Whoa! Ignoring the things like the birth of my children, I will remember today as being one of the key milestones in my life on a par with the occasion on which I first sucked air out of an dust extractor bag using a £5 venturi and realised it was doing the same thing as a £500 vacuum pump! I don’t know why, but I have never played with burnishing or polishing cream, and the little spaying that I have done has been left ‘from the gun’. I have seen these products on lacquer suppliers shelves but I guess I always considered them to be connected with the automotive finishing industry and therefore not something applicable to woodwork. How wrong I have been!
I have been spraying my ziracote guitar over the past two days (more on the grain filling experiment/debacle later) and had built up 5 coats of Morrells 30% sheen pre cat lacquer which gave a pretty good thickness of finish. I changed the bridge mask after three coats as there was too much of a ridge building up around it and I wanted to flatten it back before the final couple of coats. I was knocking it back after each coat with P500/P600 abrasive just to give a key for the next coat. For some reason I then wondered if a hand rubbed burnishing cream could achieve a finish at least comparable with a wheel buffed/polished finish. The instructions suggested finishing with a P1000 abrasive and then using a 1000RPM power finisher with the burnishing cream. I don’t have one of these as an option so I resorted to good old fashioned elbow grease. I first rubbed back the finish using the P1000 paper lubricated with water and I can’t tell you how weird it felt spraying H2O on to a wood finish. Very counter intuitive but an absolute revelation. Probably no more than 5 minutes of rubbing per face and I moved on to the burninshing using a few drops of cream on a dry cotton cloth.When this started to feel too dry I would spray on a little water to keep the movements easy. I guess I probably spent 10 minutes per side on this process and then cleaned everything down and gave a final dry buff. In total I spent about an hour on this from the point of the lacquering being completed. A M A Z I N G! I will spend a bit more time going over the whole surface aging but even now it looks beyond anything I was hoping for - almost as good as one you would buy in the shops!
Going back to the grain filler trials. Yes Mark, you have saved everyone a huge amount of time by recommending this product and I can honestly say that Aquacoat is miraculous! You look at what could be a pot of Vaseline and think ‘nah!’ but it works and absolute treat, even on dark woods. Yes it actually does dry transparent and hardly seems to shrink at all, which, for a water based product, is amazing. List every possible quality that you want in a grain filler, including those on your dream wish list, and Aquacoat delivers them all. Look no further, buy nothing else!
I did also try the proprietary grain filler recommended by Morrells and this was little short of a disaster. In fact, it very nearly cost me a guitar! The product applies ok but does feel gritty and once dry the filler in the grain dries bright white even though it is described as transparent. This apparently refers to the fact that it has no stains added an so doesn’t colour the wood it is applied to. Mmmm, not my description of ‘transparent’. Anyway, having spent two days applying and rubbing back this filler I checked with Morrells tech support fully expecting them to say that an initial coat of thinned lacquer would wet out the filler and remove the whiteness. Instead I was told that acetone could be used to remove it from the surface and it was just as well I hadn’t covered it with lacquer because the it couldn’t have been removed. Close one!
Anyway, here are a few pics of the final process and result.
Looks fantastic! I have used Aquacoat and it works a treat... Sands easy and is absolutely transparent.
But I'm curious.... what's with the brandy snifter?
Measure once, cut straight away and maybe you're lucky......
Hi Edwin,
I’m astonished that you couldn’t tell that the glass contained Armagnac rather than brandy! ? It will be a champagne glass in the photo when the guitar has strings attached! Possibly as soon as this weekend but more likely to be next week, I don’t want to rush things and bugger anything up at the last minute. This evening I inserted all the neck and fretboard dots and cut and fitted the frets. I couldn’t resist refitting the neck just to see how it looked.
? ? I suspected it wasn't lacquer thinner, but Armagnac? I wouldn't have guessed..............
You'd better take a trip to the wine cellar, because this guitar is already absolutely stunning..............
