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Using a vinyl cutter to cut covering

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Using a vinyl cutter to cut covering

Old 10-27-2016, 02:16 PM
  #1  
Stuart Chale
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Default Using a vinyl cutter to cut covering

A few years ago I purchased a "cheaper" vinyl cutter to not only cut vinyl graphics but to try to cut iron on covering too. Turned out that it works quite well for that as well. Just need to adjust the blade depth and pressure, Ultracote (Oracover) is a natural for the cutter as the backing is pretty thick similar to vinyl sign material. But Monokote can also be cut with just a little more care on adjusting the blade depth. You want the cutter to go through the covering but not through the backing. I did a pretty long thread on Flying Giants as my first attempt was on a 40% Dalton in a Red Bull scheme. Worked out quite well and when I messed up a piece of cut covering, a couple of clicks on the computer and a new piece of covering was reproduced in a couple of minutes. Imagine trying to cut out the Bull for a Red Bull scheme by hand only to mess it up and have to re-cut it again by hand

The Dalton was pretty involved with lots of lettering and curved designs on both the flying surfaces and the Fuse which was built up balsa and ply.

When covering with iron on materials I have always used the process of minimizing the covering over covering (traps air bubble to easily) I use a 4 to 5 mm overlap of the covering at the seams. Only the thinner stripes will go directly over covering anything over 10 mm wide will have bare balsa in the center. This is a fairly common method these days but not so much back in the 80's when I started using it.
In the past I made brown paper templates of the pieces to be cut out. Taped them to a sheet of covering and cut them out using an 11 blade over a sheet of glass. Straight cuts were no issue but curved cuts required curved templates like french curves, glasses, cans, dinner plates etc Some pieces required combinations of curved and straight templates. The nice thing about using a vinyl cutter is that you are designing the piece in a drawing program which makes making smooth curves a breeze and as already mentioned if you make a mistake it is easy to fix and re-cut a new piece. If you are covering more than one of the same plane or use the same pattern on each plane once the basic design is done more copies are easy to make. It is also much easier to fine tune your design as changes are much easier than redrawing the whole thing with markers and colored pencils or crayons.

This will be a how to thread on using a drawing program and vinyl cutter for the pattern community.

My prior thread on FG is at http://www.flyinggiants.com/forums/s...ad.php?t=64795
Old 10-27-2016, 02:23 PM
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Stuart Chale
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Just to give you an idea what you can do here is the completed 40% Dalton.


The bottom of the wing.


Top of the stab step by step


Even the lettering is cut from Ultracote
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Old 10-27-2016, 02:54 PM
  #3  
Stuart Chale
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That was 2011 and I think the last major covering job I did. Damn those ARF's
I offered to cover a friends wing and stab for his Allure. Lighter alternative to the composite wings that come with the plane. Many of you will recognize the scheme as Dave L's he has been using it for quite some time.
A fairly simple scheme but the curves lend themselves to this process quite well. Much easier to make nice sweeping curves with a drawing program.
As far as the drawing program any vector based program will do. I use Corel Draw, been using it since Corel 3 which came on floppy disks. If you don't know what they were you are probably too young to remember cassettes, 8 track tapes and, vinyl records as well. (antiques like the rotary phone) Any vector based program will work and a fairly good free one is called Inkscape.

Even if you do not plan on cutting graphics or covering vector based programs are great for designing color schemes for your next plane.
Using the available 3 view this is what I drew and sent to Bryan of CK Aero for my custom schemed Allure


And the plane they sent me
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Old 10-27-2016, 03:17 PM
  #4  
Stuart Chale
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Vector based drawing programs do not care if you are drawing something the size of a postage stamp or the size of a school bus, the file size does not get huge as you go larger for the most part unlike bitmap based picture editing software. Because of this we will be working with drawings that are life sized. In fact the first step is to draw accurate outlines of the wing and stab. I use measurements from the actual components as well as copying an angle or 2 from the "corners". Putting both halves on the wing and stab tube and measuring the sweep back or forward will also help you draw an accurate outline. The available 3 view of the Allure is not accurate enough in this regard as I believe the design changed after the 3 view was drawn (wing swept back further). Vinyl cutters can also be plotters and draw so drawing your life sized outline should be done before drawing the rest of your design. Get the outline right first otherwise you will be adjusting the rest of your pattern. And of course I don't know this from first hand experience. No never!

