Making Fiberglass Molds, Fiberglass Parts and Vacuum Bagging

[Big Al]

Composite Mold Making


Composite Mold Making Instructional Videos

Plug Construction & Advanced Fiberglass Mold Making. A complete demonstration of the plug design, construction, and the process of building a large polyester mold of an SAE Supermileage Racer. This project illustrates the development of a full-scale plug in an environment similar to a home garage.


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[Big Al]

Making a Fiberglass Mold and Duplicating


This is a thread that was posted on a motorcycle forum called "Do The Ton" and was posted on Feb 11, 2008. He is making a seat cowl for a classic 1971 Honda 750 and it's pretty well documented with step by step and some really good photos. The point is, he made the part the with the same process. Enjoy


Making a Fiberglass Mold and Duplicating By Old Dog on the "Do The Ton" forum Originaly Posted Feb 11 2008

A friend of mine that builds fiberglass chemical spray tanks for helicopters showed me a process for making a mold for my seat/cowl and then producing a part (or several) from the mold. I thought I would post the procedure if others want to try it. If you have worked with fiberglass before,its fairly easy but time consuming. If you have not worked with fiberglass before, I would not recommend that you jump into a project like this. You'll need an air compressor and spray gun as well. Materials needed can be obtained from a composites dealer like "Composites Canada". Just google out composites dealers and you'll find more answers there. I won't go into huge detail about mixing hardener with resin or the different weights of fiberglass materials cause it's too damned complicated for me too...read the can... One more note here. I'm sure that someone reading this will think "well there's a better or different way to do that". There probably is and feel free to add your comments. The guy that showed this procedure is well seasoned in the field and I was very impressed with what he knows. THANKS BOB!

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Shown below is the seat/cowl that I made by using the spray foam wood and fiberglass technique. It's somewhat heavy so I'm going to make a mold from it and then make a lightweight part from the mold.

[attachment=5]Honda 1.jpg[/attachment]

Prepping the part.

This is the part that I'm going to duplicate. It is important for you to know that I went through all the trouble here because I wanted to incorporate the original 1971 tail light. This part I will call the "plug". It was mounted to a flat board for a reason and you'll see why later. Important things to remember here are...the primer used here is epoxy primer (this primer has hardener that needs to be mixed in and applied with a spray gun), not acrylic which is the more commonly used primer for bodywork. The primer you get in a rattle can is acrylic and is not recommended. After you get a few coats of primer on the plug, dry sand and finally wet sand to remove as many imperfections as you can. The smoother you get the surface at this point...the less rework you will have to do when you pull a part from the mold.

[attachment=4]Honda 2.jpg[/attachment]

Aside from the resin, hardener and fiberglass that you'll need, these products are essential for mold/part fabricating. Mold release wax and coverall film. The wax goes on first and is applied like any other...wax on, wax off. The coverall film shown at right is a very important step in the process. This stuff is applied with your spray gun. No mixing, just dump it in the gun and apply it generously. When dry it will form a very thin film or barrier that resin will not penetrate. So to recap, epoxy primer...sand...apply wax...apply film. The plug is now ready to cover with material.

[attachment=3]Honda 3.jpg[/attachment]

Next step is to cover the plug with a product called "tooling gel". This stuff is a thick resin goop. Hardener is added and then applied with a brush. Tooling gel is used in the first layer of the mold because it offers a thick shell/layer that will allow you to re-tool or sand out any imperfections that may have existed on the original part. This layer took a couple of days to fully cure.

[attachment=2]Honda 4.jpg[/attachment]

After the tooling gel has hardened, your fabric layers are ready to apply. It's a very good idea to have all of your layers preselected and precut. If you have worked with resin/hardener before, you are aware that when resin starts to "kick" things start happening real fast. A good technique for laying in the resin/fabric is to use a cheap disposable paint brush and "dab" all around to remove air bubbles. For this mold, I have chosen the 5 layers as shown. The first 2 layers are called "veil". Veil is very thin and is good for conforming to tight corners and curves. This will minimize any air pockets. I applied both layers at the same time and left it overnight. The 3rd and 4th layers are similar to veil but much thicker and was referred to as "chop". The 5th layer is beefier yet and is a combination of chop and weave.

[attachment=1]Honda 5.jpg[/attachment]

Here is the mold after the tooling gel and 5 fabric layers. Ready to separate from the plug.

[attachment=0]Honda 6.jpg[/attachment]

[Big Al]

Making a Fiberglass Mold and Duplicating Cont.


Excess material around the outer edges was ground off and the mold is separated from the plug. The mold is a solid 3/16" to 1/4". I will now be able to mass produce the same part should the need arise.

