I have a 1910 house that has the original exterior paint (no additional layers - been covered by asbestos tiles which have been removed). I have been scraping where it is cracking and sanding where there is a difference between the removed paint and the boards themselves. I want to do this right and was wondering if I needed to remove all the paint (even where it is still well adhered) or is it wise to only sand out the uneveness? P.S. I am wearing a hepa face mask to do this.
When you have lead paint you have to be very careful in sanding it as this what stirs up up the lead in the paint. A good removal product is Peel Away 1 as it removes many layers of paint in one application and it a safe way to remove paint. Check with a paint store in your area to see if they carry this product.In your case you should remove all of the paint anyway to insure a long lasting paint job as that old paint will start to let go and take your new paint with it.
DO NOT REMOVE LEAD BASED PAINT BY SANDING! This only releases the lead into the air where it will spread and a hepa facemask is not sufficient to filter it all out. It can also get on your skin and be absorbed there as well. On commercial jobs we only use professionals trained for this purpose. They usually contain the entire building in an air tight tent with special ventilators before starting the job. They then use a chemical stripper and scraping followed by a pressure washer to remove all the paint. Clean up afterward is also taken very seriously. My advice is to contact a professional, or at the very least QUIT SANDING, use a chemical stripper, keep it wet, and do a thorough job of clean up afterward!