Entry for December's Guitar Of The Month contest is now open!
Search the Community
Showing results for tags 'sanding'.
Found 3 results
Making Things to Make Things to Make Things One of the reasons I love woodworking is that it is simply what it is. It’s me and the wood and nothing but a tool or two between us. And that simple relationship gives rise to beauty and function with no pretension. Well, most of the time anyway. Sometimes it turns out that I’ve spent an entire day in the shop making something that I need in order to make something that I’ll use to make something, and that’s what today’s post is actually about. Creative Problem Solving The ultimate goal in this case is the Les Paul style electric guitar that Josh and I are building. We want the traditional Les Paul 12" radius, but getting a radius on an eighteen(ish) inch by three(ish) inch board isn’t as easy as running it through a band saw. There seem to be a few common approaches to making that radius (there are actually a million ways to skin this cat, these are the ones I see most often). Hand planes. If you are good, you can plane the radius into the board with a sharp hand plane. Something along the lines of a Stanley #4 is a good choice. This takes a good bit of skill though, and is easy to mess up – which is not what you want to do with a carefully selected, highly figured piece of wenge. Router jig. There are several approaches to jigs you can build for your router that will carve the radius directly into your board. Many luthiers use this approach, and I may go there eventually, but these are often pretty involved builds, and the jig you end up with really only has one good use. So sure, when I get to the point that I’m building a guitar each month or so, this is probably where I’ll end up, but for now I’m looking for a simpler solution that hopefully can address more than just this one need. Radius sanding block. Sanding blocks with one surface cut at the desired radius can be used to sand that radius into the fretboard. If you have a block with a known and trusted radius, this is a very safe method of transferring that radius to your fretboard – it is unlikely that your sanding block will transfer a wrong radius, or will slip and gouge your board. Also, take the sandpaper off the block, and you’ve got a clamping caul with a matching radius. Simple and versatile. This is the direction I decided to go. Buy or Build? Radius sanding blocks are readily available from lots of vendors. But I tend to be a never buy what you can build kind of guy, so before I started shopping, I started drawing up ideas. Giving credit where it’s due, my initial ideas for the jigs came from a post by @hittitewarrior . His jig is a pretty large contraption and that size seemed to introduce a little too much variance in his results, so I wanted to design something smaller and simpler. I ended up with the following. A simple tower on a flat base with a couple side-supports. A small trim router attached to a board that hangs from the tower on a pivot point. There is a pivot point in the tower, and a corresponding point in the board for each radius that I’m interested in. As you can see in the pics above, I started with a metal pin in the pivot point, but I had a problem with the pivot board wanting to fall off the pin, so I had to switch that to a bolt. This was much more effective in keeping the pivot board secured to the tower. I used 1 x 3 poplar for my blocks. These are just project boards from Home Depot so they are easy to source and very inexpensive. If I wreck one for some reason or if I want more, it’s not that big a deal. The block goes under the router (duh) with some shims to get it to the right height and to keep it centered as I run it through. In this case, I attached two blocks with superglue/masking tape to get the right height. I then ran the router horizontally across the block, cutting the radius into the surface (I did try running a block using vertical passes along the length of the board, but that gave me an inconsistent radius). After each pass, I advanced the block 1 or 2 mm, then made another pass. I went halfway across the board, then turned the block around and did the other half from the other side. This allowed me to keep my fingers out of the way, but also required that I had the block centered properly so the radius would line up when run from opposite sides. After running through the jig the radius was good, but as you can see, not completely smooth. I set the board so the shadows would accentuate the ridges – they are not actually quite as bad as they look in the photo. Some sanding with a flexible sanding sponge took most of the waviness out of the block and left me with a perfectly good surface to attach sandpaper to. After finishing the 12″ block, I made another with a 9.5″ radius (assuming a future Strat-style build). Hard to Handle (so make a handle) Since I used 1 x 3 stock for the sanding block, it is a little on the thin side when it comes to actually using the thing (i.e. holding and sanding block itself). To rectify this, I made a simple handle from 3/4 plywood and attached it to the back of the block. I chiseled out some recesses to create some extra support and glue surface, and clamped lightly while the glue dried. After a couple coats of wipe-on, matte polyurethane to protect, and keep the wood from moving too much, these sanding blocks are ready for action. They haven't seen any action because as of last night the ploy was still curing, but as soon as I can get some actual sanding done, I'll post a follow-up with some results. This was a fun project with direct costs of about $5 for the wood, and whatever value you want to place on the shop scraps I used to make the jig. I figure it saved me about $30 on two blocks, and now I have a jig I can use to make as many sanding blocks or clamping cauls I want in the future. Let me know what you think or if you have any questions.
