Making Plane Parts

[Cozy1200]

I thought I start a more appropriately named thread to document my progress.

 

I prepped the foam for the seatback, F-22, & F-28 over the weekend. It rained solidly so I waited until today to slop epoxy.

 

So TONIGHT I laid the first epoxy in the plane! (where's the backflipping smilie?)

 

Total time from mixing the first batch of micro to final cleanup was just about 2 hours.

 

I was surprised how much epoxy is took to wet up everything. I'm awaiting the rebuild kit for the epoxy pump, so I'm stuck using a scale and plastic bottles. Between the confidence layup and the seatback, I've gone threw .75 liter. I'm using a 1 liter bottle. I guess I shouldn't be surprised, the seat back is a reasonable size. It's probably more physiological than anything. It seems strange to already needed to refill the bottle. It probably won't be an issue if I started using the pump.

 

 

Someone suggested that I make the micro thick to fill up the open cell foam. The plans says micro slurry should be equal parts microballoons and epoxy. I think I mixed at least two parts balloons to one part epoxy.

 

The layup went fine. I thought I was close to finishing when I applied a little more heat. I squeegeed and took off some more epoxy. Actually too much epoxy, the glass went dry. So back on with a little epoxy. I didn't realize how easy it would be over squeegee a part, especially with heat.

 

I peel-plied the entire layup. It was a little tricky to get it laid out without any wrinkles. After it was lightly wetted out, I covered it in plastic wrap. Then placedt a piece of plywood on top and threw several things on it for weight. We'll see how it turns out tomorrow.

 

 

After everything was cleaned up, I cut the glass for f-22 & f-28. The foam is ready and I should be able to do the layups tomorrow.

[Phil Kriley]

Off to a good start! I'm not sure why you think you will use less epoxy if you use a pump instead of the scale, though. You'll get a feel for how much to make for the part you are working on and will throw away less as you get experience.

 

P.S - you need to change your sig - you're a builder now!

[dirtdox]

Go Drew Go!!!!!

[Cozy1200]

I'm not sure why you think you will use less epoxy if you use a pump instead of the scale, though.

I guess I should rephrase that. Using small bottle that have to be refilled often makes it more noticeable the amount of epoxy used. The pump holds more and would need refilled less often.

[Cozy1200]

Today was a public holiday. Something about a horse race.

 

Our washer/dryer combo died today, so I worked on it for a couple hours and found a transistor on the circuit board was blown. So it looks like we'll be shopping this weekend.

 

I removed the peel-ply from the seatback to what I thought was pretty good layup. On closer inspection I think I found a few air bubbles at the angled area. I didn't think it was that tight of an angle. I wonder if the weight of the hanging cloth pull it up. It looks like I'll be injecting some epoxy soon. Other than that I'm pretty happy with the layup.

 

I wanted something else to be curing while I prep the other side of the seatback so I did the layup on F22 & F28. Again about 2 hours from first micro to cleanup. This time I did use John's plastic peel-ply technique; I'M SOLD. It was so easy to chase bubbles out. I was amazed at how little micro was needed this time. I didn't realize the different type was foam would need such a range of micro, but not it makes sense.

 

As you can see I did not cut the bulkhead foam down to the correct size. I'll be using the router & template technique. The templates were made up a couple months ago.

 

After supper I turned my attention back to the seatback. I used the Fein to remove the excess glass. Then turned it over and sanded the edges and cut the flox triangles into the edges. Using a cone Dremel bit made short work of sanding the backside of the glass in the triangle. The bit would remind you of the Permagrit bits, but I think it's carbide tipped.

 

With the Fein being so easy to use and cut, I'm going to want until AFTER I've don't the second layup to cut the corners and electrical channel. I may even hold off until I'm ready to fit it into the fuse.

 

Glass, Peel-ply, and plastic are all cut and ready for the next layup.

[Cozy1200]

Holy Cow, where do I start.

