Fun with Epoxy!

[Chuck Craven]

Fun with Epoxy!

In the past I have built several projects with fiberglass and epoxy. My results were poor at best. I have always had problems mixing and wetting out the fiberglass. The epoxy would set up in the mixing pot or would start to jell as I tried to work it in the glass cloth.
I even tried polyester resin only to have the glass and mess fall the wood a year later. So I basically gave up. Building this tear I decided to give it one more try. I also wanted to use the new water base stains. So the bottom of the floor pan seams to be the place to try both out.
First the stain, the only brand available was from General Finishes. They had a color that I liked so I bought a quart. I read the directions three times. Then I called the factory, since they are a local biasness, and asked them how to apply epoxy over there stain. I got a question back for the answer to my question, which went like this. “Epoxy? You can use any type of finish over our stain!” They were not much help. I am using ¼” B C X fur plywood on the bottom. So I read the direction again and did every thing they said not to do. I wanted to see why not to do that and what it took to fix the goof ups. First the stain is very thick. It seems to dry very fast. It’s hard to wipe off the excess. When you over lap the previous section that was stained. Where the stained aria that was over lapped it got real dark. Using a rag dampened with water helped blend out the over lap. Light sanding helped bring more definition to the grain of the wood. Also things the directions said not to do. I think thinning the stain with water may help. Not suppose to do that also. I have a lot of experimenting to do before I stain the sides of my tear.
Now Epoxy! I read every thing I could find on the Internet about how to apply epoxy. I did figure out what went wrong in the past. There is a lot to this sticky stuff. First off the glass cloth, there is three basic types, one for epoxy, one for polyester resin and one that will work for both. It’s up to you to ask what type it is. Most will not tell you as they think you know what you are doing. HA! HA! Next is the hardener for the epoxy. Lots of different types fast, slow, low temperature, high temperature, and variable density and on and on. So what to do? I decided to go with RAKA INC. I bought the resin with slow hardener at a 2 resin to 1 hardener ratio. I also got the 4-mill cloth from them. I bought a slotted roller from them but did not use it. One of the cheep bond-o plastic spreaders worked fine for spreading and working the epoxy in to the cloth. (Called wetting it out.) I mixed the epoxy in 6 Oz batches for three minutes, scrapping the edges of the mixing pot. It took 5 pots of epoxy to wet out the cloth. I had about 20 minutes of time to work in the epoxy before it started to jell in 80+ dig, outdoor tem. The finish coats use only three 6 oz pots to cover the 58” by 120” surface.
I must admit that this is the best results I have ever have gotten wile working with sticky stuff. My technique still sucks but it’s a hard weatherproof surface. I just can’t seem to let good enough alone. As there are tool marks, lines, goops and puddles in the finished product, but with some more practice I may get fair at this. Took some sanding to take out the real noticeable oops. So I have decided not to glass-epoxy the sides. I will just use several coats of the Rot-doctor’s CEPS to seal the stained wood and spar varnish over that. Since I am better at working metal than epoxy the roof will be aluminum. It will be a Tin top Woody. So if you are thinking about using epoxy and have never done it, do a lot of reading and practice! Ask the experts here lots of questions and I think an amateur can get good results from sticky stuff.

Chuck

[AmyH]

Sounds like you're getting the hang of it. I must admit I was scared to death to start putting the fiberglass and epoxy on my walls, but it went so smoothly that I started wondering why I had waited (procrastinated) so long.

One trick that I read somewhere, that I ended up using, is to pour the thoroughly mixed epoxy into a rolling pan, thus distributing the heat of the epoxy and helping to keep it from kicking off. This worked great for me, particularly since I used epoxy rollers to put on the coats.

Another trick that I used was to heat up my shop a bit prior to working and then let it cool down slowly as I finished up. I got that idea after reading that it is always good to start the epoxy at a time of the day when you know the temperature will start dropping, instead of going up. I can't exactly remember the reasons for that, but I'll consider that it helped since the epoxy worked perfectly on my trailer sides.

The last trick I learned was to aim a small halogen shop light at the epoxy containers to keep them warm, allowing the epoxy to flow out of the pumps better. I would turn on the shop light about a half hour or so prior to pumping out the epoxy, and it seems to help quite a bit. It came out of the pumps nicely. I kept the light about 24" from the containers, not that the distance is that important.

It would be great if other more experienced epoxy users can add in a few of their tried and true tips for using epoxy. As someone that is new to using this wonderful sticky stuff, I relied pretty heavily on web research and a lot of reading prior to diving in.

[Juneaudave]

Congrats Chuck!!!! Got er' done despite yourself!!!

[Chuck Craven]

Hi Amy

It’s Nice to have a workshop big enough to hold a tear.

I have to roll it in and out of the garage. So I let it sit in the sun to heat it up then applied the epoxy. Then just rolled it back in the garage to keep it away from the bugs and let it cool down. Worked quite well. Here is the link to my update pictures. http://tnttt.com/viewto ... 666#252666

Chuck

[angib]

Amy, that is so true about pouring the epoxy into a paint roller tray - it increases the 'pot' life a lot.

The reason to not apply epoxy when the temperature is going up is because the air inside the wood is expanding as it heats up - as it escapes from the surface, it blows little bubbles in the epoxy. If you catch it just wrong, you can make a surface almost like sandpaper!

Andrew

[davefullmer]

If you use epoxy for a finish and are not using glass, do you have to be concerned about the finish being affected by ultraviolet rays?

Dave

[taylorcraft078]

If you use epoxy for a finish and are not using glass, do you have to be concerned about the finish being affected by ultraviolet rays?

Dave

Yes! The glass itself isn't affected by the sun. It is after all just sand. My wife did not want a thick varnish build up on our first canoe so she didn't want it varnished each year. After a few years I noticed a cut in the glass after a trip. Not a big deal to fix usually but then I noticed it had delaminated. 10 minutes later every bit of glass was off the boat. Reglassed it and we still use it. But now each boat gets new varnish every year and they are stored under a reflective tarp.

As for putting on the glass the method that we have found best is to drape the cloth over the surface and smooth it as well as possible. Then use foam rollers and foam brushes to kind of pat the epoxy in. Use less than you think you need and you will still use too much. When there is too much resin the glass will float off of the substrate and then you have a problem.

So far we have used Raka on 4 boats.

Dave

[bug_power]

you have to put UV stabilizers in Epoxy for it not to be effected. That or you have to paint it. Check Bateau.com a boat building forum and they can tell you all about it.