Ch 25 Finishing

Date:  01-08-2019

Number of Hours:  9

Manual Reference:  25-6

A couple of days prep was needed here. Sanding with the drill attachment is very slow.

I did the usual epoxy wipe first. Then a massive fill.

For an unknown reason this time I got the pin hole disease? WTF! I haven’t had this before, same filler and mix technique. I did have the filler application with a piece of metal for smoothing. Maybe that did it?

Here’s the second wing. I applied the filler differently and got a few less pin holes although I’ll have to check tomorrow. Even after a half hour there were more than usual. I’ve not had this issue on the strakes or upper wings.

Looks like I have some sanding to do tomorrow.

Date:  01-02-2019

Number of Hours:  22

Manual Reference:  25-6

This is where I have done a LOT of work with very few pictures. I worked New Years eve, New Years day but did take Xmas day off for a family lunch. Yes I know I should have gone and done a few hours after that. Slack eh?

I’ve filled and sanded both winglets both sides now. They came out pretty well. After a massive fill I did a 4 hour session and got the four sides sanded using my air sander. Then it needed the usual spot fill and more sanding.

These are my special ‘Hoerner corners’. Which are described in his 1965 book “Fluid-Dynamic Drag”. The maths is beyond me but the pictures are great.

OK, nothing much to see in these photos of the top winglet intersection. There is a special curve in there, you’ll just have to visit the build OK?

 

The wings have also had more filling and lots of sanding. This left one is pretty close, the right still as a few spots left to finish but its not too far off.

Here are my weapons. The drill attachment with the scotch-brite pads for the initial dulling of the surface.  The red thing that looks like a toy train is an in-line pneumatic sander. Heavy, noisy and eats sandpaper for breakfast At least the cheapo stuff I use tears after a while. This is my essential tool for getting the job done fast and being less popular in the hangar.

These are the sticks of pain and my set of straight edges.

The wings and strake tops are close. Possibly several days more to be done but enough to get going on the other half. Did I mention the undersides need doing too?

 

Date:  12-30-2018

Number of Hours:  10

Manual Reference:  no ref

This is really just more of the finishing process. I want screw in tip lights (Aveo) with real nutplates and embedded as deeply as possible to reduce their footprint. I had already made provision for this when I built the wings by having an oversized indented area for the lights. I did this job along side a lot of other refinishing over many days.

First up was making a set of nutplates using some scrap aluminium. I did alodine them for good adhesion.

The dremel came out and I went for flush inserts.

After floxing them in I was going to add a ply of glass over the top. Given these are bearing just a tiny load and that they felt very secure, I omitted the glass.

While filling the winglets I did the usual tape release thing so I could knock off a couple of tenths of an inch in light fitting height.

Here’s part way through the fill. You can see the filler is also now helping to hold the nutplates in place. The edges need some work still. You get the idea.

Date:  12-28-2018

Number of Hours:  8

Manual Reference:  25-6

Finishing continues using the air powered inline sander. It makes a terrible noise and takes a bit to swing around but I’m getting the hang of it.

The inner winglet after sanding just needs a few low spots filled now.

This left wing is pretty close to OK. There are still a lot of little areas around the strakes and it seems never ending small things to get right. It’s starting to feel good when you run your ‘gloved’ hands over the profiles.

The outside of the winglets are a little easier that the inside to do. Its getting near time to sort out those tip lights so I can fill the area. Would you believe this is quite smooth now despite how it looks in the picture?

Right wing needs another fill. That was done with the strip method that I think takes more time now I have the air sander sorted.

The strake to wing intersections are getting there. I’m sure I’ll have fun getting the wings off later. At that time I can make the join areas stronger, cleaner and more exact. I still have strake smoothing and a little filling to do.

Oh, and this is only the top side which means I’m approaching halfway for the wing fill. The canard was done ages ago and of course there is still the fuselage.

Date:  12-26-2018

Number of Hours:  6

Manual Reference:  25-6

The right wing had been carefully filled using the Method B. Which are strips of filler and inch or so wide. The desired height is found and you screed in between. Today I tried something instead  instead of filler. I just put some release tape built up in a few layers. Then I had a go at screeding in between.

I think I’m too impatient for this method and not a believer. It is very hard to get an even spread with the thick filler mix. Time to try method C. Like method A you build up a heap of filler.

I started doing this in two halves. After a while I pulled out the tape and just went for one big ugly lump of filler. Fast but dirty work in the sense that it has no refinement.

From the fill I went to the winglets. The pic above is at the end of the day. I went back to find the filler had cured enough for a sand. This is my beast of an inline air powered sander. 15 minutes and I had cut the filler down to be ready for some longboard sanding and then a more elegant fill session.  I need to sort out the sandpaper I’m using as I ate a few sheets. I may need to give up on the cheapo stuff.

Overall I think this is the fastest method to fill and sand. Add a lot, cut a lot away, fast! I seemed to be in control enough not to go too deep, but you have to stay awake while using this tool or it will get away from you.

