Seeking advice on building a double top in the UK

Construction and repair of Classical Guitar and related instruments
User avatar
Stephen Anderson
Posts: 14
Joined: Mon Jan 09, 2017 8:43 am
Location: Bangor, Northern Ireland

Seeking advice on building a double top in the UK

Post by Stephen Anderson » Fri Feb 24, 2017 9:21 am

I'm wanting to build a double top (cedar/nomex/cedar) and I'm unsure exactly what to buy and where to source the nomex and the glue in the UK. I'm also unsure about the best thicknesses to work towards. From the reading I've done so far, I think that 0.6mm cedar / 2mm nomex / 0.6mm cedar should be about right. I haven't yet found this info in one place though - any thoughts?

I have found that http://www.easycomposites.co.uk/#!/core ... -honeycomb has 2 types: 3.2mm cells and 4.8mm cells.
The 3.2mm cells material is lighter and it's available in 2mm or 3mm thickness. The 4.8mm cells sheets come in a minimum thickness of 5mm. Can it be sanded down? (I've never worked with nomex before).

I'm thinking about getting the 3.2mm cells sheet at 2mm, is that too thick for the nomex sandwich? Are the cells too small?

I have been watching the O'Brien Guitars video on building a dhouble top where all the dimensions are given, but for a steel string guitar, not classical. https://www.youtube.com/watch?v=uIq-ExdmG5I

In the second part of this 2-part video, he explains that they used System Three T-88 thixotropic resin. This seems to be cheap and available in the USA but I'm having trouble finding it in the UK. Does anyone know of an alternative that has similar properties?

I know this is a lot of questions in one post. The O'Brien videos I mentioned above are full of great advice for the process - these questions are to fill the gaps I need so I can get started. I'll share my experience on the forum once I'm done so as to benefit others.

User avatar
James Lister
Luthier
Posts: 7072
Joined: Fri Nov 17, 2006 3:53 pm
Location: Sheffield, UK

Re: Seeking advice on building a double top in the UK

Post by James Lister » Fri Feb 24, 2017 9:43 am

Hi Stephen,

I think most luthiers use the 3.2mm cells and 2mm thickness - 5mm is certainly too thick. Not sure what alternative glues you can use, but I'm sure there will be something available in the UK.

At this point, however, I'm going to suggest that a double top is not the way to go if this is your first (or even second or third) build. I went to a talk by Gernot Wagner a few years ago where he went through the process is detail, and it put me off ever attempting it. I think he said he took 3 months off guitar building just to set up the specialist jigs and tools he needed to do the job properly. It can be done, of course, but I suspect that even experienced advocates of the double top build would suggest that it's not advisable unless you already have a good amount of experience building traditional guitars. In particular, cedar is difficult to handle even for a solid top guitar - and working it to 0.6mm is not for the faint-hearted, or for anyone with limited woodworking experience. I have heard experienced builders say that it took several double top builds before they were happy with the results.

Sorry to put a damper on your plans - maybe others here will have a different opinion (they often do!), but I think you'll have a much better chance of producing a guitar you're happy with if you stick with a traditional build.

James
James Lister, luthier, Sheffield UK

User avatar
Stephen Anderson
Posts: 14
Joined: Mon Jan 09, 2017 8:43 am
Location: Bangor, Northern Ireland

Re: Seeking advice on building a double top in the UK

Post by Stephen Anderson » Fri Feb 24, 2017 9:57 am

Thanks for confirming my thoughts on the right type of nomex.

Also thanks for the advice regarding double top first guitar build. You're dead right. I'm in the fortunate position of building my first guitar under the guidance of Sam Irwin at Lagan Lutherie School in Northern Ireland. It's great to be making use of his 40+ years of lutherie experience. Also working with Cónan Kilcoyne (10+ years experience).

I'm still going to discuss this with Sam in detail before committing to this type of top and I'm still open to the idea of a traditional solid top. I'm hoping that with their guidance and the school's equipment I can avoid wreaking this whole project.

I'm keeping a log at http://guitarmakingadventures.blogspot.co.uk to help me remember the process.

simonm
Amateur luthier
Posts: 6248
Joined: Sat Jun 27, 2009 10:22 am
Location: Germany, Würzburg.

Re: Seeking advice on building a double top in the UK

Post by simonm » Fri Feb 24, 2017 11:22 am

Madinter sells nomex by mail order.

There was an interesting thread(s) by a French guy called Alain Bieber over on the mimf forum some years back and he discussed the glues he tried. He was also an amateur but with coming up on 100 guitars under his belt plus some publications in the GAL magazines. I don't recall the glue he used but one point sticks in mind - there were two version of the stuff. The most successfully was the "non-foaming" variety.

This is one of the threads:
http://www.mimf.com/library/Alain_Biebe ... -2009.html
The Nomex is used only for the lower bout, with a simple rectangle of wood under the bridge. The two layers are .7 mm thick and the Nomex sanded to 1 mm, a little less on the periphery.
This refers to the particular design he is doing.

User avatar
Stephen Anderson
Posts: 14
Joined: Mon Jan 09, 2017 8:43 am
Location: Bangor, Northern Ireland

Re: Seeking advice on building a double top in the UK

Post by Stephen Anderson » Fri Feb 24, 2017 12:30 pm

Thanks Simon

I see Alain says
The only "caveat" I could emphasize is to really master the sticking of the Nomex on spruce samples before doing it on the guitar.I should have tested better.
I think I'll try that and then decide whether to go double or solid.

