fibreglass exhaust bends?

[alibi]

does anyone know how to make fibreglass exhaust bends? very familiar with composite, just need to know how to mold the bends properly

[waikikin]

alibi, mold them thinly over a steel bend, then cut/split them off & then reassemble with your tubes etc for the exhaust & proceed with the rest of your laminate. All the best from Jeff

[Frosty]

My 250Hp Engines have 5 inch soil pipe as exhausts,. It raises a few eyebrows when people see huge turbos blowing through PVC pipe.


They have been on now 5 years,--not a problem. Of course water has to go through them.

[hmattos]

Here in devon - www.explorermarine.co.uk - we have made special exhausts and silencers for diesel boats. For simple shapes we mould on existing cylindrical drums etc, but to make a complex curve, just carve the shape out of polyurethane foam - from your builders merchant - and then lay up a few layers and scrape the foam out again when it is all dry.
Remember to use a hi-temp resin and a good gelcoat to protect from the exhaust chemicals and heat. And again, you will have to have sme water cooling to keep the temps down and to silence better. Good luck
HM

[FAST FRED]

The Vernalift folks make lift mufflers and elboes of Fire Retatdant GRP.

FF

[MikeJohns]

You can get some very light wall PVC manufactured as downpiping for guttering systems with lots of bends and angles. This makes a good former for GRP that can be left in place after layup.

When the plastic vetus mufflers came out they were greeted with a fair amount of derision in some circles; they have proven to be very reliable.

As Frosty says you can use PVC plumbing pipe although it's better to use a layer of GRP over the final glued-up assembly with makes it much stronger for impact damage since the PVC is too brittle.

[Frosty]

Bunnings Australia sell the different thickness wall pipes. the noise they make is not loud but a drone,--like a Lancaster bomber.

I like it.

I was of the same opinion that they would harden with the hot -warm water. They do not seem to have done so.