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16" Archtop Guitar Restoration: 1938 Cromwell G4 By Gibson Relic


Manton Customs
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Hope it's ok to post this here, it's not a bass but thought some here may find it interesting and if it were a bass the process would be the same.

This is a 1938 Cromwell Archtop G4 I bought to restore. If you are unfamiliar with the name it's a brand which was made in the Gibson factory during the great depression for department stores. This one is in a pretty rough state...let's call it reliced! But we can make it solid and playable again. It's 24.75 scale, has Mahogany back and sides with a Spruce archtop. I believe I have accurately dated this guitar to 38 from the headstock shape amongst other details.

The goal of the restoration will to be to make it solid, playable, though still showing it's age and not to make it look brand new....A natural wartime relic from the 30s, if that's not cool I don't know what is! It still has it's original tailpiece and tuners though there are obviously some key parts missing which will be replaced/made. So, here's a quick rundown of what's wrong, what needs doing and what will remain the same.

1) Most obviously...there's no fretboard! It did come with one when I bought it but it was not original (I suspect 70s), heavily worn and no longer attached to the neck. So I'll be making a vintage correct one for it. The original fretboard would have looked quite stylish with a binding strip down the middle of the board and oversized dots, both of these will be recreated.
2) No bridge, so I'll be making one of those from Rosewood also. Though as mentioned above I do have the tailpiece.
3) Side has been heavily damaged, most of it is present, though some pieces aren't, these will require replacing with matching Mahogany
4) A crack in the top which will be re glued and 'cleated'
5) F hole damage, this will remain to avoid losing that lovely original finish, the bass side isn't too bad and I'm going to have a scratchplate covering the other. A scratchplate came with the guitar, though I need to do more research on whether it's original or not, I suspect it's not in which case I'll get one in.
6) A poor attempt at an inlay on the headstock, I'll address this.
7) Some kerfing round the damaged area is missing, so I'll be replacing that also.

That's about it, then it'll probably be time to find it a new owner (unless I decide to keep it!). It's going to be a slow project as I'm working on it in my spare time with clients builds taking priority. Though having said that a little work has already been done which I'll be updating this thread with shortly.

So here it is! Notice there is no truss rod, there never would have been though I'm guessing the slot is there from the factory where they would have made other models from the same blanks.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/61010fa5-67d6-4666-acb9-54b713ef3dbd.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/61010fa5-67d6-4666-acb9-54b713ef3dbd.jpg[/IMG][/URL]

The back is actually in great state, there is a hell of a lot of checking in the finish but I like that.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration2-1.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration2-1.jpg[/IMG][/URL]

The Gibson label.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration3.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration3.jpg[/IMG][/URL]

Here's the headstock shape and the inlay which shouldn't be there. Whoever did it didn't do a very good job and the piece can be removed easily.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration4.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration4.jpg[/IMG][/URL]

SMASH! It must have taken a big hit a some point.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration6.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration6.jpg[/IMG][/URL]

The crack in the top which was obviously held together with selotape for a long time.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration7.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration7.jpg[/IMG][/URL]

Another shot of the damage...It actually proved handy providing access to get access to the top crack.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration8-1.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration8-1.jpg[/IMG][/URL]

That's the guitar, next post will be the start of repairs. Thanks for looking :)

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I'll be following this thread. I have a Kalamazoo KG21 which were a sister brand to these, though with a smaller body size. I think mine is from 1936, going by the factory order number stamped inside. It's interesting that yours has a truss rod rout - I'm fairly sure that mine has no rod but the neck is a large V profile and has stayed straight even with 13-56 strings. They're nice guitars these, and much more attainable for most of us than Gibson branded acoustics from the same factory.

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Ok onto the repairs and for these we are going to need some glue! This type of glue has a multitude of different names: Scotch Glue, Pearl Glue, Animal Glue and most commonly Hide Glue. Whatever you want to call it, it's the best type of glue for these type of repair, it's extremely strong, vintage correct and easy to clean up and un do if necessary. For the interest of anyone attempting a similar type of repair I have included a basic tutorial on using it.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration14.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration14.jpg[/IMG][/URL]

First we soak the glue. The recipe is around 1 part glue to 1.9 parts water. This can vary depending on which brand of glue you have, though it isn't too critical and different strengths/viscosities are useful for different types of jobs. A bit of trial and error goes a long way.
The glue is put in an air tight jar and soaked for a couple of hours.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration17glue2.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration17glue2.jpg[/IMG][/URL]

Here is what the soaked glue will look like. Notice is has absorbed all the water.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration18glue3.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration18glue3.jpg[/IMG][/URL]

