Aug 13

 

To begin laying up a fender, I mix about a half a cup of gelcoat with the recommended amount of hardener.  Once this is thoroughly mixed, I use a disposable chip brush to paint the gelcoat into the mold.  I try to get a heavy layer of consistent thickness.  This gelcoat needs to cure to a tackiness before I apply the fiberglass mat and resin.  Usually this takes about 45 minutes. 

 

While I am waiting for the gelcoat to cure a bit, I begin to prepare for the next steps of this process by tearing 1 ½ ounce mat into small pieces that will be easy to lay into my mold.  Since this is a fender, it has compound curves – one that goes side to side and one that goes front to back.  In my experience, smaller pieces of mat are easier to work with in a mold like this.  Just FYI, my pieces of mat are approximately 4” X 4”.

 

Now that the gelcoat has cured to a tack, I mix an 8 ounce cup of resin and catalyst (as directed by the manufacturer) and begin to work my way around the inside of the mold with resin and mat.  I soak a chip brush with resin and use it to blot the resin onto the mat over my freshly applied gelcoat.  Since the gelcoat is still tacky to the touch, it holds the mat in place while I soak it with resin.  I work my way from one end of the fender to the other and then back again (two layers of mat and resin) being careful to make sure that the mat has no air trapped underneath and that the mat overhangs the mold by an inch or so.

 

Once this mat and resin cure to a gel-like state (this takes about ½ hour of 45 minutes) you can safely trim the overhanging extra mat with a razor knife.  If the resin pulls or is too sticky to cut, check back in another 15 minutes and try it again.  This is the best way to clean up your parts of excess fiberglass.

 

After trimming, I allow the part to sit in the mold for a day or so to let it fully cure.  Once fully cured, I pop the part from the mold using a couple of plastic putty spreaders.  I simply use my fingers to pick at the part until I get slight separation from the mold then I push the plastic spreader between the part and the mold and work my way around until the part pops out.  Since I used adequate release wax and two coats of PVA, this part easily separated from the mold.  One fender down, one to go!  

My New Beach Cruiser With Fiberglass Fenders Installed

My New Beach Cruiser With Fiberglass Fenders Installed

 

 

 

 

 
 

 

 

Aug 8
Fiberglass Model Build Part 7
posted by: Steve Jones in Uncategorized on 08 8th, 2017 | | No Comments »

Preparing the plug is the next stage of this build. I begin by mounting the two halves of the plug to a piece of inch thick MDF board. I attach the plugs by using screws from the back side of the MDF. Some people glue or epoxy their plugs to the parting plane. I prefer to use screws because I can remove the plug from the MDF after the mold is finished with out destroying it.

Once I have the plugs securely attached to the parting plane, I need to go around the base of the plugs looking for gaps between the board and the plugs. Any gaps are filled with clay. This is just a matter of forcing the clay into the gaps in order to prevent resin from getting under the plug. When the gaps are filled and all excess clay is removed, I can apply mold release wax to the plugs and the MDF parting plane. I like both McGuire’s and Part-All mold release waxes. It is important to apply at least five coats to the plugs in order to ensure adequate coverage. The plugs should be polished to a shiny smooth finish.

PVA is now sprayed onto the plugs and the parting board. The PVA is an excellent barrier between the mold and the plug. I like to spray a coat, let it dry and then re-apply. Applying two coats of PVA can result in lost detail but that is not a concern for me with this project. An additional coat of PVA will ensure an easy release when I de-mold the plugs.

I apply the PVA with my spray gun at about 60 psi and a distance of 8 to 12 inches. PVA is cheap and valuable at the same time. This set of mirror image plugs is now ready for molding.

For the molding process I need my air compressor and dump gun along with: tooling gelcoat, fiberglass resin and chopped mat, MEKP, rubber gloves, disposable brushes and a respirator or fume mask.

