New Owner - Steep Epoxy Learning Curve

[CRichardsDSX]

G'Morning All!

Recently came into a project boat, and the learning curve on the epoxy is kicking my butt.

I need to attach some blocks/brackets to the hull in the lazarette for a new battery shelf, new fuse bank for those wires running direct to/from the battery, as well as some other items. Initially I'd considered using the "Kitty Hair" product from Evercoat, after reading Maine Sail's article about backing blocks - the first project on the "hard". True to his word, though, the stuff is impossible for me to fillet nicely. Admittedly I'm a bit of a perfectionist, and I'd like to lay at least one piece of fiberglass over the blocks so ensure a good bond to the hull, as well as help waterproof them.

I'm sure this seems like the most basic of projects - but I can't seem to get it to look "right". So what are the "best" methods/products to do this work right so it looks like the parts have been there from the factory?

Thanks for your input!

 

[njlarry]

West system has free how to books where ever it is sold and fantastic phone support. They are the experts and are great at talking you through your project.
I mostly use 105 epoxy with 206 hardemer and 406 thickener. Their free user manual explains it all. The pumps make mixing easy. Did I say that I love West system?
A great book would be Fiberglass Boat Repairs Illustrated by Roger Marshall. Boatworks has a whole series of well done how to videos on YouTube.
All the above will make you an expert before you even start.

 

[MrBill_FLL]

I like west system, only because of the pumps and exact measurement.

IIRC MAS expoxy is a 50/50 mix, so easier to mix and cheaper. (but doesn't have the slow and very slow hardeners)


you can add micro balloons or talc power (west system sells that), to make the thickened paste. (I often mix up a bunch put it in a glass jar and only use as much as I need ) -it will keep about a month.

the metal roller helps get air out, with mat/roving.

I use FGCI for my supplies https://www.fgci.com/buyproducts_catalog1.aspx

-no affiliation.

 

[CRichardsDSX]

Thanks for the input!

So what I've got thus far are the parts epoxied to the hull - but with not-so-good looking fillets using the Kitty Hair. They're firmly attached, but I just want to make nicer-looking fillets. I've got some of the West System thickening media - but by the time I get it mixed to the right consistency the stuff has already kicked!

MrBill - we've got a FGCI on this cost as well - luckily right around the corner from me. Maybe the best option is to stop in and ask for a filleting mix that has some working time? Is there a specific product(s) you get from them for this application?

 

[Ukeluthier]

It's not the filleting mix that is causing your early kicking problem... it is the temperature.

In Florida, you will be much better off using "slow" or "extra slow" hardener for your epoxy.

 

[Ralph Johnstone]

Get The Books ...................

West system has free how to books where ever it is sold and fantastic phone support. They are the experts and are great at talking you through your project.

...................... as njlarry says. They're on line. Sheesh ! ! ! !

They designed the products. They have the practical experience. You're just flying by the seat of your pants. You're also a perfectionist so READ THE BOOKS :bang:! ! ! !

I use System Three epoxy, take a look at their manual (attached). Forty pages of every trick in the book for using epoxy. All epoxy companies put out huge manuals on line for their products. It's part of their PR.

 

[Bill Roosa]

aside from the temperature thing, smaller batches of epoxy don't heat up as much and set up slower, alternatly a large batch spread out quicky will also slow down the cure.
I have a whole set of PVC unions, tube and such of various diameters. These are perfect for making fillets. Just pile the epoxy puddy in the joint and then with a slight twisting motion run the PVC fitting down the fillet. You will know you are moving at the right speed when you see the twisting motion doing what you see the water at the beach do when you vibrate it with your finger. The sand gets wet and the water comes to the surface. Same thing happens with the epoxy and leaves a smooth surface. Don't try overhead or vertical fillets till you master them in the normal position. The sags can be heartbreaking. The timing of cure, putty thickness, mass of the putty in the fillet (heats up and cures faster with bigger fillets) and batch size to prevent sagging is kinda an art form.

 

[All U Get]

I put my mixing bowl in a pan of ice when the temperature heats up. That's usually one week in August. That slows down the kick.

All U Get

 

[njlarry]

The cooling effect of ice works great. Mix in a cool place with a slower hardener like 206 or 207. I have not used the filet additive but the 410 fairing additive is very easy to sand.

 

[Brian S]

For fillets, I might consider using colloidal silica for a smoother paste, and microfibers for more durability and less chance of the colloidal silica cracking. This would be West System 406 colloidal silica, and 403 microfibers. I used this mix to replace the corner and cracking I removed from my rudder (don't ask, it was ugly and my own fault...)

I had previously used the colloidal silica to try and make tips on a paddle, and that's when I learned that CS + epoxy is prone to chipping, at least in that application. The microfibers will make more of a matrix that will hold together, but it doesn't make a smooth paste, so that's why I used only CS to cover the tips of that wood paddle. Microfibers are actually really good for a laminating mix...

Keep in mind sometimes you just can't make things as smooth and as nice as you want. That's why they invented sandpaper

Wood flour plus epoxy makes a nice peanut butter consistency fillet medium - it's how you do fillets joining plywood panel seams on a stitch and glue boat construction. The epoxy bonds to the cellulose of the wood, so it ought to be darn strong for a kayak or small boat. I don't know that it would be as good a medium for tabbing wood to existing polyester fiberglass resin...