 

First I pull the peel-ply off F-22 & F-28. Both turned out real nice. I'm pleased. I am going buy some butcher paper for covering layups before weighting them down. I've been using industrial rolls of cling wrap (the stuff they wrap pallets with) to protect my plywood. The problem is no matter how careful you are, it always wrinkles a little. Especially were it touches other plastic. These wrinkles show up in the final part. Nothing that needs repair, but the part isn't as smooth as it could be.

 

Second, I HATE FLOX CORNERS! It took me between 30 minutes and an hour to put flox in the corners of the seatback. WHAT THE TRICK to putting flox in the corners? The best method I found was to put a blob on a squeegee and use a stiring stick to push it into the corner. Then go back and carefully squeegee off the excess careful not pull it away from the glass or foam. It's wasn't easy and I kept having to go back and touch some up. I still think I ended up with a few few air bubbles where the flox wasn't completely up against the inside edge of the foam.

 

So finally I got to what I thought was acceptably floxed corners. Then I went on to the micro. I made what I thought was a huge batch of micro, but nope, I need more. The center was not a problem, but what's the trick when working close to flox and how close do you get? On one edge I barely touched the flox and pulled out several chunks. I worked careful to get micro up close to the flox, but it simply took forever.

 

Onto the one layer of bid. Should be simple. Big batch of epoxy, oops need more again. A few spots don't want to wet out so add a little heat and squeegee. Well gotta get that edges to hang properly, so mix more epoxy and wet all the edges. Finally the layup looks reasonably good. Put on the peel-ply and add a little more epoxy. I realize now it was probably too little and suck some out of the layup. Squeegee the epoxy around and add a little more heat to wet it out. Now add the plastic, and squeegee more to remove some air bubbles. There's a few bubbles near where the two plies overlay each over. Squeegee a little more with some heat. A few small bubbles near the flox. I keep working it trying to get rid of the small bubbles out. The problem was I kept adding heat. I'm learning MGS 285 wets out so well that heat alone can also make if almost flow right out of the layup making it dry.

 

No I've got a bunch of airbubbles from what I believe is me over working the layup. So I lift the peel-ply add some more epoxy and stipple with some heat. I can definitely tell the layup is beginning to get stiff. A lot more work and finally it's back to a reasonable state. A few small bubbles, but it's as good as it's going to get. Finally time to move on.

 

Hmm. Amy already went to bed. She has been coming out to help stretch out the industrial cling-wrap and and carefully lay in on the layup. Let's see how I can do this by myself. Well there plastic already on the layup with a bit of epoxy. So I pull out about a foot of wrap and carfully lay the roll on the layup. Then stick the cling wrap down to the table and start of the layup. "Gee this works great" as I unroll the cling wrap. I hear some plastic poping and cracking. Oh that must be the airbubble between the plastic and the cling wrap. Move over and do it again.

 

One last look before I weigh it down and this is when I realize I shot myself in the foot. The popping sound was the plastic sticking to the roll of clingwarp. The problem is it is the side that rolling up and away from the layup. Not only did is suck up the cling-wrap, but also the plastic, the peel-ply, and the glass. There are now tones of airbubbles and lifted glass all over the layup. Many of them in different layers. Some under the glass, some between the glass and peel-ply, others between the peel-ply and plastic. So I spent another hour pushing the bubbles together. As this point I see no other options. The layup has the correct amout of epoxy, it just has trapped air-pockets, no dry spots. So finally I poke a few small holes to push the air out. I think I got all the big one and pushed out most of the small ones. I'll now more tomorrow. ...and I know NOT to do that again!

 

 

So I think I've finally learned to not worry about mixing up too much epoxy or getting it just right. It fairly easy to remove the excess and DON'T overwork it! It's good to know that I should be able to fix any screwup and learn from it. I just learned a lot in a 4 hour out layup that should have taken 2.

 

 

I hope you all get a laugh out of this. I learn how much I can laugh after I see the cured layup and see what repairs may be needed. I'll have pictures tomorrow.

 

But hey, I'm building a plane and loving it.

[aviator_edb]

Drew,

mix your flox and put it into a plastic baggie. Cut a small bit off one corner of the baggie and squeeze the flox into your corner a-la cake decorating. Takes a few tries to figure the right size hole to cut but it works pretty well.

