Cuban Mahogany and Lutz Spruce 00

[Kevin Sjostrand]

Sweet Darryl. Great way to do it.
I don't have a radius dish, now what do I do??

Kevin

[Jim_H]

Psst...

look over to the left side of the page, then click the big yellow box that says "Blues Creek Guitars" and buy yourself one :p


hehe..Sorry Kevin.. couldn't resist =)

[Darryl Young]

Was out of town all week but got a few things done since I returned on Friday.

Ended up having to make a new UTB so did that Friday night and Glued it to the soundboard. Decided to try bending my sides this weekend. Made a post here and on the OLF asking feedback on my process or tips on using the bender. Here is how I ended up bending the sides.

- Trimmed the sides 2" longer than needed (my test bends were 1/2" longer than needed and alignment was too easy to mess up).

- Traced the back radius profile on the sides using the template made earlier (see previous post), stacked the side, and trimmed near the line on the bandsaw. Cleaned the cut up on an oscillating drum sander.

- Thicknessed the Cuban Mahogany sides to 0.080" thick for bending.

- Noted which side(s) I wanted to be the outside and noted this by marking "I" on an inside corner of each side. Hoped this would help insure i bent each side the correct way.

- Made a "bending sandwaich" of (bottom to top): steel, paper, wood, paper, steel, heat blanket. I sprayed the outside of the paper with distilled water before placing inside the sandwich.

- Placed sandwich in bender made sure the waist centerline was in the correct postition and that the flat edge of the side was aligned perpendicular to the bend.

- Turned on the blanket on Full power.

- When the temp hit 240F I started bending the waist till it was roughly 3/8" from bottoming out. This seemed to lock the side in place lengthwise so I didn't have to worry about the waist being in the wrong place.

- Immediately started bending the lower bout followed by the upper bout.

- Finished up by tightening the waist the rest of the way down. This pulls everything nice and tight so I like doing the last bit of the waist last. The temp had hit 360F - 370F by the time I was finished bending.

- Turned the power off to let things cool a bit till I was down around 320F. Placed the unit on Variable power and held the temperature at 310F - 320F for 5-7 minutes.

- Turned the blanket off and let it cool down to around 260F then turned the blanket back on Varible power and held the temperature around 250F for 10 minutes.

- Turned the blanket off and let it cool. Left one side in the mold for roughly 6 hours and the other overnight.

The sides turned out pretty well.......shaped fairly nice and no cracks. There is some water stain (even though I used a light mist only on the outside of the paper). This should scrape off and not be a big issue. I have no idea if most mahogany will have some water stain after bending. Anyone know? I bent both sides yesterday and removed the second side from the bender this morning.

This afternoon I made an inside mold clamp (not sure what to call it) that tightens the waist inside the mold. I trimmed the ends of each side on my bandsaw. So now my sides are in the mold. Here is a shot of what they look like. Note I haven't yet scraped the water stains off.

SidesInMouldSideView.JPG

SidesInMoldEndView.JPG

SidesInMouldTailView.JPG

[tippie53]

water staining is normal and sands off . Be carefull as scorching can happened. 5 minutes should be plenty in the 350 to 375 range.

[Kevin Sjostrand]

Darryl, those look great! Great job. My Santos Mahogany stained, but it sands right off so I would say no big deal.
What bender do you have? You probably already told us, right?

Kevin

[Darryl Young]

Oops, you caught a mistake John. I let the sides stay for 10 minutes at 250F (not 350F). Sorry about the confusion. I went back and corrected the post. Thanks for pointing that out.

[Darryl Young]

Kevin, I bought the bender from John (including the bending form).

[tippie53]

There is one advantage to the heat blanket , you can set your coffee on it to keep it hot. If you spill it , it can pre stain the wood

[Darryl Young]

<grin> See there, you never stop learning from the experienced guys!

[tippie53]

you are welcome
We are here to help , that is why we are here .