Martin D-18 Back Stripe

[albartee]

Hello All. New to the forum here. I'm in the process of a dreadnought build and am trying to replicate as close as possible the structure and looks of an early model Martin D-18. I'm having trouble finding information on what the black back stripe consists of. Is it a separate strip of black dyed maple sandwiched between the two back plates or routed and inlaid?

Allen

[JonWint]

How early?

The 1941 I looked at had no back strip. Martin didn't/doesn't rout for back strips. All back joints are butt glued.

D-18 bindings went from rosewood ---> "tortoise plastic"---> black Boltaron ---> "faux tortoise"

[albartee]

Haven't decided on how early but will be going for the vintage with either the black Bolatron or celluloid tortoise. I've never found any articles showing when they started using the back stripe. I prefer the look of the black binding and was considering using Rocklite Ebano.

I'd like to hear more about when/how on the back stripe.

Allen

[John Arnold]

Martin has always used a backstripe on style 18. Before 1970, it's either Brazilian rosewood or black dyed veneer, 0.035" thick. A rosewood one can be hard to see after the mahogany is stained, but trust me, it is there.
Martin back stripes are always sandwiched between the halves. Not only does it save work, but it effectively makes the back wider, whch occasionally comes in handy.

D-18 bindings went from rosewood ---> "tortoise plastic"---> black Boltaron ---> "faux tortoise"

Not exactly
The sequence is as follows:
Rosewood until 1932 (later on style 21)
Black fiberloid from 1932
Black celluloid around 1934
Both tortoise celluloid and black celluloid from 1938
Tortoise celluloid only from 1940 until 1966
Black Boltaron from 1966
Tortoise celluloid returns on vintage styles in the 1980's.

All tortoise celluloid is 'faux'. AFAIK, Martin has never used real tortoiseshell for bindings.

[albartee]

I can't see how adding a veneer between plates can save work versus joining directly. I also don't see the value in adding width since tops and backs are always overlapping the rim during construction. Please elaborate.

It's interesting that they used rosewood and not always black as I had seen a few closeups of prewar d-18s that looked as if the joinery was flawed and looked like an overly fat join line but was most likely the rosewood veneer you're referring to. Seems like an odd thing to do.

Allen

[John Arnold]

Martin did not do backs without backstrips until recently. Even then, it is on cheaper models (style-16, etc.), not on style-18's.
Given that there is a backstrip, there are two ways to do it. Either join the back, then rout for an inlaid strip, or sandwich it between the halves. That saves a step.
My comment about increasing the width is valid, though a 0.035" thick strip is minimal. Style 28 and 45 have much wider backstrips. I was commenting on my practice, which is to use backs that are not always wide enough unless the backstrip is sandwiched. While that may not be the case in a modern Martin factory (where no risks are taken in the interest of saving time and labor), it wouldn't surprise me at all if Martin in the 1930's used this fact to use back wood that would not be wide enough otherwise. There is no point in overlapping the back and top when it is routed off completely for the binding. With the 1/16" binding cut in mind, the back or top don't even need to reach the edge of the sides. And with 1/8" of top purfling (28 style) and 1/32" of back purfling, the back and top can be even narrower. On style-18, the top purfling is about 1/16", and there is no back purfling.

[albartee]

I see, less work with joining for the stripe versus inlaying, not with or without stripe. Your comment on adding width makes sense with the wider strips.

I'm wondering if the D-18 black stripe varied in width over the years. Some photos I've seen looked to be closer to 1/16".