Cutting side profile

Got a new way of doing something? Or maybe an old method that needs some clarification.

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Richardl
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Cutting side profile

Post by Richardl » Wed Apr 22, 2020 7:27 pm

Hi - I'm in the middle of making my third guitar but as it has been a couple of years since the last one, I'm struggling to remember how I did a few steps. I'm having a mental block when it comes to making the side profile. So, I have bent parallel 120 mm wide sides in the mold and am about to make the head and tail blocks. I can profile the sides before fitting the linings with a sanding dish of the right radius, but do I need to trim to the profile using a side template first - I'm pretty sure I do? I'm following the gore/Gilet method so the generic side template tapers from 120 mm to 100 mm from the waist to the head block. Of course, that was marked on the sides but disappeared during bending - easy enough to re-mark and trim with a block plane once the blocks are glued in. Can someone please confirm I'm on the right track (or not). I think, from memory, that the profile in the book, being straight, is only a rough guide and it is really a curve, but that gets taken care of with using the radius dish.

Sorry for such a basic question but it is easier to ask than have to make new sides if I do something stupid!

Cheers
Richard

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Allen
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Re: Cutting side profile

Post by Allen » Thu Apr 23, 2020 11:26 am

I would cut them some or use a block plane to remove some of the material before going to the radius dish.

I have perspex side templates for all the instruments I make that leaves almost bugger all to remove in the radius dish.
Allen R. McFarlen
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Richardl
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Joined: Sat Oct 27, 2007 4:09 pm
Location: NZ (Palmerston North)

Re: Cutting side profile

Post by Richardl » Thu Apr 23, 2020 1:48 pm

Thanks Allen. So, just to confirm the sequence,
1 I'll plane the taper on the back of the sides from the waist (120 mm) to the headblock position (100 mm).
2 Then glue in the head and tail blocks.
3 I can then put the the sides in the mold on top of the radiussed dish and transfer the profile from the radiussed dish to the sides.
4 Then plane them to approximate fit before adding the kerfings and sanding with the dish.

But I need to plane the taper from 120 mm to 100 mm first, and before gluing in the head block.

Sound right?
Cheers
Richard

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Allen
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Re: Cutting side profile

Post by Allen » Thu Apr 23, 2020 3:07 pm

Something like that.

My template is exact and pencil it to the straight sides then I cut just to the outside of the line. Then bend, glue in blocks and then final profile in the radius dish which takes just a few seconds with my set up.
Allen R. McFarlen
https://www.brguitars.com
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Richardl
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Joined: Sat Oct 27, 2007 4:09 pm
Location: NZ (Palmerston North)

Re: Cutting side profile

Post by Richardl » Thu Apr 23, 2020 4:12 pm

Thanks Allen. This is guitar 3 for me so I'm just at the starting point. Being fairly inexperienced at bending sides it has been suggested that if you cant get the waist in exactly the right place, it pays to bend straight, un-profiled sides. I guess with experience, profiling the sides before bending would be the way to go.

On a different subject, I noticed a post of yours (I think) using egg albumin to pore fill prior to finishing. Do you still think that method has merit? It certainly seems less messy/expensive/difficult that other methods for a newby. Does it work well with a shellac finish on rosewood?

Cheers
Richard

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Allen
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Re: Cutting side profile

Post by Allen » Thu Apr 23, 2020 4:30 pm

It's fairly easy to get the waist in the right spot even hand bending. Give yourself some extra lenght at both the butt and neck blocks and mark your waist in the same spot on both sides. It's also a good idea to indicate the inside and the edge that will be to the soundboard. It's easy to get those mixed up and that will spoil your day. I bend by hand and always start my bend at the waist first.

I haven't used that method with egg whites in years as it is very labor intensive and rather hard on the elbow and shoulders. I need to take care of what use I have of those joints after decades of sanding in the panel beater and paint shop. Also it's not as stable (ie. shrinking or swelling) as epoxy so not appropriate for the type of work I do these days.

Egg whites is certainly cheap and as non toxic as you can get. It does work well but like all steps in getting a good finish, you have to take care that your take your time and it's getting appropriate dry time between sessions as it will continue to shrink back.
Allen R. McFarlen
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Richardl
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Re: Cutting side profile

Post by Richardl » Fri Apr 24, 2020 5:03 pm

Thanks Allen, that's helpful. I might have a go with egg white on some scrap. I'm sure epoxy is great but as I've never tried it I don't know what I don't know. At this stage, low risk is the best option. My joints are in reasonable shape so that's not my main concern right now :).
Cheers
Richard

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