burning pallets with nails?

Hi ive just built a rocket mass heater for a small meeting house in Cornwall UK, it works amazing and has changed the house completely ,im just wondering about burning pallets with nails ,probably not the best idea i know !  they are free but i dont wont to mess up the burn chamber can you give any advise please?

Hi Paul;
Congrats on building an RMH!
I'm glad to hear that it is performing up to expectations.

What size J-Tube have you built?
Is it made out of heavy firebricks?
Do you have a method for cleaning the ash from the burn tunnel and feed tube?

The ash below the riser and in the burn tunnel will be light, fluffy, and easy to move.
The ash at the bottom of the feed tube will harden up into several, inches thick chunks.

The nails will not hurt the firebricks, but could easily hurt you while cleaning ash.
Use care while cleaning, perhaps stay on top of ash removal to avoid hard chunks with hidden nails.

You may find that the smaller nails simply melt.

My experience is with a regular wood stove and pallet wood. We have a magnetic pick-up tool which I use to sort the ashes so the ash can get spread and the nails can go to metal recycling. A tool like that, picking up the nails right out of the J-tube and dropping them into a metal can might be the safer way to clean the ash out. At the very least, wearing gloves would make it easier on the skin. Ash is surprisingly abrasive and caustic.

Ours looks something like this:

Thanks for getting back to me so soon, its put my mind at rest. I made a 8inch system i havent put a finish on it yet thinking about a lime clay sand mix? Many thanks for all the videos and info its been a eye opener !

I find I need to clean the ash from my 8" J-tube every week or two, after a couple inches of buildup. As the last wood goes to coal I push it into the beginning of the burn tunnel so the air from the P-channel blows on it to burn it completely. Thus the greatest buildup occurs in the burn tunnel, and even 3" does not hamper combustion. I use a tuna can attached to a short handle to scoop out the ash. I have burned wood with nails; they corrode significantly but do not melt. A magnet to separate nails from ash would be a good idea.