# Cracker Jack 2 LSA from Pete Plumb / Wood Wing Specialty

Discussion in 'Wood Construction' started by Victor Bravo, Apr 5, 2017.

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1. Aug 29, 2018

### Topaz

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Well, clearly it's varnish that's silver in color, and it's used on wood that will be covered by brackets. Sheesh.

Yeah, I know. I have no idea either. I'll let myself out. :gig:

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2. Aug 30, 2018

### BBerson

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Aluminum dust mixed with spar varnish. My dad used barrels of the stuff to paint steel highway truss bridges. I suspect the aluminum might sacrifice to protect the steel. Red lead was also used on bridges.

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3. Sep 5, 2018

### Pete Plumb

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Silver varnish simply verifies the presence of varnish under the fittings.

That statement probably needs to be qualified somewhat. According to the "old-school" woodworking practices, all of the wood in the structure has to be coated to prevent water absorption. That means there has to either glue or varnish (generic term for wood preservatives of all kinds) with no bare wood anywhere - even under hardware and, yes, even inside of holes drilled through. All-wood type structures (as opposed to wood spar/aluminum rib type construction) are assembled hardware first and trammeled, then wood-to-wood joints glued, then the entire structure varnished, and lastly aluminum L.E. and T.E. parts are installed. A conscientious woodworker might remember to varnish the wood before installing the hardware but unless the varnish is pigmented in some way, there will be no proof that there is indeed varnish under the hardware and an inspector could make you pull it off to prove it (I would anyway :devious. Silver powder - the same stuff used in clear dope to make it UV resistant - is a convenient pigment for varnish. It is a practice I picked up in my training on Stearman wings waaaaaay back. Applied cleanly by masking the area first adds a quality touch that is rarely seen these days. Okay, my secret is out...shhhhhhh.

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4. Sep 5, 2018

### Topaz

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And when you mix red lead with white lead, we ALL know that you get a pink submarine, right? :grin:

I promise not to tell anyone. Honest!

5. Sep 7, 2018

### BJC

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Thank you Pete. I appreciate your taking the time to educate me.

BJC

6. Feb 20, 2019

### Cy V

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How's the construction coming on this project, Dave? I see that more pics have been added to your build page...

http://flypegasuspower.com/wp/davescrackerjack/

Did you finish the wings? I'm curious to see how the d-box construction looks on the finished product.

7. Feb 20, 2019

### dougwanderson

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sounds like.\$

8. Mar 16, 2019

### Dave M

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Between Pete and I dealing with the flu and other projects in the shop, work on the Crackerjack was slow for awhile. We had gear on it ( although still working on the shock system ) I made welding jig for the door/ windows, working on finishing up the cabane structure for windscreen, If we can get the header tank welded at the same time as the main tanks, then we can sheet the boot cowl. we had one wing attached and everything fit well. other wing will probably follow next week. The wings still need trailing edges, capstrips, aileron spars and ailerons and D box sheeting ( I have the buck built for forming the leading edge sheeting) but the fuel tanks will need to be sloshed, pressure tested, and fitted first. the tail feathers will be soon, once we can free up some room. Next week there should be more recent pics up !

Last edited: Mar 16, 2019
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9. Mar 16, 2019

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