背面粘合
用细砂纸清洁表面以除去任何油污。
用锉刀将底部边缘磨圆,然后打磨。
将肋骨与背部对齐并干夹。
逐段拆除夹具,然后粘合该部分。
Transcript from the video
So now that we have finished the back, we are going to prepare it to glue onto the ribs. So what we're going to do, we're going to clean the surface, and then we're going to round the edge.
But before we clean the surface, we actually want to mark exactly where the center joint is. And the way I do it is I'll pull a light over, and then I'll find the center joint. And with my very sharp knife, I'll just make a little cut there. And I'll do the same on the other side, just a tiny cut where it intersects the rib line. It just makes it easier later to find it when we're gluing on the back.
Right, once that is done, we will take some -- this is a file with a piece of 400 paper. Let's just move the light out the way. And now we're going to hold it flat. And we're just going to do this to clean the surface and get rid of any oil that might have accumulated. We don't want to do a lot of sanding, just a little bit. OK, so we've done that. And now we need to turn around the sandpaper and use the other side. OK, so one does that over the whole violin.
Well, now that the back is ready, we need to round this edge slightly. And the way you do it is you take a file. We're going to take the very fine steel sandpaper, and we can hold it at 45 degree angle. So if this is the surface, it's going to be at a 45 degree angle. Now we're going to file a chamfer on it. Now one would be wondering, how wide do you have the chamfer? Well, you can take a ruler, and you want that chamfer to be 1.3 millimeters.
So you're going to go there. And when you're doing it, the motion is not straight, but you're always moving it across slightly. So you're doing that. That way you get a nice flow. Otherwise, you're just going to get different flat areas.
When you come to do the corner, one has to be really careful that you do not round the corner. So the way you do it, you do that sort of sweeping motion away from the corner. So it's that motion outwards. Same. We want it to be 1.3 millimeters.
So when we come to do the chamfering on the C-bout, the middle part, you will see this is generally most files. They have two surfaces. They have a slightly flatter one, and then they have a slightly rounder one.
So for the middle part here, where it is slightly flatter, we're going to use the -- we're actually going to use the flatter surface. This is at the 45 degree angle to get our chamfer. And then when we come to this surface, which is more curved, we're actually going to turn the file around, and we're going to use slightly rounder surface here.
And all the time when we're chamfering, we are looking at the light to see that it's very even. So if you do it like this and like that, you will start to get -- it'll become very wavy, the line, the chamfer. We want it to be smooth. So where you see it narrow, you automatically go. Then you-- for example, there, it's a little bit narrower than there. Then I come and I just take a little bit off to get it to be an even chamfer all round.
OK, now that we've been around the whole violin and we've done the 45 degree at 1.3 millimeters, the next job is to soften those edges, because we actually want to round it. So what we do, we come with the file. There's 45, and we take it now at a 30 degree angle. We very lightly come -- we very lightly come and just soften that edge. And then we go at 60 degrees and we soften the other edge lightly. And that's where you get it to a point where we can actually sandpaper it.
And then at 60 degrees, we don't want to round it. We want to keep the corners nice and sharp, so we don't want that. We want that way, keeping that edge just over here nice and sharp.
OK, so when it comes to the button, you do not want to be chamfering it. You just want to leave it the way it is, because that gets shaped once we glue the neck in.
So now that we've finished doing all the chamfering, we're going to come with some 120 grit paper. And we're going to go-- that's about 15 to 20 millimeters. So you're going to cut the sandpaper. Then we are actually going to fold the sandpaper like that, and like that, and like that, until it becomes really stiff about four or five times.
And then we're going to put a little bit of a bend in the sandpaper to get it round like that. And now we are going to come to the edge. So you take the sandpaper, you keep it really firm onto the piece, and then you do this. Now, you don't have to do it very much, because it's already got a round shape, and we're going to finish it much later towards the end of the violin.
The same thing was when you come to the corners, then you're going to take it, and you're going to bend it the opposite way, because now you're going into that kind of curve. And then you're going to hold it, and you're going to move it, but you're not going to go around the corner.
You're actually going to move it just up to the corner and stop. I'll do this in slow motion. You get there, and then you stop. If you go like this, you've got a tendency to round that off. So you're going to work it just up to the point, like that, just slightly. We're going to be turning it like this as we move it. And then we get a nice round surface.
We do all the sandpapering, and only then do I come with a flat file, a very fine, fine flat file, and then we do the rounding. We leave that till the very end. The next job is to round this. The way we do it, this is a very fine file. This is a number two file, which is really fine. And then we hold it. We make sure we can see with the light, and then we just do the rounding motion, not rocking it either way, but keeping it really flat and firm. And then we can see by the chamfer, and we're just doing that motion, till we get a similar chamfer width to the rest of the file.