Happy Glassing


Steve

www.fiberglassmoldmanual.com

Aug 2
Fiberglass Fender Build Part 4
posted by: Steve Jones in Uncategorized on 08 2nd, 2017 | | No Comments »

In order to mount this plug to a parting plane, I am going to need a flexible piece of material, something that will easily follow the curve of my fender plug without causing distortion. What I ended up with is a six-inch wide piece of mahogany door skin that will act as the parting plane that will be mounted to a one inch thick, six inch wide by 36 inch long piece of MDF.

To mount the fender plug to the door skin, I used some bondo to stick wooden blocks to the inside of the fender plug and then I screwed the mahogany to the blocks. I then used my hot glue gun to attach the ends of my newly mounted plug and parting plane to the MDF. Just for visual reference, what I ended up with was similar looking to the Dunlop walk-over bridges that you see crossing over the track at automotive races.

With the plug mounted, I am ready to start the molding process. As with all plug molds, I begin by filling any and all gaps that exist between the plug and the parting plane with clay. In this case, I had no gaps so I went straight for the mold release wax. Since my parting plane is a very porous mahogany, I used 5 full coats of wax to ensure that the chances of my plug sticking to the final mold would be minimal. I allow the wax to completely dry and then apply two coats of PVA mold release and allow it to dry.

This plug is now ready for molding. Anyone who has read any of my prior blog projects knows the process that I am about to explain. I begin by mixing enough black tooling gelcoat to brush a nice thick coat over the surface of my plug and parting plane. Once this cures to a tack, I apply three layers of 1 ½ ounce fiberglass matt and fiberglass resin.

When applying the fiberglass mat and resin, I am always careful to make sure that the material has no air bubbles trapped inside. This is especially important with the corners. In this case the critical area is where the plug meets the parting plane. Remember, hurrying through this portion of the mold build will result in defects in your final product. The more defects that you have – the more repairs you will have to make to your parts.

Happy Glassing


Steve

www.fiberglassmoldmanual.com



Jul 31
Fiberglass Finishing
posted by: Steve Jones in Uncategorized on 07 31st, 2017 | | No Comments »

When I first started working with fiberglass, I found it a fascinating yet frustrating material. While I enjoyed the fact that it was water proof and could be formed into any shape, I was often frustrated by my attempts to finish it in a way that would make my final product look presentable. Over the years I have come to the realization that a nice fiberglass finish requires a little preparation and a little improvising.

Obtaining a nice smooth finish can be obtained on a consistent basis when using a mold to produce your parts. Even so, thought and preparation are still necessary. A nice thick gelcoat layer that is covered with a layer of veil that is then covered with a layer of chopped mat will create an end product with a nice finish and no pattern transfer to the final product. The gelcoat layer should be thick enough to allow light sanding without getting into the mat.

When repairing a broken piece of fiberglass, getting a smooth finish takes a little more work. On painted surfaces, I like to remove the paint around the damaged area with sandpaper. Depending on the size of the damaged area, I like to remove enough paint around the damaged area to give me a couple inches of working room. I will then tape over the finished side of the damaged area and apply my repair to the backside of the repair.

Once the resin has cured, I remove the tape and access the exterior of my repair. If the repair is flush or depressed, I will smooth over the surface with either bondo, finishing putty or a thick mixture of resin and cabosil. Once this has cured, I will sand it smooth, primer it, inspect it and go from there. If there are defects in the surface, I will refill them with the medium that I find appropriate and repeat the sanding, inspecting and primering that I had done before. This process continues until the finish is right.

You should not be afraid to sand fiberglass. If you happen to sand it to the point that you expose glass fibers, clip the long ones off and brush more catalyzed resin on. Let the resin cure and re-sand. You may have to repeat this process several times to get your repair right. If your sanding continues to expose fibers, you may want to cut the surface down an 1/8 of an inch or so and fill over the surface with either gelcoat, resin mixed with cabosil or even bondo. Once this has cured you will have plenty of room to shape and sand without exposing fibers.