[TMann]

...... or, better yet, just go down to the grocery store and get the disposable cake icing bags. I fold them over a cup so it resembles a funnel in the cup and load them up. Great tip.

[Big Steve]

I have a much cheaper cake decorator type aplicator. I cut aproximatly

6" X 6" piece of wrapping plastic mix up flox or micro scrape into the middle fold it so it is tight then prick a hole with a sharp object makes a nice small hole that works really good to aplicate to thin foam or cut a big hole and make a large stream of Goo. I do not know any cheaper way to do it. STeve

[rickh]

... I hope you all get a laugh out of this.

I'm thinking movie rights

 

Speaking from non experience:

 

Flox. This works for drywall mud et al... Spread a thin layer on your 'work board', 1mm thick or so. Take your putty knife (squeege?) and barely take a swipe off the board. It's a jab and stroke motion. With skill, it'll be a bead just sticking to the edge of the putty knife. Transfer to the foam. (Iz we supposed to paint the corner w/ epoxy before floxing?)

 

Table protection. Umm, swipe the surface of the table with a damp cloth, lay the plastic down before it dries. It'll stick real well. But if the plastic is pretty thin, may be a royal pain getting the wrinkles out. Can you get 2mil polyethylene there? Works much better, drips will pop off for a few uses.

 

Micro. I've understood you should get as close to the edge(s) as possible, not necessarily all the way there.

 

Zero out a board on your scale, toss the cloth on it. 100-120% of that weight for mixed epoxy.

 

YMMV, FWIW, don't forget to floss...

 

Rick

[Cozy1200]

I pulled the peel-ply on back of the seatback.

 

The peel-ply makes the surface look nice. There was only a couple shiny spots.

 

After closer examination, I'm a little concerned. The self-made fiasasco with the cling wrap has come back to haunt me. I think I'm looking at an overall dry layup. It looks like a lot of small airbubbles down under the weave. There are a several larger airbubbles less than 1" that I'm confident that I can inject. The pictures don't do justice.

 

[image1] If you look closely, you can see my pencil marks. These are the worst of the dry spots. A couple are quite large.

 

[image2] A spot next to the flox corners. I'm not sure if this is air, but it may be excess micro.

 

[image3] More dry area?

 

[image4] Airbubble. I should be able to inject epoxy here.

 

[image5] And to top it all off, I have a terrible corner that'll need a structural repair.

 

So suggestions? Oh ya, I've given up on the cling wrap.

 

I cut all the glass needed for f-22 & f-28. I'll do that layup tomorrow. I'm pretty sure I know what to avoid now.

 

The good news? I just bought 1,000 tongue depressors for $20. I think Spodman gonna want some!

[Cozy1200]

I've been thinking about the backside of the IP. The more I look at it, the more unhappy I'm with it. Tonight I filled several of air pockets with a syringe. I'm beginning to wonder about doing a structural repair on the back.

 

Here's an idea and I'm asking for some feedback.

About one inch in from each of the sides, sand down threw the one bid ply. Would it now possible to pull the unattached ply off the foam? Basically de-laminate it. Now perform a typical structural repair. I'm just thinking that trying to sand off a large quantity of glass will cause significant foam damage.

 

 

 

Want some good new?

I now have ONE completed part for my airplane. I will work tirelessly for several the next several years get back to where I'm today. That is to have one and only one complete part.

 

Now if I remember correctly, someone promised/bribed me that showing that un-named person a completed part would earn be another ride in their LEZ!

 

The IP should be done tomorrow after I do the second layup on the stiffners.

[Jon Matcho]

Here's an idea and I'm asking for some feedback.

About one inch in from each of the sides, sand down threw the one bid ply. Would it now possible to pull the unattached ply off the foam? Basically de-laminate it.

Getting the whole ply off isn't going to be pretty, so don't bother. You can cut out the area with a Dremel or with the Fein.

 

Now perform a typical structural repair. I'm just thinking that trying to sand off a large quantity of glass will cause significant foam damage.

You can always fill dings and divots with dry micro.

 

Don't go too nuts with perfecting your edges as you'll see a different perspective when time comes to taping the whole thing together.