Measure once, cut straight away and maybe you're lucky......
Another important step this evening- I glued the bridge on to the ziracote guitar. I don’t have any clamps suitable for this so I decided to make up a pair of thick laminate plates that could be screwed together on either side of the soundboard with the bridge in between. I used 4 No M4 screws for this although I drilled the jig for all six string positions. There are also two outer position screws which push down rubber pads onto the outer sections of the bridge. These aren’t tightened until the main four screws have been done up nice and tight. This all worked very well and the all round access made cleaning up the glue squeeze out a doddle. I will leave this until tomorrow afternoon before removing the clamps and in the meantime I have masked and lacquered the neck so tomorrow I hope to glue this on and starting to dress the frets. Depending on how this goes and how long it takes to make the saddle and nut I should either get some strings on this instrument on Sunday or Monday. The fizz is already chilling!!
More updates tomorrow
Hey Darren - That is genius!
Thanks for sharing that one...Hope the bolts come out OK for you - A little wax on the threads, in the area around the glue, would help them release(next time)... but I'm sure you thought of that? Also a good idea to give them a wiggle after 15-20mins (one at a time)
A bit of heat will help get them out if you have trouble. Did you use white glue as I recommend? Looks suspiciously yellow to me...that will make it harder to remove the bolts...sometimes with yellow glue you have to heat and then let cool and that is when the glue finally gives in (just when you have).
FYI - it has just occurred to me that you may not know but - there is such a thing as a vacuum clamp for this job - and you have the gear to do it? I think your way is just as good though...
Fingers crossed...Can't wait to hear it!
Might open a bottle myself 🙂
Measure twice, cut once...
Hi Mark and thanks for the feedback.
Yes, I used yellow glue, but I turned all the screws back and forth after about an hour to make sure that they were reasonably free and this ended up not be much of a problem so I don't think that much glue got onto the threads anyway.
I had a look at the vac clamp idea and I could easily make up something similar as it basically just a very small soundboard press. The maths that the guy shows on his video is a bit suspect as it seems to suggest that all the pressure from the full area of the membrane is exerted on the bridge when this clearly isn't the case. With a very flexible, elastic membrane the only useful pressure is that on the area of the bridge itself as, elsewhere, all that is happening is that atmospheric pressure is pressing the membrane down onto the sound board and this doesn't add to the pressure in the area that it is needed ie the glue line beneath the bridge.
My bridges work out at around 46cm2 and, assuming his are of a similar size, the actual pressure exerted at the 19" of Hg (64% vacuum) that his vacuum pump was developing is around 29.4kg or 65lb. Still a reasonable pressure but nowhere near the headline 228lbs he mentions in the video. Using a better pump would help but even with an oil lubricated pump generating over 99.5% vacuum the maximum useful pressure is around 45.8kg or just over 100lbs.
I have no way of measuring the actual pressure exerted by the four screws on my jig but I would hazard a guess that is is significantly more than 29.4kg and probably over 45.8kg. I am a great fan of vacuum processes but I would need to run some test to convince myself that it is the best way of apply pressure to such a small but crucial area of glueline.
Yes I suspect those figures are to impress us...Truthfully - for our purposes the amount of pressure does not matter much - as long as the pieces are held firmly together and you have squeeze-out all the way round. Even pressure is nice - that is what vacuum is best for.
As you probably know you can actually add too much pressure with mechanical clamps - crush the wood and it can spring back and actually break the joint...but I shouldn't worry about it 🙂
I'm more worried that you used yellow glue instead of the recommended White PVA - I might have to subtract a hero point for that crime!
...well...I'll let you off this time ...but if I see that again...there will be consequences...you have been warned!
Measure twice, cut once...
Hey, I'd have a plan for that. A vacuum jig that I could position over the bridge to allow me to machine it off in layers until I got down to the bare sound board again. This would be far less damaging than trying to prise it off whatever glue had used.
So c an I keep my hero point please?
