Resin prices

There are countless posts that epoxy is just a bit expensive than polyester and about the same cost as vynilester. So no point to use other than epoxy.
But for the design I am considering I have to use about 550kg epoxy. So I did a bit of local research and I found very different picture. I am from Bulgaria, we have very small market for this products, so I have expanded my search. That is an example of what I have found:
http://www.ecfibreglasssupplies.co.uk


epoxy
West 30kg - 312.75GBP 10.425GBP/kg
MAS 7.5lt -127.97GBP 17.06GBP/L
Sicomin - 7.74kg - 100.98GBP 13.04GBP/Kg


VE:
Atlac 580 25kg -149.95GBP 6GBP/kg
Crystic VE679 25kg -135GBP 5.4GBP/kg


PE:
Crystic 2-414 25kg -63.98GBP 2.56GBP/kg
225kg - 459GBP 2.04GBP/kg
491(iso) 25kg-109GBP 4.36GBP/kg

Conclusion: VE is half of the epoxy and PE is 4-5 times chepear

So in my case it will be (GBP/USD = 1.68)
5734 GBP 9633USD WS epoxy
2970 GBP 4989USD VE679
1122 GBP 1884USD PE

Going for PE will be almost 8000USD cheaper which I do not consider "small amount" of money.

Please comment

 

Prices are closer in the USA. Also many responses recommending epoxy exclusively are to questions about refurbishing a boat where the waterproof and secondary bonding strength of epoxy makes it a preferred choice.

There are two ways to consider a new boat:

1.) Many production builders still use vinylester and some polyester because these are adequate to deliver the needed specification and every dollar matters. Polyester boats have lasted 40 years and are "good enough" to outlast the engines and interiors by decades.

2.) The resin and the hull are only a fraction of the overall cost and are items that you can't upgrade at a later date.

 

There are hundreds of thousands of boats successfully built with polyester. The design has to take into account its characteristics.

 

My understanding is that epoxy really comes into its own when bonding to wood such as plywood. It is supposed to be a far superior bond compared to Polyester, not sure about VE....

 

That is my experience. I have had a single layer of polyester FRP delaminate from a plywood bulkhead. I have not had problems with 20 year old solid polyester FRP.

 

While the difference in price of the resin (epoxy, VE, PE) can be a small portion of the total cost, the ability to process the resin and glass combination can add a great deal of time and money, this is where VE and PE come into play.

The advertised strengths of epoxy are achieved after post-curing the laminate, this adds a great deal of cost and time. Plus the equipment used to process epoxy is more costly, or not available, and cure times tend to be longer.

So after looking at the total cost of producing parts, companies tend to go the PE or VE route when it comes to higher production volumes.

 

Though we use epoxy, I agree completely.

The capability for adding additional laminations a day or two later without abrading for secondary bonding procedures would make the polyester or vinyl ester essentially free compared to epoxy.

 

Ah! FMS you have suffered from the 'blind faith' school of Polyester laminating! I encounter this too much, but also see a lot of sound Polyester to ply joints. From repairing well over 100 polyester/ply bonds I believe the problem is with the original fabricator. If the ply is wetted first properly or even better fully precoated and sealed it is rare to get a bond failure unless under a lot of stress. In the interests of quick building I am convinced many small craft builders wet through a layer of dry cloth/CSM/Roving with Poyester and the joint is essentially dry - hence later problems.

Sometimes I use epoxy other times polyester in the repair, it depends on the specific case. Not had one polyester to ply joint fail though so the pre wetting and better sealing must help. We have loads of old stitch and tape Mirrors over here and many are still very sound.

As for the original posters comments, it is horses for courses. If you are going to build in carbon, what use is the resin cost? If you use cheap CSM and roving, polyester is fine and in between sits the Vinylester. So depending on your original design and performance criteria you make a choice. Sometimes even hybrid construction makes cost sense too.

 

Compare barrel to barrel to get fair comparison, thou you are right..

 

Vinylester is at least half epoxy. At least the hand layup stuff I buy is part Bisphenol A epoxy and has elongations similar to epoxy. Without the nasty aliphatic amine hardener, and a rather tunable gel time without purchasing a different hardener. Plus it can have as high or higher elevated temp properties than some garden variety Bis-A epoxies.

I can't speak to price very well, but at the *retail* level from my supplier, they are about $28, $50 and $90 per gallon, retail for *single gallons* for PE/ VE/ Epoxy.

For this reason, I am a fan of VE.

 

$90 a gallon for epoxy is retail name brand stock. Locally formulated stock at the retail level is about $60 a gallon, as well as several online distributors. If you use a reasonable quantity, this figure drops to about $40 a gallon for epoxy.

 

The same holds true for the other resins, volume matters.

There are accounts in my territory paying less than $10.00 per gallon for PE and $20 for VE

 

The glue in marine plywood is resorcinol (phenol formaldehyde) gotta be way cheaper than the other resins mentioned above and certainly does a good job bonding wood under controlled heat and pressure, probably better than epoxy. Whether it could be used for actual boat construction is another matter - you can't get the pressure required for a good joint with vacuum bagging for example. It all comes down to what material are you using for the boat and what building method you use.