Cutting with a router

[Crazycanuck]

If all goes as planned I am going to start building in the spring, so I am considering the first few chapters carefully now. The first step major step is to build are the bulkheads. One method I figured that might work better is to simply layup a fiberglass sandwich that is a little larger than what is required in the plans. Then cut a piece of plywood in the correct size and shape of each bulkhead. Then I would clamp the plywood to the cured fiberglass sandwich sheet and use a router or fromica cutter to trim the fiberglass to the exact shape of the plywood. I figure that the velocity of the cutting blade on a router would result in a nice clean cut at exactly a 90 degree angle. Does anybody see a problem with this method?

[emteeoh]

cozy1200 did pretty much the same thing. IIRC, he has videos on his site.

[TMann]

I did the same and found that one slip of the router and was was on to new foam.

My experience: Spend all that time you would have been burning to make plywood patterns on making some good bulkheads.

 

When it was all over ........ I was sorry that I had invested the time in the router template.

 

....... on the other hand, you may find someone who already has them sitting in the corner of a hangar in which case, that would be a good deal.

...... or, if your EAA chapter has a couple other guys that are thinking of building one of these, then ....... good deal.

 

For 1 plane ....... not so good ....... but that's just my opinion/experience.

 

If you were to bypass that step, you could do that chapter (4) in a week, tops.

[Lynn Erickson]

If all goes as planned I am going to start building in the spring, so I am considering the first few chapters carefully now. The first step major step is to build are the bulkheads. One method I figured that might work better is to simply layup a fiberglass sandwich that is a little larger than what is required in the plans. Then cut a piece of plywood in the correct size and shape of each bulkhead. Then I would clamp the plywood to the cured fiberglass sandwich sheet and use a router or fromica cutter to trim the fiberglass to the exact shape of the plywood. I figure that the velocity of the cutting blade on a router would result in a nice clean cut at exactly a 90 degree angle. Does anybody see a problem with this method?

Big waste of time. the foam cutting for the bulkheads is 10 minute job and very easy with a straight edge and a blade. after glassing use the same blade to trim the glass and you are done. can be trimmed faster then you can change router blades. if the glass is to hard to knife trim the next day , just warm it up with a hair drier and it will cut very easily. remember to build parts for the plane not tools unless you have no other way. every day building tools is one less day to use for flying

[argoldman]

If all goes as planned I am going to start building in the spring, so I am considering the first few chapters carefully now. The first step major step is to build are the bulkheads. One method I figured that might work better is to simply layup a fiberglass sandwich that is a little larger than what is required in the plans. Then cut a piece of plywood in the correct size and shape of each bulkhead. Then I would clamp the plywood to the cured fiberglass sandwich sheet and use a router or fromica cutter to trim the fiberglass to the exact shape of the plywood. I figure that the velocity of the cutting blade on a router would result in a nice clean cut at exactly a 90 degree angle. Does anybody see a problem with this method?

 

Great idea if you want to have a holy mess, be breathing glass fibers the rest of your life and have your walls coated with grunge.

 

I did that very thing, using a 1/8" spacer between the template and the glassed bulkhead to be so that the guide would ride on the template and cut the bulkhead true. I mounted the router on a router table and additionally mounted a shop-vac hose with about a 1/8" clearance, to evacuate the detritus. Sure did make nice looking parts, except when I slipped and had a few correctable dents. The mess was incredible even with the vacuum. I would never do it again. It was actually 2X the work, and I am still picking the glass spicules out of my Keister. A much better way to do it, I think, and the way that I would do it were I have to do it again, is to draw the glass distribution on the rough cut oversize foam. Glass appropriately, extending about 1" beyond your lines.

 

After the sandwich is cooked, if your lines are not visible, through the glass, use your paper templates, redraw the lines, and using a band saw with a 1/4" metal cutting blade, cut out your parts. Much neater and faster.

 

Understand that when you use a metal cutting blade for glass, it is forever ruined for metal, but will cut glass wonderfully for a long time. Time your projects so that you don't have to keep changing and buying new blades.