Ok, so I have now glued my first neck on with WHITE glue! BTW, you do all know that Titebond is just very good PVA with a yellow/brown dye added right? I’m not knocking it, it is a fantastic glue, but their description of it being an ‘aliphatic resin’ is a bit of a marketing thing as all PVA’s are aliphatic resins regardless of colour. And I have never understood why they add brown dye to their veneering adhesive. I tested this glue for Axminster and had to tell them that it stained anything lighter than walnut! Now if they ever bring out transparent versions of their range they will rule the world!
With regards to the guitar I think there is only one high fret so I will flatten this tomorrow and round and polish the ends of the frets with my Dremel and then put some strings on I think. Hopefully the next progress report with feature a tall flute glass and some bubbles
Hey, I'd have a plan for that. A vacuum jig that I could position over the bridge to allow me to machine it off in layers until I got down to the bare sound board again. This would be far less damaging than trying to prise it off whatever glue had used.
So c an I keep my hero point please?
Hmm...yes. OK.
Yeah sorry to be a PITA (as usual but there are tried and tested methods and that isn't one of them 🙂
I realise you are already well 'off script' but I don't like to see folks make lives difficult for themselves (or others... - I'd hate to be the one lumbered with the job of replacing that bridge - easy peasy with a white glue)
Taking a router to it at that stage would be a bit sledgehammer to crack a nut and it going wrong could be very exciting!
Measure twice, cut once...
Ok, so I have now glued my first neck on with WHITE glue!
GREAT! You will thank yourself if you ever have to remove it...we are building in future repairability...(it happens)
BTW, you do all know that Titebond is just very good PVA with a yellow/brown dye added right? I’m not knocking it, it is a fantastic glue, but their description of it being an ‘aliphatic resin’ is a bit of a marketing thing as all PVA’s are aliphatic resins regardless of colour.
? I did not know that! - but I do know from experience that Titebond (yellow) is A LOT more difficult to disassemble should the need arise. Not impossible...but as I said before it usually gives up eventually.
For any beginners reading this I feel I have to point out that white glue (any brand ordinary PVA wood glue) is best for any parts that may need to be removed i.e. neck and bridge.
Otherwise I would not be doing my job... ? again sorry to be a PITA ....lecture over - hero points retained - world saved ! ?
Measure twice, cut once...
You wouldn’t believe how many different physical properties can be engineered into a PVA adhesive these days. You really can’t assume that all white PVAs are identical. Different degrees of waterproofness, hardness of cure, temperature resistance, cure time, grab time - all are variable. The problem for us specialist woodworkers is that most branded PVAs aren’t necessarily the same product from one month to the next and so it is impossible to know exactly what you are getting. This is the key advantage of Titebond products is it the same every time, which is great, but sometimes the properties may not be ideal for our purposes. I can’t imagine using Titebond for laminating tight S curves as in this situation the adhesive has to act as a lubricant before it acts as a bonding agent. I guess if we really want to build instruments that can be readily taken apart the we should stick to (see what I did there? lol) animal or fish glues. If you have never experienced isinglass being dissolved in hot gin you haven’t lived!
Anyway, sod the boring posts about glue - it lives!! In fact, more than that, it sings - beautifully! Bubbly has been consumed and guitar well picked and strummed. It has great bass resonance and lovely crisp treble response and I am very happy with the sound.
All the questions about intonation compensation paid off as at the 12th fret I am no more than 1.0Hz out between the fretted note and the harmonic which is better than on my APX700.
Mark, I might eventually have done it without your course but, then again, I would probably have died first! Thank you for all of your help and encouragement and don’t think for one minute that, just because I have finished an instrument, I am going to stop bugging you! I have never before seen through a New Years resolution within 10 weeks before so thank you again for making it all seem so possible.
Regards
Darrem
Congrats with your newest offspring! Really great and that bridge is really something else.....
Appropriate glass of bubbly, you deserved it!!
Measure once, cut straight away and maybe you're lucky......