How Much is Enough?
We often get this question. A person will phone and ask about how much penetrant (or remover or developer) will be required for a job that needs to be inspected. Often the person does not have any data about the part size, surface condition, or other helpful (necessary) information, since the job is not at hand but is a job that he is hoping to get if he is successful at bidding on it. Of course we try to help, but often it is not easy. In those cases, we recommend that the person wait until the actual parts are at hand, and then purchase a small amount of what will be required and make an on-the-job test. From the test, which not only incorporates the actual part, but also now brings into play the actions of the person making the test, one can then estimate the actual amount that is requiredfor the job. This is a do-it-yourself test.
But people want numbers so we try to give them some estimates as a guide. A rule of thumb is 1 penetrant aerosol to 3 developer aerosols. Cleaners, well that is any ones guess. We guesstimate an aerosol can of penetrant to cover about 300’ of 1” weld or 25 square feet. But remember everyone sprays differently. For bulk use this relationship would work out to be about 300
square feet per gallon. Remember, the value of these numbers is worth what you paid to get them. Make your own tests for your application and technique.