 

I would definitely place peelply on the areas that will receive further glass, or the whole thing, at your pleasure. I then would put a layer of plastic over the sandwich. Then I put a flat board (I used kitchen sink cutouts from a cabinet maker) over the sandwich, weighted it down and let the thing cure. When you get a little confidence, you can actually do both sides at the same glassing session. (make sure you put plastic on the first side (I used 1 mil) before turning it over on your glassing table. (vacuum bag if you like) The weighted board keeps things flat when curing.

 

FWIW, when you actually install the bulkheads, you will find that micrometer accuracy is not required.

 

Welcome to the fold:)

[Crazycanuck]

I am really surprised to hear that it does work very well. I used the router method to cut a piece of complicated arborite for a renovation and I was amazed at how cleanly and exactly the piece could be cut. That is what got me thinking that it would be a good method for cutting aircraft parts. Cutting it outside would avoid the dust and would be easy enough to organize, so I am not worried about the dust issue. I am trying to picture what you mean by slipping with the router. Isn’t that the point of the template? The bearing on the router bit runs along the template so the part is cut exactly the same as the template?

[Kent Ashton]

Try the plans method first. I think you'll find it works quite well, is simple, fast and results in a very serviceable part. Millimeter exactness at this stage doesn't add anything.

[Big Steve]

If you are building tools as Lynn says build tools. If you want to fly your plane in your life time build airplane parts. Kent said it very well

Try the plans method first. I think you'll find it works quite well,

This is not rocket science and the parts dont have to be perfect to fly a really nice airplane. My .02 STeve build on

[rickh]

I thought the same... I ended up cutting all the bulkhead foam with a knife/straight-edge then glassing per plans. F28 will end up getting beveled edges where it contacts the longerons, same for the IP, ...

 

I did use a router to trim up the IP bulkhead though. The IP foam seemed way too fragile until fully glassed. I left the under leg holes, push rod holes, and heater holes until both sides were glassed. I've a few pix on my website (in sig) that may be helpful.

 

My chapter 5 page also has a slick way of trimming the ends of the sides square and straight, as well as making the spar cutout. I think it's slick anyway

 

Rick

[JTest]

G'day

 

I have to agree with the builders here. I used a hand saw to cut the foam and my perma-grit blocks to sand them. I spent several hours thinking I needed to sand everything just so. Later you will find that you will use tape to cover any mistakes on the edges. I actually think if they are perfectly strait you will never know. Kind of like painting your house crawl space....

 

I also think I have seen this question several times in the last year (bulkheads, instrument panel...). The results were the same each time, spend the time working on getting the layups correct. Do as you wish, but when you get to Chapter 7 you will wonder why you went to all the effort....

 

Hope this is some help.....

 

 

Jeff

[TMann]

For the seatbacks (keep in mind I'm building a Long-EZ not a Cozy) I cut them to size and followed the plans method.

 

For F22, F28 and F40 I drew them out on the foam and did not cutout the final shape until after I glassed both side (and cured.)

 

I plotted out the radius of the inside corners of the leg holes, and used the appropriate sized hole saw to get the shape I wanted and used a fein and saber saw to do the rest.

 

It only seemed logical to draw out the FS28 above the FS22 and process them as one piece and then parse them out.

 

........... but that's just what worked for me.

[Cozy1200]

Crazy,

 

I know I'm in the minority, but I still like the router technique. If you haven't seen it, check it out on my website.

http://www.cozy1200.com/geeklog/article.php?story=RouterTemplate

 

The excuse that it makes a mess is just non-sense. You're building a composite airplane, it's a messing process. You'll spend hours sanding glass, micro, and epoxy, so what's the big deal with a little mess? Detractors say it'll make you itchy. There's an easy cure for that; A HOT SOAPY SHOWER! Done, gone, no itch. Have you ever fiberglassed a house? It's about the same thing. I don't find it all that bad, but that's an individual thing.

 

Second, lean against any composite part with bare arms and your arms will itch a little. That's just the nature of the business. If you've done any sanding, there will be glass dust around.