[Cozy1200]

Jon I wish I would have taken your advice, but I didn't.

 

After doing the second layup on the IP stiffners, I turned my attention back to the seat back.

 

There are several airpockets about 1/2 inch that have been filled. What's been worrying me are the countless small airbubbles down under the layup. There is only one ply of Bid on this layup so it's definitely under it.

 

As you will recall this is all because I thought I would be smart and simply roll the cling-wrap out on top as a protective layer before putting a sheet of wood on top for weight. Well as the roll unrolled, it pull up the layup ever so slightly sucking in all those tiny bubbles. Big screw-up and even bigger learning mistake. I believe the layup is properly saturated with epoxy, it just has airbubbles underneath it.

 

So now I figured I have several options

 

1: leave it. The airbubbles are all very small, mostly small bubbles between the weave. There are several large sections of the layup that are this way and are probably over the 5% layup criteria.

 

2: Selectively sand away the affected area and perform a structural repair. My concern is that I'll have half the layup gone and have to be patched. Not that it is a probablem, it'll just look bad to have a repair in such a visable place.

 

3: Try to remove the glass by de-laminating it and leave and inch all the way around the layup. Then redo the layup overlapping what's left of the original.

 

4: Start Over

 

 

Well after pondering it for a while I thought I'd attempt #3. Why? I had a couple pieces of scrap from the F-22. I was able to stick a screwdriver between the ply and foam and pop the glass from the foam. Then it was fairly easy to delaminate the rest.

 

Great this should be an easy repair.... or so I thought.

 

I thought I would take the fein, cut the line around the area to be removed. Then pull off the glass. Then feather the remaining glass out by sanding before repairing it.

 

The cut went fine. I then went for the screwdriver and pop off it comes. A couple divots, but certainly repairable. As I continue I realize this wont be as easy as I first thought.

 

Some places it came off real nice right down to the bare foam. Almost good enough to do another layup. Other places the glass came off, but left the micro. And other places I damaged the foam trying to pry up the glass.

 

What I've learned is that some foam holds glass better than other. It does make sense. The seatback foam is opencell and takes a lot of micro to fill up the cells. Foam like the IP is harder and closed cell and takes less micro to fill up.

 

So I have about 1/3 of the glass off and the it pretty much a mess. Some bare foam, some still covered in micro, and a handful of divots. As I was creating this mess it was starting to dawn on me that I may ultimately be remaking the seatback. Visions of ordering a single sheet of foam and then shipping it halfway around the world are haunting me. Maybe find a piece locally. Maybe cut it in quarters and pack in in our checked luggage at Christmas.

 

I do realize that seldom is a piece so bad that it's not repairable. I'm at the point now that I'm wondering for a simple piece like the seatback if it's worth the effort to try to repair this mess or just start over.

 

So I decide see if I have any pieces of this particular foam that I wont need until awhile later. Rats, this is the only place in the plane that uses this type of foam. The plans says you need 1.5 sheets. Spruce has 2 sheets down. Hang one, each sheet is large enough for a seatback.

 

Well it looks like I have an extra sheet that won't be used. I guess spruce has an extra piece included for screwups like me. Am I correct that Spruces Ch4 has an extra sheet or will I need it later?

 

So with an extra sheet of foam and the above screwup, is there any reason not just to give up and start over?

 

One upside to redoing the seatback is improving the front. The front side of the seatback are certainly acceptable, but there are couple dings in the glass from wrinkles in the plastic used to protect the wood. Also I missed a small piece of something that stuck to the wood and created a dent in the front side. Looks bad but I figured I'd just fell it with micro later.

[Edge 513]

While I cant really see it to well from here..=].I would say to mix up some micro and brush it everywhere inside [thicker in the chunked up spots]for new attachment- flatten it out with your piece of plywood to weigh it down and let it cure out. Its hard at this point to see it[because you want everything to come out perfect being your first parts] but really, its just a seatback. You are 9/10ths there. It will be way good enough. In the scheme of things later as you look at it [and I think it will just look like a regular microed seatback if you do it this way], it will just be one of a huge # of parts rather than focusing on these few parts that you have made and one of them was a learning experience. [ But- If it was f28 or one of the other bulkheads- I would say scrap it and do it over] Don't stressssssssss IMHO:cool:

[Jon Matcho]

Drew, unless Spruce made a mistake, I seriously doubt they included extra for your convenience. Maybe you'll need it later -- I forget.

