Skip to main content

How to Fiberglass Like a Pro

Liam is a long-time writer who enjoys learning about and sharing information about health, space, and material sciences.

Working With Fiber and Resin

Fiber bonded with plastic resin has a long, long history. As with many manufacturing techniques, fiber-reinforced plastic came into wide use in the military. Part of the reason for this is the ease with which objects can be created by combining these two materials. It is also quite strong when compared with an equal weight of steel. Fiber-reinforced plastics can be as much as six times stronger than steel at an equal weight.

But the real attraction here is objects made with this material require no high temperatures, a modest collection of tools, and best of all, very little prior experience. In fact, if you've built a sandwich and painted with a brush, you know most of what you need to know about fiberglassing.

What Is Fiberglass?

Fiberglass, as a term, is really a misnomer. Glass fiber is one of the many materials that can be used along with resin (plastic) to create a strong and light composite structure. Those materials include glass fiber (of course), cloth (cotton or man-made), carbon fiber, non-woven glass or carbon mat, coir (a coconut fiber), modal (beech tree fiber), bamboo, and even hemp fiber.

In truth, what most people call fiberglass is properly referred to as Fiber Reinforced Plastic (FRP). It is a composite material, much like Carbon Fiber Reinforced Plastic (CFRP) so popular today, but FRP predates carbon fiber by at least seventy years.

One of the earliest uses of FRP was by the United States military in making helmet liners. (see picture at lower right for a World War II liner)

After the war, returning GIs began experimenting with the material in the form of car bodies and boat hulls. Sailboats were some of the first items built with this material and, a few years later, so were powered watercraft. Because so little was known about the strength of FRP in those years, most of those items were "overbuilt." Boat hulls and car bodies made in the '50s and '60s are still around today, almost indestructible in their strength.

Ideal Hobby Material

In many ways, it is an ideal hobbyist material. With a bit of patience, it is fairly easy to use, with most of your effort going into preparation, if not actual creation, of the item. No special tools are required. In fact, I recommend using old food containers to mix the resin in and purchasing or using cheap bristle paintbrushes, plastic trowels, and/or wooden dowel for applying the resin.

Not Much Dexterity Required

There isn't that much dexterity required. If you can lay a sheet of fabric out and remove all of the wrinkles, you are halfway there. If you can lay on a thick paint-like liquid without leaving behind any bubbles, you are one hundred percent of the way there. It is really pretty easy.

The only other "ingredient" is patience while waiting for the resin to harden.


FRP can be used to make auto body repairs, boat repairs, or even to create new objects that have not existed before. It is also possible to use FRP to create molds for other FRP objects. Some examples of past FRP use include Eames bucket chairs, lampshades, decorative partitions, greenhouse walls, and door panels, just to name a few.

If you've ever had or sat in an Eames bucket-style chair, you know how strong and light they are.


Fiber-reinforced plastic, by some estimates, is six times stronger than steel for the same weight in materials. It is strong enough, in fact, for use in fiberglass swimming pools (water is quite heavy) and even fiberglass buildings.

A Note on Possible Uses for FRP

After a few questions regarding specifics about using fiber-reinforced plastic techniques, I thought it best to add this note.

A Plethora of Possible Uses

This article by no means covers every type of fiberglass application you can use. It can't. The document would have to be at least one hundred times longer to cover every possible use and technique for a variety of situations.


When making repairs to existing fiberglass objects, you only need to pre-wet the area with resin, add the fiber, and then re-wet the new fiber with resin. For esthetics, this is usually best done from the inside of the object.

Strengthening Existing Objects

If you are laying a new fiber cloth coating to a boat hull, or say, a wooden deck, you don't want to pre-wet with resin, but you do want to let the cloth sit on the surface for a number of hours before adding the resin. This is so the cloth conforms to the object. Only after all of the wrinkles are out of the cloth and it conforms to the object being strengthened, then you add any resin.

