Douglas fir for OM style guitar top?

[tomigv]

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"Originally Posted on: Thu Aug 05, 2010 7:16 am

has anyone in guitarmaking land used doug fir for a top ? have a very dry 15 yr old top thicknessed to 2mm , that I/d like to use in an OM style guitar with e. indian rosewood back and sides. Even at 2mm the top feels heavy. Will have to brace it lightly, Your thoughts and opinions if you have used this wood would be appreciated.

[kiwigeo]

Douglas fir seems to be stocked by quite a few tonewood suppliers. I imagine it wouldnt be as stiff as spruce so you'd probably have to go a bit thicker than with a spruce top. Bracing would need to be adjusted to suit stiffness of final thicknessed top.

[Lillian]

I've never thought of using it for a top. We mix it with hardwoods for heating.

I do know that it's appreciably heavier than spruce and can be very resinous. It tends to toss splinters easily as well.

[peter.coombe]

Don't know about guitars, but I have used it in my mandolins. It is heavier and stiffer than Spruce, so you can thin it a bit more than Spruce. Soundwise it has a sweet tone with lots of fundamental, less overtones than Spruce, and the instrument I made was very responsive and loud. So if you want an instrument with a strong fundamental go for it.

I have found it makes great bracewood. After I ran out of Red Spruce bracewood I tried some Douglas Fir and have never used anything else since.

[kiwigeo]

kiwigeo wrote:
Douglas fir seems to be stocked by quite a few tonewood suppliers. I imagine it wouldnt be as stiff as spruce so you'd probably have to go a bit thinner than with a spruce top. Bracing would need to be adjusted to suit stiffness of final thicknessed top.

[jeffhigh]

The wood property tables I have indicate that douglas fir from coastal areas is about 20% stiffer and 20% denser than spruce.
So taking into account the "Cube Rule " you can go a little thinner than you would with spruce maybe 10% but that 2mm thickness is IMHO just too thin for an OM.
Trying to save weight by bracing lightly would just compound any structural problems from the thin top
Using it for ukulele or mandolin tops would certainly be viable

[Nick]

jeffhigh wrote:
Using it for ukulele or mandolin tops would certainly be viable

Or a Selmer Maccaferri They come in at around 2mm thick.

[John Steele]

As a side note.
I used to make a living remodeling old houses in Calif. Most were stick framed with DF. 50-75 years ago good older growth was a plentiful & common building material.
The stuff can dry and season and be incredibly hard and stong. Tough stuff for a softwood. It was a bastid to demo out. And cutting with a saw,
blade eater even without hitting nails.
I built one guitar with a DF top. I think I left the top too thick or over braced it. It seemed way too stiff.
J

[tomigv]

thanks for all the input. I left the top at 2 mm cause it felt hard and heavy compared to the usual red cedar or spruce tops. Will do a standard bracing for top using 10% thinner d, fir bracewood.,Sorry never built a macafferi, but do own one with a cedar top and brazilian rosewood back and sides circa 1972. I/ve also used d. fir on baritone uke looks good, slightly heavy though.

[Nick]

tomigv wrote:
Sorry never built a macafferi, but do own one with a cedar top and brazilian rosewood back and sides circa 1972.

I suggested that tongue-in-cheek but couldn't find the appropriate smiley A '72, that would be the Ibanez produced model?

[kiwigeo]

kiwigeo wrote:
Douglas fir seems to be stocked by quite a few tonewood suppliers. I imagine it wouldnt be as stiff as spruce so you'd probably have to go a bit thicker than with a spruce top. Bracing would need to be adjusted to suit stiffness of final thicknessed top.

Well there you go..I got it totally wrong. Dont have my wood tables with me though.

[DarwinStrings]

John Steele wrote:
As a side note.
I used to make a living remodeling old houses in Calif. Most were stick framed with DF. 50-75 years ago good older growth was a plentiful & common building material.

It used to be used for stud framing here a bit too John (Aussie carpenters call it "Oregon") and a lot of painters planks were made of it pre aluminium planks, I guess cause it was light and stiff.

