ondarvr
Supreme Mariner
- Joined
- Apr 6, 2005
- Messages
- 11,527
Re: Can I repair the transom this way?
On a typical repair it makes little difference which resin you use, doing the job correctly is far more important.
I'm always amazed at how the bonding strength of polyesters are portrayed, from reading many online descriptions you would think it will just fall off the first time you tug on it. Actually polyester to polyester bonds are pretty good and failures are rare if even some care is used in doing the job.
I'm not getting my opinion from reading an online article selling epoxy, my view comes from 40+ hands on years in the business and doing tech service work for most of the largest boat builders in the country (plus other FRP markets).
Most boats have many secondary bonds in them, the larger the boat, the more there are, and I don't see a history of these boats just falling apart on the water. Has it happened...yes... there are just too many out there, so if you look hard enough you'll find some failures, but this happens with every type of construction. The repairs that fail are done by first timers that do little or no prep work and then use cloth and the glug glug method of measuring catalyst, these repairs are doomed to fail right from the start.
Saying that epoxy has 5 times the bonding strength means little if the strength of the polyester exceeds the loads it will see in use, which it does. Many of the boats out there are made with the lowest cost resin that will get hard and even these hold up well. I think most of the people on this site that have used polyester were surprised at just how strong it was after reading online how weak its supposed to be.
If you plan on using carbon fiber, Kevlar, or other types of high end fibers, then epoxy if the way to go, but when using typical glass, polyester works very well.
There are other situations where using epoxy is required also, but doing a transom and stringers is well within what polyester can handle with ease.
If someone decides to use epoxy that?s fine, it?s a choice each person needs to make on their own, the mistake is thinking that the job can?t be done with either product and make a safe, strong, long lasting repair.
PS. On my current project I'm using 100% polyester with zero concern of poor bonds and water absorption.
On a typical repair it makes little difference which resin you use, doing the job correctly is far more important.
I'm always amazed at how the bonding strength of polyesters are portrayed, from reading many online descriptions you would think it will just fall off the first time you tug on it. Actually polyester to polyester bonds are pretty good and failures are rare if even some care is used in doing the job.
I'm not getting my opinion from reading an online article selling epoxy, my view comes from 40+ hands on years in the business and doing tech service work for most of the largest boat builders in the country (plus other FRP markets).
Most boats have many secondary bonds in them, the larger the boat, the more there are, and I don't see a history of these boats just falling apart on the water. Has it happened...yes... there are just too many out there, so if you look hard enough you'll find some failures, but this happens with every type of construction. The repairs that fail are done by first timers that do little or no prep work and then use cloth and the glug glug method of measuring catalyst, these repairs are doomed to fail right from the start.
Saying that epoxy has 5 times the bonding strength means little if the strength of the polyester exceeds the loads it will see in use, which it does. Many of the boats out there are made with the lowest cost resin that will get hard and even these hold up well. I think most of the people on this site that have used polyester were surprised at just how strong it was after reading online how weak its supposed to be.
If you plan on using carbon fiber, Kevlar, or other types of high end fibers, then epoxy if the way to go, but when using typical glass, polyester works very well.
There are other situations where using epoxy is required also, but doing a transom and stringers is well within what polyester can handle with ease.
If someone decides to use epoxy that?s fine, it?s a choice each person needs to make on their own, the mistake is thinking that the job can?t be done with either product and make a safe, strong, long lasting repair.
PS. On my current project I'm using 100% polyester with zero concern of poor bonds and water absorption.