Sanding Your Wood
So you have found wood burning or have been burning for a little while and you aren't sure about sanding. You get mixed information in social groups and you are confused. Do I sand? How high of grit do I sand? How much sanding do I need to do? The questions and answers can be overwhelming, so I'm going to give you the answers. 😉 There are several different types of Pyrography artists. There is the person who is not sure what they think of burning yet. Or the hobbyist, who burns every now again. Then there is the person who has decided they like it, but aren't sure of themselves? There is the person who has been burning for a while and is comfortable with it. Lastly, there are the people who have been burning for many many years and have a solid footing in the art media. I mention this as we all have a few things in common, with one of them being preparing our wood.
How Should I prepare the wood?
This is a great normal question. We have to get the wood prepared to have the least frustrating experience. I have found that those who give burning a try, but lack information, tend to walk away from pyrography pretty quickly if their expectations of the final product doesn't match the actual results. Correctly preparing the wood will get you off in the right direction. For this post I will be focusing on kiln dried pre-sanded purchased wood. A tree cut down from your property is going to take much more preparing and time.
Sand!
Sanding makes all the difference. You may buy a pre-sanded piece of wood and it feels smooth. But guess what? It isn't smooth enough. Most store bought wood from a craft store or purchased online is sanded to 220 grit. This is a good start, but not quite enough. Sanding a bit more, believe it or not helps. But here is the catch, you can sand too much. Just because we get a piece of wood sanded mirror smooth, this doesn't mean we won't have problems later.
So I decided to do a little test. How does the wood respond to burning when you sand to 2000 grit? My normal sanding on pre-sanded wood is 220 grit, 320 grit, 400 grit. That's it! (step by step below)
In order to go to 2000 grit, I had to buy more sand paper. I purchased a multi pack so that I wasn't paying $10-$15 per pack… that would have been an extra $40+ I didn't need to pay.
For this test, I sanded a piece of pre-sanded basswood. I did my normal sanding up to 400 grit for the entire 7" x 9" board. I then sectioned off the board into 3 sections, 400 grit, 1500 grit, and 2000 grit. With sanding, you should as much as possible, not skip a grit. I will acknowledge now that my pack went from 800 grit to 1200 grit, which skips 1000 grit. With these higher grits you do have a tad more leeway with the skip. The order in which I sanded ½ of the board with an orbital sander: 600, 800, 1200, 1500 grit. The last ¼ of the board was sanded with 2000 grit.
Next, I laid out a big circle at the location where all 3 sections met. I did this to see and feel if there was any difference in the 3 areas. In the center, I started with an Optima pen (tester pen not currently available) with the heat setting 1.5. I then switched over to the Optima 18s and lowered my heat to 1. This next part is going to be a little harder to explain. For heat setting 1-4, I used two different parts of my tip for both oval strokes. The darker area is doing oval strokes with just the tip. The second overlapping of oval strokes of the same heat setting is about half of the tip touching the wood. This is why later I added the rectangles for a test. For heat setting 5, I first did an overlapping oval stroke with the tip and then finished with a drag with ½ the tip touching down.
Final Results
Do you need to sand to 1000 grit, 1500 grit, 2000 grit or even higher in order to burn?
Answer: NO!
At 400 grit, my pen glided normally over the grain. My heat was overall even and my hand wasn’t killing me after sanding. Normal slight grain catch of the pen.
At 1500 grit, the wood burned darker on the same heat setting and pen glide was pretty much the same. I felt zero difference between the 400 grit & 1500 grit in this area. The biggest difference was the wood burning darker. Normal slight grain catch of the pen.
As for the 2000 grit, I was surprised to see that it actually burned lighter than the 400 grit… meaning the wood was now reacting differently to the heat because the wood was burnished. I also felt my pen tip being grabbed more so than normal by the grain. It took me a moment to figure out why this could be happening. I mean it is sanded extremely smooth, right?
If you think about it, it does make a bit of sense. With 400 grit you are sanding the top of the grain smooth. This keeps the top ridges of the grain pretty even and close. Meaning the distance between the valleys and mountain top are closer together and the pen can glide over to the next mountain top without catching a valley.
When you keep sanding at the higher grits, you actually turn those mountain tops into more rounded hills. As the tops get further apart the valleys widen. This means the gap between grains allows the tip to dip down into those valleys, catching the grain as it comes to the next top. Think a motocross bike going down and up hills instead of jumping from the top of one hill to the next.