Then the glue is heated in a double boiler. This is a very simple setup of a large pan, a gas hob and the jar containing the glue. Boil the water surrounding the jar until the glue has fully dissolved, but do not boil the glue as this can reduce strength.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration20glue4.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration20glue4.jpg[/IMG][/URL]

Here I have tried to get a shot of the correct thickness, it should be a continual stream from the brush to glue. Not so thick it drops in big blobs or so thin it just runs straight off.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration21glue5.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration21glue5.jpg[/IMG][/URL]

Onto putting the glue to use. Here's the crack back together, it joined nice and level. The line/roughness you are seeing is lacquer damage from where it cracked in the first place and also where the two plates have been rubbing together for what must have been a long time causing it to lift around the edges. This lacquer will be addressed later on.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/e05131a3-6904-494e-a73c-9ae7fdf8ac3c.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/e05131a3-6904-494e-a73c-9ae7fdf8ac3c.jpg[/IMG][/URL]

These are the small sections of kerfing which have been replaced, there's one in the center and one at the right hand edge of the shot.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration11.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration11.jpg[/IMG][/URL]

This is a cleat. These go on the underside of cracks to reinforce them and distribute weight across the crack. They are normally made of matching material to which you are repairing...so this one is Spruce.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration12.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration12.jpg[/IMG][/URL]

This is the side of the guitar, you'll notice I have reinforced the side with these vertical struts (three in total). These will act in a similar way to the cleats and strengthen the repairs so the guitar will last at least another 77 years! Also notice the previously mentioned cleats reinforcing the crack in the top (front). Ignore the messy glue all up the struts, this way peeled away after the picture was taken.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration13.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration13.jpg[/IMG][/URL]

That's it for now though the guitar is further advanced, I'm just sorting through the pictures for the next update...where the side is back together!

Thanks for reading :).

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[quote name='Manton Customs' timestamp='1423433933' post='2684798']
Then the glue is heated in a double boiler. This is a very simple setup of a large pan, a gas hob and the jar containing the glue. Boil the water surrounding the jar until the glue has fully dissolved, but do not boil the glue as this can reduce strength.

[url="http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration20glue4.jpg.html"][/url]

[/quote]

Presumably you loosen the lid of the jar before this stage? Things might get a little explosive if it's on tightly.

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Yes, the lid is open when being heated and the glue is stirred. This (like most of them!) was a hurried shot while I remembered to take pictures. You'd probably be ok to do it with the lid on as the temperature never gets that hot (or the glue would be ruined) but then you wouldn't be able to stir it!

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[color=#141414][font=verdana, geneva, lucida,]
Onto more gluing! Here the side after being glued back down. It took some patience and some unusual clamping techniques but eventually everything was lined up and back as it should be. There are two large areas where pieces will need to be inlaid but fortunately most of it is there.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration23sidetogether2.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration23sidetogether2.jpg[/IMG][/URL][/font][/color]
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A shot showing the larger of the missing sections. Ignore the glue squeeze out in the cracks, this will be removed later on.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration22sidetogether1.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration22sidetogether1.jpg[/IMG][/URL][/font][/color]
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Onto the next job; preparing the pieces to be inlaid. Here I'm planing the new section down to just under 2 mm to match the surrounding area (what's left of the side). This piece is much larger than I'm going to need but better that way than the other as this allows me to select the correct grain pattern and makes bending a bit easier. The new piece actually predates the guitar by about 30 years but who's counting! At least it's of a similar age and the same species of Mahogany.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration15.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration15.jpg[/IMG][/URL][/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
Next the new piece is bent to the correct shape, I used a very simple bending iron to get here and stop when it rests perfectly on the side of the guitar (next to the damaged area).[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration15bentside.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration15bentside.jpg[/IMG][/URL][/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
Now using tracing paper I trace the missing areas and attach the tracing to the inlay pieces using double sided tape. Then I cut it out using a jewelers saw as you would for inlay, next it's just trial and error with files and paper to get it to fit nice and tightly into the gaps.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration24tracing.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration24tracing.jpg[/IMG][/URL][/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
Here is one of the areas having had it's inlay piece glued in and then scraped flush. Please disregard the colour of the piece this will be added later. It's still rough at this stage and there will be a certain amount of "tidying" to go![/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration26Inlaypiece12.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration26Inlaypiece12.jpg[/IMG][/URL][/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
Another shot of the same piece.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestorationInlay25piece11.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestorationInlay25piece11.jpg[/IMG][/URL][/font][/color]
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And the larger section, the glue round the edges still needs scraping off and again the whole thing tidying up.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration27Inlaypiece21.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration27Inlaypiece21.jpg[/IMG][/URL][/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
Another shot of the large inlay piece. Still plenty of work to go on the side, filling tiny gaps around the older cracks, scraping, sanding, polishing and then finishing! But at least it's solid and together again!