The bottom line is that many people feel as though the final outer surface of a fiberglass repair must be fiberglass. This is nice if possible, but there is nothing wrong with smoothing over the outer skin of a fiberglass repair with gelcoat, bondo, resin mixed with cabosil or body putty.

Fiberglass Shooting Star Body (Speed Racer) For RC Car

Happy Glassing


Steve

www.fiberglassmoldmanual.com

Jul 25
Fiberglassing for Profit: Part 1
posted by: Steve Jones in Uncategorized on 07 25th, 2017 | | No Comments »

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 begin to build the fuselage of the model and to analyze the proportions, angles and curves of the copter.  

 

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. 

 

                          

 

 

Jul 22
Fiberglass RC Boat Project: Post #1
posted by: Steve Jones in Uncategorized on 07 22nd, 2017 | | No Comments »
A friend of mine who spent an enlistment period in the Navy as a SWCC asked me if I could build a model of the 11 meter RHIB that he became fond of while in the service. I have always enjoyed building model boats so this was an easy decision for me. Not only did I want to build it for him because I like to do those things for people that I consider friends, but this will be a unique project for me. I have never even considered building a boat with an open deck. The 11 meter RHIB has an open deck with exposed seats, control console, and armament – lots of potential detail. Lucky for me I can consult with my friend regarding the details of this project.

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

The 11 Meter RHIB

www.fiberglassmoldmanual.com

Jul 20
Joining Fiberglass Halves
posted by: Steve Jones in Uncategorized on 07 20th, 2017 | | No Comments »

There are several ways to join fiberglass halves. Fuselages, boat hulls and car bodies usually require joining of at least two pieces in order for the project to reach a point of completion.

With some applications, a sleeve can be built into the plug with will allow the second part to slip into which will result in a nice joint that can be epoxied together. An application that comes to mind in this circumstance would be the deck of a model boat to the hull. This technique needs to be planned well in advance since it requires integration into your plug. This technique also is only applicable to those projects that won’t be visually hampered by a visible seem or joint on the final product.

Most of the time, in order to obtain a clean joint that can be filled, sanded and finished in a way that produces no visible joint on the final product, you will need access to the inside of the joined pieces in order to produce a clean union. The best way to do this is to align the halves and use masking tape to hold the pieces together. I like to use thin strips of resin saturated fiberglass mat that I can lay across the inside of the seem. Depending on the strength of the bond that my project requires, I like to have about ½ inch of mat overlapping each side of the seem. Once this cures, your joint is complete. The only thing left to do at this point is finish the exterior.

Another method that I really like for joining fiberglass halves that don’t have to be water tight or incredibly strong is by using what I like to call “chemical applesauce”. “Chemical Applesauce” is a mixture of resin and cabosil that has been catalyzed with MEKP that has the consistency of applesauce. I use this mixture by taping the entire outer surface of the seem, making sure that the pieces have proper alignment. I then use a gloved finger to apply this mixture to the seem line from the inside. I use my finger to push and work the mixture into the joint. This makes an excellent filler as well. Once the mixture has cured, I can remove the masking tape and I am left with a strong, clean joint that requires only minimal sanding and finishing.

These are some of my favorite ways to join two halves of a fiberglass project. I do have a challenging project on the table now that will require special consideration when joining. I will keep you posted on my progress.

Fiberglass AH-1G Cobra

Fiberglass AH-1G Cobra

Happy Glassing


Steve

www.fiberglassmoldmanual.com

Jul 17
Fiberglass Fender Build Part 5
posted by: Steve Jones in Uncategorized on 07 17th, 2017 | | No Comments »

After the resin cures, I like to let the new mold sit untouched on the plug for a few days.  Letting the mold sit for a few days prior to de-molding helps prevent warping of the mold.  In this case, my plug is of a long, thin fender and has a much greater chance of undergoing a noticeable warp then some of my other projects so I am more careful at this stage then usual. 

