I have an old Framus 12 string with laminated back and sides, the back has no braces.
This guitar has now been rebuilt using a solid spruce top as opposed to the original laminated one.
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| Author: | aqualibguitars [ Fri Jan 20, 2017 8:08 am ] |
| Post subject: | Laminated back and sides thickness |
Hello friends Happy new year to all of you... friends after building about 15 guitars im thinking of building classical guitar on ramirez bracing pattern from 0.5 mm veneers. today i made the laminated sides from 4 layers of 0.5 mm and glued them with titebond. they are pretty well rigid and strong. now i want to glue the back veneers. so want to know the thickness of back shall i glue 5 sheets of 0.5 mm veneers to make 2.5 mm thick or 3 layers of 0.5 + 1 layer of 0.7 mm to make 2.2 mm thick. can i glue the veneers on flat granite surface and later dome with the bracing? or should i glue them in radius dish to get the dome ? if yes how it should be glued as i dont have vacum clamp.. will the radiused back will require lighter back bracing?? sry for asking too much as its 1st laminated back and sides guitar. Thanks in advance |
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| Author: | ernie [ Fri Jan 20, 2017 8:44 am ] |
| Post subject: | Re: Laminated back and sides thickness |
It all depends on what woods you are using for veneers and the type of glue .It/s a judgement call. I/ve only done it twice and went for 2pieces 1.5mm thick. that way I can thin them down more if they didn/t come out right .I used large cement blocks weighted down between a plywood sandwich. I/ve also done it with a multitude of clamps. Craig Baumgarner also explained his method in detail on the delcamp forum. I use the KISS theory keep it simple stupid, saves time and money. I prefer titebond over epoxy, but you need to find out what works best for you . With your climate workshop e.g. climate/humidity temperature . available tools / clamps etc. I personally would only use thin veneers on the inside, in case of error, and leave a thicker 1mm on the show face . Michael Thames ,may also be of help to you, he has built some double tops . I would use the radius dish for gluing in the bracing . You can use a flat granite surface for gluing the back panels , but then what species of wood you using for bracing stock ?? In trev/s book he glues in the bracing sitka spruce on the radius dish workboard in a go bar deck,. as you gain some experience , you will come up with a suitable method that works for you . Cheers ernie |
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| Author: | truckjohn [ Fri Jan 20, 2017 10:06 am ] |
| Post subject: | Re: Laminated back and sides thickness |
If you can glue them into the dome now - I would do that. You will need to make a positive form to clamp them into the dish.... Either way - it will probably take some serious clamping to get it all good and flat.. Typically, furniture makers use veneer presses to apply veneer so it's good and flat, as well as free of bubbles, lumps, and voids. |
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| Author: | Clay S. [ Fri Jan 20, 2017 12:28 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
I have built a fair number of instruments with laminated veneers for back and sides. My method orients the grain all in the same direction and uses non water based glues ( West system epoxy). I go one step further and dry the veneer under low humidity conditions to remove as much moisture as I reasonably can before laminating. I have found this gives me the most stabile layups. When gluing I press the veneer between two pieces of smooth plywood or MCP (wax paper between veneer and plywood) and use as many clamps as I can to press it flat. For sides I use the bending form and a piece of kerf kore and plenty of clamps. The finished product looks and acts much the same as solid wood. The typical flat top "doming" can be achieved without building it into the layup. |
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| Author: | aqualibguitars [ Fri Jan 20, 2017 1:09 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
Thanks friends for ur advice. im using rosewood veneer in all layers. shall i go for 4 layers or 5 layers? |
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| Author: | truckjohn [ Fri Jan 20, 2017 4:00 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
My own preference... I would go thicker on the sides (2.5-3mm) and thinner (2-2.25mm) on the back... But that's just me... |
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| Author: | Clay S. [ Fri Jan 20, 2017 4:56 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
I would use the number of veneers that will make the same final thickness as solid wood would finish at. With veneers of that thickness there is a limited amount of sanding you can do. |
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| Author: | ernie [ Fri Jan 20, 2017 9:41 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
Rahaul for your first time . I would suggest a trial run to see if you can line everything up correctly .Have every tool and wood/glue on the bench and see if you run into any snags , Anomalies may be difficult to sand out if you use .5mm veneers .I would use the .5 on the inside hidden part and thicker 1.2mm on the outside . Just in case |
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| Author: | aqualibguitars [ Sat Jan 21, 2017 12:29 am ] |
| Post subject: | Re: Laminated back and sides thickness |
Thanks friends. i will glue 3 layers today and see what happens |
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| Author: | aqualibguitars [ Tue Feb 14, 2017 1:42 am ] |
| Post subject: | Re: Laminated back and sides thickness |
Hello friends. i tried laminating with 2 part epoxy available in india called araldite. but it failed miserably. then after heart break i tried with titebond and to my surprise it went really well i glued 5 layers of 0.45 and total is coming to about 2.45 mm thick back. using it for classical guitar i cured it for 15 days. and its really going good. but after bracing the back braces the weight is too much about 364 grams. the 1st back brace is 6.5 x 15 , 2nd is 8.5 x 15 and 3rd is 8.5 x 16.5 are the braces too heavy? wat should be ideal weight of a rosewood back and should i reduce the height of the braces? waiting for ur advice |
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| Author: | ernie [ Tue Feb 14, 2017 8:56 am ] |
| Post subject: | Re: Laminated back and sides thickness |
If you are staying with the same back .I would make the braces 8-9mm wide and at least 19mm high depends on the species used for bracing spruce , mahogany? etc. Also I would radius at least 15 ft radius on to those braces or 10 ft radius if you live in a part of India with high humidity and changing cycles of low and high humidity .Titebond or HHG will work for the braces |
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| Author: | aqualibguitars [ Tue Feb 14, 2017 1:35 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
yes sir using indian mahogany. but the back is too stiff i think . it the weight ok?? |
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| Author: | ernie [ Tue Feb 14, 2017 4:19 pm ] |
| Post subject: | Re: Laminated back and sides thickness |
mahog is fine , but did you use a radius on the back braces ?? If your back is not properly done with radiused braces , you might have problems later on.You can thin the braces into a triangle to make them thinner if you feel that they are too big for a dense back .I prefer Sitka spruce for back bracing , light and strong . |
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| Author: | runamuck [ Wed Feb 15, 2017 1:52 am ] |
| Post subject: | Re: Laminated back and sides thickness |
I've never made a guitar with a laminated back but I've done my share of laminating other things over the years. I wonder if you're gluing up 3 plys for a back whether you need braces at all. |
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| Author: | aqualibguitars [ Wed Feb 15, 2017 4:26 am ] |
| Post subject: | Re: Laminated back and sides thickness |
yes sir . i have radiused braces to 15 foot radius. i have lowered the height of braces to 14 mm. and thinking of rounding it like flamenco bracings |
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| Author: | MortUK [ Wed Feb 15, 2017 4:29 am ] |
| Post subject: | Re: Laminated back and sides thickness |
I have an old Framus 12 string with laminated back and sides, the back has no braces. This guitar has now been rebuilt using a solid spruce top as opposed to the original laminated one.
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| Author: | Colin North [ Wed Feb 15, 2017 5:41 am ] |
| Post subject: | Re: Laminated back and sides thickness |
Seen quite a few laminated backs like that, but also some with braces. |
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