Many tutorials and videos out around Internetland outline the process of grain raising before proceeding to apply your final finish. They tend to do this very well, however they seldom explain the underlying problem we're solving. Why does does the grain raise anyway? What in fact are we looking at? A bit of knowledge as to what is going on helps you go into your next round of grain raising with open eyes. Most importantly it will result in a less eventful and higher quality finishing process. ----==---- The Problem... ....as most people unwittingly encounter it, is in response to the first application of stain, dye or finish to a freshly finish-sanded workpiece; the surface changes, becoming rough and "wooly" as fibres stand up. The common response is to sand the surface back to re-flatten it and simply continue from that point on. This is not too problematic if you are applying layers of an untinted or opaque finish to the wood, however it becomes unacceptable if you intend your first stage of finishing to be a dye, stain or tinted product whose look (or contribution to the final look) will be adversely affected by this sanding. Knocking back raised grain affects your schedule by adding in an extra initial step; this can be especially crucial when dialling in a very specific dye schedule on figured Maple for example. Pre-empting raised grain before finishing catches errant fibres in the act well before we commit any finish to the wood, ultimately returning freedom to our finishing process. Why It Happens Raised grain occurs at a greater degree with water-based products, however also occurs with alcohol or other solvent bases which may well contain a significant water fraction. What exactly is happening and why has water got anything to do with this? There are two factors to consider: Fundamentally, wood is hygroscopic; it attracts and holds water. Alterations in its moisture content induce dimensional changes as the cell walls of the wood swell and shrink. Wood is a dense fibrous material. Most of our work tends to involve disturbing these fibres whether we are milling, jointing, sawing or sanding. Every single invasive operation we carry out on wood causes fibres to be severed, damaged, displaced and loosened. Wood fibres are normally kept tightly locked and knitted together within the material. Our working operations alter this natural state, leaving exposed surfaces covered with both whole and partial fibres that are no longer within the strong supportive network. They sit quietly on the surface until the first coat of a finishing products hits them and pow! The fibres start to move around, warping as their cell walls swell from taking on moisture. Without a strong network around them, these unsupported fibres twist, unravel and deform freely into an ugly mess on the surface. Grain-raised Birch - this isn't going to win any contests The above photo shows a piece of Birch which had been finish-sanded and the grain raised using distilled water. What was once a seemingly-perfect clean smooth surface now resembles vegan hemp tightie-whities. Overview Of The Grain Raising Process We give the wood what it wants by wetting the surface with distilled water; this is readily taken onboard, causing the unsupported and damaged fibres to stand proud of the surface leaving secure fibres in place. The wood is left to dry thoroughly, and then given a few light sanding passes with the grain to remove raised fibres. Cleaning with a tack cloth or a little compressed air is advisable to remove loose material the eye might miss. The wetting process is repeated to confirm that the surface has been improved and taken through sanding again if necessary. Normally no more than 2-3 repetitions are required. The Solution can also be the cause of The Problem The process as described is no different to what you'd find in the majority of books and websites. It's simple and mostly effective. This said, knocking back raised grain through sanding can sometimes cause the problem to recur: Sanding with the grain can temporarily push displaced fibres back down into their original "home" instead of removing them Over-enthusiastic sanding damages more fibres which can subsequently raise from the surface during finishing So how can we hope to win? Firstly, we need to fly in the face of common wisdom a little to stack the odds. The golden rule of "only ever sand with the grain!" can unwittingly become a hindrance. In order to lessen the likelihood that fibres will be flattened instead of being removed, sanding marginally against the grain aids our cause; "half an hour off 12 and 6" or "up to 10° from parallel" is a safe and effective option. Counter-intuitively, removing raised grain by hand is better in achieving the fastest and finest results. Power sanders are more likely to damage additional surface fibres (which can raise with subsequent wetting) rather than working solely on the raised ones. Power sanders are designed to work the surface, which is exactly