[renedfuller84]

The method and technique being asked about is known as the "lost foam method", if I'm not mistaken. and works very well for molding many components.. IE cowls, wing-tips, wheel-pants, etc. and I'm sure in some cases load bearing structure as well. but I would think a load bearing structure(as in a wing that carries the lions share of weight). some sort of inner-structure must be present.. as stated, a honeycomb type material, or conventional ribbing. and no doubt some sort of spar(s). and possibly other components.. [links]

[cronicleu1]

It'll require the separate leading edge because you're not going to get it to mold cleanly around that part. Or perhaps you could feather the foam core to a thinner core at the leading edge so it can form to the bed. But this requires that you can CUT THE BED accurately. And generally that's not easy to do with a hot wire and foam. So you're better to simply use a wood leading edge cap.

[providers36]

I've done cowls using the lost foam method and it works great. But as anyone that's done these knows you need more than the thin single layer of cloth. And the binding resin needs to be stiff enough to make the cloth fibers lock rigidly together. [links]

[joeydangerous]

Beyond this you get into the idea of forming a self supporting hollow wing that uses a honey comb like method. This involves molding a sandwich of two glass skins with a dense foam core to create a built up skin that is 2 to 3mm thick with glass and resin skins inside and out. here

[Unthinkingbit]

After that some internal bracing is added (usually a few ribs and and a stout wing joiner to once again spread the flight loads) and the whole thing is assembled, generally as two clam shell style halves.

[mkfifo]

1) Take a big chunk of dense foam - pink, gray or blue extruded foam are much easier to carve and sand - to match the fuselage. I take junk pieces of foam and glue the pieces to cover the fuselage outline. Then cut the side outline using a band saw, a scroll saw, a carpet knife or a kitchen knife with small teeth. Complete the shaping and rounding by rough cutting with the knife then sand to final shape - I use a dry wall sanding pad, this is a mesh of abrasive material with plenty of holes where the foam crumbs can lodge themselves instead of rolling and making dents in your foam. All this can be done in half an hour or an hour. 2) Once satisfied with the accuracy and level of details, wrap the plug with one layer of packing tape to prevent the epoxy from getting into the foam. Apply some wax to help remove the tape later on - I will use Johnson floor wax next time. 3) If you want, you can mount it on a fixture with a nail at each end to hold the foam core off the working table. You want to be able to rotate the core like a chicken on a rotisserie so that you can work on all sides of it. 4) Apply one layer of thick fiberglass cloth - 2oz or 3oz - using 3M#77 spray to stick before the epoxy is applied. Apply the cloth in 2" or 3" overlapping strips to ease the placement. Make the strips as wide as will conform to the shape of the core. In some areas, they may be quite narrow, and others quite wide. 5) Mix your epoxy per the manufacturer's recommendations. Then brush epoxy into the glass, thoroughly saturating it. 6) Use toilet paper or paper towels to absorb as much of the epoxy as possible. Lay the paper on a portion of the fuse. Press the paper onto the glass so that it absorbs epoxy. Pull off the paper, being careful not to pull up glass cloth with it. Continue this process until the paper can absorb no more epoxy. 7) Apply the number of layers needed to obtain the rigidity you want. I used a couple of layers of medium grade cloth with additional layers in the nose and tail. 8) Let the epoxy harden for at least 24 hours if no more glass is to be applied. If more glass is needed, apply it before 24 hours. You may want to rough up the surface with sandpaper first.

here

[jesicaaba13]

Some may use polyester resins instead of epoxy, but because of the smell and appetite for foam, I never used that. So I will only describe and talk about epoxy instead. You will probably need only 1 layer over all with another layer of lighter glass in high stress areas, if you use a heavy fiberglass cloth. You may also want to add carbon fiber and/or kevlar in high stress areas. Wear protective gloves when handling epoxy. Work in a well-ventilated area. I use this technique when building scale curved fuselages. I decided to explore with the Lost Foam technique after reading about it being used by several UK modelers on PSS planes. I prefer to use this technique instead of wasting a lot of good balsa wood on a design showing plenty of compound curves. The Hurricane in the pictures is my second attempt at such a technique and gave decent results. Much lighter than my first attempt. But still lots of space for improvement. The Hurricane is 1/15 standoff scale and powered by an AP29 on 8 cells. The dark area on the bare fuselage is where the microballoons stayed in a thicker layer.
The finished fuselage for my Hurricane, created using the technique described in this article.
The finished Hurricane. The technique is fairly simple and fast. I'll give a short description with additional tips and improvements.

more

[user88]

Here are some advantages and disadvantages to consider:

[motherhumper]

1) Spray with gray, white or light gray (depending on the finish color you want) Krylon primer or something similar. Wet sand almost all of it off. Repeat this until you are happy with the surface smoothness. 2) If you make a sport model you can spray with one or two coats of Krylon fast dry enamel. Silver Krylon makes for a very nice aluminum.