[attachment=7]Honda 7.jpg[/attachment]

Now on to the second stage of the process...Making the original part. Clean the mold with soap and water. The same process that was used to coat the plug with (wax and coverall film) is used to coat the mold with. After that has dried the first layer to go on is the "gel coat" layer. This is the white layer (shown below) and was sprayed in with a gun. (Oops, forgot to mention that a special gun is required here. About $60.00 from the composites store). you could brush it in with good results but will require 2-3 coats.

[attachment=6]Honda 8.jpg[/attachment]

Once again, predetermine how many layers you want and precut all of them before you start. For my part, I'm using 5 layers of common fiberglass weave or cloth followed by a final 6th layer of chop.

[attachment=5]Honda 9.jpg[/attachment]

After 6 layers of fabric/chop was applied, The final part is ready to be released from the mold. Note. the black section inside the hump was a piece of carbon fiber that we had laying around. It was not necessary to use it.

[attachment=4]Honda 10.jpg[/attachment]

Below is the final result just pulled out of the mold. You can see the white color which is the gel coat. The stuff that is being peeled off is the "coverall film" that I mentioned earlier. It is easily washed off with soap and water.

[attachment=3]Honda 11.jpg[/attachment]

And finally, here is the part after trimming, cutting the "glove box" hole, epoxying a piece in the bottom of the cowl, mounting system etc. I had to fabricate the aluminum piece to mount the tail light and license plate to. I still have to add the decals and a few coats of clear coat to finish completely. Oh yea...and a trip to the seat upolsterer.

[attachment=2]Honda 12.jpg[/attachment]
[attachment=1]Honda 13.jpg[/attachment]

I have added this pic as a tail light comparison with a stock 71 CB750 . I wanted the original 1971 Honda tail light to fit well with the seat/cowl.

[attachment=0]Honda 14.jpg[/attachment]

[Big Al]

Making a Fibreglass Mould


That's not a misspelling that's the way they spell it in the UK!
This is a supply company in the UK and just like Fibre Glast, they have a very helpful very friendly site with lots of information and How to Videos.

Below is one of their videos on "Making a Fibreglass Mould".

This guy reminds me of Scotty "Captin! I'm givin her all she's Goot!....The Dylithium Crystals Wun't Take It!!!"


Making a Fibreglass Mould



Just like the other companies, they have all of the supplies for making fiberglass molds and parts.

Here is their link

East Coast Fibreglass Supplies

[Big Al]

Plugs


I'm just going to touch on this a little as we covered plugs pretty good in Vacuum Forming and Roto casting. All of these processes start with a plug and end with a duplicate part.

You can make plugs from many things Wood, Paper (with proper hardening technique) and my favorite is wood formers with blue foam shaped to the formers glassed and finished. This works for making fiberglass hard molds as well as making matrix mold for rotocasting and making Bucks for vacuum Forming.

Here are some examples.


Formers

[attachment=5]Formers.jpg[/attachment]

Foam Block

[attachment=4]Foam Block.jpg[/attachment]

Rough shape

[attachment=3]Rough Shape.jpg[/attachment]

Finish Shape

[attachment=2]Finish Shape.jpg[/attachment]

There are alot more steps on this helmet but from here it's ,Fill, Smooth, Glass and paint. and your ready to make your hard mold.

Ready to make a mold

[attachment=1]Ready To make mold.jpg[/attachment]

This particular Helmet plug was made for making a matrix mold for resin casting but it would work for making a hard mold as well and is a good example of making a plug from formers and Blue or Pink foam.


Here is a plug that was made by Mike James at Nextcraft and is the same method we use to make fiberglass planes.

[attachment=0]Plug.jpg[/attachment]

[Big Al]

Plugs Cont.


Ok Real quick ...This is a Martin Baker MB 3 plug that My Fiberglass Guru, Steve Nickerson made 2 hard molds from (Both Destroyed in a tragic wife vs. Garage Accident) . This plug was made just like Mike James's Plug...Formers, Blue Foam, Glass, Paint.

This Plug is about 7 years old and he gave it to me to rework inorder to make a new mold. Notice there are some bubbles toward the nose...This is due to heat during storage (De Lam)...I am currently fixing the flaws so we can make another mold ...also notice the brown resin/microbaloon filler along the the top seam (more patch). This will all be shaped and sanded then re-painted for a new mold.

[attachment=5]MB Plug 1.JPG[/attachment]

[attachment=4]MB Plug 2.JPG[/attachment]

[attachment=3]MB Plug 3.JPG[/attachment]

This is a Martin Baker

[attachment=2]martin-baker_mb-3.gif[/attachment]

This is one of the MB 3's right out of the mold

[attachment=0]MB 3.JPG[/attachment]

This pic shows the under side and the inside of this plane and it's important because next we are going to cover laminating and I wanted you to see how thin we make the plane lay up vs. making somthing like armor parts or helmets where they need to have some substantial thickness. The reason for the thin lay up is weight. we use .75 oz and another layer of 2 oz cloth with carbon fiber twine sandwiched from nose to tail for strength. it also gets wooden formers but not as many as a wood plane.

