DocJones199

I am starting a new fiberglass project that will involve plug construction, molding the plug and pulling parts from my molds. Over the next few months I will do weekly postings to act as a basic tutorial for fiberglass molding. That being said, this represents my initial post.

I have made many things out of fiberglass over the years. Typically, my projects involve building a plug, making a mold from that plug and finally using that mold to make pieces.

One project that I have wanted to do for a while was inspired by a ceiling fan that I first saw years ago. I am sure that you have seen the fans that look like the nose of a WW II fighter plane. From the moment that I saw that fan, I thought that it would be cool to have a helicopter body that would hang from the underside of the ceiling fan making the fan blades look like rotor blades. Of course the helicopter would have to be a classic – I chose the UH-1 from the Vietnam era.

Thus the project begins. The first thing I like to do when I am building something like this is to go to the hobby store and pick up a model of the helicopter that I want to build. I use this model as a three dimensional reference. While 3D references are not always available, I do like to use them when possible. For this project, I selected a 1/35 scale UH-1. Using this model, I can get a good idea of the size that the fuselage has to be relative to the diameter of the fan blades in order to maintain a scale appearance.

I began to build the fuselage of the model and began to analyze the proportions, angles and curves of the copter. See the photo of the fuselage below.

G17Staggerwing

My Feedback: (159)

Hello, My name is Nevin M. Levy also known as G17Staggerwing. I am looking forward to your progress and your posts on how you accomplish your tasks. I am very interested in doing fiberglass work and am looking forward to learning your procedures. I wouldd appreciate it if you could e-mail me as you progress just in case I might miss a posting. My e-mail address is: [email protected].
Thanx for your future tutelage
Regards
Nevin
G17Staggerwing

spad4mebaby

Your idea would work with any ceiling fan .
I can't wait to see the finished product.

The front of a tigershark airplane with toothy art pointing down from the ceiling.
A hat with a propellor on top.

DocJones199

Getting on with the helicopter...

At this point, I can begin to produce profile drawings of the copter. I definitely need to start with a view from the top and a view from the side.
Some of this is accomplished through artistic ability and some of it is cheating. The model that I bought had these views in the painting instructions. Based on the diameter of the fan blades, I figured that the fuselage should be about 40 inches from nose to tail. I simply used my copier to blow these views up to the size that I need. Then I drew in some details that were lost in the enlarging process. See the photos below.

The next step for me was to trace these profiles onto a base that I can use to build a plug. I like to use 1/8 inch mahogany door skin for this. I like mahogany because I can buy it at home depot for cheap and one sheet is more than enough material for a project like this. In the photos below you can see the cut outs that I did in the door skin.



You can see that they warp a little. This warping is no big deal since I will easily straighten the pieces out during assembly of the frame. Next, I want to decide along which line to epoxy the primary horizontal shape to the vertical shape. Having access to my plastic model makes this decision easy. In the photos below you can see how I glue two pieces like these. Angle aluminum stock is easy to clamp the pieces to and assures reasonable alignment of the parts.

In addition to angle aluminum making alignment of not so straight pieces easier, it also gives a pretty good 90 degree alignment of one piece to the other.

At this point I need to make a statement concerning scale. I am no artist, I know from the outset of a project like this that when I am done, anyone who knows anything about helicopters is going to look at this and say “Hey, that’s a Huey UH-1�. That is good enough for me. You can put as much talent and time as you wish into a project. This is your prerogative. I like to get a project’s detail to the point where I am satisfied. I think that I am usually satisfied with my projects bearing a close resemblance to the vision that I started with. That being said, nothing that I ever build will ever be completely scale (unless I happen to trip over a bucket of talent and patience)

DocJones199

Now, I move forward with creating buck stations. A buck station is a guide that ensures that your plug is going to resemble what you want it to in the end. For this project I use the same 1/8 inch mahogany that I used for the initial profile pieces. My strategy for placement of buck stations is simple, I put one anywhere that I am concerned about maintaining the correct lines of my project. Usually I am of the opinion that more stations are better.

Another rule that I like when deciding how many stations to use is to make sure that my sanding block is longer than the span between the stations. I am going to fill the spaces between the stations with floral foam blocks and then sand the foam down to the level of the buck stations. The sandpaper will easily cut the foam down. If the sanding block is shorter than the distance between the stations it will create a depression in the foam. Not that a depression in the foam is enough to ruin your project, but it is enough to cause you more work in finishing your project.

In the photos below I have placed numerous buck stations on both sides of the copter fuselage. Make sure to measure all of these out when building a mirror image project. Another way to ensure symmetry of your project is to cut the buck stations for each side at the same time, if necessary, clamp the mirror image pieces together and smooth them with a sander to ensure identical shapes and epoxy the stations in place at the same time. These procedures keep you in focus and your project symmetrical.