So instead of taking a number two file, we can take a regular file, or even a piece of wood, for that matter. And we can take some 400 paper, and we can wrap it really tightly, so it becomes like a file. This is really flat. Flatten. And then we can go, and we can use that instead of the file.
I'm going to say, now that we've done that, we are going to size the, we are going to size the, the back, and we're going to size the block. Sizing means taking a thin layer of glue along the edge, and we're going to put some glue along here as well.
We're going to do it several times on the, on the blocks, because they are end grain, and, and, and end grain just sucks in the glue. So we have to make sure we do it many, many times. Okay, so here's the glue. So what we do, we take the glue, and we sort of take a little bit. We kind of wipe it against the glass, and then we begin. So we'll start with the blocks, and we will do it several times.
Okay, now that we've done the blocks, then we're going to do the same. We're going to take some glue. We're going to sort of wipe it lightly. We don't want too much glue. And then we're going to come to the ribs, and we're just going to go once, so we're going to go lightly like that.
We're going to come to the ribs. We're just going to go lightly, and we're just going to brush it once with glue. We're going to do this about five or six times on the blocks. Each time less glue is absorbed in, and eventually we'll get to a place where we can just about see some glue on the surface. Yeah, so there I've done the blocks about five or six times. I've only done the ribbed surface once. And if you see that there's excess glue on the surface, you can actually take a clean finger, and you can just very lightly rub it in. And you can rub it in, rub it in.
So when you've done that, the next job is to actually take the glue pot and put it back onto the hot plate to heat it up again so we can size the back. Okay, now that we've sized the ribs, we are now going to do the back. So it's probably a good idea to switch places so we don't drop any glue on the back. Now, if we're doing the back, the same thing, we only got one very thin layer. So we're going to come around with the glue, and we are going to brush it.
So where the block goes, we need to make a bit more glue, more or less the shape of the block. And then here we're just going to do the edge, just very lightly coming around once. And the glue we're using is fairly thin, it doesn't have to be very thick. So from what I told you in mixing the glue, you can actually add a little bit more water for this particular job.
So the reason we are sizing the back is, it just makes it easier in many years or decades time should the violin need to be repaired. And the back has to come off, it'll just make it slightly easier to remove it from the ribs without the wood splintering.
There we go, both marked. And now you can see not much wood is taken off over here, all over there, allowing quite a lot of space for the neck joint. Okay, so now the next job we want to do is we want to trim away the wood over here. The wood over here so it doesn't actually land up sticking to the back. So we don't have to take a lot off, we just got to make sure that it is not taking some of it off.
The way we can do it, we can just come with the gouge, we can hold our hand and just lightly rock it. We can take off shavings like this, till we get to the line. That is fine, that's enough, at least it won't stick to the back. When we come to the top blocks, instead of using the gouge, we can actually use a chisel. Like so.
One thing that I like to do, which just helps with cleaning up and keeping the ribs nice and clean, is to put some masking tape just about not quite at the edge, but very close to the edge that saves the glue going on and it saves extra work. So what you do, we can cut a piece of masking tape. There we can go. And then we can lightly put it just almost at the end. Like so. So there's the tape and then you can actually wind it round. We're going to put a piece in the center box. Great, so there we have it nicely taped.
Okay, so now that we're ready, we're going to glue the ribs onto the back. We've sized everything, we've let that dry, we've sized the other side. So now I've got this cradle, but you could actually do this on a towel if you're like. So now that I'm busy aligning it, what I do, I line up the center joint onto the scratch line. And then what I might do, I'll just very lightly clamp it.
So here's the pencil, here's the scriber line that we made originally, that you'll be going to use that as a guide for lining up the ribs as well as the center joint. Okay, so what we need to do now, we need to move the ribs closer to the thing and then across till we line it up exactly with the center joint. Like so. To the scribe line, maybe a little bit up more. And there we are, now we can clamp it in place. And I will very lightly clamp this side. And then what I'll do, I'll actually turn it around. And then I'll check that the other side is also aligned to the centered line. So because it's lightly clamped, it can actually move.
And then I will put these two clamps on. So now we know that the centers are both just running through and it's centered and all the scratch line is in place. And then we can begin putting on the clamps all around the violin. We can start with the corners with the red ones. And then one yellow one's going in the middle. And so we go around the whole violin.
Yeah, so once we've done that, then we're going to come, how are we going to make these. We have a block of wood, this block of wood. I'm going to come closer to the camera so you can actually see it. So there's a block of wood. And then we're going to put a bit of leather on the wood. We're going to shape it slightly curved to take the outline of the violin. Now we're going to have a, it's going to be flat and a very fine lip of where we did the sinking of the edge.
