Peter Marreiros. Cornerstone Guitars. Luthier Interview

Peter Marreiros. Cornerstone Guitars. | 2009 | Luthier Interview

Peter Marreiros of Cornerstone Guitars

Peter Marreiros is a Westminster Ca based guitar maker who came into prominence for his modern Small Jumbo guitars. Initially Peter took cues from Kevin Ryan and has since developed his own style and techniques including an all wood double top design.

Peter Marreiros of Cornerstone Guitars

MP3: So Little Time
[audio: Little Time – Ryan.mp3]
Ryan Alexander plays “So Little Time” on a Zion.

TT – Thanks for taking the time for this interview Peter! I was wondering if we could start off by asking about how you came to take up lutherie as a career??

PM – Thanks Terence. Lutherie started merely as a means to get a nice guitar for myself. My first two never made it as full guitars as my high level of self-criticism didn’t see much of a prospect in them.

Things took off after that with my 3rd and 4th guitars. They sounded good and many people encouraged me and complimented my talent to match woods and colors together. So, to satisfy my latest hobby I decided to sell some in order to fuel the passion… the rest is history!

TT – Peter, did you start from a kit? Have a mentor?

PM – Well, my first two where fully “made from scratch” with the exception of the sides which I had bent by LMI but after that I made my own side bender and took off from there. I do still have a mentor and great influence in my work.

Kevin Ryan is a great friend and I have to give him credit for some of my success. There aren’t a lot of builders fortunate to have such an amazing builder as a friend.

As far as craftsmanship goes the bar has been set real high as I see Kevin’s work as a benchmark of perfection.

Zion Fingerstyle
(click for fullsize)
Peter Marreiros, Cornerstone Guitars
Peter Marreiros, Cornerstone Guitars
Peter Marreiros, Cornerstone Guitars
Master Grade Koa Back/Sides
Koa/Port Orford Cedar Double Top
Madagascar Rosewood Bindings
World’s 1st double top all koa!
Ryan Inspired Bevel
7 Piece Laminated Neck
Gotoh 21:1 Tuners

TT – I do see Kevin’s influence in your body shape aesthetics..

PM – I have 5 guitar models I currently offer. My most popular models is the Zion and the Small Jumbo which was modeled after Jim Olson’s famous SJ.

The Zion Fingerstyle model is an original design that aimed for a larger lower bout and tight waist and Kevin’s style armrest bevel.

The Genesis is another model that I created, an Asymmetrical Jumbo. The other models are pretty much your traditional shapes, Auditorium and Grand Auditorium. Then there is the Small Concert which is still in the works….

TT – And you also craft double topped guitars? Could you let us in your construction philosophy?

PM – I started doing double tops a few years ago. I actually offer double tops and semi-Double tops both proprietary designs. My semi-double top is aimed to strengthen high figured soundboards like curly Redwood which is known to be considerably weaker than straight grained wood.

My double tops are very similar to Nomex style construction with several differences, biggest difference being that I use an all wood core rather than Nomex. I believe wood has better tonal properties and offers a more stable glue joint thus the “All Wood Honeycomb Pattern” Double Top.

TT – I take it the construction is a very involved process? How much longer does it take to build vs. a solid top?

PM -Indeed time consuming. From plate preparation to vacuum pressing that are many steps and several hours needed. Also, much more care has to be taken due to the thickness of the top plate which could easily be sanded through if one is not careful. Like bending Brazilian, there is no going back shall the unexpected arise..

TT – How do the wood choices affect the sound of double top?

PM – I make my double top tonewood choices to achieve a goal. What ever I am shooting for in a particular guitar. I believe the fundamental attributes and tone can be altered or combined by matching different soundboards. We all know there is a radical difference between Red Cedar and Adirondack, what would happen if I used both?

Would I get a warmer, more responsive top but with a bit more attack and volume? Thats exactly what I’ve been experiencing. I tend to match spruces with redwoods and cedars because I feel that delivers the tone I’m looking for by blending the best of both worlds

TT – Okay, now’s the time to ask about back and sides woods, I guess…

PM – Terence, I believe the back and sides do play a role in the overall sound of the guitar but I’m still a firm believer that the soundboard is the biggest culprit and should get most of the credit. Sure, back and sides affect tone and volume but not nearly as much as some people give it credit for. Nonetheless, an important factor in guitar making.

