to put any heat on the flange and pipes while on their aluminum engine heads.

 

[Longboy]

The worst you can do is solder the flange to the heads. The heat will not bother them. I think your solder will melt right off the exhaust side running the engine though.

 

[tornitore45]

I think Master means to silver braze the assembly at a temperature that would melt aluminum.

Why do you want to do the temporary fix?
I assume the reason is that the pipe must assume a specific rigid position and orientation between two flanges like, for example in the Edwards Radial.

In that case you can either change the design like I did or build a replica of the flange target surfaces and their attitude in steel and then you wont be worried about melting anything.

 

[Master]

It is the Edwards radial. I think the answer is to make a jig then silver solder.

 

[tornitore45]

When I came to that part of the project I concluded that making 4 holes line up in position and orientation within 0.010" after 2 welds and multiple compounded bends in the pipe was just not possible.

Jos said he found it fiddly but succeeded, so it must be possible.

I opted to make the best on the 115 degree bend and cut the pipe 1/2" after the bend. Then make a 1" straight pipe out of the manifold and use a snug fitting plastic hose to connect the two pipes and provide the 45 degrees bend. Call it a cop out but works fine and to my eyes does not look bad.

 

[Peter Twissell]

I had a similar issue when fabricating the intake pipes and exhausts for my radial.
I assembled each pipe on the engine with the flame bolted into place, the tacked the pipe to the flange with the TIG welder.
In my case, I then removed the assembly and fully TIG welded it, but it could just as well have been silver soldered.

 

[tornitore45]

Lucky you that have a TIG welder. You can't do the same as tacking with a propane torch and silver solder. TIG let you immobilize the parts without putting too much heat all over.

 

[Peter Twissell]

Before I had a TIG welder I had carried out similar operations by gluing the parts with Cyanoacrylate.
Not to be recommended - the fumes given off when subsequently heating the parts to braze or weld are most unpleasant.