This shows the wing (with color pattern) drawn on tracing paper and laid over the wing to make sure it fits properly.


After finalizing the outline you can draw the pattern without regard to the final overlaps that you will need to have when cutting your material. The first step is to make sure you are happy with the drawing. I started with a couple of drawings and pictures with measurements from Dave.


There were more but this gives you an idea of what I used to draw the design in Corel.

Initial drawings in Corel of the top and bottom of the wing and stab


Note the use of Guidelines in Corel. These represent lines parallel and perpendicular to the fuse center line. One of the goals in the design is to have the thin outboard stripe portions of the pattern perpendicular to the center of the fuse and the outboard edges and bottom stripes parallel to the center of the fuse. Measuring the sweep with the wing and stab tubes in place and drawing them that way makes it fairly easy. I realize the camera angle makes the guidelines not look parallel in the pictures.
Note in these first drawings the base color is under the trim colors. If you delete the red, orange and yellow pieces the entire wing outline in white will remain.

A straight edge along one of the outboard stripes is nicely parallel to the wing tube.

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Last edited by Stuart Chale; 10-27-2016 at 03:27 PM.
Old 10-28-2016, 03:49 AM
  #5  
Jeff Worsham
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This is a very helpful thread. I've been wanting to learn how to do this stuff...thanks!
Old 10-28-2016, 04:13 AM
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There are several tools that I use over and over in the drawing program. To demonstrate how they are useful lets go through the process of creating a set of templates for the top of the wing.
One of the tools I frequently use is Back minus front. With 2 objects selected the front object shape is removed from the rear object. The 2 objects then meet perfectly along the same line.
To simplify making the 3 color trim on the top of the wing I will start with a rough drawing and then extend the top red down to the bottom of the yellow. Only that curve needs to look good right now.

The basic wing outline (with wing tube )


Red added


The plan is for the color stripes outboard to be 10 mm wide with a 4 mm gap between them. The inboard section just has to have a nice sweeping curve to them. I either add guide lines at the right intervals or draw rectangular pieces to act as guides with heights of 4 and 10 mm
Then add 4 mm stripes and curve the inboard section using the drawing programs node edit features.

Spacers drawn


Next draw 2 perfectly horizontal lines that are 4 mm wide.


Curve them to a pleasing shape marking the 3 sections of trim


Now is where the back minus front comes in by subtracting the 4 mm stripe you will have three areas of red. When performing the back minus front function in Corel the front piece is deleted so I often duplicate it in case I need it again which I probably will when I extend the edges of my piece over the wing root to make my templates next. One Nuance in Corel is that the 4 mm line is still just a line and I have to convert the outline to an object which is a choice under the Object menu.
Here the red has been separated into my 3 sections (spacer rectangles still in place)


Now just right click to break the curves apart and recolor the bottom 2. Basic design is finished. If you are not happy go back and tweak it.


The graphics program will also let you simply mirror your work and create the left wing in one click.
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Last edited by Stuart Chale; 10-28-2016 at 04:15 AM.
Old 10-28-2016, 04:28 AM
  #7  
Stuart Chale
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I hope it all makes sense if you have any questions just let me know.

Originally Posted by Jeff Worsham
This is a very helpful thread. I've been wanting to learn how to do this stuff...thanks!
Old 10-28-2016, 05:11 AM
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Stuart Chale
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Now that our design is complete we have to make the templates for parts to cut out.
Currently we have these pieces drawn.


The red has to be extended over the leading edge and wing root. The yellow and orange need extensions over the wing root and the white base needs to be trimmed so that the other pieces overlap by 5 mm and have extensions added where it overlaps the wing edges. I add the most at the wing tip and leading edge as I like to heat and stretch the film over curved surfaces. At the trailing edge and root you are just folding the covering over so less added material is needed. I usually add about 3" to the wing tip as this takes the most heating and stretching and I try not to burn my hands too much.
Lets handle the white first. With the trim in place back minus front using red and white (after duplicating the red) cuts away the white under the red.
Here the white has been trimmed and the red moved a way a bit to show the new cut edge.