 

Some say to follow the plans. The plan has you cut the foam to shape. Then glass and scissor trim within 1/2 inch of the foam. Then come back several hours later to knife trim. Or even reheat with a heat gun to cut. So this is the third time the shape is cut (First cut foam, second cut scissor trim, third cut knife trim). Compare this to the template process where you don't even have to scissor trim because it's oversized. You cut the templates once, then simply cut the bulkhead by using them as a guide.

 

Now the more common method is to use the fein. If you're thinking ahead, you don't cut the foam to shape. After cured, use the fein to cut the oversized foam and glass all at once. This isn't that radically different than the router method. I use the fein to cut glass all the time. It does a fein job cutting straight lines if you use a straight edge (a rudimentary template). But it's not great for cutting around corners. So now cut it over sized and then sand it down. That works fine for an outside corner, but cutting the inside corners of the leg openings would be more difficult. So now you’re sanding shapes by hands using multiple methods.

 

I find having the templates themselves are useful. Most people probably copy the M-Drawings to the foam. I instead copied them to the template. After it was cut, it was supper easy to trace the template onto the Foam. So the layout (copying) process still is only done once. Then after it's glassed I retraced it again onto the glass surface. So there's no lost energy laying out the templates. Cutting the templates is even easier. Good grief it's wood. I used MDF, it’s doesn’t get any easier to cut and sand. Certainly if I’m going to cut and sand something to shape, this is what I want to be working with. I’d loan my templates to you, but they’re in Australia and liable to be laid out upsidedown and backwards!

 

To this day I still use the templates to look at the original layup. They are handy to have around the shop to use for fitting purposes or simply confirm that it was sized currently. Questions like, gee that hole doesn't look like it's in the right position, let's hold up the template for comparison. Yep that's right, let's overlay that to the M-Drawings. Looks ok-great.

 

Someone said a slip of the router and you make a mess of your part. That’s same problem can occur if your not carful with the Fein. It comes down to knowing how to use the tool properly and what you’re comfortable using.

 

I’ve used a router more than I thought I would. So far I have:

-routed the bulkheads using templates.

-Leveled the NACA foam.

-routed the 1/16" depression around the landing brake, F22, & for LG bulkhead

-rounded over bulkheads prior to glassing during ch7

-cut the channel for the Coax going to the Antenna

 

 

My ultimate advice to anyone considering the technique is to do what you’re comfortable with. If you have used routers and templates in the past and like the process, then go for it. You’ll be happy with the results. If you don't like the idea, then skip it. It's just a technique. It's doesn't matter if you freehand cut it or use a CNC machine, most of the shapes are never seen. The inside edges of the IP and F-22 are the only ones that’ll be seen.

 

I'm a carpenter’s son and was taught to build ever part to the best that your skill level will allow regardless if it'll be seen or not. I take pride in ever part. Granted this technique may be higher precision than needed, but early in the build YOU NEED CONFIDENCE. I took my bulkheads to the SAAA (EAA in OZ) meeting and impressed many of the old-timers. That builds confidence.

 

 

BTW, study Nat's pictures closely at the end of the chapter. You CAN make the IP out of one piece of foam instead of two. There's a picture showing that he did it different than the plans.

[Vacabrava]

When I built my bulkheads, I would use the excellent and precise method of Drew. But I have to buy a router.

So I decided to move on and do as Tmann did, very simple and you do not smudge the scissors when triming, or waiting for the pot life to cut burrs.

With the plans method you need to trim very close of the foam to not have one hang out of the fibers. The prior cut of the foam with a razor is terrible, sometimes when cutting you make some holes, get some foam out, make zig-zag, etc...

Simply pass the contour to the ready laminate and trim with the fein.

Take a look in my Chapter 4, look that the IP has reinforcements on all sides, it brings much comfort to your legs. Cause the left portion of the leg cutout to the pilot is sharp edge, and to the co-pilot the rigth edge.

[TMann]

 

Take a look in my Chapter 4, look that the IP has reinforcements on all sides,....

