What can I use to even out a gasket surface?

[R2.0]

I am rebuilding my Winterwarm Large (detailed in another thread) but have come upon something that I think deserves it's own topic. One of the problems with these stoves is that, because of the multi-piece construction, the face of the firebox can be uneven. Mine is no exception. In order to get the door gasket to seal correctly some grinding needs to be done, but it still won't get the surface flat.

So the question is what can I use to "butter" the surface to even it out? My first thought is plain stove cement, but I'm worried about it spalling around the edges where it will be very thin. Next idea is a high temp metal filled epoxy.

Anyone have any experience with surface application of fillers on woodstoves?

 

[mellow]

Check out this rebuild thread of an Encore: https://www.hearth.com/talk/threads/encore-2550-rebuild-start-to-finish.112149/

 

[R2.0]

Check out this rebuild thread of an Encore: https://www.hearth.com/talk/threads/encore-2550-rebuild-start-to-finish.112149/

Excellent thread, and I will re-read it before I start my reassembly. But...didn't find any reference to what I'm talking about.

 

[mellow]

Hopefully @Defiant will see this thread, he is one of the resident VC Guru's.

 

[R2.0]

Hopefully @Defiant will see this thread, he is one of the resident VC Guru's.

That would be great, though I think this discussion might be of general benefit - surely VC owners aren't the only ones to have metal repairs needed.

 

[dmmoss51]

Maybe I am misunderstanding what you are asking, but doesn't the gasket itself serve this purpose?

 

[Heatsource]

depending on how out of whack it is you can compress gasket to make it thicker, or stretch it to make it thinner in some areas
i've done this in the past when the door or stove was warped w/good sucsess

 

[mellow]

I use a thin layer of cement on mine when putting in gaskets in steel stoves, I don't usually mess with cast iron stoves.

 

[R2.0]

Maybe I am misunderstanding what you are asking, but doesn't the gasket itself serve this purpose?

The issue is that at the joint the parts are misaligned - actually, it looks to me like the original patterns were getting worn and hadn't been repaired. So one gasket mating surface is 1/16" higher than the other. No gasket can seal at a sharp discontinuity like that - in *any* application, automotive, machinery, etc.

So the solution is to grind down one side until the transition is smooth. But in order to do it right you typically need to grind on both sides. That smooths the transition, but creates a bit of a valley. Would a gasket seal on this? Probably. But if I can make the surface more nearly flat the gasket will be less distorted.

 

[R2.0]

I use a thin layer of cement on mine when putting in gaskets in steel stoves, I don't usually mess with cast iron stoves.

This wouldn't be in the gasket channel on the door but on the stove body where the gasket bears.

 

[Defiant]

We need pictures, check your door hinges and pins for alignment...

 

[R2.0]

I'll see what I can get to tonight. I took some pics for the other thread, but no closeups.

 

[R2.0]

Finally got to take pics. Full size



Reduced. The oval marks where the core shifted or was cracked. You can't really see it but above that line the metal is 1/16" - 1/8" higher than the rest. This think could *never* have sealed correctly.


Even worse is when I pulled the hinge. The discontinuity goes through the hinge pad as well. The original finishers hit it with a grinder, but they only flattened over each screw hole, so the pad is still uneven. I broke out the Dremel and chased the ridges down. It was worse than I thought (of course) - they weren't solid but had actually formed cold shuts, so I had to go about 1/16" into the base metal to get rid of them.

So here's my plan:

1. Measure the hinge pads and screw holed for plumb and flatness; shim and trim until I get something approaching a straight line.
2. Remove the fresh, uncured stove paint I just applied as best I can.
   
3. Use this stuff to build up/smooth out the gasket bearing surfaces and fill in the divots from chasing out the cracks.
   
4. Dry with a heat gun
5. Fit up the door gaskets
   
6. Fire up the stove and let it cure.
7. Paint

I chose the exhaust repair material because it supposedly has metal in it which I think may help in a surface application.