Almost a year ago Josh R posted a really useful experiment showing different types of wood stains on various wood samples from the US materials catalogue. I thought that a NZ materials version would also be a worthwhile example because the NZ selection of woods is somewhat different from the US stock, and finishing products also differ.
I followed essentially the same steps as Josh for comparative purposes, and general results were similar. I applied one finishing coat to all samples, with one exception being the black Miro Stain where one coat didn’t provide sufficient coverage. Two coats were applied instead, but I’d happily apply another one on top of that. MDF is a very absorbent material, and using fine particle finishes such as stain, dye or spray paint isn’t economical. Since MDF doesn’t have a grain, using any grain enhancing finishes like oils and waxes is pretty futile. You’re better off spending the money on a pot of paint and a roller/brush.
If you’re working in a small space that lacks ventilation, I would recommend non-odorous finishes, such as linseed oil, Waxshine or a natural wood polish. However, these indoor-friendly finishes won’t be effective for anything designed to be used outdoors.
For best results use a soft rag such as an old t-shirt. Tissues and towelling aren’t suitable because they will pill and leave residue on the wood.