Sanding Redwood – Don’t Over-Sand
Today I will be talking about sanding redwood. I personally am not an expert, but I’ve been around it for quite some time now. I used to work in the yard a little, but now I only get to play with it a bit at home. Let me share some of what I have learned. This is geared more towards the non-professional woodworker.
The best advice I can give you is to begin with the finished product in mind.
Wood finishing can be fun and easy. Take your time and don’t rush through finishing a piece of furniture. Imagine how it will look finished in your home. It is better to take a little extra time to achieve a good end result. The most critical part of finishing a piece of furniture happens before you open a can of stain or finish of your choice. A thorough sanding is often the factor that separates “acceptable” results from “professional-looking” results.
It is important to not buy cheap sandpaper. Cheap sandpaper actually costs you more in the long run because the cheap bonding agent means you’ll go through it faster. You do want to save money and buying in bulk is the best way to do that.
The three most common types of sand paper you will find are:
Garnet: Commonly used in woodworking and designed for hand sanding.
Aluminum Oxide: The most common in widest variety of grits, lowest unit cost; can be used on metal (i.e. body shops) or wood.
Silicon Carbide: Available in very coarse grits all the way through to micro grits, common in wet applications.
Sandpaper comes in a number of different shapes and sizes:
- Sheet: Usually 9 by 11 inches, but other sizes may be available.
- Belt: Usually cloth backed, comes in different sizes to fit different belt sanders.
- Disk: Made to fit different models of disc and random orbital sanders. May be perforated for some models of sanders. Attachment includes pressure-sensitive adhesive (PSA) and “hook-and-loop” (similar to Velcro).
- Rolls: Known as “shag rolls” by many contractors
- Sponge: For tight places
Sanding can be messy, so I recommend some kind of dust collection system. I for one don’t sand and finish in the same room. I sand in my shop, and have another room on the other side of the house for finishing.
Since redwood tends to be considered a softwood, it is recommended that you start with 120 grit sandpaper if the wood is already pretty smooth to start with. But if you are starting with something that might have been milled with a chainsaw, you might want to start and 36 grit, then go to 60, then 80, and progress in steps up to 220 grit. In my projects I usually start with 80 grit because I do a lot of my final shaping with sand paper when I carve.
Proceeding through the Grits in a progressive manner will give you the smoothest of finish, and the general consensus seems to agree on 220 grit being the sweet spot.
I choose to sand my work finer. I like to go to a 400 grit using an artificial steel wool. What tends to happen when you go that fine is that it will not cut the grain; it only sands the wood between the grain. The grain will become higher that the rest of the wood, and give it somewhat of a ‘washboard’ type of finish. I really like this look and feel that it makes my finished product more tactile. However, this is not what you are looking for in finishing a table.
Making tables is definitely on my list of things to do. If you have a home shop like me, your best tool choice for surface prep is going to be a good quality random orbital sander up to about 150 grit, then hand sand to 220 grit. Always sand lightly, and sand with the grain. When using tack rags (a specialized type of wiping cloth treated with a tacky material used to remove loose particles, dust, and dirt) make sure they are oil free.
When you get to the point where you are ready to finish, make sure your room temp is above 65°. If you have any type of control over the humidity, it should be around 50%. Make sure you are not working near any vents or drafts, and out of the sunlight. Sunlight will warm the wood and release any trapped moisture, creating bubbles in your finish.