Formica guit AR-7

[Clay Schaeffer]

It's been awhile since I've built a Formica bodied guitar and I decided I would like to have one as a compact knockabout guitar. I decided to go with a size 1 body shape and my "AR-7" takedown design to take car camping. I used a solid spruce top that was originally sold for tenor ukuleles, and scrounged the rest of the materials, except for(cheap) tuners, fret wire, and strings, so if anyone wants to build a guitar on the cheap this might be a way to do it.
My wife commented that she could hear it upstairs and it sounded pretty good to her. I don't know if that was a compliment, or that the farther away you get the better it sounds!
I used kind of a slime green pattern laminate.

[Bryan Bear]

The takedown style and Formica make this ideal for camping! That color though. . .

[Clay Schaeffer]

The takedown style and Formica make this ideal for camping! That color though. . .

You don't think Gene Stoner would approve? I didn't have any camo pattern Formica.

[Bryan Bear]

What color is it exactly? It looks different on my phone than on my computer screen. I think the blue blanket is playing a role here. When I looked on my phone this morning it looked greenish (almost like a dirty mint green). Now that I see a larger image on my computer screen, it looks much less green.

I have seen a few of your formica guitar posts and have to admit that I am casually keeping an eye out for a free scrap so I can make a camping guitar someday too.

[Clay Schaeffer]

hpl trav grn.jpg (78.09 KiB) Viewed 15833 times

It's more of a light pond scum green. light green with a brown haze in places and light and dark mottles. I can't imagine who would want it for a countertop but there you have it, and some equally ugly color variations of the same pattern.

[Clay Schaeffer]

Something I tried on this one was an open harmonic bar and fan bracing extended into the upper bout. I had been using an X fan combination but this is simpler. Torres did something similar as have others, so the concept is not new. I think I made the harmonic bar heavier and kept more of it off the plate. It is resting on a tongue that sticks out from the soundhole reinforcement and supports the area the X usually crosses.
The guitar is steel strung but has a wide flat fingerboard like a classical guitar, which is what I originally learned on and prefer.

[Bryan Bear]

Have you ever made one with a Formica top? I think Martin had some guitars out there like that (maybe thicker?). If you weren’t overly concerned with tone, an all Formica body might really be good for camping. I know it is thin so it may need different bracing. Just thinking out loud.

[Tom Owen]

Martin still does make both all Formica (they call it HPL as Formica is a trade name) and spruce top HPL back and sides. They are built in their Mexico plant. Biggest problem with them is they cannot handle impacts very well the glue joint just tend to pop open. Also the HPL tops are lightly braced and they tend to distort from string pressure, bridges are glued with gel superglue which has poor sheer strength and you guessed it they tend to pop.

[Clay Schaeffer]

Hi Bryan,
As Tom mentioned Martin does make some with High Pressure Laminate tops - the same basic material as Formica, Wilsonart, Nevamar, Pionite, et al. Formica, like Kleenex is a trade name that has come to be more recognizable than the generic name for the material.The HPL topped guitars Martin makes have the problems Tom listed, and I don't think sound particularly good.
A solid spruce or western red cedar top, even when sourced from the lumberyard for not much money, I think offers a much better chance of making a good sounding instrument. WRC is more environmentally stable than spruce, but spruce is a bit tougher than WRC. I have used both with good results.
When it comes to repairing cracks in HPL you are often better off to replace the whole piece. The material is relatively cheap and easy to bend And doesn't require finish work. I think of HPL as the Hi Tech version of what Torres built his famous guitar from - Paper Mache.

[Bryan Bear]

I hadn’t considered the issues with impact and glue, especially the point about bridges popping off. My thought about an HPL top was more about sacrificing tone for a more “waterproof” or humidity tolerant guitar. Not so much about saving money on top materials. I have used Home Depot pine to make a nice sounding top costing almost no money, so that would be a good option for a camping guitar that was likely going to get really mistreated.

I was really thinking of something you could throw in the canoe in the middle of a humid Missouri summer and not worry too much about distortion or getting banged up. My thought was that an all HPL body would save a boatload of time in finishing. With no binding or decoration, you could make the box in a day. If it fell in the water you would ant be out all that much.

