Why Pre-finish the wood?
Finishing a wood project can be the least attractive part of woodworking. I know many workers who dread and dislike this part of wood working the most. And yet, no one can really dispute the importance of this step. Whether you like it or not, the first thing that most of us notice in a wood project is its finish. A finish has the power to lay waste to 200 hours spent on an otherwise a great wood project, as well as to make the mediocre project look great.
But the work can be slow, tedious and tiring specially if your project has hard to reach corners and spaces. It is difficult if not impossible to reach some of these places and do accurate work. So one of the techniques to avoid the regular woes of wood finishing work is to pre-finish the pieces before you assemble them together. For example, while building a chair. The chair will have legs, arms, slats etc. that once assembled will be a nightmare to sand and finish.
But what if you apply the finish and do all the sanding first and then assembled the pieces together…
There are many advantages to pre-finishing wood crafts before assembling them:
- Arguably, the work becomes easier and faster.
- You can apply to finish more easily. You can lay the piece down flat on your table, brush easily and get the entire area completely. The same applies to sanding. Sanding gets near impossible in corners once the piece is assembled. Here all the parts can be laid flat, rotated, picked up et cetera to give them a proper treatment.
- You end up doing a better job. You become a better woodworker for all of the above reasons. You can see easily if you have missed a spot, if there is some flaw before you assemble all the pieces together.
How To Pre-finish A Wood Project
Refinishing a piece of furniture has its conveniences. But if you think about it, there is one obvious problem and that's to do with how do you handle and wield the piece you are finishing. In this case, let's take the example of a chair leg. When it's attached to the chair it is suspended from its joint. You can finish it with the check standing upright or on its back with the leg held up in the air above the surface you are working on.
But how do you hold same piece when it is not attached to anything, still have access to all the sides, without any part of it touching the surface you are working on while the finish is still wet?
The solution is simple. You will realise that in every piece of wood furniture there is one side that never get seen. In this example of a chair leg, it's the end that attaches to the chair base. Think of any furniture part and there will always be a side that is going to be hidden from view once it is attached.
Therefore, the first thing to do is to find a small hook, the kind you see on a pegboard, make a small hole in the middle of the hidden side and screw the hook firmly into it. Now you have something to hold onto while you are brushing, spraying or sanding the furniture piece.
But why a hook and not something else? Well, personally I cannot think of any substitute for it, something that you can screw into a small hole and also get a good grip. But there is another important reason.
Once you're done applying a coat of finish to the furniture, you can use that hook to hang it on the line to dry. It's the perfect way for the finish to cure to quickly and properly. One precaution has to be taken if you are hanging out the pieces in this manner.
You realise that when you start hanging heavy wood pieces on the line, it will begin to sag in the middle.
There are two ways to prevent this from happening. Either use a nylon line and tie slipknots into it or wrap pieces of masking tape if you are using a wire or a clothesline. The last thing you want to see is to come back in the morning and discover that all while you were away, all the finished pieces collapsed onto one another while they were still wet .
A few tips and precautions on finishing wood.
- Work in a dust free environment as much as possible. Less dust settling on your freshly coated furniture means less work for you later on.
- Safety first. Always follow safety instructions that come on the label of the finishes and solvents. If they say work in a well ventilated area, they know what they are saying and mean it. Similarly, use respirators with chemical filter cartridges that will absorb fumes and gases. Wear gloves to protect your hands, glasses to protect your eyes or use a full face shield to get complete protection.
- Dip the brush only three fourth or up to an inch. Brush in only one direction. You will reduce the amount of air bubbles you catch by doing this.
- Use synthetic bristles brush for water based finishes and natural bristles for solvent based. Natural bristles absorb water. They will become limp if you use them with water based finishes.
- Wash your brushes in the solvent, then rinse of the solvent in warm water over the sink to clean them completely. Dry flat and store them flat in a Ziploc.
- Take special care of the rags that get soaked with solvents. Do not stack them up in a bin. They can heat up and spontaneously combust. Dry them on the line or rinse them in a bucket of water before throwing them away.
- Use mineral spirits to thin Polyurethane solvent based finishes. Use shellac thinner for shellac finishes.
- Use smaller jars to mix small quantities of the finish you are working with.
- Use non-woven abrasives, also called scratch pads, to sand your wood and finished surfaces. You will get better results.