I did the multi plies as a separate layup and then cut the sides nice and straight before adding them to the bulkhead.

I was vacuum bagging these.

[Cozy1200]

Take a look in my Chapter 4, look that the IP has reinforcements on all sides, it brings much comfort to your legs.

I like that. I may do that down the road. I'm hoping to squeeze another 1/2" on the outer side of each leg opening.

[Crazycanuck]

Crazy,

 

I know I'm in the minority, but I still like the router technique. If you haven't seen it, check it out on my website.

http://www.cozy1200.com/geeklog/article.php?story=RouterTemplate

 

The excuse that it makes a mess is just non-sense. You're building a composite airplane...

Cozy 1200, I did look at your website after starting this thread and I saw your videos. I found them very helpful. I especially liked the router technique for leveling the NACA scoop. I also come from a family of craftsmen and learned early in life that focusing on perfection in parts really helps things fit together later in a building process. My dad will spend 4 hours making sure a counter top is perfectly level, not because it is noticeable otherwise, but because it is simply correct. Even minor mistakes can be multiplied across a project and result in twisted result. Freehand anything is always less than perfect, so if there are more actuate tools it is usually worth the investment in time. Anyway, I appreciate your how to videos online. They are very helpful.

[Vacabrava]

I did the multi plies as a separate layup and then cut the sides nice and straight before adding them to the bulkhead.

I was vacuum bagging these.

TMann,

I remember you posting about your carbon IP. I want to see that. Post one photo to us.

 

I like that. I may do that down the road. I'm hoping to squeeze another 1/2" on the outer side of each leg opening.

Drew,

I made mine with 1", like the stiffner`s called in the plans.

And 1/4" rounded the front and the rear borders. I made one real smoth curvature. With micro on the corners.

Aft the IP I leaved the lips to fix the wires.

[TMann]

TMann,

I remember you posting about your carbon IP. I want to see that. Post one photo to us.

I'm working on the nose right now. Once that is finished, I'll project out the new line for the instrument panel (10-15 degree slant) get the new profile and THEN I'll work on laying it up. I'll cut out the cureent pane at about 6-7 inches off the floor up to about 2 inches below the top longeron (to keep everything aligned) until after the new panel is in place.I really don't know how that's going to lay out at this point but I should have an update by the end of Jan.

[Spodman]

I know I'm in the minority, but I still like the router technique.

I've seen the work and it looks gooooood. If I was building more than two of anything I would do it too, or one if there were templates being handed/loaned around, (thinks: Get started Spod before you-know-who buggars orf!) On the other hand, for the exposed leg-holes and top of the instrument panel they just look factory made and I will do it for that result. Or will I end up cutting out the panel an putting in an aluminium one? Decisions, decisions...

[rickh]

Here's one for the books.

 

I opted to cut/insert the elevator hinge hardpoints in the canard before glassing the bottom skin, so I made a jig... for the router.

 

Canard is resting level in the "K" jigs, all I needed was a foot on the table end of the jig (under the boxes of nails). The 'bit' in the router is a 1/4" drill bit.

 

Only disadvantage, if you can really call it that, is the pocket corners are all 1/8" radius. Foam shouldn't stress crack...

 

Rick

[TMann]

That's the same way I did mine. I cut them (the hard points) out on the bandsaw using the hotwire templates as a guide. If you are carefiul with the cutout of the wing foam. you can reuse the trailing edge piece on your hardpoint (assuming you cut the hardpoint to it's finished top profile.) That way you already have several reference points as to how the finished trailing edge profile should look.

 

If you have a long sanding board (I use a 1'x4" x 6' piece of aluminum extrusion) you can cut within a 1/4 inch and then sand the rest to the hardpoint profiles without damaging them.

 

I usd a hand held hotwire tool to do the actual cutout prior to installing,

[TMann]

Here's a link to the post that explains my approach to the hardpoints:

http://www.canardzone.com/forum/showpost.php?p=23997&postcount=18

 

I'm currently rebuilding my canard and this time I am pre-cutting the hardpoints using the hotwire templates as a guide vs. the portion I had removed.