SealCoat and woodstain are both products used in the process of finishing wood. SealCoat is a brand name of wood finish made by Zinsser. Woodstain is a product that comes in different colors and is meant to give the wood a darker or lighter appearance without concealing the grain of the wood. These products can be used in conjunction with one another.
SealCoat and Woodstain
SealCoat is a wax-free shellac that is meant to penetrate into the pores of wood, sealing and protecting it against years of use and exposure to dirt, dust and more. SealCoat in particular is guaranteed to be compatible with oil-base polyurethanes, acrylic finishes, lacquers, catalyzed finishes and varnishes. Shellac leaves a brilliant shine on the surface that it is used on and can be applied more than once to add shine to the surface of your wood.
Woodstain leaves an opaque look to the wood it is used on. There are interior and exterior stains. Interior stains are meant for furniture that will be kept indoors, and exterior stains are meant for wood that is outdoors, such as siding. Wood stain is typically applied with a rag or a paint brush, with the excess being wiped off to control the amount of stain that is absorbed by the wood.
Using SealCoat and Woodstain
Not all projects require staining, and not all projects require the high gloss shine of shellac. What you use depends on the look that you want to obtain once your piece is finished. Shellac can act as a sealant to the wood, and can be applied with other varnishes and with stain as well. But if you want an opaque finish you can use a wood sealer that does not change the appearance of the wood. If you like the color of the wood you're working with, you may not want to stain it in order to keep its original appearance, but you may want to use shellac to seal it and add a glossy shine.
When you go to the hardware or home improvement store to pick out your wood finish(es), ask a salesperson about the different kinds of shellac and stain. Ask what effect they will produce on the wood. Shellacs that contain wax are not compatible with all kinds of stain, and they are also not waterproof. Some choose to mix their sealant and their stain together at one time, if you're interested in that option make sure the two you choose are compatible. You can do this by reading the labels and asking a professional.