May 20

Recently I had my first really bad experience with making a mold for a plug that I built.  This was a big disappointment for me.  I had spent about eight weeks building a model of a Porsche 917K body in 1/10 scale that I intended to mold then reproduce.  My model was built to fit a Tamiya TT-01 R/C car chassis.  I had looked for months on the Internet for a 1/10 scale R/C body of this car with no luck so I decided to make my own. Read the rest of this entry »

May 14
Fiberglass Copter Build Part 8
posted by: Steve Jones in Uncategorized on 05 14th, 2017 | | No Comments »

I begin by applying black tooling gelcoat with a dump gun at about 80 psi. I make sure to keep the gun close to my work because gelcoat makes a huge mess if it gets on something other than your project. I lay down a nice thick layer of gelcoat making sure to get good coverage around the base where the plug meets the board.

Once the plug is covered with gelcoat, I let it cure to a tack. I did this project on a nice hot San Diego day so it cured to a tack in about 45 minutes.

At this step I used a different approach than I am used to. I came into possession of a large roll of veil that I decided to use in the corners and angles of the mold. In the past I have always used a combination of cabosil and resin. I found the veil easy to work with, especially when pushing it into corners with a chip brush. With the veil in place, I proceed to build the mold with three layers of 1 ½ ounce chopped mat.

I begin applying the chopped mat by brushing a nice thick layer of catalyzed resin over the area of the plug that I am working on. Then I place a piece of mat that has been pulled off of my roll and lay it on the plug. I like to keep the pieces fairly small on a project like this, no larger than 6 inches square. Pulling the mat apart will leave many loose fibers that will help the strength of my final product once it has cured. When applying the mat, I like to overlap my pieces by about 20% and build a nice flange around the base of the plug.

Happy Glassing


May 4
Building Fiberglass Models Part 5
posted by: Steve Jones in Uncategorized on 05 4th, 2017 | | No Comments »

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, I can start applying chopped mat over the foam.

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. It is time to put the chemicals away and clean up.

After the resin cures, the surface can be rough sanded to knock down any loose fibers.

Once the surface of the plug has been cleaned up with coarse sandpaper, I can examine the pieces and decide where to go with this plug from this point. I began this plug imagining depressions with well defined edges where the windows should be. At this point, it seems that following this course will make this plug much more difficult to complete. This being the case, I have decided that the next phase of this plug build will see the side windows smoothed flush. Flush windows will make building the mold and pulling parts from the mold much easier.

After the rough sanding is complete, I can apply bondo to smooth out the surface of the helicopter. I only mix enough bondo that I can use in a few minutes. By mixing a little less bondo than I can comfortably work with, I am able to be much more efficient from a number of perspectives. First of all, I have time to work the bondo on the surface since I am not rushed by the thought of unused bondo curing on my mixing surface. Secondly, when I mix too much bondo, I end up just piling it on only to have to remove most of it later on because of sloppy application.

Happy Glassing