Epoxy Fairing Compounds

Anyone here had any experience with Mas epoxy? Mas recommends a compound of resin, silica and micro-balloons as a deck fairing compound. I am restoring the deck of my old cruiser. After fighting with it a bit I finally came up wit a mixture that goes on ok but it is very hard to sand. The paper cloggs and loses its cut very quickly. Am I going to be sanding forever here?

 

It doesn't matter about what brand of epoxy you use; if the amount of silica is quite high, sanding is almost impossible. If you want an easy sanding mixture, add microballoons to the mixed epoxy until fairly thick, then add a bit of silica to stop the mixture sagging under its own weight. The microballoons allow very easy sanding if the silica content is quite low.

 

Easy sand filler

I've used Superfil extensively. It's made by Poly-fiber and available thru Aircraft Spruce and Specialty-877-477-7823 www.aircraftspruce.com
It's epoxy based , non shrinking and weighs less than 5lb. per gallon. Sands very easily...

 

Finding a balance

I'm struggling with the same issue. I know how to make it more sandable with microballoons, but more sandable is just another way of saying less abrasion-resistant (and usually less dent and gouge resistant too). Not the best tradeoff for a deck. I'm thinking that I will put up with some difficulty sanding, try to fair it with as little excess to be sanded as possible, swear a lot while I'm sanding, give up, and then add more micorballons/ less silica to the next batch.

 

The first coat I put on was too thin. I kept sanding through. The second coat is thicker, and more expensive, and was less fair due to trowel marks and inexperience. I have finished the first sanding of all but about 2 feet of the starboard gunnel. I will have to go back and do some additional filling of some low spots and continue after I can afford some more supplies. I guess I am being a big baby. It's true that a harder surface will be less prone to damage but MAN are my arms tired. Proportions per Mas Epoxy:
1 prt. resin
1 prt. silica
3 prts. balloons They say this compound is trowelable but I had trouble with the mix pulling under the trowel. Due to amb temp and climate I guess.

My mix: 1 prt. resin
1 prt. silica
enough balloons to easily spread. Consistency of cake batter.
See the mistake? Guess I should have backed off the silica as well. I guess I will end up with an extra hard deck and big shoulders!

 

Big shoulders aren't all bad...

...well, maybe on my wife.

I admire your perseverance. I think power tools are in order here. "Hmmmm, do I buy epoxy to sand, or a sander to sand it with? I can't afford both."

The good news is that the mix on your second batch was harder because of the lower proportion of microballoons. No matter what you do on future batches, it should be easier to sand than that one was.

If you have it pretty close to fair already so that it would just be a tiny bit here and there, maybe you could use a fairly soft mix to finish smoothing, sand that, and then paint it with a mix that has no microballoons, but will not need to be sanded. What say the experts?

 

In trying to get the balance between easy to sand and abrasion resistance, the mix containing say around three times the volume of microballoons compared with silica, is still pretty hard. As far as walking on it with rubber sole shoes, you won't wear it out for many years.

 

So maybe the original recipe was pretty close?

If he used the original mix with just a little more epoxy to make it less stiff, would he be in the ballpark?

 

I am using an orbital sander, a 7 inch sander polisher, two palm sanders, a finishing sander, 16 inch and 6 inch sanding blocks for flatness, and every other abrasive instrument in my shop. Get the idea? This stuff is real hard. It also sands to a glass smooth surface when you finally get there. I am having a fit getting there but I am very happy with that part of it. I have a picture in my gallery of the forward hatch just after it had been coated with the second coat of compound and before sanding. I used the hatch for practice before starting on the deck. I intend on uploading some more pictures of the deck as the project goes along including priming and painting as those steps get completed. I have a more complete set of pictures of the project on Kodak.com let me know if you want an invite to view them. The deck is just the start of a complete paint job. The whole boat will be painted including the hull. I will be taking pictures of the process as I go along.

 

I thin Stevel hit the nail on the head.

 

I can't hit my thumb EVERY time.

You are ahead of me on your project. I'm sticking to my plan to do everything from the rubrail down this haul-out and do the deck and cabin work on the next haul-out. So far I have stayed with the tough stuff from about 2-3" above the waterline on down. I'm just now getting to the hull sides, and will probably "cheat" a bit on that. I'm dreading the work on the deck.

This discussion gives me an idea about a new thread to work out my rubrail connundrum :idea:

When we both end up with ginormuos shoulders from sanding wanna arm-wrestle?

 

That's why I started where I did. I knew the deck would be the most difficult part of the project. Thankfully the hull is in pretty good shape with some minor scratches and some screw holes to fill. When I started the deck had been painted with latex house paint. I looked as though the previous owner had started to gel coat the deck and stopped just forward of the transom. The rest had been coated in house paint! I had to strip all the old latex off before starting.

 

Just read your profile

Congrats on the new rugrat!

I see you are a diesel mech. What do you work on? Who do you work for,...etc.? Is the boat gettin a diesel if it doesn't already have one?

 

U.S. paint, the guys who also make awlgrip put out a system called awlfair. Its a two part epoxy which basically consist of what your mixing. It sands like butter and is tuff as nails. Real easy to work with and has a nice working time. Only drawback is it takes like 8 hrs to cure. Its about $70 for a 2 quart kit but will save lots of time. Give it a try. Its very popular down here.

 

My profile is a little old. My little girl a now 5mos. I work for an OTR trucking company based here in Chattanooga. One of the top three in the nation. Our fleet consists of Freightliner, Volvo and International trucks and an array of different trailer brands. I have been with them for about 8 years now. I am a general maintenance mechanic, meaning I am total chassis qualified. In short, I get all the junk to fix.
I wish I could put a diesel in the boat but I cannot really justify the expense considering she has a good drive train. I have spent the last 2 years getting the old 273m and the velvet drive up to snuff and a repower at this point would probably cause my wife to leave me. The boat has new wiring through out, including the addition of a shore power system, on board charger, automatic bilge heater, and new instruments. I put new lights everywhere along with a second spotlight. I like the lake at night. I also upgraded the charging system, added two deep cycle batteries, and installed a battery combiner and smart voltage regulator. The head was an over board dump, so the old macerator was removed, a 15gal. holding tank added and a Jabsco head installed. My wife and I used the boat here on the Tennessee river during which all these upgrades were completed. When the baby was born we decided to lose the slip fees for awhile and I started the prettying up process we have been discussing.
I have plans for a fuel system upgrade, new controls, new galley pump, full interior, cockpit inclosure, paint job, new rub rail and about a million other things to keep me busy. I should be finished about the time my daughter leaves for college. Thats ok though. I love doing it. I have always been into old boats.