The Bryn Production

Rather a lot of pictures of laburnum coming up - and it's not the prettiest of colours.  A long time ago they used to sell six-inch-long sticks in sweet-shops and you put them in your mouth and gnawed at them as you walked home from school and the inside was the same sort of colour as laburnum wood.  

This is about the bridge.  It's the same as the last bridge I made except that I've decided to split the saddle into three pieces this time and, when I've finalised the positions for each string on the saddle(s), I'll saw a little groove joining the two dots and pop a piece of fret wire in there and that will be the last contact the string makes with solid ground.  At least, that's the plan.  

Bridges start with a piece of wood:



Here's mine with everything that matters marked out on it;  There are dots for the holes and for then ends of the string channels and for the saddles.  In fact, I've started excavating the channels and I decided to do it with a nice slow drill in a stand so that I was not startled by the roar of the router.  (You may have guessed that I broke the router bit I normally use last week and ruined the first blank at the same time).  I drilled some 4mm (diameter) holes to a depth of about 6 mm and then cleaned them up with a chisel;  a bit like real woodwork.




I then drilled reference holes right through to the back so that I could locate the correct position of the little "housings" where the ball-ends of the strings sit when they are under tension:




Next drilled out these housings on the reverse:



They're only about 4.5mm deep.

Back to the front to drill the holes through at about 20 degrees:



and this is what you're left with:




(The odd hole in the corner is, of course, just a practice run).
Next a variety of tools to try to scoop out some neat channels for the strings to run in:




And then the base needs sanding to suit the front of the guitar:



Yes, I've just noticed it's backwards, too.  Of course that shouldn't make any difference but I'll just check it's okay tomorrow.

Finally, I cut it out approximately to shape:



I'm sure I would have got back on schedule by finishing the whole thing if it hadn't been for an appointment at the orthodontists - now there's an area the NHS could save an awful lot of money - with Bryn the boy (not the guitar).  That was followed by a visit to the vet with Jack the dog all rounded off by picking up the other boy who had had yet another puncture.  And then taking the first one to scouts.  Oh and finally mending the puncture.  Dinner....  Washing up....  That's why this is a bit late tonight....

I made the decision to veneer the headstock with a bit of burr walnut (to match the back - sort of) so got the hot hide glue on to heat up good and early - about 9 - to give it chance to go off a bit before I needed to trim the veneer and polish it.  The traditional process involves hot glue and hot wood and a veneering hammer.  Normally you have to veneer both sides of the board because the veneer gets swollen by all the heat and moisture and stretched by all the pushing around with the veneering hammer so that, when the glue cools and the veneer dries off, it shrinks back and can warp the board unless both sides are being pulled equally.  It's only a little headstock and relatively thick so I didn't bother.  Here is my hand and the hammer squeezing out the glue:



And this is the result:



Looks like a mess but is pretty easy to clean up.  Ten minutes later I noticed that the veneer was indeed exerting a bit of a pull:



See the gap opening up?  Yes, it was pulling the Douglas Fir off the headstock along one side.  This is not the first time things have come unglued on this guitar so I just get on with fixing it now.  The hot glue was ready and my feeler-gauges at the ready to slide into the gap and then I cramped it up:



While that was sorting itself out, I could start staining and polishing at the other end.  The soundboard and purfling/binding were not to be stained so I masked off the fingerboard and neck and then put a couple of fads of shellac over the soundboard to seal it off



and then took a fine sable brush and coated in all the maple lines and sapele binding - in other words, everything that wasn't walnut (back and sides) or mahogany (neck & heel):



Twice I did this though, as I discovered later, this was not quite enough to ward off the ferocious activities of the bichromate of potash (This stuff is dangerous; use conventional stains instead.).  Anyway, with rising heart-rate and a freshly mixed jar of potassium bichromate solution in one hand and a piece of skin-wadding in the other, I set about the chemical staining of the walnut and mahogany.  The effects were dramatic.  Here it is still wet, which gives a better idea of the colour it will be when polished:





Sorry they're nasty flash photos but I didn't have time for anything else because they were drying off as I watched.  As I hinted earlier, the maple lines and the Douglas Fir strip down the middle of the neck were slightly infiltrated by the stain - 3 coats next time - but altogether quite an effective 10 minutes!  The walnut has gone a walnut colour and the mahogany has gone incredibly dark but, I imagine, by the light of day and with some polish, will be a rich red Victorian mahogany colour.

Tomorrow I can begin by coating the whole thing in with shellac and then fill any remaining crevices before polishing on.  The neck will have to wait until I have loaded the frets on to the fingerboard since I don't want to damage the fresh polish on the back of the neck when banging them home.  I'll have to give the polish time to go off from time to time so this will be a good use of my free moments.

Here is the last picture I took today of a dry but stained guitar - (is it a bit flash?):

Rob,

Looking magnificent

Potassium bichromate is a new one on me - is it used a lot in furniture making and restoring? Having Googled it I was a little scared to read it being "acutely and chronically harmful to health" as it is supposed to be carcinogenic and "highly likely to induce sensitization leading to dermatitis, especially of the hand and fore-arms, which is chronic and difficult to treat." But I suppose there's a lot of things that we use in guitar making that have similar properties - we just need to know how to take care.

I love lists - the greatest invention. They were successfully introduced to increase civil aviation safety levels. I'm also reminded of the luthier's mantra "so little time, so much to stuff up"

Just thinking about it you've got me a bit worried. There's always the chance that someone might use it a little carelessly after reading my stuff! I wonder if the powers that be on this forum could add a few words to my thread so that it says, "This stuff is dangerous; use conventional stains instead" whenever Potassium Bichromate is mentioned. How do I go about that?

Rob,

Don't worry - I think you just have. As I say there's lots of other stuff like this that is used that has similar dangers and is generally available. People using them should make them selves aware of how to use them safely.

Great build thread, Rob. So detailed with lots of reasoning/explanation and great photos

Spent a fair time scraping and sanding the surface off maple lines and starting to fill irregularities with pigment in shellac and with wax of various hues to make sure everything was fairly tidy before I started polishing.  Then I put a fad - a screwed up piece of skin wadding - cotton wadding with a skin on it - - of shellac over all the bare parts of the guitar apart from the fingerboard.  This takes it to something like the finished colour:





And the headstock was, I think, the right decision:



I then set about polishing the front and one side;  you have to lay it down on the back and side as you go so you can't do the whole thing at once.





Hope you appreciate the action shots!  And my hand is in the hole because the front, you'll remember, is sticky with polish and you've got to hold it firmly somehow.  

I then turned to preparing some frets while I let the front and side harden off to some extent.  I've decided - another change of mind and miles from the careful planning of a week ago - to put the frets in once all the polishing is done and just hope I can get away without damaging the polish on the neck;  it's easy enough to repair, anyway.  (At least that's the plan at the moment).  I started by unbending a longish piece of fret wire - Evo gold - until it approximated a 16" radius;  I see you can spend rather a lot on a tool to do this but my rough-and-ready method seemed to match my target fairly closely.  Then I cut pieces to length - with a bit over:



Yes, one day I'll make one with 21 frets!  They also make a rather more useful tool for removing a bit of tang from each end of the fret;  without it, it takes quite a lot of fiddling with needle files and a junior hacksaw to arrive at the desired form:



I did three and then decided I could get back on to polishing the back and the other side;  the front and first side were still soft but I used a sheet of foam covered with greaseproof paper under it and look quite a lot of care not to damage the work I'd already done.  In fact it doesn't seem right to end without some final photos so I'll just go and get it from the workshop to take a last photo







or three!