The Bryn Production

Perhaps someone out there with a classics background could tell me whether "Rob ille fecit" means something.  "R the F" might guide you to what I'm looking for.

Apart from investigating Latin, I don't seem to have got a lot done today though I did prepare various foodstuffs for my son's cooking lesson before school this morning, and I went for a run at 11.30 and I was called out to rescue the other son with a bike puncture on his way home from school at about 4.30 this afternoon.  Perhaps that explains it.

What I did do was to fine-sand (down to 240 grit) the inside of the back plate in preparation for polishing in the near future...  but not before I had lined up the notches in the linings to take the ends of the various braces.  Of course, you'll be observing, I ought to have done this before attaching the soundboard to the sides since I would have been able to access everything rather more easily.  Still, I managed to line everything up and make some marks on the side which ought to be accurate enough:






Someone recently was asking about "raising grain";  i.e.  wetting wood to raise the grain which can then be lightly sanded before treating the wood with anything water-based.  In the photo above there is a lovely example of a piece of walnut that's been wetted (during the bending process) and not yet sanded;  "rough as a bear's bottom" to paraphrase what they used to say in workshop where I used to work.

I then set about preparing slivers of Douglas Fir to reinforced the join down the middle of the back plate.  This was very fiddly and time-consuming but I managed to end the day (after mending the puncture) by gluing these and the remaining brace on to the back plate:



The bottle on the right, by the way, is not cold hide glue as it says on the label;  it contains some of my fish glue, which is what I used to glue this little lot and which ought to be ready to face some activity by the morning. The side-to-side brace on the left is supposed to butt up against the end of the heel-block by the way;  it'll be interesting to see how close it is to actually doing that when I finally put everything together.  Before that I will have to carve the braces, trim their ends to fit into the linings and polish the inside of the back and sides.  I wonder how much of that I'll get done tomorrow.

Plain sailing but, unfortunately, I didn't see the large fish lurking beneath the waves...

To begin at the beginning.  I made a fairly neat job of rectifying last night's problem.  I think I actually used a bit of ash in the end rather than oak, but it's hard to tell the difference with small pieces like this:




I then moved on to successfully getting the sides to lie flush on the top where I had let the ends of the back-braces into the linings.  



Whilst doing this, I happened to notice that the lining on the new section of rim - the cutaway - seemed to have moved slightly.  I pushed it again and, sure enough, it slowly slid out of place and I was then able to peel it off.  Strange, I thought.  Warmed up some hot hide glue and re-attached it.

I then decided to experiment with bichromate of potash on the inside of the box before polishing it.  I carefully brushed it on and the walnut went a very nice dark... well, walnut colour.  I later tried it on the braces etc. (Douglas Fir) but didn't like the effect so much - it was a bit too dark - and on the ash it went a peculiar greenish yellow.  I coated these in with shellac when they were dry to get the true colour.  Then I noticed that the ends of the newly attached side-to-side brace was lifting off at the ends.  Upon investigation I found that this, too, peeled off when a little leverage was applied and it was still sticky;  in other words the fish glue hadn't gone off (or "dried" in this case) even though it had been cramped up for well over 12 hours.  The hot hide glue was still hot so I re-attached it.  Then I noticed that the ends of the larger cross brace was lifting slightly at both ends and this was glued on two or three days ago.  A little help and it, too, came gently unstuck.  Then I noticed that the ends of the X-braces were lifting off:




By this time I was starting to recognise a pattern.  Not much left to come apart but I thought I'd better check the centre join:




Now things were getting tricky because, although it's reasonably straightforward to glue braces back on, gluing two pieces of 2mm board edge to edge is not my idea of easy.  By this stage the only bit still stuck was the cross-brace that I had earlier re-glued with hot hide glue so I thought I'd better make a fresh start and so removed it.  Here is how things stand now:




Not a pretty sight, I think you'll agree.  Since there didn't seem to be any alcohol in the house, I decided there were two courses of action open to me:  either sit and sob or write about it on Acoustic Soundboard.  I feel much better already!