Even then, you don't use a lot of resin. Only a small amount of resin (about 1 cup per 10 square feet) is required depending on the size of the object. Then you want to work the resin into the cloth as thinly as possible. Even then, the amount of resin used is variable due to the different absorption rates of various types of cloth/mat.

Work Inside Out

If you are repairing a hull breach (a hole below the water line of a boat), you will want to repair from the inside of the hull, not the outside. To effect a good solid hull breach repair, you'll have to make the inner hole three times the size of the outside breach to make an effective repair. The hole should be cone-shaped, too, so that the outside of the breach is no larger than when you started. This is done to make the strongest possible repair to a hole.

New Objects

If you are making a new object, you want to work from the outside in; just the opposite of above. This does not even mention the necessity of a mold, what the mold is made of, and what you need to do to get the new object to release from the mold. However, you can make molds from wood, plasticine, or even existing objects. The mold will have to be perfect, smooth, waxed (wax is a releasing agent), and very clean.

This is not even the "tip of the iceberg" as to techniques; it all depends on what you are trying to do.

So, at best, this is an overview of how to use fiber-reinforced plastic.

Fiberglass helmet liner. You can see the glass cloth strips embedded in the plastic in this photo.

Fiberglass helmet liner. You can see the glass cloth strips embedded in the plastic in this photo.

Fiberglass Material

Fiberglass is the actual cloth or mat made up of glass fibers. As noted above, the fiber DOES NOT have to be glass. However, this section will cover glass fiber specifically.

The list below contains common designations for this material.

  • Woven roving
  • Glass cloth (AKA bi-axial)
  • Woven fabric (AKA bi-axial)
  • Glass mat: This material has no weaving or set orientation.
  • Knitted fabric has the typical cloth pattern with additional runs of fiber at 45-degree angles.

Other Fibers

The fiber in FRP does not need to be glass fiber either; it can be cotton, linen, bamboo, coconut fiber, beech tree fiber, or even hemp. Carbon fiber is "burnt" Kevlar embedded in resin. So, in actuality, carbon-fiber objects are just another form of FRP.

Preparation Is Everything!

Well, almost everything. You'll need the right weather conditions or temperature and humidity, the right tools, and the right surface preparation to get a quality job. Likely, you'll also need to know how long it takes for a piece to cure when you can add to it and how to protect it once it's finished.

  • Weather is very important. Ambient temperature should be between sixty (60) and eighty-five degrees (85) Fahrenheit or between sixteen (16) and thirty (30) degrees Celsius. Temperatures below sixty (16) will mean extremely long cure times or no cure at all. In fact, if ambient temperatures are at or near freezing, the resins won't cure at all.
  • Relative humidity should be below sixty percent (60%) though epoxy is not as susceptible to humidity as poly-resin. You do not want to lay up an FRP job in the rain. Trapped moisture will not stop the curing process or even slow it down, but water bubbles in your layup can cause the layers to come apart months or years later. This, in turn, will compromise the strength of your creation, so avoid it if possible.

Note: I use yogurt cups, pudding cups, cottage cheese, and cream cheese containers. I measure a set amount of water into one of the containers and use a permanent marker to draw a fill line on the outside of the container. This way, I have a disposable mixer/measuring cup for measuring the resin components.

If you are using a polyester resin, only the resin needs to be measured; the catalyst is a few drops of liquid. If using epoxy, you must measure both the resin and catalyst, so two measuring containers may be required.

Epoxy resin and hardener: resin is the large container; catalyst is the small container.

Epoxy resin and hardener: resin is the large container; catalyst is the small container.