what we don't need. Lighter, less aggressive hand sanding gently catches dry raised fibres rather than further abrading the surface itself. Tips Ultra-fine Scotchbrite pads (grey) are fantastic at catching raised fibres, nibs and removing loose debris. Low angle (raking) light highlights raised fibres by them causing long shadows across the surface of the wood. The first photo was taken with light at approximately 10-20° to the surface. Using a combination of raking light and regularly examining the surface as you knock back the fibres tells you when you can stop. When they're gone, move along before you any cause more! Our example piece.... The board used in photography is a piece of Birch, finish sanded up to 320 grit by hand. The first application of water was done as though it were being flooded with a dye. The contrast created by the raking light makes this piece look especially ugly, and rightly so. A surprisingly large amount of grain raised from the surface within minutes. The piece was left to dry for several hours so that the raised fibres could release their water back into the air, harden off and become "sandable". click to enlarge Since the surface was so rough, a made a few very light passes using a 240 grit foam pad to "catch" the larger fibres before moving back up to 320 grit paper. I didn't want to stick with 240 for any longer than necessary. After finishing up with 320, the surface was brushed clean and re-wetted. After drying, I was left with this. Still not perfect, but a long mile better than the first round...especially with the raking light! click to enlarge Again, I hand-sanded the piece using 320 grit paper. Fewer than 10 strokes is all it took. The surface was re-wetted and allowed to dry, producing little to no raised grain. This surface is good to go. Again, I photographed this with raking light. A little contrast in post to highlight raised grain, or the lack of it. click to enlarge Seen at a "normal" angle, the wetted and dried surface looks as good as you could expect it to. Whilst it doesn't entirely feel as silky as the freshly finish-sanded surface, it nonetheless is perfect for subsequent finishing operations with zero concerns. click to enlarge In Closing An understanding of the mechanisms behind grain-raising, what we're attempting to minimise and how we best apply ourselves to the problem is essential in trouble-free high quality finishing. We can't change the properties of wood or completely eliminate grain raising during finishing, however we can do our level best to understand how and why it reacts the way it does and keep the issue within our control.
Hi there, First up and I'm a bit of a novice, thought I have previously done a paint job on a les paul to make a replica of Zakk Wylde's Rebel guitar (burnt, bottlecaps n'all) - which looks pretty decent! I've now acquired a Danelectro DC59 which was maroon and came with a nasty hole in the body. I repaired the hole in the body and have resprayed the guitar matt black (nice and smooth) and now I've got to the stage where I need to varnish/lacquer the guitar - which is proving a bit trickier than I'd hoped for! When I did my previous guitar, which was red/white/blue. After painting, I applied several coats of Plastikote clear acrylic (matt) spray to the body, which seemed to do the job really well. But the finish on this guitar doesn't appear as smooth and there seems to be a bit of an 'orange peel' effect on it. This guitar is a matt black finish (Halfords spray paint) which I guess is a lot less forgiving and shows up any blemishes a lot more. As well as the Plastikote, another varnish I have and have tried is a can of Dulux clear matt varnish spray. This seemed to leave more of a speckled finish. Note: between using the Plastikote and Dulux, I have sanded back and even respray the guitar so I wasn't mixing the two. From what I've read the trick to get rid of this is after applying the lacquer/varnish, sand the body with wet & dry paper and then use steel wool to smooth it out. And repeat a few times. I've done this with 400 grit wet & dry paper, then wiped down/dried the body and then went over it with some fine steel wool. The finish does feel lovely and smooth but it does have lots of small scratches on the body (image attached). I'm going to buy some 0000 steel wool from town just incase what I have is a little too heavy but I'm not sure if I'll end up with the same result? The scratches do look worse in the attached image, the spot light really emphasises them. In reality you do have to have it in your hands to see the find marks. I'm not apposed to sanding down the finish and applying another coat of matt black paint and varnishing again ...but I've already done this! And I'm a bit concerned I'll end up with the same result and it'll be a never ending circle and I'll never get it finished! I'd really appreciate some help on this if anyone can and I'll get back to you with any extra information you need. Thanks in advance, Ste