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Tostra

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Everything posted by Tostra

  1. Thank you, that's a great tip! I'll do that right away. Now, I've had time to relax a bit and think. I observed the hygrometers in the room where the cello has been, and it seems to be dluctuatong between 20 and 30%. I put them in the UV box for a while, and it reads 20%. It's about 22C in there and It's been running for two hours now. The seam seems to be settling a little bit, and I'm starting to think that it might not be shrinkage as much as just a bad spot in the seam. The "best" thing would probably be to wait till It's warmed up outside to start varnishing, but I honestly don't think I could wait that long. My current plan is to see if I can align this seam tonight and glue it back, then check the UV tent tomorrow when it has been running for four hours. In case it is not too warm and dry, I would resume the tanning of the cello, but on a 2 hours on/1 hour off cycle with the extra ventilation, a bowl of water and the door unzipped in one side. This feels overly gentle and should barely even heat up I think, but of course I would stay by it a full day with a freshly calibrated hygrometer to see if the humidity drops afterall. Does this sound irresponsible to you?
  2. I found my hygrometers. Apparently I have two. One says +14, one says +24 in my handwriting, which means I've tested them at some point and they're both terrible. Where I found them they read 50 and 60%, with the +14 giving the highest number and not reverse, and in the room where the cello has been for the past month they read 30 and 40%. I have no idea how I tested them, but if they're that inaccurate, I'm not even sure if the reading shows the right ballpark. I'll bring them to the UV box as soon as possible though, at least they will show the differential between the two
  3. I know I can buy one online, but from amazon or ebay it's a solid 3 weeks before arrival. That doesn't help much in saving the cello. I can probably find one online in Denmark, but that's still a few days, and I'm trying to find out the best thing to do right now to not potentially ruin this cello that I've spent the last few months making... I'll get a good hygrometer, don't worry, but for now I'm just trying to decide if it's best to leave it in UV or not, to glue it or not and then how to humidify the UV tent with some passive system. I'm sorry if I sound a little on edge. I know writing is not the best thing to do when you're stressed out, but I really don't know what to do. I have spent so much of my time making this and was just excited to start varnishing one of these days (I'm not giving it a heavy tan, just a few days), and now it seems that the top is shrinking on me... It may not even be that bad, but I would obviously like to do whatever gives it the best chance of springing back in place and staying there
  4. Yeah I suppose I do. It's not like I'm trying to screw it up, you know, I've just never had any issues with humidity before on any of my instruments, new or old, so it's not a thing I even considered when shopping for this setup. I have a hygrometer somewhere, but not a very precise one. I hope I can find it, because everyting is still closed down here in Denmark, so buying one isn't that easy. The box wasn't actually that hot, about 25C or so. But that's still significant. To be fair though, the wood is "used to" this level of humidity over the last few months with -15 at night, so it's not as drastic of a change as if I'd brought it from 70% for instance. I guess that's why I only have an open seam and not an open top...
  5. Actually, if it's cold outside and warm inside, the humidity would be low inside, right... Yeah, I didn't think that through. I'll definitely figure that out before putting it back in the tent
  6. Yeah, a wick of some sort would be a decent increase in surface area. I live in Denmark, we just broke back above the freezing point a few days ago, it's 3C outside right now with a good amount of melting snow and slush around. Probably not ideal varnishing weather I guess
  7. Actually, I have one if those small ultrasound cold mist things. The mist would all stay by the bottom, but would it be better than just a bowl with a rag? It would have to be on for as long as the lights, however, and it splashes water up in the air, so I'm not too happy about the idea while varnishing
  8. Davide, that is good to know... I think I have one somewhere, I'll look for it. When you say rewetting, should I dampen the top? It might be a little much a little fast, especially since I can only wet the outside..? I'm just trying to save the cello right now. I don't think It's very dry, however. Doesn't feel like it, and the weather forecast says It's 95% outside. However, the top is not as seasoned as the rest, so I am a little worried about what you're saying...
  9. Haven't had a chance to read it through yet, but I will have a look. I don't have the possibility to gave any active control though, so it has to be some passive solution like a tub of water. Edward, would you not be worried about it warping if you don't glue it back in place? Would you not even take it out and let it rehumidify? I could put it back immediately, but I would like to see if it corrects itself by tonight. A tub and a rag I can do though. Can it be too humid or should I just give as much surface area to the water as possible?