One thing for sure is that guitar will smell great.

Jim

Life is good when you are amongst the wood

[Taffy Evans]

Oregon, now I know what you's all talking about.

[Bob Connor]

If it was Oregon I used to have an old house in Tassie that was full of it (bit like meself at times)

[tomigv]

Surprised the 1972 oval soundhole macafferi with red cedar top was built by veteran Vancouver bc luthier michael dunn , who is still building.

[Localele]

Also known over this way as O'Regon or "Irish Pine". I have some very close grain count stuff in the shed and thought it would make uke tops just haven't got around to it yet. Looks like one going in the next batch.

[Nick]

tomigv wrote:
Surprised the 1972 oval soundhole macafferi with red cedar top was built by veteran Vancouver bc luthier michael dunn , who is still building.

Niiiiice. Excellent Builder! That'll be a keeper Tom.

[woodrat]

peter.coombe wrote:


I have found it makes great bracewood. After I ran out of Red Spruce bracewood I tried some Douglas Fir and have never used anything else since.

I agree with Peter on this. I dont use it for tops but I cant see any reason that it wouldn't be very suitable. I have a billet of old growth DF that has tight straight grain lines and is very stiff that I get all of my bracewood out of. Its very good for that.

[Stephen Kinnaird]

+2 for brace stock. Wonderful material.
When we read--years back--that Maurice Dupont used it exclusively for braces, that seemed like a good endoresment.
I think the French call it something like "Oregon Pine".

Steve

[Kim]

Yep DF is known as Oregon Pine here in AU as well. Shiploads of the stuff bought into Australia before Glulam tech came into play. Nearly every old warehouse/factory or any other building in AU that required a large span, weight bearing structural beam that was built pre-war and up until around 1958 when Ralph Symonds introduced box ply beams will have Oregon pine right through the roof.

Symonds' factory built 1958

figure13.gif (96.78 KiB) Viewed 24981 times

Douglas Fir/Oregan Pine is relatively light, incredibly strong and was available in cross sections and lengths that no native tree with a similar strength to weight ratio could produce. I had seen some 'huge' beams of clear and better doug fir craned from the roof tops of the many buildings I worked on that were demolished in Fremantle just prior to 1987 to make way for redevelopment of that great little city in readiness to host the Americas Cup yacht race.

For a long time large span buildings with wood/oregon bearers were cheaper to insure against fire than similar buildings with steel bearers. Sounds bizarre but its true. The reason was/is that these large beams take a long time to burn through and could easily be replaced if the fire was bought under control. By contrast, steel beams quickly expand with the effects of heat and then sag under their own weight. Often as they cool, because their span is effectively shorter because of the sag, they will pull their supportive walls inward as they contract which will collapse the whole building. So don't brace your guitar with steel and set it on fire of you will be real sorry.

Cheers

[Stephen Kinnaird]

Kim wrote:
So don't brace your guitar with steel and set it on fire or you will be real sorry.

Cheers

Kim

A word to the wise for sure. Kim, you really helped curb a temptation of mine... How did you know?

Steve

[Dennis Leahy]

I played a couple of guitars made with Douglas Fir soundboards, just a couple of weeks ago. It's a fine tone wood.

Dennis

[jayluthier]

I've used old growth Douglas Fir thinned to about .100" for tops on parlor guitars. One with Bubinga back & sides, the other with Osage Orange back and sides. Both were killer guitars. Great projection for such a small guitar. I've found that Doug Fir is heavier,,but quite a bit stiffer (non-scientific term) so it can be thinned much further. I would not hesitate using it. Just watch out for runout. Other than that..go for it.
Jay

[jeffhigh]

The .100" you used for parlour guitars is equivalent to 2.54mm, Jay
The original poster already has his thicknessed to 2mm (.078") and is wanting to use it for an OM.
Using douglas fir is not the problem, but starting with that thickness is.

[kiwigeo]

jeffhigh wrote:


The original poster already has his thicknessed to 2mm (.078") and is wanting to use it for an OM.

May not be good for an OM but would be spot on for a Lute