[attachment=1]MB Part 1.JPG[/attachment]

Once the lay up is made in the mold, both left and right sides are vacuum bagged until cured. Then the two half molds are joined and a strip of fiberglass tape and resin are used to join the two parts inside the molds.

[Big Al]

In The Mold Fiberglass Lay Up


Laminating fiberglass can be simple like the method we use for making the planes , 2 layers of glass, .75 Oz for the skin and 2 Oz behind that. or it can be several layers of different cloth weights and types such as chopped mat, 2 Oz, 4, Oz , 6 Oz, and so on depending on the strength you want, Or it can be a combination of glass and other material such as carbon and kevlar.

[attachment=1]Laminating 1.jpg[/attachment]

This is a boat lamination example

[attachment=0]Lamination2.jpg[/attachment]

These next tutorials show a demonsrtation of a simple lamination for making parts for R/C Model Subs.

After these Tutorials I will cover Sandwich construction (Different than Lam) and Vacuum Bagging


This is a Great Site! This guy has a great photo blog or photo essay, step by step detail on actualy making the fiberglass part in your mold. The name of the site is Rigid 'N' Soft Mold Technology. He has many other tutorials on making molds and plugs as well as plans and techniques.

They build model submarines so the Tutorial and pics are of nose cones being made and it is a perfect example of the process.


Rigid mold preparation, fiberglass reinforced epoxy(FRE) cloth layup. Rigid molds are used to create identical copies of a part. Each part is a hollow shell constructed from fiberglass reinforced epoxy(FRE). Of interest here, the molds are also constructed from FRE. This chapter takes you through the mold preparation and layup of the part. The next chapter deals with demolding the part after the epoxy has cured.

Here is the Tutorial


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 1

Rigid molds are used to make repeated identical copies. Two shapes will be used for the purpose of demonstrating rigid molds, this one is the bow to a radio control model of the USN Los Angeles Class attack submarine. This part has a smooth finish, rounded at one end and a cylindrical shape at the other end. The line in the center is a parting line, the demarcation point between two mold parts. Such marks are common on manufactured items.

[attachment=3]Tut 01.jpg[/attachment]




Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 2

Rigid molds are used to make repeated identical copies. The second shape used for the purpose of this demonstration is the stern to a radio control model of the USN Los Angeles Class attack submarine. This part has detailed finish, with a long tapered cone at one end and a cylindrical shape at the other end. Two parting lines are visible, as are the multiple shapes of the sound dampening acoustic tiles attached all over US Navy submarines. Rigid molds are able to carry great detail over onto the part. There are small circular markings along the part lines, these indicate where hardware is to be installed. This ability to transfer details and markings makes rigid molds a very valuable tool.

[attachment=2]Tut 2.jpg[/attachment]

[Big Al]

Fiberglass Lay Up Cont.


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 3

The bow part mold is the front four parts in this image, alternating yellow and blue. The stern part mold parts are slightly longer and are arranged in the back. The spray bottle in the lower right corner is one part PVA mold release solution and two parts denatured alcohol. The resulting spray is a very fine mist. The heat gun allows the alcohol to be evaporated quickly, allowing for faster recoating. The molds will receive at least six layers of PVA solution.

Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 4

The mold sections are stood vertically and sprayed with PVA solution. The sections will be rotated around to insure that PVA coverage is 100% of all areas that will be exposed to epoxy. Take a look at the blue bow section in front, laying down like this there are two vertical surfaces that the PVA will not stick to. By standing the sections upright, those surfaces are now horizontal and able to receive good PVA spray coverage. The PVA will be dried by the heat gun and the mold sections will be rotated to insure that all areas get good PVA coverage.

[Big Al]

Fiberglass Lay Up Cont. 2



Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 5

Take a look at the depleted PVA spray bottle, that was how much it took to apply six well rounded layers onto the molds. Considering during each layer the sections were turned, some areas receive more coverage than others. The misted on applications make these heavier areas indistinguishable from every area covered with PVA mold release solution. The PVA coverage is now complete.

Rigid mold prep, fiberglass reinforced epoxy(FRE) layup Overview-Page 6

The bow and the stern mold each have four sections. The sections will now be bolted into paired units. Each section fits in only one spot, bolt hole alignment and other marks keep sections from being assembled in the wrong order. A shallow tray is handy to keep small tools and hardware in on the workbench. These are 6-32 socket head screws with washers for each side and hex nut fasteners. The section fit is so fine on these molds the hardware only has to be snug for a good assembly.

[attachment=0]Tut 6.jpg[/attachment]

[Big Al]

Fiberglass Lay Up Cont. 3


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 7

For the epoxy layup it is preferable for the mold to be in half sections. The design of this mold allows it to stand on the table without support. The mold cavity is wide open without obstructions, ready to be worked on. The stern mold sections stand in the background waiting to be similarly assembled.

Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 8

The bow and stern half mold sections stand ready to receive epoxy.

WARNING!

Great care is taken from this point forward not to damage the PVA mold release, which is like a very thin plastic skin over the mold. If this skin were to be scratched, it would break the barrier that keeps the mold safe from epoxy, and the entire process would have to be started over.

[Big Al]

Fiberglass Lay Up Cont.4


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 9

Now it is time to apply the epoxy, in this case the first coat has been thickened to a consistency where a small dollop will adhere to a vertical surface without falling. Please review thickening materials in the epoxy supplies chapter. The epoxy brush has been trimmed about 1/8 inch shorter than provided, this gives the bristles some spring and some give. Never pour epoxy in a rigid mold for the first coat! Start at one end and brush epoxy on, always advancing with full coverage. Thin spots are ok, just make sure there are no breaks in the coverage.

Tip: Do not leave the epoxy edge alone, keep advancing the line until coverage is complete. If epoxy sits for any amount of time, it cures faster than moving epoxy. Even a few minutes sitting will cause a chemical change to the color at the edge. If the epoxy in this mold were left as is until second coat, there would be an ugly white line in a black part that would follow the existing edge you see.

Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 10


The next step is a deceptively simple process called "edging". The two halves of this mold will need to come together cleanly later on. Right now there are many tiny epoxy incursions over the edge of the mold cavity and onto the flat flange area. A finger dragged lightly over the edge of the mold cavity will pick up these bits of errant epoxy quite easily. Care must be taken not to apply enough finger pressure that the PVA barrier is breached. This is easy to do when the epoxy is wet. However if this step is overlooked, small hard nodules of epoxy will form on the mating flange surfaces. This will prevent a successful closing of the mold and may render the part inside useless. The mating edge of the flanges must be clean! This step is repeated for every layer of epoxy applied into the mold.

[Big Al]

Fiberglass Lay Up Cont. 5


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 11


Here is a closer look at the edging process. Once you pick up some epoxy, wipe finger on a towel to remove. Go all the way around the edge to remove all epoxy that might be in the wrong place.

[attachment=1]Tut 11.jpg[/attachment]



Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 12

The little blue towel comes in really handy during the edging process. Wipe off your finger on a clean spot, then continue edging until all flange areas are clean.

[attachment=0]Tut 12.jpg[/attachment]

[Big Al]

Fiberglass Lay Up Cont. 6


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 13


Here is a bow and stern mold half after receiving the fourth coat of epoxy. This layer of epoxy has more volume and is thicker than the previous layers. This was in part to fill in the large right angle area of the mold cavity, and to act as a cushion for the fiberglass cloth coming soon. Note the skin detail of the stern is no longer visible under the epoxy in that section. Also take a look at the edges, you can see slightly beveled areas where a finger has passed through the thicker epoxy.

[attachment=1]Tut 13.jpg[/attachment]



Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 14

With the forth layer of epoxy just applied, the fiberglass cloth is prepared for use. These two inch wide strips of 1.5 ounce deck cloth were cut prior to epoxy mixing, they will now be trimmed into smaller sizes.

[attachment=0]Tut 14.jpg[/attachment]

[Big Al]

Fiberglass Lay Up Cont. 7


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 15

These small strips of fiberglass cloth will be used around the edges of the mold and wherever gaps are between pieces. Some larger pieces will be cut to cover greater areas inside the mold. Once you start work laying in the fiberglass cloth, it is best to have enough cut material on hand to finish. If necessary however, you can pause to cut more. Just make sure that wet epoxy does not get on the scissors!

[attachment=1]Tut 15.jpg[/attachment]



Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 16

A full layer of fiberglass cloth has been laid into the mold cavities. The wet epoxy from the previous layer has adhered to the cloth holding it in place. The black pigment in the epoxy makes it easy to tell what areas of the cloth need more epoxy soaking.

[attachment=0]Tut 16.jpg[/attachment]

[Big Al]

Fiberglass Lay Up Cont. 8


Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 17

Close up of the fiberglass cloth layup in the mold cavities. Overlapping the cloth is ok,that will increase the strength of the part.

[attachment=1]Tut 17.jpg[/attachment]



Rigid mold prep, fiberglass reinforced epoxy (FRE) layup Overview-Page 18

The final mix of epoxy has been applied into the mold cavity. This layer is different than all the others, it must soak into 100% of the fiberglass cloth and this layer must overlap the edge.

The overlapping edge layer is the seal that will bind the two half parts together when the mold is closed. This layer is best applied when the fiberglass layers of epoxy are also still soft, this way any excess epoxy near the edges will be squeezed flat when the mold is closed.

[attachment=0]Tut 18.jpg[/attachment]