Painterwork - Blistering and Cracking

Blistering and Cracking

The blistering of painted surfaces may be caused in several ways. If on iron, it may be the result of a particle of rust which, not having been removed in the process of cleaning, has increased in size and loosened the paint. If on plaster, a particle of unslaked lime may have blown, with a similar result. On wood, blistering is usually caused by painting upon a wet surface or upon unseasoned wood. Blisters may also be caused by the use of too much oil in paint exposed to heat, or the application of one coat upon another before the latter is properly dry. To prevent blistering a method that has been tried with good results is to apply two coats of water paint (washable distemper) and follow by two coats of oil color or varnish. Cracking is caused by the use of too much oil in the under coats and too little in the topcoats.