Build thread - Blackwood & Bunya Dreadnought

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demonx
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Thu Aug 21, 2014 4:57 pm

colburge wrote:Oxalic acid works in no time, you will be right.

Col
Awesome. Thanks.

I've now bent the second side and it's now in the form, looks just as the other one did so no point posting a photo. I'm just happy I now have two sides that are not burned, have no splits or ripples!
GregL wrote:Hi Allan,

I'm afraid I can't offer any help, sorry. But I would be interested if you could post what finally works for you at the end of your journey. I have some Blackwood sides to bend in future, it would be useful to know any tips and tricks (I have bent Mahogany and Australian Red Cedar sides with no problems - though that's probably pretty easy timber to bend).

Thanks,
GregL.
Greg, I've done pretty much as the guys above have described.

I made up the sandwich as per the instructions with the bender, however I added grease proof baking paper between the blackwood and the foil.

Rather than the 320+ temp recommended in the guide I used the guys above advice and I settled on a bending temp of 260 and I baked at 160 for 15 minutes. I then let the whole lot cool down for an hour or so before removing and placing in the form.

As you've probably picked up, I'm no expert in this side bending business, but I just managed to bend two fiddle back sides incident free, so I'd call that a success!

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by DarwinStrings » Thu Aug 21, 2014 9:52 pm

Glad you got there in the end Allan.

Jim
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Fri Aug 22, 2014 12:47 pm

Just scrubbed the cutaway piece with the oxalic acid. It appears to have taken away the water marks, but also a lot of the timber color with it. I guess the lighter timber is the lesser of the two evils
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Fri Aug 22, 2014 1:07 pm

Here they are drying in the sun, free from water stains (thanks guys) before I throw them back in the form
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Fri Aug 22, 2014 2:05 pm

New clamps and a new back to match the new sides!
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Sat Aug 23, 2014 10:24 am

Today's little task for this one was meant to be the center strip on the new back, but when I peeled the tape off it seems the glue hasn't dried completely, so I'll let it air for another day to be safe.

In the mean time, here's my highly sophisticated cutaway form. Can't tell you how I made it, secret!
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by kiwigeo » Sat Aug 23, 2014 10:27 am

demonx wrote:Today's little task for this one was meant to be the center strip on the new back, but when I peeled the tape off it seems the glue hasn't dried completely, so I'll let it air for another day to be safe.

In the mean time, here's my highly sophisticated cutaway form. Can't tell you how I made it, secret!
$100,000 Laser cutter? :roll:
Martin

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by kiwigeo » Sat Aug 23, 2014 10:29 am

demonx wrote:Just scrubbed the cutaway piece with the oxalic acid. It appears to have taken away the water marks, but also a lot of the timber color with it. I guess the lighter timber is the lesser of the two evils
You need to brush on the oxalic acid and then rinse it off fairly quickly. I found the wash actually brought out alot more reds in the wood. The wood will look alot better under a finish.
Martin

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Sat Aug 23, 2014 10:49 am

kiwigeo wrote: $100,000 Laser cutter? :roll:
If you replace that with elcheapo bandsaw then yeah, secrets out.
kiwigeo wrote:
demonx wrote:Just scrubbed the cutaway piece with the oxalic acid. It appears to have taken away the water marks, but also a lot of the timber color with it. I guess the lighter timber is the lesser of the two evils
You need to brush on the oxalic acid and then rinse it off fairly quickly. I found the wash actually brought out alot more reds in the wood. The wood will look alot better under a finish.
I used a scourer and scrubbed. I don't see how some of the "hard" spots would come off without scrubbing.

I had one tub of the mixed acid and one tub of clean water. I scrubbed rather quickly and then rinsed it off, then air hosed it to get the majority of the water off before sitting it in the tiny bit of sun we had that day. After rinsing and air hosing I went back to have a second go at a few spots.

This pic is pretty much self explanatory

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Sat Aug 23, 2014 3:58 pm

After a bit of an inspection I decided the glue had aired off enough to be able to drum sand the back, turned out to be one really nice bit of Blackwood!
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Sat Aug 23, 2014 4:17 pm

Back strip in clamps.
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Tue Aug 26, 2014 11:51 am

Moving onto the blocks.