[Bob Gramann]

I made a Wilsonart (Formica of another brand) guitar a couple of decades ago. I used epoxy almost throughout so it wouldn’t dissolve if it fell in the water. With a little experimentation, I settled on polyurethane (Gorilla) glue to attach the bridge. The guitar was okay, but I didn’t like it. What brought about it’s demise was the epoxy creeping in the heel and scarf joints of the neck. I didn’t like the guitar enough to make another neck for it. None of my joints separated. It was just the wood to wood neck joints that crept.

I’m not sure that the backside of the laminate really has enough integrity to support gluing on narrow braces. It almost seems like brown kraft paper. We glue kraft paper between layers that we might want to separate later. It is probably possible to just tear a brace off of a laminate guitar. I haven’t run the experiment. (I did run the experiment with a piece of a redwood top—redwood sheds braces pretty easily).

I bought a $100 plywood guitar to take in the canoe. I hated that, so I built a small travel guitar (full scale—I like this one and I’ve sold several like it) and bought a waterproof case. That was the final solution.

[Tom Owen]

Or... just go with a Kala Waterman ukulele. All plastic, sort of a modern take on a Macaferri ukulele. Plus they are under $100. Also they sound pretty good.

[Mark McLean]

I recently rebuilt an old HPL guitar to try out a few design ideas. It originally had a HPL top but it distorted under string pressure (badly - it was a 12-string) and the bridge came unglued, twice. I retopped it with redwood, and I painted the HPL back and sides a matt black (kind of Ovation-like). I used a two pack paint designed for kitchen cupboards and benchtops. If you don't like the colour of your instrument you can do the same. It is super hard wearing, practically bulletproof.

[Clay Schaeffer]

Hi Mark,
I had plenty of other colors to choose from but pond scum green suits me. Ugly looks fine in a campground setting. Nothing wrong with painting it if you didn't like the color.
Bryan,
If you use western red cedar for the top the guitar will be fairly humidity tolerant and if you use Titebond 3 it will be fairly waterproof and sound much better than an HPL top. A couple of coats of a brush on polyurethane on the top and neck wouldn't require much effort and provide some protection. With a decent soundboard there is no reason why the guitar can't sound good.
Bob,
As you said, high pressure laminate is basically sheets of paper, but it is impregnated and bonded under high pressure with a phenolic resin. You might be able to tear a brace off of it but it is doubtful you will take any kraft paper with it. More likely the glue joint or wood would fail first. The back of HPL sheets are scarified to provided mechanical bonding of glues. HPL does have it's down sides - like people, I think it gets brittle with age, so you may not see too many 200 year old Martin X guitars.

[Alan Carruth]

Redwood tends to have low surface energy; you need to be careful to always glue to a freshly worked surface. I made I allowed the the two halves of the first redwood top I made on class to sit for a week after planing the joint. We were using a gluing press, which was occupied with another top, and figured we'd have plenty of pressure. Wrong; the joint fell apart as soon as I picked up the top. A freshly planed surface held fine. That was a real puzzle at the time; I had not heard of surface energy.

[Bob Gramann]

My redwood failure had a thin layer of redwood attached to the brace all along the glued surface. I did the experiment with a cutoff after a brace came loose on a redwood topped guitar. That top also split. I retopped that guitar. When I r3moved the topped, the braces pulled off with a layer of redwood attached like I had painted it on. I haven’t had the problem with any other piece of redwood yet. That piece just didn’t have any integrity.

[Alan Carruth]

I've seen redwood like that. How was the tap tone?

[Bob Gramann]

I don’t remember how it tapped. But, the guitar sounded wonderful. It was a shame it didn’t have lasting power. I didn’t have another piece of redwood then, so I retopped it with Engelmann. IZt still sounded good but in a different way. I’ve made another redwood topped guitar since then. That top had integrity. And, that guitar sounded wonderful.

[Clay Schaeffer]

I've been reluctant to use redwood for guitar soundboards. The redwood I've worked with on other projects would split very easily. Western red cedar can sometimes be weak like that so you have to select the right piece, but I haven't had any trouble gluing it. If I can find the right piece of redwood I would like to try it. Those who use it report good things for it's sound.

[Bob Gramann]

The redwood I’ve bought from Vincent Strauss (Pacific Coast Tonewoods) seems to be good. I like to make a guitar occasionally for extra light strings or silk and steel only. I’ve been reserving the redwood for those guitars—the extra light strings can drive it and there is less stress on the soundboard with the lighter strings. I’ve been using cedar for my classical guitar experiments. Both woods have a warmer sound than either the Sitka or Engelmann spruces that I use on other guitars.