  10. Right... So you're thinking humidity as well? I changed my mind and brought the cello with me back home. I'll let it return to normal humidity and see if the seam closes back up on its own. And then I'll check how much water has evaporated from the glass tomorrow. Should I worry about too high humidity if I have a large volume of water, or should I just get a big pool in there? I don't know if I have a hygrometer, but I think you're right.
  11. Hello everyone I just put a white instrument in a UV box for the first time, and I have a few opening seams on it. Luckily It's only the rib/top seam, not a joint. I've had some areas of that seam open up already with the varying temperaturen we've had because of the winter wearher, so I'm not too surprised to see it. The instrument is a cello, the box is a 180*80*80cm growth tent with three 36W armatures inside on an on/off cycle of 4/1/4/1/6/8 hours, so that It's off at night and has 1hour cooling breaks. It's been in there for about 24 hours now. What worries me is that one of the failing joints was across the lower block, and the rib overhang on the block is 1-2mm smaller than it was. The joint is wide open, so my thought is that it could be the the top shrinking in low humidity, pulling the rib out? For now I have put it back in the UV, but unzipped all vents I can find and leaving the top a little open. I also put a bit of water in there. Now, I have three questions for the hivemind: Do you think shrinkink is the cause, and should I be worried about it? Should I take it out of UV and glue it, or is it fine to leave the seams open till It's been there for a few days? And lastly, does a glass of water and open slits in the tent sound like a sufficient change to keep it from happening again? Thanks in advance!
  12. Looks like each of those 200 violins has received a lot of love and attention, really gonna be some lovely instruments with their own peronality ;-) Seriously though, I don't see why that wouldn't work, in theory, if the bar really fits perfectly and nothing moves. But I don't think it would go well in reality...
  13. Sure looks helpful! Keeping the plate from moving without a frame is difficult, so I have often considered making a sturdy plate for keeping it flat. That design doesn't look bad, is it stable enough?
  14. It's not a saying here in Denmark, but I get what you mean. I honestly thought two was enough, and it was plenty for fitting the bar, but I didn't think for a second that the bar could curve sideways. But I guess that was just one last lesson of 2020 for me. It makes perfect sense to have it supported at the bridge position now I think about it. I do think three will be plenty, even though I've seen five many times. The outer ones don't really do much for me except making my life a bit more difficult when applying chalk. I also think less tension is going to be very helpful, as I noticed the hard clamping and 2mm spring made it want to open up in some areas between the clamps. I only have seven clamps which are 1) deep enough to reach the bar, some through the Fs or clamping on an extension and 2) not too heavy. Is there a trick to better distribute the force, like having a spring steel strip on the outside of the top or something? I don't know where I would find a spring steel strip, but I imagine it could help? I'll plane out the bar today so I'm not tempted to keep it. I'm determined to make a great cello out of this, and I regret considering this as the final bass bar. I guess I was just frustrated from all that work going to waste... But I ordered a bar from Dictum along with a madder lake to have a little fun arrive in the package as well. Looking forward to improving it!
  15. Oh... Well I may be mistaken, but I have heard a few places that a wider sound post/bass bar position, ie smaller overstand of the bridge feet, gives a more powerful sound which in turn requires more energy to play. I have seen a similar trend so far in building and repairing, but I'm afraid I don't have much more than a trust in the people who told me so and a gut feeling to back it up. I suppose I could use a narrower bridge to get the same overstand if I kept the bar, but then again I can't believe it's the overstand that should define such a thing rather than the relation between the body width and the bridge width for instance. So basically, this is what I choose to follow for now, although it might be a flawed model
  16. I remember now on my first cello, I think I did almost no spring amd found that much easier. Maybe that's my issue than, having to clamp too hard with too few clamps. Yes I am chalk fitting. Is there any other way to reliably fit the bar? I'll check it out and see if there's any new klittle tricks for me I'm not using those, but I have considered making some, and then I'll make sure not to glue it in too tall I also think that I'm probably worrying too much. I'm sure this will work but I'm worried it might not work as well as I'd hoped. The cello is for myself, and so far I've made sure that it's the best thing I have ever made. Already before I posted this I had the thought of "I can just keep it, and then some day I or someone else will make a better bar", but would I really enjoy playing it like that? I think for my peace of mind I'm better off making it nice from the start and not starting to lower my standards this close to the finish line Mark, I'm very curious to hear how you did it? Hot opening knife? I'm most likely not going to need it ever, but who knows what repairs I need to do one day...
