BYO: The Pliage

max

Craig was wery, as always, kind to give me a lot of info and encouragement a few years back when I was struggling with the pliage.

Here is a variation of Craigs setup.
I am by all means wery much a beginner, so take it for what it´s worth.

As i don´t have a heatblanket as Craig described earlier I preheat the wood
with a heatgun just over the bending area, then heat up a copperpipe, spray some water if it´s starting to get to hot, and then press in the wedge.
I also clamp everything to have it as flat and "true" as possible.






I joint the two halfs the same way Craig does, on a precut form of mdf.
This form also serve as a shooting board for trueing up the sides of the top after the bending prior to the glueing. The only tricky thing is to make sure the blade of the plane is exactly parallell to the the sole.



As Craig mentioned, it´s important to get a good pressure over the joint, for me a go bar deck have worked really well.
And as mentioned in Collins book, plain tape gives enough force to close the joint.
I´ve had tops cracking on my guitars, but not in the joint..

This is what the angles look like after glueup.


And ribs installed


Body closed


All the above are just my way of doing it, and I thought it might be of interest to some of you. I also like to say thanks to people like Craig and Bob Holo for sharing their knowledge..


If I may, I´d also like to discuss a related matter: Installing the rosette

here is how I see it,

When bending the top one would like to have them as close to final dimension as possible, right? but still separate.

That would be in the area of 1,9 - 2,3 mm aprox.

That leaves wery little material left in the rosette "side wall" channel when it´s routed, at least for me, and it´s wery tricky to get a "clean" rosette as the veener wants to pop out on the sides no matter what I do to try and stop it.

You can clearly see in Mateos video that he channel in his top is seriously deep.. making for more support.

Last build I tried to make a precut rosette, as I saw AJL is using that, but nah it didn´t turn out all that good..



Obviously I need to get better at installing rosettes no matter what, but I keep thinkin it would be a alot easier to do this prior to the thicknessing/pliage but then I would have the problem of bending the jointed top and possibly mess up the strenght of that..

So, does anyone favor precut rosettes or loose stripes of veneer?.
Any tip of how to get a nice looking rosette is appreciated..

Bones

Very cool. Thanks Max!

As far as the rosette I'm no expert because I have mostly made archtops and only one Selmac (D hole) a long time ago and I can't remember how I did the rosette but it turned out ok. I'll try to find my old jigs and see if I can remember how I did it.

Craig Bumgarner

Bones, I favor the inside edge of each half a bit when bending, but what ever bend is left on the outside edge, I just flatten it out when clamping and gluing to the sides.

Hey Max, good to see you here! Thanks for the pictures of your method, looks good and the results look like you are getting it done! I know another builder (DJ, are you listening?) who worked out something similar. He uses a 3/4" black iron pipe and pulls it down with bolts on the end, but same idea. I'd encourage you to try bending freehand over a hot pipe, it is easy if the pipe hot enough. I heat the pipe with a propane torch, stick the nozzle up the pipe, water goes puff when sprayed on.

Regards the rosette, I have always laid up individual strips in the channel, all at once. I cut a 7/16" or 1/2" channel about .060" deep. My strips are .080" wide and .020-.022" thick. I calculate the number of strips based on the thickness of the strips and the width of the channel. I test run the layup dry all the way around to be sure it both fits the channel and the strips are the right length. A pusher stick helps. If too loose, you will see gaps on the outside edge of the channel, if so, add a strip to the bunch. If too tight, a stroke or two of sand paper on each strip is usually enough. Once laid in dry and fitting, I carefully pop it back out and lay fish glue in the channel and reinstall the strips. You have to work quickly because the glue will swell the strips.

Another method is to lay the strips in dry and then flood with super glue. This works, but it can stain the top wood and darkens the light colored strips. To prevent the end grain of the spruce from soaking up super glue, seal the channel with blonde unwaxed shellac or egg white.

Either way, the rosette is the first thing I do after gluing the bent halves.
Sounds like you already have cutting the rosette channel out, but if you need ideas there, let me know.

Here is a pic of one under way, dry.

Bones

Ok thanks CB. I'm getting psyched up for getting back out in the shop one of these days.

Bones

Big thanks to Max and Craig B for all the info on my first pliage. I started out years ago doing carved archtops and had also built one Selmac with a domed/forced top but this is my first attempt at a pliage top. Got a little scorching so I think I need to dial in the temp a bit better but otherwise it went well. As I understand it some of the originals had scorching and it is pretty shallow in the surface anyway so I'm not concerned but next time I will try a lower temp to see if I can avoid that. It's just that it seemed like I needed the higher temp to get the spruce pliable but maybe I was just impatient. Here's some pics. I made a 6 degree angle fixture and used a 'go-bar deck' to keep everything lined up when I glued the two halves together. I used some 1/2" bar clamps with light pressure in addition to the tape to hold the glue joint together as I am used to joining 1" archtop wood and I can't seem to get used to the idea of just using the tape. The pipe clamps usually use steel pipe but that is too heavy and distorts the thin, flimsy top plates so I used lightweight PVC pipe instead which worked great since I am only using light pressure anyway.

Bones

BTW I wasn't feeling good about using a propane torch for my heat source in the shop so I used a 1500W Wagner heat gun from Home Cheapo and it was PLENTY hot. Even at a moderate heat setting it is hot enough to scorch the spruce.

Craig Bumgarner

I have to laugh because the only fire in my shop in 45 years was a heat gun that burst into flames with my back turned. Imagine my surprise when I turned around. Fortunately, there was a window nearby and I through it out the window into a snow bank.

billyshakes

What I love about this forum is that you not only have some of the best and most original players but also these incredible folks who are building the instruments. I'm inspired by both. Thanks for sharing pictures of your projects and techniques for those of us with lesser skills so that we can support your craft and live vicariously through you!

Bones

Yeah Craig I took your advice seriously and kept a good eye on that heat gun until it was well cooled down. I'm sure running it into that copper pipe with the other end MOSTLY capped off is not the best idea either. :-)

Here's a pic of the inside mostly sanded smooth. I think I'm going to leave a little 'ghost' mark of the scorch just because I think it's kinda cool. As you can see from the scorch, Craig, I also took your advice about focusing the bend at the middle of the top and didn't worry so much about getting the full 6 degrees at the outer edges since that will end up getting pulled flat down to the sides anyway so I kept the middle part closest to the heat source.

AndrewUlle

Instead of using the bar clamp, I wonder if you could modify the method shown here (create a bent frame)? It seems to keep everything lined up well.