Exhaust system putties

**bob ward** · 13th May 2014, 03:33 AM

I'm working on a Howard 12 rotary hoe, it has a Howard water cooled V twin side valve engine, the exhaust stubs on which are severely eroded/corroded to the point that its no longer possible to connect the exhaust flexes to them.

The fix is going to be very low tech, the engine is a runner and I want to leave well enough alone, so no dismantling welding or machining of the barrels.

I'll make a pair of steel adaptors which I will shape as best I can to fit up inside the stubs and secure them with fasteners through the stub walls where I can. I'm going to end with varying gaps between the two, of probably between 1mm and 5mm which I'll fill with 'something'.

There are lots of exhaust putties on the market, does anyone know which of them are better for this sort of application?
Will silicon work?
The hoe is never going to do any serious work, it will just do short demos now and then at Laidley Pioneer Village.
One of the brutes in action https://www.youtube.com/watch?v=dSDaNh6NIgI

The 2 corroded exhaust stubs

A dodgy photo of the engine

**nearnexus** · 13th May 2014, 01:25 PM

You would be better off cleaning up the parts and using hard bronze as a gap filler and locating agent for a new piece of pipe etc.

I did this on my ute muffler after it had done 150 K and 20 K later it's still quite OK.

Rob

**Combustor** · 13th May 2014, 11:42 PM

Hello Bob,
Guess ther is nothing to lose by trying bronze, though I suspect you won't get enough heat into the engine block to make it bond. May well not hold for long as I recall those pipes used to glow in the dark when at working temperature. These great old machines do have value to collectors and restorers these days, so time invested in getting a professional type repair would not be wasted in the long term. May be possible to grind or machine the stub away to a flat surface and have enough metal to drill and tap for studs to fit a flange welded to the new pipes. Any machinery restoration groups nearby who may be equipped to help with a good repair at reasonable cost? May well be someone around with experience who can help or advise on this type of repair. To some of these guys nothing is impossible. It just takes a little longer. Regards, Combustor.

**nearnexus** · 14th May 2014, 02:18 PM

The other option would be to use some car exhaust pipe that fits over the outside diameter of the stub.

Slit the end for compression and clamp it on with some regular exhaust clamps and some muffler puttey to fill rust holes etc.

That way you are not reducing the inside diameter of the exhaust stub, and it should work OK.

Maybe also add a support bracket to one of the clamps to brace the joint.

Rob

**Karl Robbers** · 15th May 2014, 01:25 AM

Howard 12, the rotary hoe that thinks it's a Harley!
I have one, that used to run, seized now - don't ask, I still have feelings of extreme violence toward the person responsible.
I would second the advice given to do a proper repair job on the old girl. With the heat, exhaust blast and vibration generated by the beast, I don't see any of the putties lasting terribly well.

**Evanism** · 15th May 2014, 01:40 AM

Mig weld a sleeve on. Take it to an exhaust shop and they'll have it done in 5 minutes.

They also sell very cool looking metal sleeves with fingers that tighten over such ends.

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