Tools and Materials Needed

  • Basic Tools: You'll need sandpaper, acetone, or denatured alcohol, tack cloth, distilled water, glass cloth, resin, mixing containers, and a paintbrush or roller. Patience too. Tools are probably the cheapest part of this. The cloth is the next cheapest and the resin the most expensive of all the items required. I strongly recommend using Polyester resin for this first attempt, as it is cheaper and more forgiving.
  • Safety Wear: Since the resins are hard on your skin, you'll want gloves and eye protection. A long-sleeved shirt, shoes, and long pants (not shorts) should be fine.
  • Cutting: I recommend an old pair of scissors. The cloth is much harder to cut with a knife though it can be done.
  • Mixing Containers: Of course, you'll want an accurate measurement of your liquid components, but you can get an inexpensive measuring cup at a paint or hardware store. Save your money on mixing containers. Since you don't want to start out with a huge job, you can do this with old margarine tubs or other used food containers. Just be sure they are clean and dry. This way, you won't feel bad throwing them out afterward, either.
  • Spreading/Leveling Tools: Use old cheap paintbrushes or the cheap synthetic paintbrushes. The brush does not have to be the same high quality you'd use on a paint job because all you'll be doing is spreading the resin around. Do not use a foam brush; it will melt with polyester resins.
  • You'll also want 1/2" thick wooden dowel material to serve as a roller. You'll use this to make sure all the air bubbles are out of your work. You could buy a specialized fiberglass roller, but they cost more than dowel and are harder to clean. A specialized resin roller is only worth the cost if you are planning on doing a lot of FRP work. Wooden dowel, on the other hand, can be cut to the right width (about six inches) and thrown away without much worry.
  • Sandpaper: You'll want a 60 grit and a 120 grit at least. If you are doing finish work (work that will be painted), use higher grits in the 300 and 400 range.
  • Solvents: Like acetone and/or denatured alcohol are used to degrease and clean the areas you are going to lay FRP on top of. Oil and grease will prevent the resin from sticking (this is a hint about release agents), so you don't want any residue, not even the oil from your hands, on the area to be fiberglassed. Acetone will remove most types of paint, too, so start with alcohol until you gain some experience.
  • Final Cleaning: Your final cleaning of the FRP surface will require a tack rag and distilled water, and lint-free cloth. This is probably not really necessary, but I always go this extra step and have never been sorry.

This is basically what you'll need. Oh, and the reinforcing fabric and resin, of course.

The "F" in FRP

There is a wide range of cloth that can be used for the fiber component. The most commonly thought of for FRP is fiberglass, but you don't really have to stick with that for projects that don't require a lot of strength.

Cotton, hemp, wool, kevlar, carbon fiber, or any natural or human-made material that will bind with the resin will work well as the fiber part of the FRP. It doesn't even have to be woven cloth; it can be a "felted" cloth with no weaving.


If the object you are creating or reinforcing needs to be strong, then the cloth component should be woven. Woven cloth is strong in tensile (pulling apart) strength and, with the resin embedded into it, is also strong in compressive (pushed together) strength.

If the object you are creating only needs to be strong enough to support its own weight plus some and is primarily decorative, then a non-woven (felted) cloth works well too.

Types of Cloth Used in Fiber Reinforced Plastic



Lamp-shade, room partition


Fiberglass felt

Upper body (boat or car)

Polyester or epoxy


Tublar frames (bicycle)


Fiberglass cloth

Boat hull or car body


This is a polyester resin using MEKP as a catalyst

This is a polyester resin using MEKP as a catalyst

Preparing and Glassing Your Surface (Repair)

  1. Figure out how much resin you are going to use (assuming polyester). If you are fiberglassing a one-foot square area, figure on one cup of resin and however many drops of hardener recommended by the manufacturer. Do not prepare the resin yet. The resin will start to cure as soon as it is mixed, so you want to do this just before you apply it.

