This paper presents a synthesis of a large body of experimental data on growth rates of ash deposits from the air and oxy-combustion of multiple pulverized solid fuels, including coal, biomass, and their blends. The experimental data were obtained from 35 tests in a 100 kW (rated) entrained-flow combustor that allowed for self-sustained combustion of solid fuels. Ash deposition rates were measured using a wall-temperature-controlled ash deposition probe. The collected deposits were divided into tightly bound "inside deposits" adjacent to the heat transfer surface and loosely bound "outside deposits" that grow further out. Ash aerosol particle size distributions (psd's) and size-segregated compositions were obtained through electric mobility, light scattering, and impactor methods. Rates of ash deposition for both inside and outside deposits are presented. Rates of growth of the inside deposit were proportional to the sub-micrometer particle (PM1) concentration in the flue gas but correlated poorly with the alkali concentration in the flue gas, while rates of growth of the outer deposits correlated poorly with PM1 but well with the total alkali content in the flue gas. The data on growth rates of both types of deposits are interpreted in the light of available mechanisms. These involve a "glue effect" that was independent of composition of PM, for the inside deposits and a "bounce-off" criterion that depended upon the total alkali concentration in the flue gas for the outer deposits. These data from all 35 tests, burning 11 very different fuels, under similar (but not identical) aerodynamic conditions allow for prediction of changes in deposition rates of both inside and outside deposits as a result of changes in aerosol psd's and compositions. Data presented here may form the basis for future work leading to statistical models or mechanistic simulations of the ash deposition process.