Next I want to expand the white by 5 mm. Doing this all around will be fine as the wing tip, root and trailing edge will need to be extended even further. Corel has a feature called "contour" which will do this for us. I will add a 1 step contour to the outside of the white 5 mm.
When first performed it looks like this the black line being 5 mm wide on the outside of the original white piece. The guidelines are where the edges of the red will go.


To finish this step in Corel you select the contour area right click and select break contour group apart then select the center area and delete it and change the remaining black area to white which is now the original white area just 5 mm bigger around all of its border.


Still have to cut out under the wider sections of the orange and yellow. As the thin stripe portion of the trim is 10 mm wide there will be no cut out under that area. Using the same contour tool we can contour the inside of the orange and yellow and then again break the contour groups apart.


Once again back minus front using the white base and black inside contours will open up bare wood under the yellow and orange trim pieces.
Here the yellow and orange have been removed to show the white piece underneath.


At this point I put all the pieces together shown here in wireframe mode to show the overlaps.


I will also print out the pattern on tracing paper using the vinyl cutter . This is my template for part locations on the wing.
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Old 10-28-2016, 06:21 AM
  #9  
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Stu. this is Awesome!

Bryan
Old 10-28-2016, 06:31 AM
  #10  
flywilly
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Thanks for sharing, Stu!
This will motivate me to get my cutter out of the box (where it has been hiding for quite a while) and functional.
Old 10-28-2016, 10:33 AM
  #11  
Stuart Chale
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Any piece (all in this design) that hits the leading or trailing edge, wing root or wing tip needs to be extended over that edge. How much depends on your covering techniques. This does waste material but I would rather have extra to grab onto especially at the wing tip to help me apply the covering wrinkle free. There are several ways to do this in a drawing program. I generally add rectangular guides the size of the amount of additional material I want to add and either "weld" that with the software to the current piece or using the shape tool grab and move the corner nodes to where I need them.
This image shows a 2" rectangle on the leading edge of the red and a 1" rectangle on the root side (could probably do with less here)


Using the shape tool I can move drag the nodes to their new positions along the leading edge and root leaving the area on the wing unchanged. The root leading edge is not critical but the edge of the red towards the wing tip needs to stay perfectly straight with the current edge. Select the node and using the arrow key to move it up is the bast method for this node. The lower root corner of the red I want to follow the current curve which is why I put the black 4 mm line back in place.
The red piece is finished and just needs to be mirrored to make a piece for the left wing.


Here are the final parts for the top of the wing all extended as needed. Note the aileron piece is extended on all 4 sides and the aileron cutout on the wing is also extended in to cover the edges which is why the aileron piece looks so much bigger than the aileron cutout.
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Last edited by Stuart Chale; 10-28-2016 at 10:35 AM.
Old 10-28-2016, 10:54 AM
  #12  
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Next step before cutting the pieces is to pack them as best you can on a page size 23.5" wide which is what Ultracote is. There are programs that do this for you to minimize wasted space on your vinyl but I haven't found one (free or demo) that actually works.
These are the parts for both wings and stabs tops and bottoms.
White parts


Red parts


Yellow parts


Orange parts


There are extra copies of the orange and yellow parts as otherwise you would just be wasting a bunch of material. They are just in case or for the next plane

The guidelines on the red and white parts are where I will cut to with each group. Much easier to cut 3 or 4 feet worth of graphics cut that off and then cut the next group than trying to cut 15 feet worth at once. There is a lot of white pieces and a 10 meter roll is more economical to cut from than trying to fit the pieces on individual regular sized rolls. There will be less waste.
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Old 10-28-2016, 11:08 AM
  #13  
Stuart Chale
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Final step before cutting your material is to draw out your final designs on paper. This will help show that your piece placement when packed is all good and sometimes reveal a little kink in one of your curves that you thought was OK. An extra node from trying to tweak the design just a little too much.
Things that are easy to fix before you cut your expensive covering. I noticed a little hesitation at the points of the inner white cutouts. An extra node making a microscopic W instead of a V.