I couldn’t think of an easy way to do this part of the fill. So I went for ugly. Slap it on, after cure I’ll do a sand and slap some more on.

More filling. Sanding is tomorrow.

No one said this is easy. Maybe it is some secret initiation rite that Long-EZ builders go through and never talk about. I see the stick of pain in my future.   …but I have another special sanding tool to try first.

Date:  12-23-2018

Number of Hours:  6

Manual Reference:  25-6

I should have done this before filling. Sometimes jobs seem to need a little more thought and I just plough ahead instead of thinking ahead. Overall I find it is better to keep moving rather than being stuck. Sometimes I do make things a little harder.

Yes it would have been better to do this before I did the first strake and wing fill.

At least this side had the wing area unfilled. As you can see I’ve laid up BID on plastic and foil. Its three ply and 1.8″ wide.

I added a little peel ply but its probably more harm than good. The gap is quite wide but its not a lot of glass to sand later before filling.

Gravity was defied yet again with the same layup on the underside. I did do this last and gave the epoxy a chance to sit for an hour or so. It worked and the glass and epoxy tapes just stayed there.

I’ve made a cut with a hobby saw and later I did open it up further with the vibrational cutter. The strips are Mylar. I’m putting them in the cut slot and using this as a barrier when I add filler. It will maintain my cut line. I have lost ‘the cut’ in the past and had to dig areas out to find the edges again. I’ve decided there is no need to make the same mistakes more than a couple of times.

Date:  12-22-2018

Number of Hours:  20

Manual Reference:  25-6

The right wing fill continues with Method B, the filling of strips in prep for the screeding between. At the same time Method A continues, old school with heaps of filler and then sand it all away.

Here we have the strips of filler carefully applied and a little sanding to lower the heights.

Just to explain this is the tool to ‘screed’ with. This dictates how far apart the strips need to be. A smaller or longer tool would mean different pile distance gaps.

After a LOT of sanding the strips were just above the wing. Next we did an ‘epoxy wipe’ a minimum amount of pure epoxy to prime the surface before the filler goes on. Yes there was another step before this. The surface was ‘energised’ with a vigorous scrub with a huge scotch-brite pad. I have no clue how much is needed here. When I do it, its not so strenuous. Michael did this one and the plane was shaking!

Technique here is everything with a mass of filler. The idea is to get it as smooth and even as possible so that later sanding is minimised. Factors like temperature and the viscosity of the mix come into play.

Our mix is 50 grams of West 105 resin, 10 grams of West 205 fast hardener and 5 grams of West 410 filler. YMMV. A timed 2 minute mix of the epoxy then get that filler in fast and make it smooth. Then out of the mixing tub as fast as you can onto the surface of the job and spread out. This stuff will exotherm faster than any epoxy I have every worked with. Hence small batches and get it on the job quickly. Two people working together gets it does efficiently, a mixing person and a spreader person.

Meanwhile back on the left wing we are doing the fill and sand and still making progress.

This is the right wing, method B after a good sand and it needs another fill. BUT with considerable refinement of the technique this may be the faster method and may be less sanding.

Back to the left wing again and it just got another fill. After a sand with the ‘stick of pain’ this will, be pretty close to OK.

 

 

Date:  12-19-2018

Number of Hours:  15

Manual Reference:  no ref

The first wing fill has begun.

Michael W. is seen here with the squeegee carefully applying our mix of West epoxy and 410 filler.

While a great job after cure and a sand we could see we needed a thicker mix.

A day later after a much thicker mix there is now a LOT of sanding to do with the stick of pain.

Michael wanted to try another method. This is where you establish a series of high points.

Once these are cured we will sand them down to the perfect level and height. Then the idea is to screed filler mix between these points. If it works, it means minimal sanding. It took all afternoon to do these four points and then it will be another day to sand and maybe do the filling. I have no idea if this will work or be more or less work than just the sanding as will be done on the other wing. That’s right, I have no idea. This is experimental aviation after all.

Date:  12-18-2018

Number of Hours:  15

Manual Reference:  no ref

The strake filling continues.

What can I say? Filling and sanding is hours of work and it all looks the same in the pictures.

Here, there is a slight dip that I’ve decided to fix. I was working on this today for a few hours, yes just sanding and blending that one area.

More sanding and filling at the edges. I’m going to have to deal with those big intersection gaps soon.

This right strake is getting pretty close.

Date:  12-06-2018

Number of Hours:  26

Manual Reference:  25-6

More countless hours sanding and filling the strakes. I’m going to be doing the winglet intersection fairings soon. This meant the rudders should be sanded and filled first.

The rudders took 4 separate cures of filler to get them evenly filled. Most of this was sanded off. It took a while with yet more sanding in between. I used a 150mm air powered rotary sanding attachment with mainly 80grit paper. Worked a treat getting it nice and flat.

Getting the rudders back on with the click bond threads is always a fun way to spend an hour on three nuts. I didn’t bother with the full 10!

This is the intersection that I’ll be doing the new fairing in. I now have the rudder thickness with only a coat of paint to go, which would equal a bit of release tape.