Now we'll discuss burnishing, as I mentioned burnishing above. What is burnishing? Burnishing is the act of pushing the grain (for our purposes) down, causing the wood pores to close. Wood is extremely fibrous with millions of microscopic holes. When you close off these holes you’re actively changing how the wood reacts to what is being applied including heat. If you look at the instructions careful for varnish & stain (any brand), it specifically says to apply to wood sanded to 220 grit. Why is this a part of the instructions? The stain does not soak into the wood correctly and the same for varnish. The stain will actually come out lighter because enough of the dye molecules did not penetrate the wood grain.
Now you may be thinking, “well I don’t add liquid color of any kind to my pieces, I use colored pencils”. The higher grit sanding (burnishing) of the wood causes issues with colored pencils as well. The wax and oils of colored pencils use the “tooth” of a surface to detach from the pencil core and adhere the pigment to the surface. You may have heard the term “tooth”, which is normally used to describe the surface of paper. It refers to how rough the surface of the paper material is. If paper is too smooth (lacks tooth), colored pencils have a much harder time adhering to it and you can’t apply as many layers. This same thing happens with wood as well. If it is too smooth, colored pencils have a harder time embedding into the wood grain. With this, think drawing on a mirror with a colored pencil… it won’t stick as it has nothing to grab onto. You might get streaks, but you won’t get the full pigmentation of the pencil. When wood is too smooth, it lacks tooth.
How I sand my wood
When sanding, ALWAYS! ALWAYS! Sand in the direction of the grain for all sanding levels. Never sand against the grain as this will create scratches that are not only apparent during burning, but also when you varnishing. Once sealed, the scratched will be permanent and very visible. When burning lighter values, the scratches can show through.
Step 1: I identify what type of grain my wood has. There are three different cuts: Long grain, Short grain, and End grain. This is describing the direction in which the grain lays based on the long edge of the board or how theboard was cut.
Long cut is the grain running parallel to the long edge of the board. Meaning the grain runs along with the long cut of the board.
Short cut is the grain running perpendicular to the long edge of the board. This means the grain is running across the board. This happens when they rotate a long grain board and cut across the grain to make smaller boards.
Edge cut is where the wood has been cut as a slice. This means the center of the wood has been included. You see this with your oval live edge pieces of wood. This grain follows the center of the wood as well as shoots off in a direction heading to the edge.
Step 2 (220 grit): Once I have identified my grain direction, using an orbital sander, I sand the entire board with 220 grit. I sand back and forth WITH the grain. I make sure to overlap my passes to keep everything even. Once done with this direction, I turn the board in a 180 rotation and then sand in the opposite direction with the grain. I will do this 180 rotation with the board several times to ensure all of the grain has been sanded. I sand both sides and then finish off by running my fingers across the grain. With sanding you can feel a whole lot better than you can see.
Step 3 (320 grit): Now that I have ran my hand across the board and everything feels even, I remove the 220 grit disc from the loop & hook sanding pad and apply the 320 grit disc. I repeat exactly what I did in step 2. I sand back and forth with the grain. If I flip to the back side of the board I only sand about 50% of the back side to allow for a smoother burn signature.
Step 4 (400 grit): I repeat the same steps above for this last step. I remove the 320 grit disc from the loop & hook sanding pad and apply the 400 grit disc. This time I only sand the front of my board. Once I am all done sanding, I use a microfiber towel to wipe off all of the sanding dust. I then bring the wood into my studio and wipe the board off quickly with denatured alcohol and let it dry. The wood is now ready for me to transfer my pattern.
This is it… all of the sanding and then I am done! The shortest instructions I have ever written, lol. I will sand multiple pieces of wood during a sanding session, so that I have sanded extras that I can grab if I need them. I always wear an N95 sanding mask from the hardware store to sand. I had an extremely bad experience back in 2010. I didn’t wear a mask at that time for sanding and during this sanding session, I was sanding Yew. Before you leave a comment about Yew; yes I learned much later that Yew is a toxic wood and you must be very careful with it. Actually, you are much better off NEVER working with Yew for pyrography. Anyway, I coughed up wood particles for weeks and was extremely ill. Since that happened, I ALWAYS wear a mask to sand no matter how uncomfortable it is and for me and it is extremely uncomfortable. If you need a stronger mask, absolutely invest in one!
I know I said above I sand to 400 grit and stop. I also said the instructions on varnishes say to use on 220 grit sanded wood. Do I have an issue between the two? No, I have not had an issue with my varnish as there is still plenty of open grain allowing the varnish to soak in. When you sand to the higher grits and then apply varnish, you are opening up a possible can of worms for later.
