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| Double sides questions... http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=52472 |
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| Author: | meddlingfool [ Thu Sep 26, 2019 3:45 pm ] |
| Post subject: | Double sides questions... |
Suddenly and unexpectedly I need to make a double sided guitar, to salvage a set of ziricote that was cut too thin. SMH. So for folks that do so... How thick do you make your lams? What adhesive do you use? What determines your wood choice of the inner backup layer? |
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| Author: | Terence Kennedy [ Thu Sep 26, 2019 4:31 pm ] |
| Post subject: | Re: Double sides questions... |
Usually around .050-.060 outer and .045 innermost. Normally same wood although a Rosewood inner side on a Maple guitar has provided a nice tone for me and people seem to like it. Unibond 800. Dries hard like glass. |
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| Author: | Clay S. [ Thu Sep 26, 2019 5:04 pm ] |
| Post subject: | Re: Double sides questions... |
I would be inclined to use EIR (lower grade or mismatched set) as an inner layer. The radial, tangential, and volumetric shrinkage numbers are not too far different from Ziricote, and it is a similar dark color. Although I do a fair amount of laminated work, my own peculiar method (relaminating flitch matched veneers back together) limits my experience somewhat. Many people prefer to use a lower cost wood for the inner plies and cross the grain as in plywood which may have some advantages when laminating dissimilar woods. I use west system epoxy and dry out the woods just prior to laminating. For open pored woods I think the epoxy is drawn into some of the places the water has left and makes for a more stable lamination. Again, others use different glues and report success with them. Since the sides have a somewhat serpentine shape a two layer lamination might be O.K., so thicker pieces than typical veneer might work O.K. Hopefully others will post with their experiences making double sides. |
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| Author: | James Orr [ Thu Sep 26, 2019 5:08 pm ] |
| Post subject: | Re: Double sides questions... |
I use Unibond 800 like Terrance. Not only does it dry hard as glass, it doesn't bleed through like West epoxy. .06/.06 because that's what my sand can comfortably handle. I laminate on my solid bending mold with vacuum and bag. I like EIR inner laminates because LMI sells them inexpensively. I tried some port orford cedar, but it wasn't stiff enough for my liking. Would have made an amazing smelling body though... |
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| Author: | meddlingfool [ Thu Sep 26, 2019 5:37 pm ] |
| Post subject: | Re: Double sides questions... |
Hmm, I have no orphaned RW sides. I was thinking of black walnut as I have some... |
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| Author: | Clay S. [ Thu Sep 26, 2019 5:50 pm ] |
| Post subject: | Re: Double sides questions... |
I picked EIR because the color and "shrinkage" numbers aren't too far out from Ziricote's and it is readily available. Walnut is not as close but it may work fine too. I have an old 1800's parlor guitar that is BRW veneer over spruce and it has held up o.k.. |
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| Author: | Terence Kennedy [ Thu Sep 26, 2019 6:08 pm ] |
| Post subject: | Re: Double sides questions... |
I just bought some lower grade Mahogany from Hibdon for less than $10/set to use for inner lams. Actually looked pretty good. |
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| Author: | meddlingfool [ Thu Sep 26, 2019 6:36 pm ] |
| Post subject: | Re: Double sides questions... |
Ha! I do have a spare set of mahogany sides but they're precious. Getting mahogany in Canada is not as easy as your side of the line. Any reason not to use the walnut? |
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| Author: | James Orr [ Thu Sep 26, 2019 9:25 pm ] |
| Post subject: | Re: Double sides questions... |
I can’t think of one. Sent from my iPhone using Tapatalk |
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| Author: | meddlingfool [ Thu Sep 26, 2019 9:30 pm ] |
| Post subject: | Re: Double sides questions... |
Forward! |
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| Author: | Terence Kennedy [ Thu Sep 26, 2019 9:53 pm ] |
| Post subject: | Re: Double sides questions... |
meddlingfool wrote: Ha! I do have a spare set of mahogany sides but they're precious. Getting mahogany in Canada is not as easy as your side of the line. Any reason not to use the walnut? Go for it!! Report back. I think you'll like the double side sound if you have not done it before. |
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| Author: | meddlingfool [ Fri Sep 27, 2019 12:50 am ] |
| Post subject: | Re: Double sides questions... |
Fortunately it’s appropriate for this project as the client is looking for a modern slap and tickle guitar. I would have strongly reinforced the sides with braces anyway. How do you actually glue the lams together? Would love to see some pics. Pretty sure I’m going with epoxy... |
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| Author: | meddlingfool [ Fri Sep 27, 2019 12:55 am ] |
