Sep 24
Joining Fiberglass Halves
posted by: Steve Jones in Uncategorized on 09 24th, 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

Sep 22
Fiberglass Fenders Part Two
posted by: Steve Jones in Uncategorized on 09 22nd, 2017 | | No Comments »

Now that the foundation for my plug is laid, I can start building a fender. At this point I will just take a moment to regress.

When I was younger, I am sure that this plug would have been built from a much more difficult process than what I have outlined. I am not sure how I would have done this but it wouldn’t have been easy – I probably would have used a template of the rim, done complicated measurements of the total tire diameter and so forth. Building plugs for projects like this are much easier and more likely to provide a nice product if you can use the base object as the foundation for your plug. In this case, I used the actual rim itself. In one of my manuals, I actually used the hood of my jeep as the foundation for building a plug for the hood scoop. This method of plug building takes much of the guess work out of the building process.

Getting back to the plug, I begin building the plug by laying a layer of 1 ½ ounce mat and resin over the foam. Once this cures, I follow with a plastic spreader and bondo to smooth out the surface of the fender. Once the bondo is cured, I smooth out the surface with my electric sander with a course (100 grit) sandpaper to smooth it out. Like with any plug build, I go through many bondo applications followed by sanding to smooth out the surface.

As with many plugs, just about the time that I get this thing smoothed out I see a problem with it. From a side view, it appears as though the center section of the fender, when viewed from the side, isn’t as thick as the ends of the fender. In order to check this, I drilled a hole in the end of a 1/8 inch, inch wide by 36 inch long piece of aluminum stock. The hole is just large enough to slip onto the hub of my rim. I then clamp an L bracket onto the stock aluminum and slid it down until it makes contact with the fender at what I perceive to be the highest point. As I sweep the L bracket around the top of the fender from one end to the other it becomes obvious that not only is my center section low, but I have many uneven points along the surface of the plug.

Fixing these uneven points is pretty easy. I now have a way to measure the outer diameter of the fender and I can use this tool to obtain consistency in the outer diameter.

To smooth out the surface of my fender, I lay a bead of bondo in the center along the length of the plug. While the bondo is still able to be spread, I drag the L bracket which is still attached to the hub through the aluminum stock along the surface of the plug at a level that represents the highest point of the plug. The L bracket levels the surface of the plug creating consistent thickness of the plug.

After this application of bondo cures, I can begin spreading bondo over the surface again to smooth it out. This time I am careful to use the newly laid central ridge of bondo as a guide.

Happy Glassing


Steve

www.fiberglassmoldmanual.com



Sep 21
Fiberglass Mold Construction Part 9
posted by: Steve Jones in Uncategorized on 09 21st, 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

Sep 19
This Fiberglass Mold Making Blog Was Hacked
posted by: Steve Jones in Blog Issues on 09 19th, 2017 | | 1 Comment »

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

Sep 18
Fiberglass Mold Release – PVA Pros and Cons
posted by: Steve Jones in Uncategorized on 09 18th, 2017 | | No Comments »

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

1/10 Scale Radio Controlled Fiberglass Mach 5

1/10 Scale Radio Controlled Fiberglass Mach 5

Happy Glassing


Steve

www.fiberglassmoldmanual.com

Sep 16
Fiberglass Boat Repair 11 Meter RHIB Model
posted by: Steve Jones in Fiberglass Boat on 09 16th, 2017 | | No Comments »

Once I realized that my sponsons were too large (had I been paying better attention I would have figured this out prior to covering them with fiberglass!) my attention turned to what to do about them. Read the rest of this entry »

Sep 15
Fiberglass Mold Release Agents
posted by: Steve Jones in Uncategorized on 09 15th, 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

Sep 13
Fiberglass Finishing
posted by: Steve Jones in Uncategorized on 09 13th, 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

Sep 12
Fiberglass Molds – Multipiece Benefits
posted by: Steve Jones in Uncategorized on 09 12th, 2017 | | No Comments »

I just finished building a new mold for a 1/10 scale radio controlled car. One of the great things about making radio controlled car bodies out of fiberglass is the detail and the undercuts that can be formed using multi-piece molds. The realism is much greater than that which can be found in a vacuum formed body.

Multi-piece molds are always necessary for building three dimensional objects – whether those objects are hobby related or not. With the exception of very simple molds, multi-piece molds are almost always required or at least preferable. The obvious reasons for the use of a multi-piece mold are driven by the ease of extracting your parts from that mold. Molds that are very deep are difficult to lay-up parts in and can be very difficult to pull your parts out of.

The draft angle of your plug is a major determining factor that will determine the need for a multi-piece mold. Smaller parts may require no draft angle while larger parts that are deeper than 12 inches will require a draft angle of up to 5 degrees.

Automotive parts other than hood scoops, fender flairs, spoilers, etc are often done with one piece molds. Larger parts, such as doors, hoods, entire bodies and the like are almost always done as two piece molds.

I was looking at my first and main Fiberglass Mold Manual in which I outline the procedures for building a simple one piece mold. The funny thing about this manual is that the project that I follow in this manual ultimately required 3 separate one piece molds. A project requiring 3 separate one piece molds can also be labeled as a multi-piece mold.

Multi-piece molds do give many benefits to the builder, but there are a few drawbacks. Multi-piece molds do produce a flash line that must be dealt with. Flash lines require filling, sanding and refinishing. Flash lines are created by imperfections in the edge of the mold and in the general alignment of the pieces of the mold. In my opinion flash lines are a minor trade off for the many benefits of a multi-piece mold.

Happy Glassing


Steve

www.fiberglassmoldmanual.com

Sep 10

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 »

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