Fiberglass Mold Making and Fabrication How To – Project Blog

With the recent application of bondo leveled and cured, I can now smooth out the surface of my fender – again. As it turned out, the two outer thirds of the circumference of my fender were about the same height. The middle section was about ¼ to 1/3 inch on the shallow side. It is in this center section that I need to reshape the fender around my newly formed ridge of bondo. I accomplish this with more bondo and a credit card that I use as a spreader. I like using credit cards or other thin pieces of plastic as spreaders because they can be used to produce a flat smooth surface or a nice smooth curved surface. Read the rest of this entry »

As I studied the layout of the bottom of the hull, I identify the important features that I want to maintain throughout the building of this model. Obviously, an outline of the hull Read the rest of this entry »

Continuing with the helicopter build …

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 what I consider 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.                            

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. 

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.  Angle aluminum stock helps me align the mahogany pieces with each other.  I use the angle aluminum to clamp the pieces to each other which assures reasonably accurate 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. 

Hello fiberglassers,

I maintain Steve Jone’s web sites and blogs.  Well, I sort of maintain them. I had to move this blog to a new server due to a couple of issues.

1. I did not stay up with WordPress Security Updates which resulted in the site getting hacked. (You would think hackers could find something constructive to do with their time.)
2. The older version was a pain for Steve to manage.

I am sincerely sorry and apologize to you for the time this blog was down.  Know that Steve will be posting his no fluff straight talk posts on Fiberglass Mold Making and Fiberglass Fabrication.

Thank you for your patience and understanding,

Mike Claggett

Once again work has gotten in the way of my fiberglass molding project.

In my last post I had described how I had finally sorted out the underside of the hull of my 11 meter rhib. I want to move this project forward and I think I have the right plan to do so. I have spent so much time getting the hull of this boat right that I am afraid to do anything that might generate more work on this portion of my build … Read the rest of this entry »

Getting back to building the base for the assembly of my hull, in the previous post I had just assembled the base and am now preparing to attach the piece of cut mahogany that will define the periphery of my hull.

[caption id=”attachment_83″ align=”aligncenter” width=”300″ caption=”The Building Base will define the shape Read the rest of this entry »

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

Steve

www.fiberglassmoldmanual.com

For my friends purpose, this is going to be a display only model. I will definitely make mine radio controlled. The differences in the two models should be minimal with the RC version simply allowing for easier access to the underside of the deck.

The full scale 11 meter RHIB is approximately 36 feet long. The first this that needs to happen is we need to decide on a size. My buddies wife would be happy if it were no longer than a foot from stem to stern. I think that making it 1/6 scale to fit GI Joe would be the way to go. Obviously we are pretty far apart on this so we decided on 1/10 scale making it about 43 inches long. This sized boat will allow me to buy some off the shelf detail pieces such as guns, ammo boxes and maybe even the 50 caliber machine guns (hopefully, I would hate to have to make these!)

Scale is important with a project like this. To make sure that I get as close as possible, I scour the internet looking for photographs and drawings of the 11 meter. I was able to get my hands on a digital owners manual which was of great help as well. The first thing that I did with my photographs and drawings was to use my copier to blow up a drawing of the 11 meter from the top and from the side. My copier has a function that lets me resize a picture up to 200% with each pass through the machine. I did the math and ended up with side and top perspective drawings that give a length of exactly 43 inches long and 16.5 inches wide.

This series of blog posts will be done in real time and will follow my project as I make progress. Stay tuned!! I will post pictures as I progress.

Happy Glassing

Steve

www.fiberglassmoldmanual.com

A little more here regarding removing your fiberglass part from your mold.

If you waxed your mold well and applied a good coat or two of  PVA, your part should easily pop out of the mold.

The operative word in the ^^ Sentence Above ^^ is “SHOULD”!  For a better understanding of why it may not “Easily” pop out of the mold, read my previous post: Read the rest of this entry »

In general, epoxy resin laminates are considered to be superior when compared to polyester resins. That being stated, epoxy does not produce as hard a surface as polyester tooling gel coat so it is not quite as suitable for mold making. If you are planning on turning out even a small volume of parts, you really want the mold to carry the harder surface provided by Read the rest of this entry »