You can’t see the many hours here. Just trust me this strake is 80% filled and smooth. I have the area behind that straight edge and some at the sides. A day or two at most. OK maybe three. Oh yeah, I need a better curve at the leading edge so I’ll look at that too. Of course the right stake is not as advanced. Getting there….slowly.

Here’s a good look at my work area in the hangar. Fantastic to be walking around the plane with wings on.

This is nothing to do with my build. On the other side of the hangar from where my plane is, I helped get a huge 4 ton Trojan inside on the weekend. Fun to be in the middle of all the activity.

Its really big!

Date:  11-28-2018

Number of Hours:  22

Manual Reference:  25-6

There is not a lot to show for the last 6 days of strake filling and some wing surface prep work. I’ve put 22 hours for the log but I think its a few more.

Its a process of prepping the surface the adding filler.

The experiment with plastic covering the filler is over. It makes craters of air pockets and big pins holes. Worth a try.  Plan B is in action, put heaps on, sand it off…

I’m back to the blob method of adding filler. You might notice some smooth areas in the pic. Yes there has been a lot of sanding in between as I identify the low areas.

Meanwhile as a break I use the drill and scotch-brite to keep working on the wings. Getting that surface dull so I can later add a skim coat of filler, not like the handfuls on the strake tops.

This is the stick of pain. 50mm x 25mm x ‘a length’ of electrical conduit with 40 grit glued to it. A simple lightweight tool. I’ve since made a few more of varying lengths.

By some miracle of physics and sweat part of the strakes are quite straight with a nice curve. Its a matter of finding the high point where I’m almost at the glass and have filler for the rest. This will give the minimum added weight. I’ve got a few correct areas now but it needs more filling at the low points. Fill and sand, fill and sand…

 

 

Date:  11-22-2018

Number of Hours:  30

Manual Reference:  25-6

I knew the stakes were going to be tough to fill to get the profile nice and clean. I had a lot of trouble with the blended airfoils that we did. If you have endured this long on a reading journey you might remember I had a herculean struggle with the tops and there were a few dips and valleys not to plan. The bottoms seemed to work out a lot better.

This is an electric drill attachment on my cordless multi-tool. The discs are a course type of Scotch-Brite material. The idea is that the low speed and this material will allow me to take off the shine from raw glass without doing too much damage to the glass fiber. I’ve already done the strakes upper and lower. In between filler cures, I am getting the top surface of the wings done.

It is many many slow hours. If I’d peel plied the lot, this step would largely be omitted. If you are building, save yourself a few weeks of being up close and personal with the whole plane, inch by inch.

Once ‘sanded’ I gave the strakes a coat of pure epoxy and then cleaned off as much as I could with paper towels. Then the first and followed by another dozen or so coats of West epoxy and 410 filler in a very thick mix.

My thinking is that a thick mix will be lighter than a runny mix after its all sanded and perfect. This seems like some time in the misty distant future.

Every angle I take has dips and faults. I’m yet to find a way to do this. A part of the answer is to just start. I know what I want in the end and have to be patient for the magic unknown that is the middle part.

I’m sanding the surface dull between filler applications where I haven’t done sanding work.

Here’s the left wing which I’m doing a bit of every day.

I’ve tried several types of sanding sticks so far. 40 grit contact glued to plastic electrical conduit is my favorite. I’ve made a bunch of things of different lengths and thicknesses.

The key to this picture is that it shows a sanding system. I had a chat with ‘Greg’ in the hangar who is a real metal working craftsman and does glass work as well. We concluded that I need a repeatable system to deal with the undulating compound curves that the blended airfoils and some imperfect work have produced.

I also thought a lot about how the particles of air are traveling and the relative wind over the strakes, assuming I’m not slipping or skidding.

I ended up with going for a sweep from parallel to the strake leading edge and back to the spar to wing join. The pic below gives the idea. I’m ignoring to some degree right next to the canopy where there is a slight rise and then at the other outboard side where we must join with the wing.

The wings themselves in contrast are really good. Very straight and consistent across the profile. They shouldn’t need much filler at all.

The sanding system in the last two pics is on the sides. I have A to G marked out to get my fan pattern and matching straight edges of length that works in the middle of the strake. I don’t need the edges to be perfect as I want to blend to the extremities but I do want to have a pretty flat ‘fan area’.

The idea is to match say the A to A line with the A length straight edge (which also does the B datum) and fill underneath it until its close. After that I’ll be ready to sand. I want a lot of filler on and then I’ll take it nearly to the glass at the high points. I hope this will be the most efficient method.

Today produced a new technique for me. After scuffing the strake I went for the biggest ugliest fill area, covered it with plastic and then used the A-A straight edge to smooth it out. It seems to have worked.

I’ll scuff it up tomorrow and do more until its looking good under the ‘edge’. I’m planning to do the entire strake this way before I go for the profile sanding. Its only that front part that seems to need heaps of filler further back is a lot better.

Hopefully its only these strakes tops that are so difficult. The rest of the plane seems pretty good, or so I keep telling myself.