    Assemble the tools you'll need. Cloth, resin, gloves, glasses, measuring containers, dowel or roller, sandpaper, alcohol (denatured), water, clean lint-free cloth, and paintbrushes.
  2. Prepare the surface to be fiberglassed. You want to use a rough sandpaper and remove any paint, varnish, oil, and/or dirt. It's best if you sand right down to the original surface. You can use a power sander if you wish. You do not even have to get the surface particularly flat.
  3. This is the point at which you want the gloves and safety glasses. Clean the surface. You want to vacuum it or use denatured alcohol on a lint-free rag to get any of the sanding debris off. Do this two or three times to make sure that the surface is perfectly clean.
  4. Clean the surface a final time with distilled water and a lint-free cloth. Let air dry or blow dry with compressed air. Use the tack rag last to make sure every contaminant is gone.
  5. Cut your fiber cloth to the size of the repair. The easiest way to do this is to cut the cloth, hold it to the repair area, and trim some as needed. Now that you have the right dimension, set the cloth aside on a clean work surface.
  6. Prepare the resin. Following the manufacturer's instructions, pour the resin into the measuring cup to the recommended amount (see above) and carefully add the hardener drops. Stir this mixture thoroughly and slowly. Avoid churning air into the resin. You'll notice it's about the consistency of pancake syrup. If you are using epoxy, then you are looking at a half-and-half or possibly two (2) parts resin to one (1) part catalyst. Polyester resins use MEKP (a few drops) as a catalyst.
  7. Apply a layer of resin S.L.O.W.L.Y. Because of the viscosity, it will tend to run off of your paintbrush in long strands and get everywhere. Working with it slowly will ensure it goes where you want it to go.
  8. Apply the cloth layer (You should have your gloves on, remember?) and lightly press it into the resin with your fingertips. It should stick readily. Now, add a little more resin on top of the cloth. As you do this, use the paintbrush to spread the resin evenly; you want it to penetrate the cloth and leave a thin layer of resin on top. If you see any air bubbles, brush them out. You can also use the doweling if necessary to press the resin/glass sandwich together and remove any additional air.

    Air bubbles are bad; they weaken the composite.
  9. Wait! Curing will take from two to four hours, depending on the resin. Check the manufacturer's label.

Ambient air temperature is important. Most resins need to be twenty or more degrees above freezing to set. Check the resin label for ideal temperatures and humidity levels.


If you are planning to add another layer, watch this cure time closely. The resin will cure to a hard yet sticky state after the prescribed (two to four hours) amount of time.

When the resin is hard and sticky is the ideal time to add another layer of resin and glass without any preparation. Mix another batch of resin, apply it, the fiber (cloth or mat), and more resin. Roll out the composite with dowel of brush out bubbles and wait the prescribed curing time. You can do this many times as long as you add the next layer before the resin cures to a non-tacky surface.

If you let the resin cure for a full twenty-four hours, you will have to sand it and clean it as outlined in the third and fourth steps above.

If it's getting late in the day and you have leftover pre-mixed resin, it can be put in a covered container and stored overnight in your freezer. It will not cure at or near freezing. The next day, pull it out of the freezer, and as soon as it thaws, use it.

Using the method described above, successive layers of glass and resin can be layered, ending with glass mat for a paint-able surface. I strongly recommend using a primer and then finish paint for a professional look. Paints should be polyurethane or two-part epoxy. The two-part epoxy paint is tougher but harder to come by (some states now ban its use by all but certified professionals). Epoxy paint is also better for "immersion service," e.g., use below water.

Note that the pigment (and often additives) in the paint prevent epoxy-based paints from reacting to ultra-violet or sunlight.

New Surface vs. Repair

All of the steps above assume you are making a repair.

If, on the other hand, you are adding a new fiber-reinforced coating to, say, a surfboard, boat bottom, or other undamaged object, you do not want to pre-wet.

You do want the fiber cloth to sit on the object for a few hours. Overnight is best, so its shape conforms to the object. You will then apply the resin once you are sure the cloth conforms to the shape of the object. If you've got wrinkles, smooth them down with your clean, dry, or gloved hands.

Because it is likely just you doing this, and you don't have a team, limit your work area to three or four square feet. There is no reason why you can bond fiber fabric to your surface in steps.

Add the small amount of resin, half a cup or so, and work it into the cloth over and over until the brush or putty knife starts to drag. You want to do this to keep the cloth down against the surface until bonding starts to take place.

