Isophthalic Polyester Resin vs Standard Polyester REsin

[woodman7975]

Is Isophthalic Polyester Resin worth the extra price over standard polyester resin? Is Isophthalic Resin a good choice for glassing in stringers and transoms? At US Composites it is about $35 more for a 5 gallon bucket. I was able to find information on both, but none specifically geared towards boat repair. Isophthalic is supposed to be stronger and provides less water absorption.

 

[gm280]

I can't say for sure if one is that much better then the other. Most people on these forums use polyester resin and don't seem to have any issues. As for the more expensive poly, that is up to you. I've never used it myself, but I am sure some others will chime in with their opinions...

 

[AShipShow]

probably not worth the extra money spent unless you were building a hull from scratch. For repairs, if you're concerned about strength/water resistance, you should either use vinyl ester or eeeeeeeeepoxy.

 

[tpenfield]

You got your iso and your ortho

Orthophthalic polyester resin is the standard economic resin used by many people.

Isophthalic polyester resin is now becoming the preferred material in industries such as marine where its superior water resistance is desirable.

I can't even pronounce those words, nevermind tell the difference

Then there is 'saturated', 'promoted', and a whole bunch of other terms used to describe resin. I think all of these words were invented to add to the mystique.

 

[Woodonglass]

Standard Poly IS more than adequate for your boat restoration as long as proper PREP is done. If you want (not needed) to go a bit Above and Beyond then use Vinylester. Either way your repairs will last a LOT longer than you'll own the boat!!!