| Post subject: | Re: Double sides questions... |
Going with epoxy because I have it. Can’t find unibond without having to wait for shipping, will check Windsor’s AM... |
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| Author: | Colin North [ Fri Sep 27, 2019 6:47 am ] |
| Post subject: | Re: Double sides questions... |
meddlingfool wrote: Going with epoxy because I have it. Can’t find unibond without having to wait for shipping, will check Windsor’s AM... If you're using epoxy and an epoxy pore fill, you won't see and bleed though anyway |
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| Author: | Ernie Kleinman [ Fri Sep 27, 2019 8:18 am ] |
| Post subject: | Re: Double sides questions... |
For 2 ply .060 each for 3 ply .060 and 2 .022. T1 glue, weldwood plastic resin glue |
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| Author: | James Orr [ Fri Sep 27, 2019 10:57 am ] |
| Post subject: | Re: Double sides questions... |
meddlingfool wrote: How do you actually glue the lams together? I use a vacuum pump and my bending form. I use solid bending forms, so I put some foil over the the form to keep it from getting gunked up with glue. Then I spread the adhesive and use low tack tape to tape the two lams together since they have a tendency to slide around at first. Once that's done, I just put them on the mold, slide it in the vacuum bag, and hit the on switch. |
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| Author: | meddlingfool [ Fri Sep 27, 2019 11:16 am ] |
| Post subject: | Re: Double sides questions... |
Right. I think I'm going to have to go with the Bogdanovich approach. Sounds like a chess move... |
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| Author: | doncaparker [ Fri Sep 27, 2019 11:51 am ] |
| Post subject: | Re: Double sides questions... |
Or fencing . . . Inigo Montoya: You are using Bonetti’s Defense against me, ah? Man in Black: I thought it fitting considering the rocky terrain. Inigo: Naturally, you must suspect me to attack with Capa Ferro? Man in Black: Naturally, but I find that Thibault cancels out Capa Ferro. Don’t you? Inigo: Unless the enemy has studied his Agrippa… which I have. |
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| Author: | DarrenFiggs [ Fri Sep 27, 2019 12:32 pm ] |
| Post subject: | Re: Double sides questions... |
How are you guys prepping these laminates before bending? What are you sanding to and how much more material can one expect to remove when cleaning up after the bend? I ask because going this thin doesn't leave much room for error (sand-through). |
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| Author: | meddlingfool [ Fri Sep 27, 2019 12:35 pm ] |
| Post subject: | Re: Double sides questions... |
It sure doesn't. I think that's why the solid bending forms or moulds are required, so that when you clamp it, the sandwich gets flat within the range of thickness of the outer side. By the time my ziricote sides were free of saw marks they were .065... 
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| Author: | James Orr [ Fri Sep 27, 2019 2:19 pm ] |
| Post subject: | Re: Double sides questions... |
meddlingfool wrote: Right. I think I'm going to have to go with the Bogdanovich approach. Sounds like a chess move... Naw. It’s really easy. You’re basically put the two lams on the mold and sliding it in the bag. Speed certainly isn’t an issue because the glue has such a long open time. Sent from my iPhone using Tapatalk |
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| Author: | James Orr [ Fri Sep 27, 2019 2:20 pm ] |
| Post subject: | Double sides questions... |
DarrenFiggs wrote: How are you guys prepping these laminates before bending? What are you sanding to and how much more material can one expect to remove when cleaning up after the bend? I ask because going this thin doesn't leave much room for error (sand-through). Thickness sander has 80 grit. I quickly sand the outer faces to 100 before bending. The two inner faces (the two sides that get the glue) don’t need to be cleaned up at all. You’re not removing enough material to make a difference. Sent from my iPhone using Tapatalk |
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| Author: | Terence Kennedy [ Fri Sep 27, 2019 3:40 pm ] |
| Post subject: | Re: Double sides questions... |
This is my rig. I shaped the cauls pretty close and then coated them with Durhams Rock Hard putty and pressed them against the form and later added a layer of gasket cork. I use the laminating form as the bending form as well. 
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| Author: | meddlingfool [ Fri Sep 27, 2019 4:07 pm ] |
| Post subject: | Re: Double sides questions... |
That looks pretty straight forward Terence, is your form solid or with pipes across it? |
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| Author: | Terence Kennedy [ Sat Sep 28, 2019 9:24 am ] |
| Post subject: | Re: Double sides questions... |
It is solid but I just drilled holes in it with a forstner bit on the drill press for the clamps. Actually pipes are not a bad idea for strength. The holes have held up OK though. If I ever get a vacuum pump that sounds like a great approach. If you bend the two lams together in the bender they fit perfectly so you really don’t need massive pressure. 
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