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Repairing imperfections in epoxy?

Posted:
Sat Oct 02, 2010 7:58 pm
by Nosty
Hi All,
I'm getting ready to put a third coat of epoxy on my TTT tomorrow and noticed a few remaining screw holes and minor imperfections in the surface.
What do you use to fill/fix these places? Bondo? Epoxy? I'm assuming you can use Bondo, but I thought I'd ask you knowledgeable folks to see if you might have any better ways to do it.
As always, thanks for all your help along the way.
Brian

Posted:
Sat Oct 02, 2010 8:27 pm
by parnold
Bondo is the cheapest and easiest fix. You might want to look for Dynatron (3M) putty coat, or US Chemical Icing. They are thinner than regular "bondo" and sand a little easier. They are considered finishing putties, for minor imperfections. They are a lot more expensive than regular Bondo, so may not be worth the money for the little effort they will save.

Posted:
Sat Oct 02, 2010 10:04 pm
by rmclarke
Brian,
What kind of epoxy are you using?
Richard

Posted:
Sat Oct 02, 2010 10:06 pm
by doug hodder
Most epoxy systems have additives for a lot of different situations. Microballoons can thicken up epoxy like peanut butter. works easily, and it's epoxy on epoxy...won't tend to crack like a bondo might. Just an idea. Doug

Posted:
Sun Oct 03, 2010 12:33 am
by madjack
I favor the microballoon additives as well...makes a real nice putty...you can order from RAKA but may not be cost/time effective for you...may be available from local auto body paint suppliers...if not, a 2 part bondo or wood putty may be your next best option...............
madjack
p.s. 2oz is a pints worth...4oz is a quarts worth...
http://store.raka.com/phenolicmicroball ... t-2oz.aspx
Phenolic Micro Balloons...hollow reddish brown spheres that make excellent light weight putties with superior feather edge sanding qualities. They sand easier, smoother and have better sag resistant properties than the white bubbles. Phenolic is the best quality filler for an easy sanding fairing putty

Posted:
Sun Oct 03, 2010 10:33 am
by Nosty
Thanks everyone.
Mad Jack, I, initially, used Plastic Wood to fill all the holes as I was building. Unfortunately, after an email to DAP, I was told that Plastic Wood and epoxy don't play nice together. While I was applying the epoxy, the well-hardened and cured Plastic Wood just liquefied and ran out in a lot of places.
Richard, I'm using the RAKA epoxy with the non-blush hardener. Very pleased with it. I've only had one 8oz batch go off in my hand. Everything else with it has been great.
Thankfully, in as much as I hate sanding, I did do a lot of prep work before I started with the epoxy so most of the repairs I have to do will be filling some countersunk screw holes and a few dents and cracks in the plywood. I've used a lot of Bondo over the years so, if it'll work with the epoxy, I'll just use that. I have some on hand.
Thanks for all the replies. I do appreciate the help.
Have a great Sunday.
Brian

Posted:
Sun Oct 03, 2010 1:58 pm
by Nosty
I was thinking while I was out there working. Have any of you tried that two part epoxy in the hypodermic looking applicator?
I was wondering whether that might not be a good way to fill the screw holes and plywood imperfections. You could just point the tip into the hole and fill it, then sand it smooth when it dries? I've seen some that say that you can sand them in fifteen minutes.
Have any of you tried this and, if so, did it work?
Thanks again,
Brian

Posted:
Sun Oct 03, 2010 5:10 pm
by Larry C
Nosty wrote:I was thinking while I was out there working. Have any of you tried that two part epoxy in the hypodermic looking applicator?
I was wondering whether that might not be a good way to fill the screw holes and plywood imperfections. You could just point the tip into the hole and fill it, then sand it smooth when it dries? I've seen some that say that you can sand them in fifteen minutes.
Have any of you tried this and, if so, did it work?
Thanks again,
Brian
Most
5 minute epoxies I have seen are NOT WATER PROOF......


Posted:
Sun Oct 03, 2010 11:24 pm
by madjack
...plus, while it is in an application syringe, it just gives you a set measure of both, but once dispensed, it still needs to be mixed...use some bondo or 2part wood putty................
madjack


Posted:
Tue Oct 05, 2010 12:55 pm
by Nosty
Well guys, you haven't failed me yet so I'm certainly not going to break the cycle.
I stopped by West Marine on my way in to work yesterday and picked up some of those micro-balloons. You were right in that it's keeping everything the same, Doug and Madjack. I'm going to fill all the holes this weekend and, hopefully, get the epoxy finished. I've got between 2 and three coats on various parts. I'm thinking that I'll get three all around and four on the front and roof. The tape has all but disappeared so I'm thinking that should about do it.
I'm assuming, from what I read on the RAKA site, that a week should be enough time to let the epoxy cure before painting. Is this correct? The daytime temps. here are supposed to be near 80 and 50's at night. I'm hoping to finish the epoxy this weekend and paint next weekend.
Just wanted to thank you all for the help. I really appreciate it. It's great to know that knowledgeable help is just a logon away when you get into something you don't know much about.
Have a great week.
Brian

Posted:
Tue Oct 05, 2010 4:25 pm
by madjack
Brian, when you mix up your putty, keep in mind, it may take more of the microballoons than you would expect...keep adding until it is the consistency of peanut butter...it may help to "wet" out the spots you wish to fill with some straight epoxy to help the putty stick really good...properly mixed it should be just about like the bondo you have used in the past...............
madjack


Posted:
Wed Oct 06, 2010 6:08 am
by GPW
Just a note on safety ...Having used micro balloons in the past on model planes , you don't want to breathe in micro balloons ... WEAR A MASK !!!
Soon as you open the container ,they go everywhere...


Posted:
Thu Oct 07, 2010 12:53 pm
by Nosty
Thanks guys. I'll definitely wear a mask. I usually do for sanding anyway. It'd be a real kick in the pants to end up with a fatal disease from building something that's supposed to be fun and relaxing.
I was a little leery about going with the epoxy in the beginning but, seeing it now, I can't imagine building without it. There's just too much wood exposed to the elements in some really vulnerable places to trust it to paint alone.
I've been reading a lot of the wooden boat builder forums and I have found that a lot of them are using Benjamin Moore M22 urethane enamel over their epoxy coated boats. Lots of good reviews on it. I've decided to go with that once the epoxy cures, (hopefully next weekend).
Thanks again for all the input. You have all helped more than you can imagine.
See you in the funny papers.
Brian

Posted:
Sat Oct 09, 2010 6:11 am
by GPW
Nosty, best save up and build a shed for that trailer... Over the years , the Sun will eat even the best of paints ... Just kept covered , the problems are lessened exponentially ... I just built a simple little Teardrop shaped (

) Shed for the boat and TD ... Paint problems went away ...
Now i've got Wasps ...


Posted:
Sat Oct 09, 2010 3:34 pm
by Nosty
Got that covered, GPW. I've got one of those portable garages I've been keeping the "work in progress" in. It should serve as a nice place to keep it out of the elements when it's not in use.
As for the micro-balloons, guys, they worked great! You were right: that was the way to go. I've about had all the sanding I can take for this lifetime, but that's part of the process. I just finished applying the last, (4th), coat of epoxy to the outer shell. A little more touch up here and there and it should be ready to paint next weekend.
Thank you all for all your help. I really do appreciate it.
Have a great weekend.
Brian