A test drawing of a section of white parts.



One of those little mistakes due to an extra node off the main path.


Another test to make sure problem has been corrected. This is the white on top of the stabs.
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Old 10-28-2016, 11:10 AM
  #14  
Stuart Chale
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That's pretty much where I am right now. I have a little filling and sanding on the wings and stabs while I wait for the Ultracote to arrive.
Old 10-28-2016, 12:14 PM
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Simply Brilliant!

Thanks for sharing.

Clear Skies

-PD
Old 10-28-2016, 07:54 PM
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Excellent article...Thanks a bunch!
Old 10-30-2016, 11:05 AM
  #17  
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I usually make little cap pieces for the aileron and elevator ends and surface cutouts in the wing and stabs. I piece of covering attached to the root also makes it easier to seal the top and bottom covering over those inboard edges. You can make those from scrap or have the cutter make them for you as well. In order to make this thread complete I will have the cutter cut them for me. These are generally small pieces (except the wing root) and can usually be put into the wasted space between the other pieces so no additional material is used. On the edges that are hidden I usually put a piece of covering on first just shy of the edges and then fold the top and bottom covering over and seal to it with an eighth inch overlap or so. In the corners of the aileron and elevator cutouts I keep the piece full height to minimize any gap when the top and bottom pieces are folded over. This might make more sense when I actually do it. If I have a flat exposed surface like the inboard elevator edge or if the wing tip or the top of the vertical stab was flat as in many scale aerobatic style planes I will put the pre-cut piece on last to improve the appearance. Again I make it just undersized so the edges will not be caught and peeled back.

You can measure the pieces that you want to draw and draw them, although in this case I find it easier to trace the outlines on tracing paper, tape the paper to your computer and copy the outlines which you should be able to do if the paper is translucent enough (tracing paper) . These are the parts for one Stab/elevator.



Just make sure that you are drawing at 1 to 1 scale. This may be 100% zoom or on my monitor it is 105%. Just draw a square of say 10 inches and adjust the zoom till it measures 10 inches. Some monitors may be a perfect 1 to 1 at 100% and if not and you want to, you can usually calibrate it.
For the curved objects like the stab root, just draw a rectangular shape and convert the top bottom and leading edge to a curve using the shape tool, this only took 10-15 seconds to draw that way.
The other pieces are adjusted for anything that doesn't look square or symmetrical. The bottom piece shown which is for the outboard cutout on the stab just had a rectangle "welded" to one end which will cover the inner corner. See the picture below.



You can print them out with the vinyl cutter.
Cu them out and check for fit


I actually want these just under sized so once again you can use the contour function and use 1 step to the inside by 1 mm or whatever you think you need after test fitting them. Break apart the contour group and use the inside piece. Print out and retest the fit.
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Last edited by Stuart Chale; 10-30-2016 at 11:08 AM.
Old 10-31-2016, 05:12 AM
  #18  
Stuart Chale
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Vinyl cutter doing its thing. Drawing the resized stab and elevator ends.

https://youtu.be/J-50wceZPgI
Old 11-08-2016, 04:46 PM
  #19  
Stuart Chale
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The Ultracote has arrived so just some final filling and sanding.
The wings and stabs are foam core and constructed by the late Matt Kebabjian. He was a builder of the highest caliber so my finishing work is minimal. Mostly just filling a bit of hanger rash and trimming the ailerons a little to fit their cutouts. Sorry Matt I don't think I can keep them from binding with your precise 1/64" spacing (total). A little trimming and sanding for about 3/64" total gap,

Like painting, film covering also begins with the base. The smoother it is the better the final finish. I end up sanding to 600 grit. I use 220 for the filler, then go over the entire surface with 320, 400 and finally 600. I use a standard 9 x 3" drywall type sanding block on large surfaces and smaller pieces of balsa wrapped with the sandpaper for the smaller surfaces.

