Oct 12

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 »

Oct 8

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 »

Oct 5

I have written blog entries in the past in which I have shared my experiences with new techniques and new products that are available for construction with composites.  This is another one of those.

Whenever I am building the surface of a part that is being made of chopped mat, I end up with a fairly course surface that will need a final finishing.

I have employed various means to smooth out a fiberglass surface.  Some of these finishing methods include the following: Read the rest of this entry »

Oct 1

First I want to wish you a HAPPY NEW YEAR ! ! ! !

I hope your new year celebration was safe and enjoyable.

I have covered the following information in a post quite some time back before the last time this blog was hacked.

I have been getting some more question I think this will address regarding Epoxy Resin for Mold making. Read the rest of this entry »

Sep 25

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 »

Sep 3

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



Aug 30
Why Vacuum Bag Fiberglass Parts
posted by: Steve Jones in Fiberglass Tips & Trix on 08 30th, 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 »

Aug 29
Tooling Gelcoat for a High Gloss Finish
posted by: Steve Jones in Fiberglass Tips & Trix on 08 29th, 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 »

Aug 14

I have a bit of experience working with silicon molds so as expected, the mold cures perfectly and peals easily from the parting plane and the plate.  Oddly enough, the mold removed some rusted paint flecks from the plate – oh well!


With a perfect mold I go ahead and load it up with a layer of gel coat and a few layers of resin and mat.  Since this process is covered completely in the fiberglass mold manuals I won’t do too much detail on this except for re-hashing the differences between a fiberglass mold and a silicon mold.


When using a silicon mold you have to make sure that the mold is sitting on a flat surface – if the surface is curved your mold will be curved as will your final parts.  The other major difference here is that the silicon needs no prior preparation before making parts.  Simply apply gel coat, fiberglass mat and resin into the mold – no need for mold release wax or PVA.


Mold ready for Gel Coat


With a layer of Gel Coat applied I can now lay a resin and mat.


Plate is removed from the mold about 24 hrs later and is ready for paint.


This was a very simple process and in the case of duplicating a flat object like this license plate was much easier than using a traditional fiberglass mold.  Please email me at srjones199@yahoo.com should you have any questions regarding plate duplication.

Aug 10

Ask any group of composites fabricators, and it is quickly apparent that everyone has encountered a problem with sticking a part in a new mold. It is just a fact of life in the open molding business, that on occasion a new mold will stick the initial part, regardless of the  Read the rest of this entry »

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