 

Whatever you do, just make sure it's symmetric and the looks won't be a big deal (especially after the paint goes on). Also, you can sand quite a bit of the seatback foam to be thinner than the original without too much worry. You could also do this on purpose to make bucket-ish seats.

 

Piecing together 1/4 parts of seatback foam isn't a bad option either.

 

Don't go too nuts -- you can always change your mind later, even after fuselage assembly (if you insist).

 

Press on!

[Spodman]

The first project I saw the builder had trashed his seatback and was considering those very options when I visited. Don't know what he did, but he had already dismissed the notion of local supply as while he could get the foam, he could only get a whole sheet which cost MUCH more than the amount he needed from ASS. If you find a local supply that isn't too much more than twice the price I'll take a bit. You could always patch what you have and blame it on the neighbor's bunyip...

 

In the light of these two examples downunder I think I'll start on something OTHER than the seatback though.

[CFernandez]

Hi Drew,

 

My $.02 After the fact...

 

Using plastic wrap on flat surfaces is tricky with little benefit. The only time I use plastic wrap is on small compound curves when the glass and peel ply won't stay still on their own. Then you still have to be careful to get all the air out and not stretch the plastic wrap.

 

On large flat the plastic wrap will stretch and pull and make bubbles, its not worth it.Your biggest benefit is using peel ply and rolling the air out of it.

 

 

 

 

PS Jon, how's your project coming?

[Jon Matcho]

PS Jon, how's your project coming?

No progress, but looking to force change upon myself over the upcoming holidays.

[Cozy1200]

The first project I saw the builder had trashed his seatback and was considering those very options ...

I can't tell you how many times that have been ringing in my head since this happened. I think it's all your fault for telling me that.

 

Actually it's one of those sophomore mistakes. I had just gotten comfortable doing layups. Amy had been helping me stretch the plastic out, but she was in bed. That's when I got the wild idea to simply unroll it. The only reason I was using it was it was cheap and readily available in the shop.

 

I think I finally figured out a plan which involves using a router to remove just he cloth and micro. I leaning towards saving the piece now. I don't want to admit that it's one of those screwup that mean the piece has to be scrapped. I think it's more beneficial from a learning perspective to repair the piece versus starting over. I'm learning what works and doesn't work on a not so crucial component. If it turns out, you shouldn't hardly notice the repair. Better than spot repairs over several places.

 

Time wise it'll probably take just as long to repair as to start over, but I won't have to pay for an extra sheet of foam.

[Big Steve]

I tried using plastic on my seat back. What a mistake that was. I have learned that plastic is a bubble maker in fiberglass never again. That is the only part of the plane I have had to repair so far in the build was the huge bubbles on the back side of my seat back. I have also found that using to much peel ply does add weight you can never soak up enough resin to fill the peel ply weave you have to add a little. I learned this on my elevators one weighs more than the other because of peel ply. Be picky but dont be crazy picky or you will never finish. my .02 STeve

[Phil Kriley]

Peel ply makes it heavier? First I've heard that.

[Jon Matcho]

Check out this post or search for 'peel ply weight' here to find a few discussions on the topic.

[Jason Heath]

Peel ply makes it heavier? First I've heard that.

Additional epoxy to fill the weave = more weight, I couldn't tell you how much over the entire plane as it would vary, but it's still more weight.

[TMann]

These parts are a great place to start learning how to vacuum bag.

The result is zero bubbles and zero excess epoxy weight.

 

As a side note, I rebuilt FS22 twice and had to rebuild the pilots seatback once when I broke it (long unpleasent story there.)

Plus I ended up cutting out the passenger seatback out and moved it forward 5 inches.

 

So ......... it's a good thing to start with the small pieces. I got off to a rocky start but learned a lot.