So what could the explanation be?  Well, it could be a bad batch of glue.  Perhaps more likely is the weather;  it has been very damp here for the last three or four days and my workshop is not hermetically sealed or controlled in terms of humidity.  Moreover, since it has been unseasonably mild, I have not had much heating on in the workshop so I wonder if it's become too humid in there for fish glue to go off properly.  After all, let's face it, all it does is dry and, if it's too humid, all it does is not dry.  What worries me somewhat is the fact that the boards were glued together two or three weeks ago when it wasn't particularly humid.  I was wondering if I'd sloshed the bichomate on over-liberally but, as you can see, the stain hasn't even gone into the joints at all.  I did also gently apply warm/hot air to prepare for the hot hide glue when re-attaching the cross-brace, which is why the board started to curl slightly and reveal that it wasn't glued to the braces any more;  I was being pretty careful with it, though.

The upshot is that I think I'll give fish-glue a miss until the weather changes and even then I'll be a bit suspicious of it.  The next challenge is to put this jigsaw back together using hot hide glue.  Sorry not to be able to bring better news and I hope I haven't spoiled anyone's weekend.

I was actually trying to avoid anything to do with fish this evening but thanks for your fellow feeling. I actually got hold of bottle of Old Hookey from somewhere in the Cotswolds which seemed to do the trick - and a curry! Good luck with your tuners.

Thanks for taking time out for such a detailed reply; it's much appreciated. I was aware that all "proper" luthiers have humidity control but didn't really think I could justify the time and money. However, it would seem I don't have much choice. I'm sure it wasn't the chemical I used because I painted that on with a watercolour brush in a very controlled way to avoid wetting the fairly freshly glued joints. I'll have a detailed read of what you've suggested some time tomorrow and I'll let you know what I can come up with. Thanks again for stepping forward with a helping hand.

Rob,

Dehumidifiers will help but are pricey to buy and run. The first thing I'd do is get some heat in your workshop - I don't know how big a space it is but in my workshop (shed ) one or two small electric convector heaters do the trick. With these on I can usually get the humidity down to the 40-50% range for gluing jobs. The humidifier will perhaps get it lower to say 35-40% but I very rarely have to use it. The legends of the Martin workshop with the log burners at full pelt, the hide glue pots cooking and the workers in their underpants makes a lot of sense in this context

I've ordered a dehumidifier because I suspect the workshop is a bit damp from beneath and I can't use heat alone to drive that off because I reckon it might be a bit damp in there even in the summer.  It's actually a brick-built (single skin) "tandem garage" (if you know what that means) but it's only about 10 years old and, although I said it's not hermetically sealed, it's not very far off that since I put in new doors and ceiling and sealed off the up-and-over door when I first converted it to a workshop.  I also have heating:  I have a fairly large storage heater wired in and an oil-filled radiator to boost it if needed.  So I took davewhite's advice on board and whacked on the heating overnight and during the day.  It was actually too hot to work down there so I took it fairly easy today.  At one point over the weekend the humidity went up to 80%, which confirmed what I feared, but by this afternoon this is how things stood:




Of course, as soon as I put on some hot hide glue, the humidity did creep back up slightly but I'm getting a grip on things.  In fact I've decided to use hot hide glue for as much as possible from now on (as - sort of - recommended by DaveWhite) and, since I wanted to start retrieving the situation today, I thought I'd see if I could get the centre joint sorted out.  Before I did that, however, I took my opportunity to get a couple of photos of something you don't normally see;  it's the box with the back miraculously removed:







Anyway, I then fired up the heating and the glue-pot (but kept my trousers on) and tried a sort of a rubbed joint between the two walnut boards of the back;  the sash-cramps aren't really doing anything much but the G-cramps and the lump of iron are an attempt to keep everything flush.  (Note that I have also learnt my lesson so that everything is swathed in baking paper.)





It'll be interesting to see how flat the resulting joint is in the knowledge that I can easily move the joint around or even take it apart again.

Another weather report coming soon.