Avoid working from the center out. This just complicates things—work from one edge down. Your object is to work the resin completely into the cloth and stretch that resin as far as you can. Resin, once cured, is really strong, so a thin layer is not only acceptable but is desired.

If you are adding another layer, wait the prescribed cure time before adding the next layer. If you are using cloth, try putting the next layer down so that the warp and woof (the threads in the fabric) are at a 45° angle to the previous layer. As before, work in sections and work the resin as thin as possible.

Do you have a snag in the cloth? With your forefinger, starting from the outside of the snag and working in, draw an ever-tightening circle with your finger working in toward the center. You can do this before adding resin or after (because sometimes snags occur after adding resin). You may need to "circle" the snag a number of times, but this method is effective.

Video Below

The video below is an excellent example of fiberglass layup from start to finish. It's a time-lapse presentation, so you may want to hit the pause button from time to time to grasp the finer points. There is also commentary embedded in the video to explain what's going on.

I find it particularly useful since the videographer also used releasing agent at the beginning. You see why that agent was used at the end, as well as what the part created is used for.

And what is the releasing agent? Ordinary car wax without any additives.

First rate!

Notes on the Above Video

  1. He puts wax on his mold as a release agent. This makes taking the cured part out of the mold much easier.
  2. Notice he puts masking tape around the edge of the mold. This gives him something to grab when it's time to separate the part from the mold.
  3. The first thing applied is called GelCoat. It is colored resin without the fiber reinforcement. Just prior to spraying it on, he adds the catalyst and then stirs the mixture. You'll notice it's pretty thick; this is fine and should be thick. Once cured, the GelCoat has a very smooth finish against the mold, and a rougher finish on the side fiber will be added too.
  4. He applies seven layers of resin and five of fiberglass. You'll notice the first three layers of fiberglass are held in place with a blue resin. This is polyester resin.
  5. The last two layers are held in place with a yellowish resin. This is epoxy resin.
  6. With seven layers of resin and five of fiberglass, these items are very, very strong.
  7. At some point, he uses a bandsaw and drill to cut the pieces out and create holes. These steps are not shown in the video though the final product is.
  8. If you haven't guessed by now, these items go just over the headlights and are held in place by two screws under the hood. They give the "nose" of the car (a Mistubishi, if I'm not mistaken) a slightly different look.

A Note About This Article

The author has received no money, discounts, or freebies for any products that may be mentioned in this article.

Again, this article is geared toward readers who are considering fiberglass as a hobby. Because I've been getting comments lately toward more professional, salable results, I want to remind the reader what this article was written for.

Many, if not all, of these additions involve techniques and materials geared toward high-volume, fiberglass product production. That is not what this article is about. This article was written for the hobbyist with frugality and reasonable costs in mind. Since this is the idea behind this article, I will not be adding much more to it, especially if that "more" involves materials and techniques geared toward high production, high volume, or high cost to the reader.

Additionally, there is no way this article can cover every technique necessary for working with fiber-reinforced plastic. Repair techniques are necessarily different than those for creating a molded object and are different yet again for creating something like a surfboard.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


Jeremy Livingstone on August 29, 2020:

Thanks for details... excellent layout of explanations...I made Kayaks in my Youth Now wish to hone my FRP Skills on Boat Purchase repairs

LiamBean (author) from Los Angeles, Calilfornia on April 30, 2020:

I guess it depends on whether the straps need to be flexible or not. If it doesn't matter that they are a bit stiff, epoxy is more resistant to gasoline and other fuel types (a possible consideration). Epoxy is generally more durable too, but sunlight is harder on it.

A Poly resin does better in sunlight and will give your a more flexible strap, however it will break down rapidly if gasoline or other fuels are spilled on it.

Hope this helps.

ivang57 on April 26, 2020:

Hey there,

Awesome article. I'm trying to make use of some fiberglass straps and I'm not sure of how to treat them. Would using an epoxy resin be a good method to make them usable as a regular strap or is there a better way to treat them?

