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View Full Version : Which bolt into cast iron in firebox?!



Dusty Dave
5th Sep 2020, 02:37 AM
Bit of a weird one this, but hoping someone here will know the answer!

I have a problem with my wood stove. The cast iron baffle plate basically just rests on a couple of tabs at the front and the wetback tank at the back. The problem is if it gets knocked when loading a log, it pops up and slides back over the wetback and drops off its front tabs into the firebox. As you can imagine, much hilarity ensues.

After much thought, the only practical solution I can come up with is to tap a thread into the plate at the back, and insert a bolt. The bolt can just snug up to the structure above and stop the baffle plate from being pushed up.

I know that tapping the cast iron plate is doable. What I'm not sure about is how to ensure a long service life from the bolt in the hostile environment of a hardworking redgum-fuelled firebox. Obviously it needs to be removable for future cleaning and servicing.

I was thinking of using a stainless bolt as in my experience stainless tends to hold up better to intense heat than mild steel. But I don't know whether differential expansion or galvanic action or some other vector will cause trouble over time. Is there a particular type of bolt that is a best choice for this application?

caskwarrior
5th Sep 2020, 01:14 PM
Considering tthere is no load you could make a cast iron bolt.

pipeclay
5th Sep 2020, 08:52 PM
Based on what you are looking to do I am not sure if cast iron would be a good choice for your locating bolt,Stainless might be the better alternative.
If the locating bolt/ support needs to be removed periodically even a through hole through your damper with a bolt with nut top and bottom may work.

Dusty Dave
5th Sep 2020, 11:34 PM
Thanks guys, I may be totally overthinking this, I just don't want to have to try and drill out a buggered bolt at the back of the firebox the next time I need to replace some bricks. I think I'll go with a stainless bolt and maybe a smear of copper antiseize just for fun.

Gavin Newman
6th Sep 2020, 09:38 AM
I think I'll go with a stainless bolt and maybe a smear of copper antiseize just for fun.

For what it's worth, we use Loctite LB-771, which is nickel based, in the the locomotive smokeboxes as it stands up to high temperatures and corrosive atmospheres much better than the copper or silver grades.