Cornerstone Guitars
Back and sides
(click for fullsize)

Peter Marreiros, Cornerstone Guitars

Peter Marreiros, Cornerstone GuitarsBlack Limba
Peter Marreiros, Cornerstone GuitarsKoa

TT – What are your favorites? How would you describe the various tonewood characteristics?

PM – My favorites are Brazilian Rosewood, Madrose, Camatillo Rosewood, Koa and Ebonies to name a few that come to mind. To me there is nothing like Brazilian, its like magic…. the color and grain, the crisp tone, even the smell is beautiful. Madagascar comes pretty close in my opinion but I would say the Camatillo is closer tonally, probably closer to Brazilian than Honduran Rosewood.

I also love the beauty of a nicely figured set of Koa or Tasmanian Blackwood. I could go on and give you my opinion on many tonal characteristics of various backs and sides but there are so many other important factors in a guitar that without knowing the type of guitar, soundboard, bracing patterns and specific set of wood I can only generalize…..

I would say that in my experience Rosewoods tend to offer a crisp tone with great note separation and sustain. Koa and Acacias are a bit closer to mahogany which seam to make warmer guitars with slightly less volume than Rosewood or Ebony but that would vary from set to set.

TT – Thanks for that Peter. I was wondering if you might let us in a little on your build and bracing philosophies?

PM – You’re welcome Terence. I try to get my tops as stiff and light as possible. As Kevin Ryan told me once before “weight is the enemy” and I firmly believe that and hear a difference in soundboards where measures where taken to address the issue of weight.

It is a critical part of the guitar’s fundamental structure and sound so one has to remove mass while retaining structural integrity. Lately with double tops, drilled braces and my latest “parabolic lattice Bracing” I’ve been able to reduce weight substantially and increase stiffness. I’ll let you know how it turns out as soon as I string her up…

TT – And I understand you’ve also built a Koa double top- how did that come out?

PM – Yep, I believe its the world’s first ever in Koa. It was a beautiful guitar. It sounded better than a regular Koa guitar top with a bit more bite and sustain. I will definitely do it again.

TT – Do you think the same process would work with say mahogany?

PM – Actually my intent is to make several guitars in the same way. All mahogany, all Tasmanian Blackwood and all Myrtle….when time permits.

TT – How about all spruce?

PM – I’ve seen an All-Spruce guitar 2 or 3 years ago. At this time I have no plans to do one. I think the back and sides may be too delicate…. I did think about an All-Redwood though.

TT – But isn’t redwood quite brittle?

PM – Redwood can split and tear at the end-grain but once its glued up its pretty stable. It is soft like Spruce but that’s been done before!

TT – How about double backs Peter?

PM – I have considered it but at this time I am too busy to invested the time needed in research. Maybe sometime.

TT – Any interesting projects coming up you’d like to share with us?

PM – At this time I have my first one out of a series of 7 in Olive wood on Cedar that will be making its debut at the Healdsburg Festival this August.

TT – Olive wood is rather unusual, can you tell us a little more about it?

PM – It’s pretty unusual indeed.This guitar was made after a verse in Scripture that kinda jumped out to me. So I decided to use Olive wood and Cedar to go with that verse. Olive feels a bit like Myrtle to me in texture and tap tone, if it turns out like I expect, it should be a pretty nice sounding guitar.


-Port Orford Cedar: here.
-More tonewoods: here.
-Double top luthiers:
Alan Dunwell

Kevin Muidermann
-Cornerstone guitars here.

TT – I think that’s enough about construction- what advise would be give someone looking for a custom guitar, Peter?

PM – I think one of the best advices I can offer is to trust your Luthier. There is so much contradictory information online that can confuse the buyer and while some information may be useful sometimes the differences experienced with different guitars pertain mostly to a particular builder’s methods rather than a generalized idea. Research your tonewoods and options but do give your builder room to work, it will be for the best.

TT – Thanks Peter!

PM – Terence, thanks for taking the time. It was nice talking with you.

©2009 Terence Tan.
Pictures courtesy of Peter Marreiros
Check out Peter’s great website: link

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