LiamBean (author) from Los Angeles, Calilfornia on September 26, 2019:

I have found that if you apply the next coat of "glass" and resin, while the previous coat is still a bit tacky to the touch, that you don't need to sand.

Sanding is performed to rough up the surface so that the next layer binds to the cured layer.

If you lay down the next layer before the "cure" has fully hardened, you can forgo the sanding step.

The final exterior surface will certainly need to be cured fully (not tacky) and sanded before a primer or paint coat goes on.

At least, that has been my experience over the years.

jgattitrash on September 02, 2019:

This is a great primer!

I'm just starting to experiment with resin.

In your video, Is your gel coat "no wax?" I'm assuming so since you layer without sanding. If that is the case, is the final exterior surface tacky or is it smooth because it was not exposed to air as it cured? Trying to decide if I need to buy gel coat with or without wax.

thx much.

LiamBean (author) from Los Angeles, Calilfornia on September 15, 2011:

pauls_boats: "good hub on basic fiber-glassing, i prefer to use epoxy resin not polyester resin partly due to my past experiences with either polyester resin not going off or going off to fast but it was most likely my own fault as i never new that you should not use it in hot weather or high humidity and living in Puerto Rico we have both if i use epoxy resin i can change the type from slow to fast or somewhere in between with the type of epoxy hardener, there is a great shop in Florida called US Composites which sell all types of fiberglass equipment for a low price and are willing to ship for a decent price."

they are happy to sell to the novice and have lots of products and great tips on use."

pauls_boats: Thanks for the comments AND the information. I had to remove the link due to hubpages policies regarding external links.

LiamBean (author) from Los Angeles, Calilfornia on March 11, 2011:

Navitas: I'm not sure where you got your information, but you better alert all the epoxy makers and let them know they are wrong. Every brand/type of epoxy I've used it time dependent depending on TEMPERATURE not UV light. Perhaps you weren't getting the catalyst to resin ratio right? I know this is bad information because every bit of repair I've done has been out of sunlight and sometimes even at night. I've always gotten a good cure regardless of light conditions, but always right in line with what the manufacturer states on the label.

Navitas on March 11, 2011:

You have to remember that curing is not time dependent as much as it's UV light dependent! I discovered this by fluke when I was wondering why certain parts (in dark spaces) would never set, even though other places would. You should work this in low UV light places and when you are ready to cure it, either use the sun or a black light to harden the resin in seconds! That is also the same technique used by dentists to set white fillings.

LiamBean (author) from Los Angeles, Calilfornia on June 08, 2010:

Tony: Thanks for asking. I'm not sure where you live so "locally" isn't a question I can answer. Please don't share that here either as your privacy is important.

Most better boating supply stores carry gel-coat, though the ones I visit typically carry no more than quart sizes.

You can also order it online and might get a better deal on it that way.

Tony on June 07, 2010:

One more question, could you recommend anywhere to get gel coat locally? or will I have to order it online?

LiamBean (author) from Los Angeles, Calilfornia on June 04, 2010:

Tony: It should. Of course the two coats should be a fairly glossy paint or gel-coat. If you are going to make many copies there are release agents (see comments above) designed for ten applications. But if you aren't a simple wax (carnuba or auto wax without polymers) should work just fine.

Simply apply the wax, allow to dry, and wipe off. You should end up with a very glossy non-stick surface.

Tony on June 04, 2010:

Hello great tutorial. I am building a mold out of wood since that seems to be the easiest so far. If i seal it with like 2 coats and then use a release wax will that work fine?

LiamBean (author) from Los Angeles, Calilfornia on April 11, 2010:

Thanks Luciano. Done right, and I'm sure you did it right, it's a strong light material that lasts a very long time. Thanks for reading.

Luciano Bove from Paris on April 11, 2010:

Great Hub, I learned how to do fiberglass back in school making a flower pot. I went through all process until final paint job! Great experience, after more than 20 years I still have my flower light green pot!


