Old French Bass full Restoration

[Allen]

How weak of a glue mix are you going for Matthew? How do you know when you get it right?

[matthew]

usual is to dilute your normal glue mix with 50% again water. Its not a science, sometimes its enough to prime both edges with glue then when dry align the two edges and run a hot wet paintbrush along the joint.

[matthew]

Here’s a summary of the ironwork I’ve removed from this patient to date:



I had a look to see if the tuners had any identifying marks, but nothing exciting to report. Some of the brass plates are worn at the bearings, but the brass cogs, spindles and the worm gears are perfectly fine. We’ll have to decide whether its worth getting the bearings rebuilt, rebushed or just get new tuners. I’m not a metalworker. Any suggestions?



Here’s another bit of fun for later Sad



I started gluing some of the newer and cleaner cracks first, and cleaning up glueing edges.



My “in situ” lamp is very useful.



Here’s a horrible mess to clear up. Nails didn’t help at all.



Here’s a closeup of one of the crack edges. The wider part is where the crack sits just below the FFs and the thinner part - about 6-7mm - is the lower bout.

I have had to break the longer cracks right open in order to properly clean the gluing surfaces, which are contaminated with varnish and dust and goo. And what looks like read lead paint in places!



This is a dry run of the first big crack clamping setup. It gets tricky near the FFs where the wood has twisted under bridge pressure. It’s going to be interesting getting this to clamp up tightly.

[Lillian]

Looks like your patient had a bit of heavy metal poisoning.

Those are cool clamps Matthew. I like the system.

[matthew]

Lillian, note also the wedges in the top of some of the paired turrets. This allows me to angle the clamping pressure wherever I want.

I am not looking forward to gluing this one up. Will be very tricky within the short HHG gel time ...

[Nick]

This post is really interesting to watch Matthew, appreciate the time you're spending putting it up for us. Are the brass bearings a separate piece or are they part of the block arrangement you are showing? I could machine new pieces for you (either bushes or the whole bearing kit & caboodle) if you are interested in the option & I'm sure we could settle on some sort of "arrangement" Wink, would just need a sketch of the assembly and any & all important Dimensions. Just a thought/option.

Good to see it had a hearty pair of nuts too!

[matthew]

that's an interesting proposition Nick. The bushes you can see in this closeup photo. You can see the worn bit on the inside edge of the "U" bolt thingy - should be just straight edge there, no shiny groove. One of the "u" thingys has a removable section, as you can see, the other appears to be brazed shut, and you insert the free end of the worm gear into it.

So I guess you could either drill out existing wear, and insert new bushings, or make completely new brass baseplates.



I'll have to chat to you about this later when i get around to this stage of the repair. I was just trying to see if there were any identifying stamps on the machines. They don't look hugely high quality - this was probably a "factory" bass of the time - but they are certainly still solid.

[Lillian]

I am not looking forward to gluing this one up. Will be very tricky within the short HHG gel time ...

Heat lamps, heating blanket and the room set at 32C?

[matthew]

Yep. And hot water to keep my fingers clean!

[liam_fnq]

hey matthew, how do those clamps you use to pull the soundboard cracks closed operate. i can't work out how the little turrets are held to the soundboard.

loving this repair thread btw

[Nick]

It's certainly cut itself a new one on the thrust face! In my opinion, if you are going to the trouble of making the rest of it 'like new' and collectable, then it would be just as easy to make a whole new base plate than it would be to bush it and have the re-bushed base plate 'show' that it's been repaired. But that's just me, it would be up to you & the client at the end of the day. Just contact me as the time gets nearer.
I'm sure also that we would have a chemical at hand here at work that could age the new plates. Unless you wanted them all shite & briny.

[matthew]

The turrets are spot glued on with hide glue. I start with tall turrets and re-use them as I go, so they get a bit shorter each time!

They are cut so that the grain runs parallel with the top which means they can easily be split off when finished and planed flat with the surface.

The clamps are made from 90mm PVC pipe split on one side. Some have a bolt across the middle for extra clamping pressure.

@Nick - Ve heff zose chemicals here too MOOOHAHAHAHAHAHA ....

[Nick]

@Nick - Ve heff zose chemicals here too MOOOHAHAHAHAHAHA ....

[matthew]

The top is glueing together quite well. This is the first long crack after the turrets are removed and before cleanup and cleating. Looks a mess, but actually the repair is good.



This is the view from the other side, there were two parallel cracks but they've come together quite neatly! The wood is beginning to show through too, after some cleaning with warm water.



Here's the second long crack gluing. You can see the soundpost crack too; I mark the path of each crack with a chinagraph marker so I know exactly where I have to cleat later. Sometimes the glue line is virtually invisible.



This is one of the previous repairs, done quite well, but I don't like square cleats so I'll probably remove them and replace with diamond ones.
The bass-bar on this bass is exactly parallel with the centre seam.



This is a view of the soundpost crack before glueing. nasty.



There seems to be some kind of orange primer used at some point; perhaps its a ground?

[Lillian]

Its coming along nicely. She is looking a bit better just from the quick bath.

I can see the wedges better in this group of photos. Nice system.

[Allen]

Are those clamps made from PVC pipe and a bolt to apply the tension?

[Lillian]

That's exactly what they are Allen. I know a builder that uses the larger diameter black pipe as clamps. He cuts them into about an inch, inch and a half rings and then cuts a section out of the ring that allows the clamp to open enough for what he's clamping but still small enough to give pressure. No bolts. I'll see if I can find the builder and/or pictures.

[matthew]

No Allen, they're actually Teflon-coated Kevlar focus-rings as used in the Hubble telescope, with reverse-thread titanium bolts.

Some people find that North Queensland calamari rings work quite well too if you tenderise them for several hours ...

[Paul B]

I've used some of those clamps when I was into kayak building. Didn't use bolts for extra tension tho, just used longer sections of pipe. I think I like the bolts better.

[Lillian]

Oops. Sorry for the misinformation Allen.

Matthew, you did realize that the Hubble has been sending home garbage of late? Doesn't that bother you just a bit?

[matthew]

Oops. Sorry for the misinformation Allen.

Matthew, you did realize that the Hubble has been sending home garbage of late? Doesn't that bother you just a bit?

Not at all. Usually its me that has to worry about the garbage.

[Lillian]

Oops. Sorry for the misinformation Allen.

Matthew, you did realize that the Hubble has been sending home garbage of late? Doesn't that bother you just a bit?

Not at all. Usually its me that has to worry about the garbage.

[rocket]

Mathew, i'm loving this, such a privilage to be able to watch a craftsman such as yourself disassemble, repair, and reassemble this old instrument, you must be getting such a thrill and a huge amount of satisfaction from this. I hope your client apreciates it as much as we do!!! Cheers Rod.

[Allen]

Some people find that North Queensland calamari rings work quite well too if you tenderise them for several hours ...

I had some of them when we went out for tea on Saturday night. Just about right for clamps.

[Stephen Kinnaird]

Matthew, I'm with Rocket: totally enjoying this thread.
Keep spewing your "garbage" our way. Mr. Green

Steve