 

De-molding the fender becomes an easy task.  The PVA and wax layers were not breached and as soon as I began to pull one corner of the fender plug loose the entire mold separated from the plug.  Just as planned – so far.

 

The next step in a project like this is to clean up the new mold of any defects or sharp edges around the flange areas.  I begin by using a rag and water to remove the PVA from the inside of the mold.  The result of my cleaning reveals a perfect molding surface.  Had I found any defects, I would have filled them with bondo, sanded them smooth and then thoroughly waxed over them before molding any parts.

 

In order to make my first parts with this mold I begin by applying several (four) coats of mold release wax to my mold’s surface.  When the wax has dried and has been polished to a smooth shiny finish, I apply two coats of PVA with a foam brush.  On larger projects I will use my air gun but this project didn’t warrant that much hassle.  In this case, I applied a light PVA coat, allowed it to fully dry, then applied a second coat for extra protection.  With both the PVA and the wax applications I made sure to cover any areas of my mold, including the flanges that were formed over the parting plane.  This will insure that my parts don’t get stuck on the mold.

 

Jul 11
Fiberglass Mold Release Agents
posted by: Steve Jones in Uncategorized on 07 11th, 2017 | | 1 Comment »

I have received many questions from those who purchased my manual set regarding mold releases. Especially when preparing the plug. The bulk of the questions seem to come from the use of PVA as a mold release.

Let me start by saying that I like and prefer to use PVA (polyvinyl alcohol) mold release at all stages of my projects – both to release the plug and my parts. I like the security it provides. I have never had a part or a plug get stuck in mold when I have used PVA.

The problem that some people have with PVA is the orange peel appearance that is left on the inner surface of the mold after you have separated the plug from the mold. More often than not this orange peel is visible but can’t be detected by touch. Unfortunately, sometimes the orange peel appearance can transfer to the parts that you will make with your mold.

For me, this orange peel appearance has never been a problem because of the type of projects that I like to build. If you are planning on painting your finished pieces, as I do, the orange peel look of the gelcoat is of no concern. You will be at the least priming and painting the parts so you will never see the gelcoat. Even with R/C boat hulls that I have made I always plan on painting them for the final finish.

If you want to produce finished parts that have that glowing perfect gelcoat surface you will need to take a different approach with the plug. You will have to rely on mold release wax alone to allow for the separation of the plug from the mold. With this approach, you will want to follow the waxing procedures outlined in my manual. Use great care with applying and polishing the plug.

Another consideration with an approach that doesn’t involve the use of PVA is that more than likely you will damage (if not destroy) your plug when you de-mold. This is another reason why I like using PVA – I work hard on the plugs that I build and I like to save them.

I hope that this helps with your PVA questions

Happy Glassing


Steve

www.fiberglassmoldmanual.com

Jul 9
Fiberglass Mold Construction Part 9
posted by: Steve Jones in Uncategorized on 07 9th, 2017 | | No Comments »

I let this mold cure on the plug for almost a week before demolding. This mold popped off its parting board with little effort. Likewise, the mold separated from the plugs with ease. The process for removing the mold from the plug is simple. I use a half dozed small plastic putty knives that I insert between the mold and the parting plane.

Once I have one putty knife between the mold and the parting plane, I simply insert another putty knife at the edge of the separation that occurred as a result of the first knife. This is repeated time and time again as I work my way around the perimeter of the mold. Once you get started, this is an easy process.

At this point the mold is inspected for any flaws, repaired and then prepped for its first part pulls.

Making parts with this mold is very similar to making the mold itself. I begin by applying five coats of mold release wax to the inside of the mold. Once the mold is waxed, I can apply a coat of PVA to the inside of the mold with my spray gun. After the PVA dries, I can do my first parts lay-up. This is part that I really enjoy – I am very close to seeing the results of my efforts and planning.

Happy Glassing


Steve

www.fiberglassmoldmanual.com

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