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  #1  
Old 03-26-2010, 10:35 PM
sblair sblair is offline
 
Join Date: Dec 2008
Location: Colorado Springs, CO
Posts: 13
Default trim tab blocks

Hey everyone. I'm getting ready to bend the trim tab and elevator skin. What is a good way to produce the wooden blocks used in this process?

Just trace one of the ribs to get the shape?

Thanks,

Sean
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  #2  
Old 03-27-2010, 11:46 AM
DaAV8R DaAV8R is offline
 
Join Date: Jul 2009
Location: Lee's Summit, MO
Posts: 747
Default Bending Blocks

Sean,

I make several sets of blocks using progressively harder woods. I wanted to practice the bends with some scrap before attacking the real thing. I was getting slight deformation on the corner of the wood block when practicing resulting in a buggered edge for the real thing. Eventually I hardend the corner of the bending block with some cyanoacrylate otherwise know as CA in the modeling world. It is available at the local hobby or craft store. The glue is available in several thicknesses. The thin CA wicks into the wood and makes the bending edge very hard. If your prone to glueing your fingers together, you might want to pick up some debonding agent when you pick up your glue.
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  #3  
Old 03-27-2010, 01:01 PM
sblair sblair is offline
 
Join Date: Dec 2008
Location: Colorado Springs, CO
Posts: 13
Default pattern?

Robert,

Thanks for the idea with the CA. I've used a little of it in R/C Aircraft, too.

To get the angle for the blocks...did you just use a rib and trace the pattern to get the angle?

Thanks again.

Sean
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  #4  
Old 03-27-2010, 03:46 PM
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papamike papamike is offline
 
Join Date: Nov 2009
Location: McKinney, TX
Posts: 113
Default

I'm there too, but I'm seriously considering installing a rib in the elevator instead of bending it. Still have to come up with a form to bend it to.
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  #5  
Old 03-27-2010, 07:06 PM
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SeanB SeanB is offline
 
Join Date: Dec 2006
Location: Colorado Springs
Posts: 576
Default Still looking for answer to pattern

I didn't seem to have much of a problem with these on my 10 build. In that case, you have to build two trim tabs and two close-outs on the elevators. I was fortunate to have the wooden forming blocks from another builder. Make sure you use double sided tape and enough clamping pressure.
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  #6  
Old 03-27-2010, 07:28 PM
Transporter Transporter is offline
 
Join Date: Jun 2007
Location: Lee's Summit, MO
Posts: 743
Default Pattern

I used a rib from the right elevator to make my blocks. Cut the outer and inner from one piece and flattened the surface on a sanding disc (could also be surfaced using a piece of sand paper on a flat workbench).

Robert's idea about using the CA to harden the edge is a good one.

A hard wood such as maple is another option.

Don't forget to radius the forming edge to allow for the bend.

Good luck,
Mike
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  #7  
Old 03-27-2010, 07:34 PM
sblair sblair is offline
 
Join Date: Dec 2008
Location: Colorado Springs, CO
Posts: 13
Default Thanks

That's what I needed...thanks!

I just found the CA glue, too. Here goes!
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  #8  
Old 03-28-2010, 07:58 AM
Mike Coady Mike Coady is offline
 
Join Date: Oct 2009
Location: Taylorville, IL.
Posts: 107
Default trim tab bend

Use as hard a wood as possible to make make your bending block from! I used a thick paricle board which the plans said was OK but the particle board broke causing the metal to shift...not good. Make sure to use the double sided tape on your bending block to the skin and that you have your setup clamped down very firmly. Go slow when you get to using your rivet gun if you use it. Good luck. HARD WOOD ONLY FOR BENDING BLOCK!
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  #9  
Old 03-28-2010, 08:34 AM
sblair sblair is offline
 
Join Date: Dec 2008
Location: Colorado Springs, CO
Posts: 13
Default Will do

Thanks, Mike. I've got a piece of red oak that should do the trick. Got the double sided tape and good clamps, too. I'm minorly concerned about clamping too tight and creasing the skins.

Thanks,

Sean
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  #10  
Old 03-28-2010, 09:06 AM
txnbuilder txnbuilder is offline
 
Join Date: Sep 2006
Posts: 66
Default I used MDF

Sean,

I ended up making a little rib for the elevator (because I screwed up the bend by trying to use a piece of 2x4 as my bending form).

For the trim tab, I used 3/4" MDF. It came out great.

To make the form, I just traced the outline of the trim tab on the MDF and then used a jigsaw with a guide to cut it.

Here are some pictures:

http://rv7a.fabs-designs.com/2007/02...-the-trim-tab/

Good luck!

Luis
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Last edited by txnbuilder : 05-31-2011 at 08:39 AM.
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