Jun 27

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 Read the rest of this entry »

Jun 26
Tooling Gelcoat for a High Gloss Finish
posted by: Steve Jones in Fiberglass Tips & Trix on 06 26th, 2017 | | No Comments »

I’ve received some more questions about Fiberglass Mold Making Gelcoat and how to end up with a high gloss shiny finish.

Sonic 1 High Gloss

When constructing a mold for duplication of parts, there are several considerations that must be addressed.  The main reasons for using tooling gelcoat versus finishing gelcoat have to do with the hardness of the finish and the shine of the finish.

The finished surface of your mold should be abrasion resistant.  Polyester gelcoat is used for making tooling masters and molds where good gloss retention of the surface is of paramount importance.   A high gloss finish of the molds surface allows for easier release of your parts and thus extends the life of the mold. Read the rest of this entry »

Jun 24
Fiberglass Fender Build Part 4
posted by: Steve Jones in Uncategorized on 06 24th, 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



Jun 22

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 »

Jun 21
Why Vacuum Bag Fiberglass Parts
posted by: Steve Jones in Fiberglass Tips & Trix on 06 21st, 2017 | | No Comments »

One way to make light, strong and clean parts is through a technique called vacuum bagging.  In general, parts made with vacuum bagging techniques show better strength and stiffness than simple molding lay-ups and they are smoother to the touch.  The strength and stiffness of vacuum bagged parts obviously comes from  Read the rest of this entry »

Jun 19

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 »

Jun 18
Fiberglass Fenders
posted by: Steve Jones in Uncategorized on 06 18th, 2017 | | No Comments »

My most recent fiberglass project is a set of fenders for my beach cruiser. I know that there are already fenders available on the market, but I really didn’t care for them. In addition, I do enjoy building my own things when I can and it just so happened that this would be one of those projects.

To start with a project like this, I first needed to decide how I would get the shape and size of a fender that I was looking for. I want to have a fender with a round contour that would provide better coverage of the tire than what store bought fenders provide.

Initially I considered obtaining the right shape for the fenders by covering an inflated tire on the rim with foam weather stripping and then using that as the foundation on which to build a fender. The more I thought about this the more problems I was imagining.

Then one day I was walking by the 99 cent store and I saw those round foam pool toys that the kids use, I think they are called noodles. I knew right away that I was 99 cents away from the perfect base on which to build a plug for my fenders.

Once I got that foam roll home I pulled a wheel off my bike, removed the tire and proceeded to tape that foam roll to my rim. It fit the channel perfectly, and was the right height and width. I wanted my fender to cover about one half of the diameter of my tires so I used enough of the foam to accomplish this.

With the foam roll secured to the rim, I decided to cover the foam with a layer of masking tape. I did this to protect the rim and because I wasn’t entirely sure what the fiberglass resin would do to the foam, or if it would release cleanly from the foam.

At this point it is time to think about applying the fiberglass resin and mat. I began by building a simple cardboard stand to hold the rim steady while the materials are applied. Once I was happy with the stand I covered the entire rim and tape covered foam with PVA release agent.

Now I am ready to build a fender plug.

Happy Glassing



Jun 16

Now, I move forward with creating buck stations. A buck station is a guide that ensures that your plug is going to resemble what you want it to in the end. For this project I use the same 1/8 inch mahogany that I used for the initial profile pieces. My strategy for placement of buck stations is simple, I put one anywhere that I am concerned about maintaining the correct lines of my project. Usually I am of the opinion that more stations are better. Read the rest of this entry »

Jun 15

Last summer a buddy of mine asked me if I could make him a duplicate license plate for his vintage truck.  The original California plate that he had was black with yellow lettering and he wanted to keep that plate.  Apparently you can’t purchase duplicate California plates so his only option was to make a copy.

Even though I have never attempted a project like this one I jumped at the opportunity.  The concepts of the making of a fiberglass mold don’t change so I knew that if I followed the standard protocol that it would work out fine.

This project went smoothly – just like planned.  The old plate was stripped of its registration tags and it was straightened out as good as possible.  It was then mounted to a parting plane with wood screws and the edges were sealed with clay.  The plate was then waxed heavily with mold release wax and then it was sprayed twice with PVA and set aside to dry.

When the time came to build the mold itself I started getting nervous.  While I have only once before had a plug ruined by a combination of failed release agents and tooling gel coat that failed to cure, I really didn’t want this to happen to  my buddies license plate.  That being said I did what I always do and pushed forward.

After a liberal application of tooling gel coat followed by fiberglass resin and a few layers of 1 ½ oz mat my mold was complete.  I was thrilled when I de-molded a few days later and found a perfect mold and even better – an un-marred original plate.  Whew!

With my new mold I went ahead and prepared it with mold release wax and PVA and proceeded to follow all the steps to make a part with this mold (all of these steps are covered in my series of fiberglass mold manuals).  Just like with the making of the mold, making this part went just as planned and I ended up with a near perfect duplicate of my buddy’s license plate.  The mold however did not do so well.  After pulling the part from the mold a host of flaws were revealed in the mold – most of them were air pockets / voids in the tooling gel coat.  The flaws in the mold were significant enough to make the mold not suitable for further use.

After this experience I decided to try this project again – only this time I would use silicone rubber for making the mold and simply make parts by laying gel coat, fiberglass resin and mat into the silicone mold.  There are several benefits to this process for this particular mold as compared to making a fiberglass mold.  More on this project in the next post!

Happy Glassing



Jun 13
Fiberglass Boat Build Continues
posted by: Steve Jones in Fiberglass Boat on 06 13th, 2017 | | No Comments »

Now it is time to break out the fiberglass. Fiberglass resin and 1 ½ ounce mat is applied over the foam surfaces and allowed to cure. When I fiberglass over this kind of foam, I like to brush a nice thick layer of resin directly on top of the foam and then lay resin soaked pieces of mat on top of that. Like with all my projects, I allow the mat and fiberglass resin to Read the rest of this entry »

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