Also I think I'll take note of James point on thin cedar and go spruce instead.

simonm
Amateur luthier
Posts: 6248
Joined: Sat Jun 27, 2009 10:22 am
Location: Germany, Würzburg.

Re: Seeking advice on building a double top in the UK

Post by simonm » Fri Feb 24, 2017 1:49 pm

Stephen Anderson wrote:Thanks Simon

I see Alain says
The only "caveat" I could emphasize is to really master the sticking of the Nomex on spruce samples before doing it on the guitar.I should have tested better.
I think I'll try that and then decide whether to go double or solid.

Also I think I'll take note of James point on thin cedar and go spruce instead.
I am pretty sure that Alain had a later detailed thread about the next double top. Finding it is the only issue.

User avatar
Stephen Anderson
Posts: 14
Joined: Mon Jan 09, 2017 8:43 am
Location: Bangor, Northern Ireland

Re: Seeking advice on building a double top in the UK

Post by Stephen Anderson » Wed Mar 01, 2017 1:41 pm

Does the quality or grade of the inner soundboard make as much difference in a double top as the outer soundboard?

I.E. does it make a difference if both inner and outer soundboards are both AAA grade or if the inner (or outer?) soundboard is a lower grade?

(AAA would probably be what I'd aim for but just wondering if it really makes a difference in anyone's experience)

plectR1st
Posts: 6
Joined: Wed Mar 01, 2017 4:55 pm

Re: Seeking advice on building a double top in the UK

Post by plectR1st » Wed Mar 01, 2017 8:08 pm

I am thinking of commissioning a double-top archtop guitar with Nomex as the core and was wondering about grain orientation of the inner plate - should it be in-line with the outer plate or should it be placed cross-wise? If you have any views on this, I would appreciate your findings in relation to classical guitar.
Manuel Raimundo Concert 148, 1995

plectR1st
Posts: 6
Joined: Wed Mar 01, 2017 4:55 pm

Re: Seeking advice on building a double top in the UK

Post by plectR1st » Sat Sep 09, 2017 8:29 pm

Well, I have discussed this with my builder and the grain will be parallel in-line for inner and outer plates. However, I would still like to hear from other members on this subject - luthiers or players!
Manuel Raimundo Concert 148, 1995

Marcus Dominelli
Luthier
Posts: 2774
Joined: Thu Mar 08, 2007 4:52 pm
Location: Victoria, B.C. Canada

Re: Seeking advice on building a double top in the UK

Post by Marcus Dominelli » Sat Sep 09, 2017 11:41 pm

plectR1st wrote:
Wed Mar 01, 2017 8:08 pm
I am thinking of commissioning a double-top archtop guitar with Nomex as the core and was wondering about grain orientation of the inner plate - should it be in-line with the outer plate or should it be placed cross-wise? If you have any views on this, I would appreciate your findings in relation to classical guitar.
The inner and outer skins should have parallel grain. Even though Nomex tops are relatively stable and crack resistant, relative to a solid top, the thin skins do shrink and expand with changes in humidity. So having the skins with perpendicular grain could induce serious stresses, which would be much less pronounced with parallel skins.
In this sense, the double top lamination is not like a three-ply "all wood" type of plywood lamination. The double top is more flexible and sensitive.
plectR1st wrote:
Wed Mar 01, 2017 8:08 pm
Does the quality or grade of the inner soundboard make as much difference in a double top as the outer soundboard?
I'd say the quality of the inner layer is very important, but the aesthetics are not, so I often use high grade cedar or spruce (no runout) for the inside layer, but I will often use pieces with color variation, which would make them technically (although not sonically or structurally) a lower grade.

The outer skin seems to be dominant in terms of what we hear. But this last one is tricky. Are we really hearing spruce? Or are we hearing spruce because we first see the spruce? I believe I am actually hearing spruce, but I would have to do some "objective" tests to really know...

plectR1st
Posts: 6
Joined: Wed Mar 01, 2017 4:55 pm

Re: Seeking advice on building a double top in the UK

Post by plectR1st » Wed Sep 13, 2017 12:57 pm

Thank you Marcus for your quick reply which I have just seen today. Your advice is greatly appreciated and, by the way, your website is brilliant. Lead-times are very long with the luthier I have commissioned in UK but I can probably send you some process pictures eventually if you are interested.

Best regards
Manuel Raimundo Concert 148, 1995

Marcus Dominelli
Luthier
Posts: 2774
Joined: Thu Mar 08, 2007 4:52 pm
Location: Victoria, B.C. Canada

Re: Seeking advice on building a double top in the UK

Post by Marcus Dominelli » Thu Sep 14, 2017 2:30 am

plectR1st wrote:
Wed Sep 13, 2017 12:57 pm
Thank you Marcus for your quick reply which I have just seen today. Your advice is greatly appreciated and, by the way, your website is brilliant. Lead-times are very long with the luthier I have commissioned in UK but I can probably send you some process pictures eventually if you are interested.
Thanks. I'm always interested in how other people are doing their double tops. There are many ways to skin this cat!! So yeah, if you want to send me anything that would be cool.

Return to “Luthiers”

Who is online

Users browsing this forum: Alan Hamley, bftobin, CommonCrawl [Bot], coreybox, dandan, doralikesmath, doug, Google [Bot], hgabriel, ivan, JohnH, Matt Jacobs, Ruki1414, senunkan, Yvon and 60 guests