Looking for Exhaust Advice

[ndutton]

I'm deeply concerned with the ability of solder to withstand the temperatures in that area. This is not meant to be an "it'll never work" comment but please keep a very careful eye on the solder joint during testing and the first few trips under load.

The workmanship looks great.

[edwardc]

Although some solders can melt as low as 190 F, most commonly used solders melt between 360 -370 F (Wikipedia)

The water won't get that hot, but the dry part of the hot stack certainly will.

As Neil says, keep an eye on it. If it does start to fail, you could try brazing, which is essentially like soldering, but with materials that melt at a much higher temperature.

[LastLeg]

Perhaps I should try to braze this prior to installing. (I have never brazed before). Is this difficult?

[edwardc]

Perhaps I should try to braze this prior to installing. (I have never brazed before). Is this difficult?

No, its almost exactly like soldering, in that you are melting the brazing rod but not the base material. The hardest thing is getting a hot enough flame. Propane won't cut it, and MAAP just barely makes it. MAPP/Oxygen or Acetylene/Oxygen both work fine. For just a one-shot effort, the Bernz-O-Matic yellow MAPP and red Oxygen bottles work fine, but the oxygen is expensive per unit volume if you're going to be doing a lot of brazing. The bottles, and an inexpensive hose/nozzle, are available at Home-Depot or Lowes.

[ndutton]

I'm not so sure this is the project on which to learn brazing. This exhaust system is essentially irreplaceable so burning a hole through the copper would be a step in the wrong direction. Paying for experienced hands in this case might be the best money you ever spent.

Rattling somewhere around in my head is 600°F operational temperature for the hot pipe. The black iron we use for hot sections is ABYC & USCG approved up to a maximum of only 900°F.

[romantic comedy]

I use my 25 dollar infra red thermometer on the exhaust flange. It goes as high as 525 degrees.

[Mo]

infra red thermometer

Bought one 2 months ago. Funny you should mention it. I was fixing a leaking bolt at mast plate today and threw 4200 etc in the truck...when getting stuff off the floor of the truck I noticed the infra red thermometer...so it finally made it to the boat. Been sitting on the floor behind the driver's seat for months.
LOL

[romantic comedy]

Mo, the infra red thermometer is just a toy for me. I can get repeatable measurements, for the most part.

How is yours?

[Mo]

Still in the box it came in LOL...

[Skywalker]

Never have enough toys, I mean tools!

[hanleyclifford]

The smart play now is to use bronze or red brass nipple in that contraption so you don't have to do this drill again.

[TomG]

I'm not so sure this is the project on which to learn brazing. This exhaust system is essentially irreplaceable so burning a hole through the copper would be a step in the wrong direction. Paying for experienced hands in this case might be the best money you ever spent.

Sage advice.

And probably not that expensive...

[Bold Rascal]

Call a plumber

Most of your typical home service type plumbers will have what you need to properly "braze" this for you. Probably wouldn't take them more than 30 min's.

[Carl-T705]

Last Leg, I'm with Neal on this, get it fixed before installing. Go to an experienced shop for this , not some place with good intentions and no hutspa. The last thing you want to hear is, Well we tried....but that "thing" is pretty old,. that'll be $60.00 Please. Remember you are not only concerned about heat and a leak, vibration also enters the picture. Get it right the first time, even a masochist doesn't want to tackle an exhaust system twice in the same decade. I think you did very well for the first time though, what you did would definitely get the boat home if you were in a jam. Be prepared though, on your dock, after this exercise, you have now become the "go to guy" for exhaust work,

[sastanley]

I use my 25 dollar infra red thermometer on the exhaust flange. It goes as high as 525 degrees.

RC..that sounds about right..I am over 400° at the hot section/flange area.

I am amazed how hot the spark plugs are too compared to most of the rest of the engine. That ceramic does a great job of cooling off before the plug wire boots melt onto the tops of the plugs.