  17. Well, I guess I could just order one from Dictum, actually, didn't realize they had bass bar blanks before I checked a second ago. I guess this is really the build that teaches me patience and repetition... I find myself redoing things that don't meet my expectations rather than just accepting them. Of course that should go for the bass bar as well. Damn it, time to do things properly then. So basically the only thing I need to do differently is add a third cleat in the middle? I should get more clamps too, but I simply can't afford it at the moment. Don, you say light pressure. I suppose you're not springing them? I think having a slight spring of 1-2mm is best for my setup, but I could probably still clamp a lot less than what I did here, at least in the middle
  18. Exactly, that bar is bugging me. The first try went wrong because the glue gelled. The second was much better and it didn't gel up at all. However, the clamping pressure was all fairly vertical, so yes, it might very well have slid down. Since I don't have a new blank and can't get one easily, corona and so on... Is it possible to take it out and redo it? I took apart a top joint once, and that was a destructive process. Wouldn't want to do anything like that on a finished top, but if I could get it out somewhat easily, there would be no issue just gluing it again with a third cleat. The bar isn't very tall in the center, you're completely right. I got it from a luthier who had cut it down to 25mm. I wanted it 24mm in the center, but it ended up 23 I believe. A bit to the short side, but I thought it was fine as long as I kept it a little less tapered in the center. As you can hear, I have a lot of issues with this bar and is definitely going towards redoing it to some extent. I don't like doing bass bars though, so if I could have used this one which had a good fit (finally), I would have been happy. Sounds like it's not a great idea though?
  19. Yes, next time I will certainly add a center cleat if that is my issue, be it on this cello or the next one. I have been checking for straightness of course, and it has been parallel with the ribs/perpendicular to the top gluing surface all along. Still, it sounds like this is not something completely unheard of to you? Maybe you know whether or not it's usable with a bend like this? It's not huge, but definitely a 2,5mm difference from my plan is significant...
  20. Here are some very quick mobile pics. I promise it looked a whole lot better before gluing or I would never have used it. But should I plane off this bar and start over, or is it not as bad as I make it? I do want a very powerful tone, so having the bar further in concerns me. The little locating blocks were higher while fitting,, I just shaved them down when I removed the clamps.
  21. Thank you Brad. This is, however, pretty close to what I did. I have a block temporarily glued about 1/3 towards each end on the inner side which I hold the bar on to have a stable reference when fitting. I could have had one in the center, but I never thought the bar could bend like that
  22. Hi everyone, I need the advice of someone more experienced. The last couple of days I have been fitting the bass bar of my cello. It was a good fit, so today I glued it. I had some issues from gluing it out of alignment, so I had to remove it, rinse off the glue with water and try again. Second try was still a bit annoying to clamp, but seemed to have a good fit. After 9 hours of drying I took off the clamps and discovered a very weird issue... The bar is bent along the length sideways? It still looks to have a good fit, but I don't know what could have caused this. Too strong pressure in the center pushing the middle inwards? The water warping the bar sideways? What really bothers me is the fact that I now only have 41,5mm from the center to the outside of the bridge, while I planned 44mm. I suppose this will give a less powerful tone than I had planned for, or is the strength still distributed along a straight line in the center of the curve and therefore effectively further out towards my goal of 44mm? Obviously I did something wrong and this is a less than optimal bass bar. It's my fourth bar, have done two violins and a cello previously with no issues. How can I prevent this another time? And is the bar just scrap and I have to redo it, or can I use it? I don't have the opportunity to get another bass bar blank and is therefore tempted to leave it, since the joint is otherwise good and there is no visible warping to the top, but the cello is otherwise a very promising piece of work, so I don't want to ruin its chances of becoming a nice instrument by keeping a terrible bass bar Thanks in advice!
  23. Haha, that's true... But to be honest, the gouging of a cello plate is plenty exercise for me, I don't need the clamps to contribute as well
  24. I mean... I'd imagine a lighter clamp is better than a heavy one? Not so much because of me handling them but if a weight hangs off the side of the joint, that would pull the joint sideways to some extent? But maybe that just comes from my somewhat unsucceessful attempts to juggle very vintage and very heavy steel clamps.
  25. Yeah, that's one of the many types of clamps I'd like to get and the one I felt like I was missing for this. They're called sash clamps, right? Wonder what they are in Danish so I can find some...
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