How Do I Choose the Right Epoxy?

I have a pahi 42 built of ply/glass I did a refit and reglassed some of the boat. Used west system and have been happy with it. If you want to talk to somone who know epoxy better than anyone call Greg loer of resin research. He is the man when it comes to epoxy.

 

BTW a trick to lay up glass on a vertical surface is... mix epoxy add 20-30% denatured alchahoal cover the panels you are going to laminate. Wait till it kicks and gets tacky. your glass will stick to the walls so no stappling or any of that crap. then whn you stick on your glass wet out with a fresh batch. Just a tip I wish I could do laminating class for home builders. When you learn how to make surfboards boats are a joke to laminate.

always glass above 60 F it makes a difference.
Also if you layup after a layer has lost its takiness make sure you hit it lightly with 100 grit and blow it out afterwards to get the dust off.
If you have any q's email me through my blog girvinsurfboards.blogspot.com

 

You really don't want to be adding 20-30% of anything to epoxy, its not a good idea.

 

Its not a structural layer of epoxy. YOu put it on super thin. When you wet out the glass with the main layer of epoxy it will soak all the way through to the ply and chemically bond all the way through. I do not have 40 years of fiberglass exp like you. So maybe I am wrong but have fixed many boats and have laminated over 1000 surfboards in epoxy. 20 where wood. All the wood one's where done with the denatured alchahol layer first to seal the wood. No delams with tons of sessions on each. YOu could do strait epoxy but it will be thicker as a tacky layer.

 

If you look at the test results when epoxy is reduced with relatively small amounts of even reactive diluents you will see how dramatically the physical properties and water resistance drops off.

After saying that, there are some applications where you may not see the negative effects of thinning epoxy, but long term the part will hold up much better by using the products correctly.

Thinning epoxy seems on the surface to be a good idea, low viscosity, good penetration, thin coat, etc, but none of these really add up to making a better part.

I looked at your wood boards, they're nice.

 

Thanks, yeah I havn't used it for a structural bond and wouldn't I agree about that.

 

girvin, thanks for coming back and explaining the reason why you recommended thinning epoxy with alcohol, initially I could not see the reasoning. But I am totally with ondarvr with this.

Richard, yes you are correct, you also might like to know that I do not disagree with what you have been saying in the threads started by catbuilder or any other threads.

cheers
Andrew

 

If you don't like the alcohol you can just use a thin layer with the epoxy just make sure its warm enough to be thin. I use it with surfboards where people ***** about and ounce here and there LOL. Good luck with your build

 

You could also heat up the resin quite easily in a microwave. Just do not heat up your dinner in the same microwave afterwards...

About which epoxy to choose:

I would go for preferably 1 resin, and 2 or more hardeners, slow and fast. Use the slow ones for large jobs, and the fast ones for small jobs.

Talk to other builders in that area, to see what they are using, and their experience with those materials. The only one I know is Meritt, somewhere north of Ft. Lauderdale. But I am sure there are more.

 

How can i be sure in a world of delaminations,
How can I be sure, where I stand with glue
Whenever I, whenever I am away from glue,
I want to try,. Try another sort of glue
Maybe I’m just standing around,
With my feet stuck, stuck to the ground
Waiting for acetone to free me from glue

 

Hey Peter, I didn't realize that you were so creative!

I haven't been here for awhile (busy at the boat) but wanted to weigh in on the epoxy question.

All the talk about layups aside I'm just wondering......

Could it be that we're just "married" to various brands of epoxy when none of them are materially different? I've used West, System Three, and even some hobby resins (like the five minute stuff that the model builders like to use) and find no big differences. I noticed the five minute stuff is smellier but that's just a personal taste observation

I settled on System Three because I like the 2 to 1 mix ratio. I figure it's easier to get a good mix and not mess up when you only have to count to two. Other resins are five to one and when I've used them I had fine results too.

I wonder if it's like motor oil. I like the full synthetics. I've used Penzoil, Castrol, Quaker State, Mobil One, Havoline and others. They all worked fine and I didn't notice any difference with any of them. So now I just buy what's on sale. I wouldn't mix epoxy brands to save money but.....

Why not just pick a reputable brand and be done with it? After all it takes long enough to build a boat without agonizing over epoxy brands.



MIA

 

About not mixing brands: How come that there are producers of fine epoxy hardeners, but these do not produce resin at all? Same the other way round.

Most popular brand names are blenders (at most) that buy their base epoxy resins and curing agents from various sources. It really depends on their knowledge and process control to get a consistent output (most epoxy manufacturers change hands and factories often, and this influences properties. For instance, West used to be toxic in the past. The materials used then are not the same now. However, handling and characteristics are the same. So all I can say is: Well done!.

In general, one can say that in boatbuilding there is only a limited amount of applications, and there are many brands fulfilling the needs for that application.

 

I just mixed and used up nine gallons of RAKA epoxy. I used their slowest hardener on a cylinder mold lamination, with good results.

The wet out, for a 40 foot section with three layers of 3mm okume took three of us about an hour, using foam rollers and a mechanical mixer, in about 78F, mixing three gallons at a time for about six minutes per batch, and immediately spreading it out into flat trays. We probably could have taken two hours and still been OK.

The end result seems fine to me. I saved a 3mm section to test later if I need to.

RAKA has given good support and prompt service. I would not hesitate to purchase from them again.

Charly


Dang. I meant to put this in the RAKA thread. sorry bout that

 

This is just incredible first hand information for my personal situation. Thank you for posting it.

I am doing the same exact build and trying to select the right epoxy for the conditions. Great to hear how this went.

Thanks to everyone else too... I've been reading this thread and absorbing the information.

 

Putting it into flat trays is important it helps keep the kick time longer and less exotherm.