# Forum Home Renovation Metalwork & Welding  How To Protect Outside Firebox

## abrogard

Made this firebox and I want it to live outside.  How to treat the metal?  Tried some 'fireproof' auto paint and it was useless. 
So I need protection for the outside of it, capable of handling the heat. 
And I could use advice on this inside - it is just a skin of steel, no firebrick or anything else. Should I change that do you think? 
And I'm wondering what to do about the top.  It has been handy when starting a fire to take the top off - it slides forward from under the angle iron.  Then I could lay the fire and get it going good nice and easy.  But the thin steel top is warping from the heat and doesn't slide so easy.  It is not so good. 
Thinking of making a heavier top.  3mm steel or more.  Maybe would be okay to lay that on the top?  Or might need some seal of some sort what do you think?  That could be a cooking top.  But then how do you keep the rust off that? 
Has to be covered all the time, is that it? 
Maybe hinge it.  Heavy steel top hinged.  Might not leak too much around the sides? 
Willing to read any suggestions, advice, from anyone in the firebox building business.  I've noticed there's kinda a whole sort of special area of blokes that build fireboxes, smokeboxes, etc. 
But mainly:  how to protect it from the weather?

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## Marc

Slow combustion wood heaters are painted with high temperature paint.
Yet they also have a coat of bricks refractory or some other sort of protection. If you fire up your box to red hot, there is no paint in this world that can resist above 1000C temperature. Not even creamic coating. 
So you either line the box with something that shields the steel from extreem heat, or you resign yourself to rust.
A temporary solution if you have the patience to repeat it from time to time is rub the outside with Plumbago.

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## abrogard

yep, I'd have the patience. But what's plumbago?  I googled and got a plant ! 
so it's firebricks are needed.  Any alternative to that?  You did say 'some other sort of protection..'  is there some other way?  Some slurry or something, perhaps.... ?

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## Marc

Easiest is fire bricks really, even clay bricks. There is refractory mortar that can be made or bought but keeping it on the walls will be a challenge. Refractory mortar is grey cement, lime sand and clay, plenty of formulas on the internet
Plumbago is graphite used in casting. Cheap if you get the right supplier. I buy from the UK from time to time. Graphite can be expensive if it is in pure form and very fine, something you don't need. Try Blackwoods and explain you want the graphite used in sand casting. 
You rub the powder with a rag over the steel over and over. It will give a metallic shine that keeps, providing the temperatures are not extreme. If so just repeat even over rust. It used to be the treatment given to steam locomotives. http://artisanfoundry.co.uk/product_...products_id=48

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## Marc

Plumbago auriculata  :Smilie:

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## abrogard

Yep. Thanks for that. Very interesting. I better get some firebricks then.  And some black lead.  I googled it.  It's the same stuff my old mother used to scrub onto the fireplace metalwork when I was a kid - saw the words 'black lead' and it rang a bell.  Apparently the railways mixed it with old oil or even linseed oil (!) to put on the boilers.

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## PlatypusGardens

How did I miss this???!!   :Shock:  
Nice firebox, top job.
Yeh it will definitely warp from the heat.
My outdoor open box (3 sides) made from 6mm hard steel plate has buckled! 
Meanwhile, my potbelly made from 3mm stainless hot water tank hasn't moved an inch.
And that gets red hot. 
A lot of people seem to have good results with the potbelly black paint.
I've not tried it myself.
I hever seem to get around to painting anything I make haha.

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## toooldforthis

yeah, I used pot belly black paint - no probs.

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