Patching a Firebox

RocDoc · Patching a Firebox

Hi,

Some of you may have seen my M167 restoration thread and seen that part of the firebox is 'holed' at the front end (there is a nice close up photo on the thread). Are there any standard ways of patching such holes?

I had thought about using wire mesh to provide reinforement and then cover with Holts Gun Gum which is a type of paste filler used to repair exhaust pipes and silencers (good heat resistant stuff). The repair would be done on the inside of the firebox (you won't be able to see it anyway) with some filler on the outside, then cover with lots of VHT paint. Is this a good plan?

Cheers

Pete

Wallace

Hi Pete.

Sounds like a brilliant idea, and something I never thought of using.

I think it would be far neater and easier than using a plate soldered/riveted in.

I know the stuff you mean. I have used permatex brand before. It was like a grey coloured paste where water could be added to get the right consistency. Goes rock hard when dry and is very strong

Sandman

Don't know how it would react to water.

If I remember correctly when using gun gum, the repair had to be covered with metal foil before application.

Worth a try though.

Wallace

Good point Sandy. Well worth looking into depending on brand

I know the stuff I have is fine with water.

This is the stuff I used (but I had it in a tin)

http://www.brandsport.com/pmtx-80333.html

mc_mc

I'd have thought exhaust pipes would get splashed with water thrown up as a vehicle travels along on a wet day, so it should cope with the spits that come out of the engine. But there's only one way to find out...

Reid

It will surely work out fine so long as you can ensure its lasting adhesion.

The spots that will show through and need painting, will soak in the VHT at first (I'm presuming) and so it might pay to hand-paint those spots first with a couple or more coats of VHT, and bake the box,
and wet sand the spots before overcoating the entire box.

Just my intuitive guesses.
The pastes I've used on pipes in the past were to be rubbed into a fiberglass-like blanket. Some are putties, like for holes,
and all would last for a limited period of time in service.
They were air/heat cure pastes in a base containing water.
However for a firebox I'd expect the results to be quite permanent:
no pressure, no explosion pressures.

RocDoc

Hi,

Thanks for all your encouraging comments.

I'll give it a go and post the before-progress-after photos on the 167 restoration thread.

Cheers

Pete