Finally decided on a contour for the cutaway so the heel block has to reflect the same if its going to work how I'm hoping (flush)
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Tue Aug 26, 2014 12:29 pm

Heel block in clamps.

I also feel like a bit of an idiot, this is the second heel block I made. The first one somehow ended out being left handed. No idea how, but it was a mirror of what I needed!
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by Nick » Tue Aug 26, 2014 12:47 pm

demonx wrote:Heel block in clamps.

I also feel like a bit of an idiot, this is the second heel block I made. The first one somehow ended out being left handed. No idea how, but it was a mirror of what I needed!
I'm sure most of us here could fill pages up with cock-ups we've made and failed ideas that never quite worked out the same as they did in our head. All part of the process Alan! And as the saying goes...."The person that's never made a mistake has never made anything."
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by DarwinStrings » Tue Aug 26, 2014 1:20 pm

I'm with Nick on that. I couldn't count the amount of doors I have swung in my time but the other day I swung one at home. After cutting the hinge rebates in the door I put it up to swing it and had marked the rebates out upsidedown, had to re-do the rebates and patch the wrong ones, glad its only a paint grade.

Jim
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by rocket » Tue Aug 26, 2014 6:35 pm

Hey Jim, i swung a louvre pantry door upside down once, didn't notice it till i was having some lunch and thought what's wrong with that door? looks real strange, then the apprentice pipes up and says, i think it's upside down!!! :toi :toi : Shit does happen to us all!!
Cheers,, Rod.
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by Kim » Tue Aug 26, 2014 9:40 pm

rocket wrote: Shit does happen to us all!!
Cheers,, Rod.
No it doesn't...never ever!!!!... :oops: :oops: :oops:


Great thread thanks Allan enjoying it very much. :cl :cl :cl

Cheers

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Wed Aug 27, 2014 11:38 am

I'm sure there's a trick I'm yet to pick up to putting sides in the form.

This lover one split trying to wriggle the slippery bugger in, I'm just very lucky it's the lower part that will be removed for the cutaway section, could have been much worse
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Wed Aug 27, 2014 11:39 am

Also glued in the back block this morning
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Fri Aug 29, 2014 2:21 pm

I was getting very frustrated by all the deep throat clamps I've bought for this acoustic piling up on my workbench as they don't fit on my other clamp trolley, so I've built another one out of scraps laying around. I just had to hunt down four casters which were $3.59 ea

There's enough space for another twenty or so to squeeze in around the twenty already on there and I'll be adding another part on the side of the same trolley to hold all my sash clamps.

I'll most likely turn the unused side into another lot of shelves like I have on my other clamp trolley as it's pretty handy to throw cauls and other blocks etc in ready to grab quickly when doing lams
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Fri Aug 29, 2014 4:35 pm

This head block is probably what I have found most tricky so far.

Being the way I wanted the cutaway to meet flush with the neck block and taper out on a curve, means the join in that one place is a 3D twist as it has the "C" curve for the cutaway on the top plane, then on the front plane it has the "S" curve of the heel block. Made it tricky to clamp and even though it looks right now, I won't be completely sure until I un clamp tomorrow and file it flush.

I think in the future if I continue to use this cutaway/neck join I might make up a 3D clamping block, but it'll have to be an exact negative of the head block.

Something to think about anyway
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Sat Aug 30, 2014 10:57 am

So far it's this join that I've been most concerned about, but after a bit of a file and scrape this morning I can finally breath!
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Re: Build thread - Blackwood & Bunya Dreadnought

Post by demonx » Sat Aug 30, 2014 11:58 am

Today's big question - light or dark center strip?

I can't decide!

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by colburge » Sat Aug 30, 2014 12:06 pm

Dark :D

Col

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Re: Build thread - Blackwood & Bunya Dreadnought

Post by kiwigeo » Sat Aug 30, 2014 4:15 pm

My centre strips are always a piece of wood taken off the sides....personal choice of course but it's what works for me.
Martin

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