Choosing the Right Resin

Resin selection is based on fabric compatibility, service conditions, and the desired characteristics of the finished part. There are three common types of thermosetting resin to choose from: epoxy, vinyl ester and polyester.

Moldmaking, molding and laminating operations can be performed with any system. Epoxy is the higher performance and higher priced system. It is used in weight critical, high strength, and dimensionally accurate applications. Vinyl Ester resin offers corrosion resistance, heat resistance and is blended for toughness. Polyester resins are less expensive, offer some corrosion resistance, and are more forgiving than epoxies. For this reason, they are the most widely used.

System 2000 Epoxy Resin
Uses: Structural application, High-strength projects, Adhesion to metal.

Pros:
- High strength properties
- Superior to other room-temperature epoxies
- Maximizes the physical properties of carbon fiber, KEVLAR® and fiberglass
- Multiple cure options
- Can be used in vacuum infusion applications
- Easy to handle
- Medium viscosity

Cons:
- Cannot be used with chopped strand mat
- Not UV stable. Will deteriorate without a top coat when exposed to UV rays.

Vinyl Ester Resin

Uses: Gas tanks, Boat hulls, Heat resistant applications.

Pros:
- Extremely tough
- Corrosion Resistant
- Heat Resistant

Cons:
- 3 month shelf-life

Isophthalic Polyester Resin

Uses: Dimensionally stable molds, Durable repairs, Corrosion resistant applications.

Pros:
- 225 degree service temperature
- Dimensionally stable (minimal shrinkage)
- Resists post cure problems
- Can be used in food contact applications

Cons:
Slightly more expensive than general purpose polyester resins

Polyester Laminating Resin

Uses: General purpose, Hand lay-up, Lamination on plywood.

Pros:
- Easy to work with
- High thixotropic index (won’t run on vertical surfaces)
- Waxed to prevent surface tackiness
- Inexpensive

Cons:
- The wax must be sanded off prior to applying subsequent layers

Polyester Molding Resin

Uses: General purpose, Hand lay-up, Moldmaking.

Pros:
- Inexpensive
- Easy to work with
- Rapid wet-out
- High thixotropic index (won’t run on vertical surfaces)
- Perfect for molds

Cons:
- Lower physical properties compared to more expensive resins

31 comments

1 Dave { 12.28.12 at 5:47 pm }

How long is lay up polyester good for…shelf life. How about gelcoat?

2 nengels@fibreglast.com { 01.24.13 at 2:46 pm }

All of our products except Vinyl Ester Resin are guaranteed to have a six-month shelf life from date of purchase when stored in unopened containers and at ambient temperatures. Vinyl Ester Resin has only a three-month guarantee.

You can see our policies and guidelines for all our product here

But….many customers do report that in some instances they have had resin for 1 year and it was still useable (we just don’t guarantee it) . I hope this helps

3 Dave G { 03.05.13 at 5:54 am }

Where can I find cure times for your epoxy resins? I need to know how long to hold vacuum and keep my heat source on. Using 2060 hardener at 150 degrees.

4 mtruax@fibreglast.com { 03.06.13 at 6:09 pm }

The time is project dependent, and may be different based on the ambient temperature and thickness of the laminate. Our, product data sheet ( http://cdn.fibreglast.com/downloads/00343-A.pdf ) should give you direction on this question.

5 John { 03.08.13 at 1:02 pm }

I work mainly in urethane and polyester resins. For top coat is there a clear epoxy resin with low viscosity that can be sprayed with a cup-gun and that offers UV properties?

6 mtruax@fibreglast.com { 03.08.13 at 9:30 pm }

We carry a urethane coating resin (#3500 Clear Urethane Casting/Coating Resin) that gives epoxy parts a UV protective coat, but it cannot be sprayed.

7 Brian Smith { 03.18.13 at 4:05 pm }

I’m just getting started in cpoomposites. I’ve used some epoxies before but am curious about polyester. I’ve heard it smells quite bad and needs lots of ventilation. Is this true. Can I use it in my lab or should we work outside?
I’m not concerned with any real performance benefits between epoxy and polyester. We are just going to be making flat fiberglass panels that will be cut on the CNC router.
Thanks for your help

8 manuel { 03.19.13 at 1:00 am }

I need to fix a water tank, it have baffles, i need a resin that work in vertical position. what kind of resin should i use? .

9 mtruax@fibreglast.com { 03.19.13 at 12:42 pm }

If you’re working in a shop, you definitely need great ventilation, but that goes for any resin. If you decide to work outside, make sure that it’s out of sunlight, the humidity is not high and the temperature stays above 60 F during the part’s cure schedule.

10 Jim { 05.11.13 at 2:52 pm }

We have a fibreglass lined concrete swimming pool. The original fiberglass and resin (type unknown) are still in excellent shape. Polyester resins seem to chip and delaminate. Swimming pool paints (latex) and epoxy paints turn to chalk after just a couple of years. We have been told that vinyl ester resin and gelcoat is the only combination to use for swimming pools. Can you comment?