My all time favorite filler is Pactra Plastic Balsa. Dries nice and hard but sands as easy as balsa. Can be used to fix dented or damaged corners of balsa as well. I suspect that it is no longer available for sale. A quick Google search did not show it. So usually I use the standard lightweight filler available from the home stores. Red Devil or DAP. Not as strong as the "plastic balsa" and sometimes doesn't really harden as well as I would like. If I have a big gap to fill or damaged corner/edge I just cut in a new piece of balsa. Lightly sand with 220 grit and try to avoid grabbing a chunk between your sand paper and plane or you will add new gouges. Another way to fix dents is to wet them and let the water expand the wood. Sometimes this is all you need. I understand that saliva also works in a pinch but I wouldn't know anything about that first hand!

When I build I constantly try to protect the wood surface and fix any damage when I see it. That makes your work minimal when it comes down to final sanding. I sand my sheeting to 220 before even applying it to the foam cores.

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Old 11-08-2016, 05:02 PM
  #20  
Stuart Chale
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Back in the 80's I developed this method of applying plastic film. Mostly using Monokote at the time. At that time Top Flite did not even have a hot glove covering tool. The heat gun was only to shrink material over open bays. They did not recommend applying Monokote in this way. In fact when I demonstrated it to Top Flite at a WRAM show back then to "complain" about some rolls of covering not shrinking as easily as the "good" rolls and not producing as nice a finish I was told that if I applied it with just an iron as recommended that it would work just fine. Of course with this method wrinkles rarely appeared and the finish looked better. Very few people applied plastic covering that well back then. Now it is pretty common practice and lots of plastic film covered models look really good. Most covering jobs use the piece method with a small overlap. Back in the 80's it was trim colors over solid covered bases.

Not sure when I wrote this but it was a whie ago Found it with a search of the Internet. But this is the basic method I have used since the 80's. With an added comment from Dean Pappas. Of course now we can use the cutter instead of hand cutting the pieces in this manner. I cut them on a sheet of glass. In fact I still have the patterns for my Brushfire, Atlanta, Desire, and probably several others


If I can add my 2 cents worth on monokoting. I have won 4 past WRAM shows with monokoted pattern planes. Forget about applying monokote over monokote! Pinholes, soap, chemicals are totally unneccessary. To acheive that showroom finish, you still have to go back to the basics, surface preparation. Protect the wood during the building phase and repair all dings as they occur. Final sanding needs to be done with 200 followed by400 followed by 600 grade paper, the wood should be as smooth as the proverbial baby's well you know. I fully agree with piecing your pattern together using about 3/16 inch overlaps. Yes the base material can be cut on the surface of the wing but I prefer to make a pattern out of brown paper, the stuff you mask the plane with for painting. The pattern is taped to the monokote and cut with a sharp blade and straight edge. Expect to go through several dozen blades to cover a plane!! Place small pencil marks on the wood to line up your piece. After tack ragging both the wood and monokote, put the piece into position. My method is to use the iron to tack the edges down and then use the gun and a wad of cotton to seal the rest. You need to leave an open edge to blow the air out. A little practice is required to perfect the technique, but basically start at the far end from the open edge, heat until shrunk and rub lightly with the cotton wad while still hot, pushing the air toward the open end, you will see some of the wood pattern show through but you must press it down (lightly) to adhere it. If you just shrink the monikote you will really get that showroom finish but it will wrinkle. Continue to the open edge, which ideally would be the trailing edge, but sometimes must be the leading edge or wing tip.In that case make sure you have plenty of overlap and pull and heat with the gun and then finish with the iron. This edge must be cut on the wing. As long as you use a straight edge and very sharp #11 blade with just the weight of the knife, you will not cut into the wood or underlying monokote.The trim colors are also made from patterns and adhered to the edges of the base monokote. This does take more time but the results are worth it. As anadditional benifit, you get very little bubbling or wrinkles later on, and any that do appear can usually be reattached with the gun and cotton,unless you trapped air under the monokote, in which case a pin hole would need to be made. I have an Atlanta in my basement, covered with dust but no wrinkles. I am not even sure what year this is from! Try it you will likeit.
-Stuart Chale