We'll be onto the fingerboard next update and return to the side at a later date.[/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
[URL=http://s1067.photobucket.com/user/Manton-Customs/media/1938CromwellbyGibsonG4MantonCustomsRestoration28Inlaypiece22.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/1938CromwellbyGibsonG4MantonCustomsRestoration28Inlaypiece22.jpg[/IMG][/URL][/font][/color]
[color=#141414][font=verdana, geneva, lucida,]
Thanks for reading :)[/font][/color]

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Thanks!

True unfortunately due to the F hole damage, but at least one of them will be hidden under the pickguard. I'm also expecting the side repairs to be very inconspicuous when finished and colour matched. But yes, the important thing is that it'll soon be playable and it'll play better than it did when new!

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  • 1 month later...

I've had a bit of a break from this project (working on other people guitars!), but have now made some meaningful progress. This update is all about the fingerboard, so it's more standard guitar building than restoration.

This is the fingerboard I will be using, a preslotted (19 frets) rosewood board with good figure.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20Fretboard%20blank.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20Fretboard%20blank.jpg[/IMG][/URL]

The first job was to the taper the fingerboard to the neck. This was done by first making a template then using this template to rout the fingerboard.

Now the guitar earns it's stripes...Literally! The Cromwell guitars often featured a rather attractive touch, having either one or two binding stripes down the fingerboard. For a guitar of this era a single stripe was more common, so that's what I have gone with! This slot was cut in the same way I would a truss rod (though much narrower and shallower!). Please excuse the white double sided tape residue.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20stripe.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20stripe.jpg[/IMG][/URL]

Next the board was given it's radius, then the inlay installed.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20inlay.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20inlay.jpg[/IMG][/URL]

Before the binding gets fitted I ensure all fret slots are cut to the correct depth after the radiusing. This is done with a saw and depth stop.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20cutting%20slots.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20cutting%20slots.jpg[/IMG][/URL]

Binding glued and being planed to the board using a small block plane.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20planing%20binding.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20planing%20binding.jpg[/IMG][/URL]

I now move onto fretting. Tapping them in before the board was glued to the neck made the most sense to avoid hammering onto the guitar and having to support the neck. The wire is pre bent and the tang removed from each end, the section beyond the tang is not yet cut to size (so there isn't as much tang missing as it looks)

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/4aecbc39-cf57-41da-80da-18d8d6410f8b.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/4aecbc39-cf57-41da-80da-18d8d6410f8b.jpg[/IMG][/URL]

The surface of the neck needed planing as previous fingerboards (!) had left pieces behind and a lot of glue. I used the two planes here for this task removing very little material.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/2325b72a-4ab8-4f8e-8858-5282f3e42fb8.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/2325b72a-4ab8-4f8e-8858-5282f3e42fb8.jpg[/IMG][/URL]

You'll notice here there is a fret missing...well actually there are two missing, one towards the heel and the first one (pictured here). These two will be installed after the fingerboard has been glued to the neck so I can utilise the slots for alingment pins, this ensures the neck does not slip during glue up.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/b612e021-f4d6-4b62-8a89-0fa5a3df14a4.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/b612e021-f4d6-4b62-8a89-0fa5a3df14a4.jpg[/IMG][/URL]

Here you can see the frets have been beveled and the side dots fitted. These jobs were actually completed before the board was glued but I didn't get a picture till after. So here the board has now been glued up.

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20side%20dots.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20side%20dots.jpg[/IMG][/URL]

A shot of the fingerboard post glue up!

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20Fretboard%20on%203.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20Fretboard%20on%203.jpg[/IMG][/URL]

A shot of the full guitar

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/c7881cf3-5be1-4ff0-b41e-cfd9d3b7af30.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/c7881cf3-5be1-4ff0-b41e-cfd9d3b7af30.jpg[/IMG][/URL]

The Cromwell in it's natural habitat!

[URL=http://s1067.photobucket.com/user/Manton-Customs/media/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20Fretboard%20on.jpg.html][IMG]http://i1067.photobucket.com/albums/u425/Manton-Customs/Gibson%20Cromwell%20G4%20Manton%20Customs%20Restoration%20Fretboard%20on.jpg[/IMG][/URL]

That's all for now, thanks for checking this restoration out :) More soon!

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