So once we've done that, we're going to come and we're going to put this block underneath on the back of the violin. Okay. Like so. And then we're going to take a bit of cork. This is cork that comes from a floor tile. It's a very thick piece of cork. We're going to put a piece of cork on the top to protect the surface. Then we're going to come with a small G-clamp, the ones that we used when we were doing the ribs. And then we're going to come, and we're going to actually let it come over the edge. And then we're going to clamp it down like this.
Right. Okay, we've got the brush there. Right. So now we have our glue ready. So what we do, we're going to take off a clamp on either side here. And we're going to put the clamp down there. Then we're going to use a knife for this job.
And there's our glue. So then it comes. So we're going to dip, we're going to dip the knife in the glue. We've got everything ready. We've got our block, we've got our clamp, we have a paper towel. Now we're going to dip our knife in the glue. And then what we're going to do, we're going to lift it and we're going to slide it between the ribs and the back. We're going to slide in the glue. So you take it, you do it a couple times just to make sure you're getting enough glue in there. Then you're going to come with a paper towel and you're going to just wipe the outside excess glue. We're going to take our block, we're going to put it underneath. We have our cork ready. We're going to clamp it lightly.
We can come with our paper towel and we can wash away any excess, we can wipe away any excess glue. Then we're going to come, then we're going to put our two clamps back again. Then we're going to come with our brush. We're going to dip it in the water. We do not want to thin down the glue a lot. We're going to dip the brush in the water. We're going to take it on the paper towel so it's just hot and dry. And then we're going to come and then we're going to wipe away the excess glue.
Okay, so now that we've glued this section, what we're going to do, we're going to take off these clamps along here. Okay, so we're going to take them or we can actually put them down in front. Okay. But we are also going to take this one off. Although there's glue there, we're going to take it off because we're going to, because the glue hasn't quite set yet, we're going to run the knife in so we can make sure that we're getting enough glue there.
So here we are. We come again, take our glue with our knife and we can hold this. And then we're going to put the glue in and then we're going to come where we glued and we're going to work it up. Great. So it loosens it again. That ensures that we're getting glue everywhere. There we go there. Get some more glue. Come with the knife the other way. Make sure we get ample glue. We can come with our paper towel and we can just briefly wipe away any excess. And then we begin to clamp. The way I like to do it, I like to start with one in the middle of the area that we glued just to bring it down in place. Okay. And then we can begin doing them all. Want to be fairly quick because the glue does set.
Okay. Okay. Then now that's all clamped. Once again, we come with the brush, dip it in the hot water. We wipe it on the paper towel to get rid of all the excess. So it's just a hot dry brush. And then we come in here and then we clean away all the excess glue. This one's a little bit loose. We clean away the excess glue.
So we don't want to do the clamps really tight. We just want to have enough pressure to close them. If you go and you're really tight on it, you can have a danger of actually cracking a rib. Right. So now that we've completed this section, every time we need to take the glue and we need to put it back on the hot plate. So we do a section, we put it back on the hot plate, till the water around it boils so it gets to the right temperature and we keep coming backwards and forwards.
We've taken off the clamps and put the knife in the glue. We're going to put some glue in the coming like so. We can actually turn the knife around, put some more glue. We're going to turn it to the faces the other way. Then we're going to go and we're going to put some glue halfway like so. And we're going to come. We're going to take our paper towel. We're going to wipe away the excess glue. We're going to come and we're going to put the first one on the corner like so. And then we can put the one in the middle, the yellow one. And we're going to put the other red one on. Okay, and then we can put the blue one back from before we were previously glued.
Okay. Right. Now we can take the brush, put it in the water, make it dry. We can clean away any excess glue. Back in the water. Clean it with a bit more excess glue. Okay.
So the knife that I'm using, the knife that I'm using, this is one of those bone handled knives that you can find in an antique shop. It's a very, it's a very blunt knife, but it has a really nice thin area and it works perfectly for this job.
Okay. So we've come to the very last stage now. We've, we've gone all the way around the violin. I've taken off these clamps and we're going to do the last bit now. So once again, we take the knife, dip it in the glue. I've taken off the clamp before where it was glued. And now you're going to come and we're going to put in the glue just like that. I'm going to work it up to there. We're going to come, actually going to turn down the knife slightly, turn it around. I'm going to come and I'm going to put the glue in like so. I'm going to work it.
And over here, we've, this is already set now because we've glued it. So what I'm going to do, I'll put a little bit more glue on there. I try and go as far as I can. And then what I do, I come with the brush and I put some glue on the brush and then I run some glue down, lift it up, run some glue so it fills any gap that I couldn't quite get to. And then I work it up like this and that's fine. And you're going to come with the paper towel. You're going to wipe away the excess glue.
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