Hello Scott, Do just as Stu tells 'ya. That ATLANTA *has* to date from '86, and I think I remember it at DCRC, that year. The way stu told you to steam roller the air out witha cotton wad works (even for me). After watching his technique at a club meeting, I did an LA-1 wing that is now eleven years old. I just gave the plane away, but the wing has no wrinkles. The planes second stab was quickly covered the "normal" way: it was a prune. -Dean Pappas

Last edited by Stuart Chale; 11-08-2016 at 05:11 PM.
Old 11-11-2016, 07:58 AM
  #21  
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Default Time to get started

OK time to get started. Lost a day because I found my heat gun was making a funny noise (reminder to self: do not drop heat gun) fan motor broke lose. Sort of fixed the plastic housing but messed up the fine resistor wire and it burned up when I turned it on

First step is to clean the work bench. A "clean room" would be great.
Everything ready to get started. Cut white and red covering is on the table. I regrouped only the stab pieces to cut out so the larger wing pieces are not taking up space right now.


All of the balsa parts get cleaned with compressed air (outside of the room) and then tack ragged before each piece is applied. The covering also gets a quick wipe with the tack rag. The better your finish the more obvious is a stray piece of crap caught under the covering.

I use 2 irons and the heat gun. The first iron is set to about 200 degrees and does most of the work. The other is at about 250 and is used to seal the corners. I bump it up to about 285 for the wing tips.

I'll tackle the stab first, better to relearn how to do this with small parts than larger ones
Stab root piece and outboard corner where the elevator sits are first.


Pieces come off the sheet nice and easily when properly cut.


The bottom of the stab is first light colors before dark.


The piece is first tacked to all 4 corners then the leading edge, trailing edge, and outboard edge are sealed using the 200 degree iron. The leading edge is wrapped and smoothed past the mid line. The excess is cut away before shrinking the center of the piece. Excess air is pushed out towards the root which was not sealed yet. The center of the piece is shrunk and sealed to the wood with the wad of cotton, moving towards the root while still hot so all the expanded air is pushed out and the covering is adhered to the wood. A slight wood grain appearance is visible after you push the covering down. The smoother the wood the less wood grain that will show. Then the excess material at the root is cut back to about 3/16" and folded over with the hotter iron sealing it to the piece applied to the root earlier. Excess material is cut off with a straight edge right on the stab. as long as the knife is fresh it will cut through without much additional pressure.

Excess cut from this piece. Even more is wasted on the wing and stab tips.
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Old 11-11-2016, 08:11 AM
  #22  
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Wing tips are one of the harder parts to do well. After using my 200 degree iron to seal partway up the leading edge and wing tip I switch to the hotter iron now turned up to 285 (probably needs to be hotter for Monokote) and heat and stretch the material over the curves. The curve where the leading edge meets the wing tip is the toughest part. Once smoothed past the center line the excess is trimmed off and then the main part of the piece is shrunk and sealed with the gun, You need enough excess material at the wing tip to be able to grab onto it and pull without burning your self with the iron. The heat gun can also be used to heat while you stretch but then burning yourself is almost a certain thing!



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Old 11-11-2016, 12:08 PM
  #23  
Stuart Chale
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Bottom is done. Done for today, have to go to work!

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Old 11-12-2016, 07:37 AM
  #24  
Stuart Chale
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Got a few pieces applied to the top of the stab this morning. Hopefully I will finish the stab later today.
In order to position pieces with cutouts where I want them I use my drawing laid over the surface and use a push pin to mark key spots (corners of cutouts and inboard and outboard edge). Just enough to position the piece properly. The holes are small enough not to show up and are at the edge of an overlap hiding them more.


Those pin holes were to locate this piece. One additional marking was at the stab tip.


I do use a pen to put markings on the white where the overlap should be for the next piece. You might be able to make that out on a few of the pics.


The leading edge and wing tip are finished.


Stab root


The carcass from the cut piece of red material.
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Old 11-12-2016, 07:41 PM
  #25  
Stuart Chale
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Trim colors applied to one of the stabs.

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