Hi I made a pit fire with Bbq top grill out of a 45 gallon drum, I sprayed it on the outside with a heat resistant paint spray I bought in my local DIY store. The fire has set for upto 3 weeks I took it outside last night and lite it for the first time, the paint bubbled, blistered and has started peeling. Can you advise what I need to put this right. Thanks Paul D