11 daldrich@fibreglast.com { 05.13.13 at 12:33 pm }

If you would like to speak with a Fibre Glast Customer Service Representative, please call 800-821-3283.

We would be glad to help you.

12 ed { 05.21.13 at 9:18 pm }

Iam covering a wooden boat with 4 oz glass and am looking for a clear finish, what is the best epoxy to use.

13 ccaldwell@fibreglast.com { 06.04.13 at 5:33 pm }

If you are tied to an Epoxy resin, we do not have an offering that will offer a clear finish. Our System 2000 Epoxy has a light amber tint. If you aren’t set on an epoxy resin, our #83 Polyester Laminating Resin sounds like it might be an appropriate fit for your application. That said, our resins aren’t formulated to yield the clearest finish. If you need additional assistance, feel free to call one of our Fibre Glast Customer Service Representatives, at 800-821-3283.

Regards,

-c

14 Rick Kraus { 08.23.13 at 1:51 am }

I”m putting in a new floor in my boat and i”m using 1,5 oz strand mat. What is the best resin for this application

15 ccaldwell@fibreglast.com { 08.23.13 at 1:01 pm }

Thanks for the question Rick. There are a few factors that can go into answering that question based on the boat design and use. You might be best served calling one of our Fibre Glast Customer Service Representatives, at 800-821-3283.

16 Paola { 09.30.13 at 9:32 pm }

Hi
I am doing an sculpture of plaster of paris, and I would like to apply on top of it a polyester resin, Please can you tell me if will work out the combination, I tried before but with fiberglass and worked perfect. Thank you!!

17 Felipe Jugo { 10.07.13 at 2:47 am }

I want to laminate a boat hull skin in glass and vinylester resin to minimize osmosis risk , and then laminate the internal structure in poliester resin to keep cost down. Is this OK? Is there a technical reason for not doing it?
Thanks

18 ccaldwell@fibreglast.com { 10.18.13 at 12:19 pm }

It used to be pretty common to make plugs or molds out of plaster of paris and then laminate with resin and fiber. That will certainly work. I’m not positive I was understanding your question though. If you need additional assistance, feel free to call our customer service line and we might be able to help you more. 800-821-3283 or customerservice@fibreglast.com.

19 richard { 10.19.13 at 3:14 am }

I am looking at building whitewater paddles what is the strongest most durable epoxy?

20 Jacob J { 11.18.13 at 10:02 pm }

Do you happen to know if I can use polyester resin/fiberglass to make a mold from a sulphor free, oil based clay sculpture? Any ideas would be incredibly helpfully! Thank you

21 Carbon Epoxy { 02.17.14 at 12:41 am }

Carbon is good to use as it is light and strong.

22 Turki { 05.10.14 at 10:03 am }

could anyone provide the sound properties of fiberglass with polyester resin? I need them for noise reduction enclosure
thanx in advance :)

23 Van { 06.18.14 at 9:49 am }

Do you mind if I quote a few of your posts as long as I provide
credit and sources back to your weblog? My website is in the
exact same niche as yours and my visitors would really benefit from some of the information you provide here.
Please let me know if this ok with you. Thanks!

24 ccaldwell@fibreglast.com { 06.18.14 at 2:32 pm }

You can certainly quote our blog, providing links to us.

Thanks,

25 curt { 06.23.14 at 4:14 am }

i have systen 2000 epoxy can i use vinyl ester on top of the epoxy on stringers

26 ccaldwell@fibreglast.com { 06.23.14 at 12:31 pm }

We would not recommend putting vinyl ester or polyester resins on top of epoxy. They do not bond with the epoxy.

27 Ben { 07.06.14 at 2:04 pm }

I’m rebuilding a fiberglass body kit for a truck. Can I lay vinyl ester resin over the original polyester(?) resin?

28 ccaldwell@fibreglast.com { 07.07.14 at 12:36 pm }

As long as you prepare the surface correctly, vinyl ester resin will bond and is suitable for use over polyester resin.

Thanks,

29 dan iverson { 07.07.14 at 1:37 pm }

I have a Coleman camper (Cheyenne series) made of a white polyester plastic type of material that has developed some cracking in a number of places on the roof surface, some of them over 1/8 of an inch wide. I was wondering if a “new” hard shell could be created by coating the roof with a resin of some kind

30 ccaldwell@fibreglast.com { 07.07.14 at 6:45 pm }

Depending upon the severity of the damage, you may or may not need to add reinforcement fabric for your repair.

If the damage is largely cosmetic, our #4116 polyester filler is a no-shrink solution that will be exceptionally rigid and strong. If you need a bit more strength, or have minor holes, you may need to start with our #4100 polyester fairing compound, a fibrous filler for structural repairs.

If there is structural damage, the best bet would be performing a full repair with multiple layers of reinforcement fabric. Check out the newest blog post about repairing canoes for an overview on the repair process.

31 Paul { 07.15.14 at 5:55 pm }

Which polyester resin is best for doing multiple layers of 1708 bixial fiberglass for a boat transom?

Leave a Comment

*