You have yourself a real project there. You are dealing with either raised grain from the stripper being washed off, or the stripper ate into the wood a bit, leaving it rough. In either case, you can use a sanding sealer, probably more than one coat, sanding lightly between coats. Are you going to paint, stain, or just clear finish these chairs? Have you estimated the time it will take to do the refinishing, compared to the cost of comparable new chairs, and found it is in fact worth you time (at whatever rate your time is worth)? Frequently, unless you are dealing with antique restoration, it's not feasable. If you are restoring antiques, do you know what the original finish was, and can you duplicate it well? Perhaps this is a family heirloom, in which case the sentimental value of the chairs overrides the cost of refinishing them (labor of love)? Just a few things to think about, hopefully before you invest a lot of time in this.