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        Discussion Concave/convex planking.

#1 Jon Snow Nov 06, 2012 08:02 AM

Concave/convex planking.
 
I've got some of the above in my near future.The fit is better if the cuts are at an angle.I've been thinking about trying to pack the blade on the stripper out and turning the sheet over after each cut.
How do you guys do this,is there an angle adjustable stripper out there?
Regards Stuart

#2 epoxyearl Nov 06, 2012 09:10 AM

There is no easy way to do it,because if you're doing a round,tapered,piece,each strip will be different..
There was a thread here a little while back where some one shows how to make an aluminum tapered guide to cut each strip so it fits..
It sure looked as if it would work....
Most of the planking I do is on large models,so a very slight angle is required- I usually sand,or plane,it in as I go.

Maybe someone can link you to the thread.

#3 Curare Nov 06, 2012 04:54 PM

can you show us the area that you're trying to plank?

There may be other ways of doing things...

#4 Jon Snow Nov 07, 2012 04:28 AM

1 Attachment(s)
Not a great deal to show as yet.The part is a fixed u/c pylon which also has a nacelle mounted either side.The concave part is where the nacelles will fit,the convex(which is parallel most of it's length so no problem) will be split and hinged to cover the wheels in flight.
The foam blank is the overall shape,I've sectioned this to get the formers.
I've just cut a few out of liteply to make sure the concept is sound and I can fit the hinges etc.
This is pretty much a make it up as I go build,no drawings apart from some outline ones I took off an original factory drawing which never got used.(HoXVIII)
The wings aren't a problem,but the pylons are unusual to say the least,and will need to be fairly robust.
Stuart
http://www.rcgroups.com/forums/attac...mentid=5279914

#5 epoxyearl Nov 07, 2012 04:50 AM

bent balsa
 
In your link,I saw that you are making a concave insert that tapers...I have had great success in preforming those around various sizes of PVC pipe..Soaked balsa wrapped with Ace bandages, and allowed to dry, work perfectly.
No difficult sanding is involved with single-piece seamless parts.

Some convex parts can be pre-formed also,if they are relatively straight.

I don't think pre-forming is any less workman-like than strip planking.

#6 Jon Snow Nov 07, 2012 06:40 AM

Quote:

Originally Posted by epoxyearl (Post 23204978)
In your link,I saw that you are making a concave insert that tapers...I have had great success in preforming those around various sizes of PVC pipe..Soaked balsa wrapped with Ace bandages, and allowed to dry, work perfectly.
No difficult sanding is involved with single-piece seamless parts.

Some convex parts can be pre-formed also,if they are relatively straight.

I don't think pre-forming is any less workman-like than strip planking.

With you on the performing.Still looking at options,
Regards Stuart.

#7 Al Offt Nov 07, 2012 07:13 AM

You might want to look at the article http://www.raysmodels.ca/Technical%2...%20article.doc It is a nice article on one technique for planking and making an angled stripper.

Alan

If I have typed the URL incorrectly, you can also find a reference it in the first post of http://www.rcgroups.com/forums/showt...ighlight=plank

#8 Jon Snow Nov 07, 2012 08:15 AM

Quote:

Originally Posted by Al Offt (Post 23205548)
You might want to look at the article http://www.raysmodels.ca/Technical%2...%20article.doc It is a nice article on one technique for planking and making an angled stripper.

Alan

If I have typed the URL incorrectly, you can also find a reference it in the first post of http://www.rcgroups.com/forums/showt...ighlight=plank

Thanks for the link Alan.Unfortunately the pics aren't coming up,tried it twice.I have the same stripper,I presume he modified it as I suggested in #1.
I have an idea in mind to make a jig to taper the planks,I'll post if it comes off.

Regards Stuart

#9 Jon Snow Nov 07, 2012 04:29 PM

1 Attachment(s)
Cracked it!The sheet has to be reversed each cut to keep the grain,but this is needed to get the bevel edge anyway.The angle of the bevel can be set by packing the channel.
Stuart

#10 Al Offt Nov 09, 2012 07:12 AM

3 Attachment(s)
Sorry you were not able to open the pictures. Attached are a few key ones although they may be hard to understand out of context with the rest of the article.

If you would PM me your email address, I'll be glad to send the whole article as an attachment (I can't attach a document to a PM).

Alan

#11 epoxyearl Nov 09, 2012 06:42 PM

RE:report #10
 
If it's not intruding too much,what glue are you using for the planking?-writing a book-lol.

I had been using a straightedge and an angled knife to strip my planking.I now understand the angled stripper.......

#12 Al Offt Nov 10, 2012 09:24 AM

Earl,
I have not actually planked a fuselage but want to try one this winter. What you see in the pictures are from the article.

I have gathered a few other articles on technique and glues. One suggests using Titebond along the edge of the strip, hold the strip in place and place drops of CA at the bulkheads inside the fuselage where the strip meets the bulkhead. You repeat the hold and CA application progressively along the strip from one end to the other or just at the ends if you are lucky. You just have to hold the strip in place long enough to have the CA set up. Another article suggests Titebond along the strip edge, some thin Titebond on the bulk head and then CA drops at the bulkhead as you hold the strips in place . These gluing techniques require that you hold the piece in the air to gain access to the inside of the fuselage during most of the planking process.

Since I like a little more insurance that the fuselage will be straight, I plan to build fuselage halves on a flat work surface over the plan and then glue the halves together after the halves have been planked. That means I won't have access to the inside and will probably try the CA on top of Titebond approach if I can get the strips in their final position before the CA sets up. If that does not work, I'll resort to some kind in 'clamping/holding' fixture (scrap wood cut to match the circular shape of bulkheads at the end of the strips that I will hold down with weights. I won't know what technique works until I try it.

Alan

#13 kenh3497 Nov 10, 2012 09:25 AM

When I did the top of tank area (firewall to canopy) of my CAP 232 I used thin CA to attach the strips. The inside got a coat of thinned epoxy for fuel proofing and also to make a better bond where the CA didn't take. I had no issues with sanding the outside to a smooth finish. 3/4 oz glass and epoxy finished the outside.

Ken

#14 Circlip Nov 10, 2012 10:13 AM

If the strips cut in #10 are alternated as shown, you end up with a flat sheet again.

Regards Ian.

#15 Jon Snow Nov 10, 2012 10:53 AM

Quote:

Originally Posted by Circlip (Post 23233157)
If the strips cut in #10 are alternated as shown, you end up with a flat sheet again.

Regards Ian.

I'd noticed that also.The angle needs to be cut so they butt against each other
Stuart


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