With all of the buck stations in place, I can examine the two halves of this project for symmetry. It doesn’t have to be perfect, but it should be pretty close. Once I am comfortable with the symmetry, I can move on and start filling the two halves with foam.

dreadnaut

My Feedback: (5)

Doc,

I have been watching this thread with interest. I have been working on someting like this and using a method very similar to what you are doing. My project is a 42" wingsapn Yak 54 for E-power (3-4 cell li-po). The difference is that I am using hard board. The stuff is cheep, but hard to work with, and I may cut the formers from wood (I have done the profiles and cruches from hard board)

I was planning to plank the thing with balsa, but may go with flower shop foam. I used CAD to generate the patterns.

DocJones199

Foam works awsome. It is cheap, shapes exactly how you want it and it really speeds the completion of your project. This project is nearly done but my writing slows the posting process (not enough time) Here are a few pictures of what the copter looked like in the foam stage. I will get the full post up this weekend. I have used hardboard for builds in the past, I think I like mohagany door skin better. It seems to have many properties that make it easier than hardboard. Here are some pictures of the copter filled with foam and taking shape. All this was done in a few hours one afternoon. Very fast method.

Deadstik

My Feedback: (8)

Great Thread Doc... looking forward to the next post.... going to have to try this technique...

Dan

daven

My Feedback: (1)

Looks great, neat project.

Left_Turn

what are you using for glue and are you glueing all sides that have contact with the blocks?

DocJones199

Thanks all for the kind words on my project so far. I have done many of these and it looks about how it should at this point. As far as glue goes, believe it or not I use bondo. It cures fast and penetrates deep enough to hold the foam during the shaping / sanding process. I try not to get bondo on any area of the foam that will need sanding. I will provide more information on this in my next post.

Left_Turn

So much for doing this in the house [&o]. Looks like I will have to wait for spring, its too cold to do this out in my shed .

DocJones199

This post in the build of this copter is short because I had no time to write this weekend and I covered some of this in a mid week post. Moving on, filling the voids with dry floral foam is easy. I simply push the foam into the forms in away that gives the best use of each foam block. When necessary, I use an adhesive to secure the foam to the developing plug. I love using regular automotive bondo as an adhesive. It holds strong, cures fast and is cheap compared to epoxy adhesives. The photos below show the insertion of the first few foam blocks.

I like to rough trim the foam with a blade to make it easier to work with. Trimming can be done with a sawing motion using any type of serrated blade. Usually I use a hacksaw blade – I couldn’t find it so I used this coping saw instead.

I continue placing more foam between the buck stations. This is my breaking point for my first session of foaming. Kind of looks like a mess but I am right on track.

dreadnaut

My Feedback: (5)

The floral foam is real easy to shape, but have a shop vac handy. It can gets real dusty. A dust mask while working with this stuff is a good idea too.

DocJones199

I am glad you tried the foam - works great doesn't it? You are right, a shop vac amd mask are useful.

RaceCraftRC

this is so sweat hurry back doc

DocJones199

Here is some more on this tutorial, sorry it took me longer than I thought - pre holiday hang-ups. Sanding will make short work of this foam. I like to use a sixty grit paper on a block. One quick sanding session and this thing is really starting to look like a helicopter. I will continue placing foam in the voids until everything is filled and shaped. Continue filling with foam and sanding.

At this point, I will start to fiberglass over the foam. I have decided to hold off on forming in the turbine housing and the top of the tail section. My thoughts are that I would like to have something to place clamps on so I can check the alignment of the body halves during this next phase of the plug build.

I begin the fiberglassing process by using a brush (a cheap disposable brush is best) to cover the foam with catalyzed resin. I have decided that initially I will only do the main part of the fuselage and I will do the tail later. Once the foam has been soaked with a coat of resin (see picture below) I can start applying chopped mat over the foam.

I work the mat onto the surface of the fuselage. It must lay as flat as you can get it. I have spent a bit of time forming this fuselage. I don’t want to get sloppy at this point. Laying fiberglass mat over the foam will provide a nice hard surface for the next step of this build which will be the bondo application. Once the fiberglass has been laid, the only thing to do is let it cure. Time to put the chemicals away, clean up and let the resin cure.

Spike

My Feedback: (1)

It's interesting that you go right for the chopped mat instead of a 4oz cloth or something like that which I would think would give you a smoother surface. Is the chopped mat due to the complex shape?

DocJones199

Yes. I like the way the chopped mat conforms. It is not as smooth when cured but it will need more shaping anyway.

dreadnaut

My Feedback: (5)

Remember that he is working in reverse. The finish layer is on the outside, and goes on last.

Spike

My Feedback: (1)

Ahhhhh. That makes sense!

RaceCraftRC

allright now i am a little confused will the foam stay in it the whole time or will the fiberglassed half be pulled from it?

Spike

My Feedback: (1)

I would think that the current piece will be the plug to make the mold from.

DocJones199

That is it. The plug construction is what I am outlining at this point.

RaceCraftRC

ok got it thanks so this is the negative