Can anyone briefly describe the characteristics and advantages of ISO, ORTHO and SILMAR resins? I thought I read that either Iso or Ortho were banned in So. Calif, thus the builders and glass shops no longer have a choice if they prefer a stronger grade.
Of the popular name surfboards for example, who uses what resin type? Or does it even make a difference for strength and longevity?
Thanks, John
Hi -
I don’t know anything about the current regs in SoCal. Maybe try the local Air Quality Management District?
You’d have to check each manufacturer to see what they use. I’d imagine that shops can mix and match for different purposes.
Greg Liddle used ISO when he was in California but says it isn’t available in Hawaii.
From his website…
Resin
The resin I use is unfortunately the same resin as most commercial glass shops. Because I am somewhat isolated I cannot use the material that I used for 20 years in California. The Dion isothalic resin which added longevity and flexibility to the California produced boards is simply not available here to me. So I take more precaution with the boards I build now to keep them in a board bag when not in use and out of the sun and heat to lengthen their life.
The other answers can be found in the resources section. I haven’t listed links to Vinylester or Epoxy which might be worth a look.
SILMAR is just a brand name, Reichold is another.
The Fiberglass Supply website has a ton of technical data if you dig… I think you’d have to be a chemist to understand where it goes beyond these resources. You could also call them and they might be able to help.
ISO - http://www.fiberglasssupply.com/pdf/polyester/6631_tds.pdf
ORTHO - http://www.fiberglasssupply.com/pdf/polyester/S249.pdf
ISO/ORTHO mix - http://www.fiberglasssupply.com/pdf/polyester/S929.pdf
Howzit John, From what I understand 1421 resin which is an Iso/Ortho blend is not available in Ca due to EPA. That's the extent of my knowledge on Ca EPA restrictions. Aloha,Kokua
from http://www.fiber-tek.com/resin.htm:
Orthophthalic
Orthophthalic(ortho) resins are the basic chemistry of polyester resins. It is a raw material utilized in general purpose polyester resin and has a type of molecular structure that is considered to be the standard in the industry.
Isophthalic
Isophthalic (iso) resins are higher grade resins than ortho resins in that the molecular structure is denser. it is a special raw material utilized in corrosion resistant and/or premium grade polyester resins. These resins will exhibit a higher heat distortion temperature, higher strength, greater flexibility and are more waterproof than orthophthalic resins.
A very basic description. From a tooling standpoint. Iso is considered the tooling resin. With less shrinkage and better ability to handle the repeated heat of the curing process of doing mulitple parts in the tool. If your going to be making a polyester tool (mold) that you want to produce multiple parts from you’ll be wanting Iso tooling resin and gelcoat. Some can be quite expensive.
Ortho is what is used for laminating most parts.
I was always under the impression, but I could be wrong, is that Iso is also more brittle. And therefore would not be a good choice for surfboard laminating.
Fiberglass Hawaii offers Y2K surfboard resin that is an ortho iso blend. It is 30% stronger than regular ortho and it is also clearer.
Thanks guys - spot on info/facts, as usual. So a ortho/iso blend would be your preference over a Dion iso due to a possible proclivity for brittleness with the Dion?
Thanks, John
Technically all the polyester surfboard resins in use today have emisions higher than what is legal in open wet lay-up laminating according to SCAQMD’s 1162 and the new federal EPA MACT standards. What this means is that if SCAQMD or the EPA chances a visit at your establishment (usually because of a complaint that has been filed with them) then they can use that oppritunity to throw the book at you and if there has been complaints, they will. As of right now there will probably be no new polyester shops allowed in SoCal in the future. MACT will probably make that nationwide in the near future. I know that in some areas there is already a moritorium on this and other areas there are very low use limits according to your square footage. From my perspective (and this will probably come as a shock to many here) it’s almost inconsevable that, with the impovments in epoxy surfboard resins over the last 10 years or so, anyone is still using polyester. Clearer, stronger, safer, soap and water clean up, no more expensive to use and NO GOVERNMENT INTERFERENCE. What’s everybody thinkin’?
I was in Epoxy Pro last summer and accidently got some Epoxy on me, it was not wasable with soap and water, are you kidding me guy?
Clearer, they yellow like you wouldn’t believe!!
Not standard soap… GoJo, Fast Orange, stuff like that takes it off easy. Cleans your hands better than solvents. The trick is to wear gloves and not get it on you. Clean up squeegees with scrap glass or a paper towel. Use chip brushes for hot coats and throw them away… 3" brushes cost 50 cents and you can’t clean them for 50 cents worth of acetone.
Yellowing has to do with which epoxy your using. All thermosets yellow, polyester does too. The best epoxies don’t yellow any worse than the best polyesters.
The government will always find an excuse to interfere. It’s their most favorite thing to do. For example, they might decide to declare that more widespread use of certain soaps for cleanup produces more antibiotic resistant strains of bacteria, and put additional sanctions on the soap.