[links]

[chrisdbc]

Everyone has its own preferred way of building; some like to carve balsa, some like to bend sticks, some like to get deep in epoxy and polyester or foam and paper. There are certainly a lot of different ways. The Lost Foam technique is just one of them. I will present a bit of a description for this method. Maybe some day you will be tempted to try it. A related molding technique, called the Lost Wax Molding, has been in use for several centuries. In the case of the Lost Wax, the wax is often used to build the second part of the mold but during the process the wax is being replaced by metal in fusion. The wax in the mold melts or evaporates upon contact of the hot liquid metal leaving space for the metal to fill the mold. When the metal turn to solid, the mold is open and the metal piece retrieved. In the Lost Foam technique, the foam is the mold and you dissolve the foam (or just part of the foam to keep more rigidity) when the piece is done to leave you with the resulting part. In short, you carve the shape you want in foam, cover the foam shape with layers of fiberglass and epoxy, and then get rid of the foam. It is used mostly for fuselages and nacelles, but there is nothing preventing you from doing a hollow composite wing this way.

[bitcoinuser]

Mix the resin and hardener properly. Make sure to mix in a well-ventilated area to avoid respiratory problems. Saw off large portion of fiberglass that is not necessarily needed. Slide the knife across the fiberglass then add particles of foam off until the shape is leveled equally. Dip the fiberglass cloth inside the resin mixture. Then place the cloth on the structure on the right position. Avoid the bubbles then continue to wet and place the pieces of the cloth until the full form is covered.

[michb]

Blue Line Fiberglass Sculpture offers many benefits over other such structures. It’s lightweight, that’s why it can be transported very easily from one place to other and shipped cost effectively. It’s also very tough and can resist the environmental hazards if it can placed outdoors. Making a fiberglass sculpture is a time-taking task, it’s also very labor-intensive procedure, but it is an outstanding way to create works of art that will last for years to come.

[nikileshsa]

For making a fiberglass sculpture, an artist not necessary have to purchase fancy carving tools or knife that is used on stone or other carving. He/She needs only the following: more

[xuO4k04c6Ng]

To produce a fiberglass figure, you need to have the correct tools and substance. The steps in making fiberglass sculpture need to have proficiency without any problems. In making your own fiberglass sculpture, the first thing you need to achieve is to gather up your idea and a reference image of any actual piece from all the angles.

[benderamp]

Use the fiberglass cloth overlooking the first shape. If your figure needs to be cut in part, you can work using tinny wire-meshes that are bent into the correct shape.

[hjordanfishere]

Once you have the basic large shape of foam properly proportioned, cut as several pieces as needed to whole and block out the rest of the basic figure. Make sure to have more foam in the right areas, so when you cut and make shape of the foam, you don’t need to add more to achieve the ruined part. here

[Dynotor]

Once the cast has been finished by sanding it, spray with Kylon primer or a similar product of your desired color. After painting or in between coats, be sure to continuously wet sand the surface until you achieve the desired smoothness.

[angie2020]

Everyone has their own preferred method of building molds, as there are a lot of different ways of doing the same thing. However, in order to make a foam mold for fiberglass, some people prefer to use the lost foam technique. This technique has been in existence for quite a long time and is widely used especially for molds that don’t need to be too complex. [links]

[koskenkorva]

Step 4: When working with fibreglass, make sure to take adequate safety precautions. Begin by applying a layer of fiberglass cloth, using 3M #77 spray before applying the epoxy. Apply the cloth in about 3” overlapping strips to ease the placement. You can mix your epoxy by using the manufacturer’s directions as a guide. here

[ptime]

Once you’ve finalised your design with a CAD file, the steps below will help you to prepare your layup for mold making. here

[jglass]

Step 1: Carve out a big chunk of the foam to match the design, and then cut out the sides using a carpet or kitchen knife. Rough cut the sides with the knife to complete the shape according to your dimensions and sand or otherwise smooth out the foam to achieve the perfect shape. This step shouldn’t take you too long, especially if the mold you’re creating is for a straightforward shape. more

[marcpage]

Step 2: Mix a blend of microballoons and epoxy to use as a filling agent and brush the outside of the entire mold. Give the mold at least a day in order for it to harden. more