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Vince124 · 24-09-2019, 15:33

I'm replacing my exhaust gooseneck made of crumbling galvanized pipe and wanted to get opinions on using thick walled ABS pipe. Vetus makes their goosenecks out of plastic and since ABS doesn't have a true melting point, I'm thinking this should work. Thoughts?

Compass790 · 24-09-2019, 15:39

If it's well after the water injection point it will work. Before, no chance. If before I'd recommend sched 10 316 ss pipe. You can do it screwed or welded. If welded should be 316L ss.
hope that helps

Vince124 · 24-09-2019, 16:04

Quote:

Originally Posted by Compass790

If it's well after the water injection point it will work. Before, no chance. If before I'd recommend sched 10 316 ss pipe. You can do it screwed or welded. If welded should be 316L ss.
hope that helps

Thanks. The engine is a Yanmar 1GM10 and the water injection is right on the exhaust elbow. The ABS gooseneck is on the exhaust thru hull on the transom, so the distance is more than 6 feet between the two.

Checkswrecks · 24-09-2019, 16:06

No melting point? ABS softens and then can melt (depending on type) at not much more than boiling water. I make things out of ABS tubing all the time and it doesn't take a lot of heat.

I'd second the suggestion of Compass790 to try to stay with a metal and preferably SS.

Compass790 · 24-09-2019, 16:16

Quote:

Originally Posted by Checkswrecks

No melting point? ABS softens and then can melt (depending on type) at not much more than boiling water. I make things out of ABS tubing all the time and it doesn't take a lot of heat.

I'd second the suggestion of Compass790 to try to stay with a metal and preferably SS.

No, actually my suggestion for ss was only on the hot/dry side. We have a YSM8 yammer which is the precursor to OP's 1GM10 & we use PVC pipe in the exhaust about 300mm past water injection which I'd GUESS is similar to ABS in it's heat resistance.
They are small raw water cooled engines that don't run very hot. I think he's be fine in his application. In fact I'd rather use PVC or ABS than ss there as it's cheaper, lighter & doesn't corrode.
Remember many boats use some kind of plastic waterlock muffler in the exhaust.
Hope that's clear

toddster8 · 24-09-2019, 16:17

It sounds sketchy, but my boat came to me with a schedule 40 PVC exhaust pipe (creatively attached with radiator hose at each end.) No way of knowing how many years or engine hours it was like that. It seemed a little less crazy after I paid for the marine exhaust hose to replace it. $Wow.
Just a little less crazy though.

Compass790 · 24-09-2019, 16:26

Quote:

Originally Posted by toddster8

It sounds sketchy, but my boat came to me with a schedule 40 PVC exhaust pipe (creatively attached with radiator hose at each end.) No way of knowing how many years or engine hours it was like that. It seemed a little less crazy after I paid for the marine exhaust hose to replace it. $Wow.
Just a little less crazy though.

FYI we have been running for 7+ years with PVC pipe. I'm sure the "marine" exhaust hose would last longer than the PVC if no water was getting injected but thats why we have a water alarm.
YMMV

**Wotname** · 24-09-2019, 16:31

I reckon it will be fine - there are a lot of plastic waterlocks and goosenecks around and they hold up well for years and years.

Check the temperature of the water stream exiting the exhaust and you will be surprised how cool it is. My 2GM20 was around 40C just after the injection point and way way cooler (barely warm) when it reached the gooseneck.

Vince124 · 24-09-2019, 16:31

My boat had some PVC pipe in the exhaust too. I thought it was odd, but it did last for at least a thousand miles.
As for the low melting point of ABS plastic mentioned above. 105°C is the glass transition temperature, when it starts to become somewhat flexible.

“Acrylonitrile butadiene styrene (ABA) is a common thermoplastic polymer. Its glass transition temperature is approximately 105 °C (221 °F). ABS is amorphous and therefore has no true melting point.”

Checkswrecks · 24-09-2019, 16:49

Quote:

Originally Posted by Wotname

I reckon it will be fine - there are a lot of plastic waterlocks and goosenecks around and they hold up well for years and years.

Check the temperature of the water stream exiting the exhaust and you will be surprised how cool it is. My 2GM20 was around 40C just after the injection point and way way cooler (barely warm) when it reached the gooseneck.

I appreciate that as I wasn't aware it was that cool.

Ken Z · 25-09-2019, 08:57

I would not use abs, use metal, galv or better ss or exhaust hose, beside the heat issue, facture cracks happen.

Maclir · 25-09-2019, 09:24

Don't use abs. Use stainless steel 316 for peace of mind.

Cheechako · 25-09-2019, 09:31

No, not ABS. Not PVC either. Both are very crack prone from vibration. Don't ask how I know this, but it involved the EPA and a truck load of anti freeze. Also, temps can exceed what it is good for.