LiamBean (author) from Los Angeles, Calilfornia on April 11, 2010:

Thanks agvulpes. I love fiberglass. It's not quite as strong as carbon fiber composites, but it's still a very strong composite material. Best of all it's a relatively inexpensive way to create new objects for the average Joe/Josefina.

Peter from Australia on April 11, 2010:

Wow, Liam you are so right about this guy Colin Christian. I found the discuss thrower you mentioned and I thought it worth while putting the link in here:

Thanks a lot for this info?

LiamBean (author) from Los Angeles, Calilfornia on April 10, 2010:

An artist named Colin Christian does extensive work in fiberglass and silicon. His specialty is crafting "space girl" statues and enormous doll heads. One of his works was chosen for the Olympic Games in China. She was a futuristic discus thrower complete with 50s style space helmet including antenna sprouting from the ear areas.

The bodies are fiberglass with silicon applied to areas that would normally be exposed skin. They are quite amazing to look at. If you get a chance look him up to see what's possible with this material.

Peter from Australia on April 10, 2010:

Liam Bean, great Hub with heaps of great advise, I have repaired some fiberglass in the past but I have never done any mold work with it as yet. I think it would be a great art form ?

LiamBean (author) from Los Angeles, Calilfornia on March 23, 2010:

How To: Love the video. Very nice. I have to say that has to be one VERY STRONG fiberform you created there. Nice job. And the video shows anyone interested just how easy it is to create a part (a very strong and light part) with a beautiful finish with fiberglass reinforced plastic.

How To Fiberglass on March 23, 2010:

what an awesome hub. Great detail too. Thanks for the read!

LiamBean (author) from Los Angeles, Calilfornia on October 30, 2009:

Thanks for reading sabbatha1!

sabbatha1 from on October 30, 2009:

Great hub keep on hubbing. Excellent information.

LiamBean (author) from Los Angeles, Calilfornia on October 30, 2009:

harry says: Thanks for reading.

You are going to want a "release agent" as the industry calls it. This is basically high temperature wax. I also found a product called "ChemRelease" which is quite a bit more expensive, but is designed to be used up to ten times without being reapplied. Since ChemRelease comes in a can I doubt it's wax. The manufacturer also claims that the agent does not stick to your final product. Still, this might be the better product type for your needs.

Release agents not only keep fiberglass from sticking to other surfaces during cure, they can also help smooth out imperfections in the mold. So, a release agent could be applied between two cured fiberglass parts so that they are easy to separate once the part between them has cured.

You can find this on-line at fiberglass supply houses.

In fact, all I did was "google" the phrase "release agent" and found a number of products and places that carry them.

harry on October 29, 2009:

I'd like to know how to make a two part mold for fishing worms out of risen. How do I keep the parts from sticking when building the mold?

Sexy jonty from India on October 20, 2009:

Very well written hub .....

very much informative ......

Thank you very much for your great hub, for good advice, good wishes and support. Thanks for sharing your experience with all of us.

vinner from India on October 20, 2009:

amazing hub

sheryld30 from California on October 11, 2009:

Wow!~ This is Awesome-Amazing. Love it! Thank you soooo much for sharing! :)

LiamBean (author) from Los Angeles, Calilfornia on October 16, 2008:

Hank: PolymerBoy has good advice. Bear in mind that with very few exceptions you will want to paint the fiberglass once cured. The tackiness is actually a good thing when following up with paint. Use a polymer paint (one or two part) over your fiberglass. Be sure it's clean with a regimen of window cleaner, denatured alcohol, and distilled water in that order. Be sure your temperature and humidity ranges are correct.

If the fiberglass is still tacky that's a good thing. Paint will bind much better to a fiberglass finish that is slightly tacky.

polymerboy on September 08, 2008:


the surface of the frp will always remain sticky because during curing, it is exposed to air.

u can prevent this by covering the layer with a film called lumirror while curing.

or u can apply a tack remover to the surface.

Hank Nash on August 07, 2008:

Thanks for the great info, I'm finding that the resin is staying sticky is there a way to correct this problem?