Like stain and colored pencils, varnish needs to soak into the wood a bit to adhere and protect. If it can’t adhere correctly you are opening up the possibility of the varnish lifting from the wood and peeling. Now I can’t give you a time frame as to how long this can take. All of our environments are different. I live in what is called a high desert in northern Arizona. We do not have a constant level of higher humidity. Monsoon season in the summer can see higher humidity levels, but it dries out pretty fast. Less humidity allows the wood to remain more stable, meaning the wood is not swelling and contracting as much due to a higher percentage of water in the air. This wood movement can cause the varnish to detach.
I do want to address one more aspect of sanding which is called, raising the grain. If you aren't sure what this is, it is the practice of introducing water to a dry piece of wood to expand and raise the grain. This does not take a lot of water, in fact the more water you add, the higher the likelihood of the wood warping. I am actually on the fence about whether we should be raising the grain or not for pyrography. I definitely think raising the grain on a rough hewn board is extremely helpful for a smoother finish. Where I am on the fence is in regards to the store purchased pre-sanded wood.
I have raised the grain and not raised the grain on my pre-sanded boards and I have to confess I don’t really feel or see an overall difference in burning. I will occasionally do so on a Walnut Hollow live edge basswood plaque if the grain looks or feels a bit more rough. I take it on a piece by piece basis. When I do raise the grain, I raise it before any sanding. I will take a damp cloth and wipe the board on both sides and allow it to sit for an hour to dry. Remember, I live in a drier climate so it takes less time for things to dry, like my long hair. In Texas and Washington it would take 45 - 60 minutes for my hair to be mostly dry with a hair dryer. Here in Arizona it’s 15 minutes tops. There is a big difference in time due to humidity levels. The same humidity levels that affect wood.
For raising the grain, both sides of the wood need to be dampened as you are introducing water back into the wood. A dry piece of wood has an average water percentage of 7% to 12% any more and the wood is not considered fully dry. If you don’t equally wet both sides, the board will warp as it dries, as the wet side of the grain is swelling and contracting which pulls up the edges. Unwarping a board is time consuming… believe me I know. Fixing a board that is cupping (warped) requires a damp towel, a hot clothes iron and time. The towel and iron are in effect steaming the board to later straighten out hopefully as it dries.
Once fully dry on both sides, I will start with 220 grit and then slowly work my way up to 400 grit. I do not raise the grain again after this point, as I have seen others mention. Why do more prep than you really have to? The more you raise the grain and then sand, raise the grain and sand; you are once again closing off the wood pores, burnishing the wood. I see some people say it makes the wood like glass and their pen tips glide better. Well it isn't the wood causing the glide issue, it’s your pen tips.
You could do less sanding and instead polish your tips and stop using abrasives to clean your pen tips. Fine grit abrasive paste and a soft buffing wheel will do the job. Note: I am not an expert on polishing tips. There is a bit more to it and I recommend getting in touch with someone like Pat from Optima to get the ends and outs on polishing. I will say, you will be much happier with a highly polished tip and less sanding of wood. An average 9” x 12” board takes me approximately 7 minutes or less to fully sand… meaning I have done all of my sanding and it is now ready for the pattern and burn.
Like in life, everything in burning is a balance. We are creating our art on a natural surface that reacts in it’s own way. The wood is dead, meaning no longer growing; but it still exhibits its own personality as we work with it. Each wood species has its particular likes & dislikes of how it likes being prepped and burned. Learning these attributes will help you with your prepping, burning, and final outcome. We all should prepare our wood for a more satisfying burn and outcome; however we shouldn’t make it more time consuming than it already is.
Higher grit sanding for flat pyrography work is not only unnecessary, but can actually interfere with our final outcome. Wood is not a piece of smooth paper or a piece of glass... you know, a man made surface. Therefore you shouldn’t expect it to behave in that way. You are fighting with your wood instead of going with it. Relax! Enjoy the process and remember a piece of wood will never be perfect and this is a part of it’s beauty and charm of pyrography.
Recommended Products
Amazon Affiliate links
Orbital sander: https://amzn.to/3roc1jK
(I have not used this sander. My sanders are an older ryobi orbital sander & another brand)
Replacement orbital sander pads: https://amzn.to/3aE9StM
(I use this product)
400 grit 5" orbital sandpaper: https://amzn.to/3aAhkpG
(I use this product)
320 grit sandnet (sandpaper): https://amzn.to/3cNUkGr
(I use this product)
220 grit sandnet (sandpaper): https://amzn.to/36KZuz6
(I use this product)