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EPO rudder refinish problems http://www.hobie.com/forums/viewtopic.php?f=20&t=50757 |
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Author: | srm [ Wed Mar 19, 2014 9:12 am ] |
Post subject: | Re: EPO rudder refinish problems |
On the EPO's I've done, where there were exposed fibers, I lightly sanded them off first using 80 or 100 grit paper. Obviously you don't want to go overboard here, but I think you're better off starting with a smooth surface rather than trying to get the fibers to lay back down. Starting with a clean, roughed up surface is critical. Lightly sand the entire rudder with 100 grit or higher sand paper to give the epoxy something to grab on to (a sanding sponge works well). Then clean the rudder really well with acetone. Also, when I did this, I only did one side of the rudder at a time so the epoxy wouldn't drip. I painted the unthickened epoxy on using a disposable 1" brush. I know one of the rudders I resurfaced had a lot of exposed fibers and started out really bad, but I sanded off the exposed stuff, resurfaced and painted it and it came out really nice. I think if you're worried that sanding off the exposed fibers is going to weaken the rudder, you'd still be better off sanding them away and then add a new ply of glass fabric over the rudder when you coat it with epoxy. Anyway, you've got epoxy on there now. I'd sand it all down smooth and then maybe put another thin coating on. The problem now is the surface is so uneven, you're going to have a tough time getting it back fair. I would use coarse sand paper on a sanding block to knock down all the high spots and then use a sanding sponge to fair it out. sm |
Author: | PurdueZach [ Wed Mar 19, 2014 9:23 am ] |
Post subject: | Re: EPO rudder refinish problems |
Thanks so much. So you're saying that I can just sand off the fibers? I didn't know that they would break off that easily. Luckily I've only done one side of each rudder. |
Author: | rattle 'n hum [ Wed Mar 19, 2014 10:26 am ] |
Post subject: | Re: EPO rudder refinish problems |
All I have to offer (in case you didn't know) is.....get that major sanding done as soon as the epoxy has cured enough that it's not too gummy. If you wait too long, it'll be hard as a rock.....especially if you added any silica to inhibit running. Good luck! |
Author: | PurdueZach [ Wed Mar 19, 2014 10:29 am ] |
Post subject: | Re: EPO rudder refinish problems |
Luckily I didn't add any filler. I'll sand tonight and see how it goes. I was surprised at how slowly it cured with the slow hardener. Temperature was 70 degrees in the basement. It took all night to harden to a semi-tacky texture. |
Author: | srm [ Wed Mar 19, 2014 11:10 am ] |
Post subject: | Re: EPO rudder refinish problems |
Contrary to rattle 'n hum's advice, I would suggest you let the epoxy fully cure before attempting to sand it. If it is not fully cured, it will gum up your sand paper and make removal even more difficult. It's better (easier) to sand epoxy that is good and hard than soft epoxy. Just use a more coarse grade of sand paper. And yes, I would sand off all loose fibers prior to coating with epoxy. As I said above, I would sand the entire rudder lightly (scuff the surface to a cloudy haze) before coating. Regarding cure time, this is all based on temperature. Slow hardeners are typically for 80 degress or higher. If you were at 70 degrees, then it is certainly going to take a while to cure. Also, since the resin is being spread over a large, thin area, it doesn't build up heat which adds to the cure time. The resin in your mixing cup will cure much more quickly than the resin on the rudder blade because the resin in the cup builds up heat which is not easily dissipated. sm |
Author: | PurdueZach [ Thu Mar 20, 2014 10:35 am ] |
Post subject: | Re: EPO rudder refinish problems |
I sanded a little this morning and it looks like I'll be able to make this work. Thanks for the advice! I'll post pictures once I'm done. |
Author: | rattle 'n hum [ Thu Mar 20, 2014 11:07 am ] |
Post subject: | Re: EPO rudder refinish problems |
Apparently there are differences of experiences/opinions, maybe due to the use of different products, etc. I'll clarify mine for the consideration of future readers if not Zach. As I stated above, one would not want to sand when the epoxy is still too gummy. However, there is a big difference (in time and hardness) between the point of just being not gummy and being "fully cured." After a day or so, when the epoxy is just cured enough that it's not gummy, it's still relatively easy to sand in my experience. After a week when it's fully cured, it's much more difficult. |
Author: | smittyt2k6 [ Tue May 13, 2014 5:56 am ] |
Post subject: | Re: EPO rudder refinish problems |
Hey I have been working on my EPOs as well, depending on your location (temperature) you might have better luck with a quicker set epoxy. For me living in new hampshire trying to get anything to set under 60 deg is tough. The other advice I got off the forum that has been a huge help is to use graphite filler 423 from westsys its very thin and easily sanded. If your using the quick pump system, 1 squirt ea with about a half teaspoon graphite will do the trick for painting one side on each board. the last bit of advice is put on very thin coats, roll it on first with a micro roller, then tip with a foam brush. here is what I have done sand with 100 (I had exposed fibers too) first coat sand 220 second coat sand 600 wet third coat <- hopefully get this done tonight sand 1200 wet? wax/polish hope this helps, you if you search EPO repair you can find the quick build page that I used. |
Author: | Fxloop [ Tue May 13, 2014 7:18 pm ] |
Post subject: | Re: EPO rudder refinish problems |
Damn i'm glad i found this! I have a set of EPO's needing the same treatment. Are older EPO's the same size as the new ones? |
Author: | ronholm [ Tue May 13, 2014 8:19 pm ] |
Post subject: | Re: EPO rudder refinish problems |
Fxloop wrote: Are older EPO's the same size as the new ones? Yes the original EPO's and EPO2 should measure just about the same, and in some ways they are sometimes better... I have seen (minor) symmetry issues on several different EPO2 rudders that I have yet to see on the original EPO rudders. I haven't got to play with the EPO3 rudders yet. |
Author: | Tri_X_Troll [ Tue May 12, 2015 11:31 am ] |
Post subject: | Re: EPO rudder refinish problems |
Zach, did you ever get yours done? I'm getting ready to tackle this project and don't want to buy an entire quart, does anyone know where to buy smaller quantities of the epoxy? I don't see myself ever using an entire quart and would rather just buy enough to get my rudders done. |
Author: | srm [ Tue May 12, 2015 4:07 pm ] |
Post subject: | Re: EPO rudder refinish problems |
uscomposites.com sells 16oz containers of epoxy. It actually ends up being more than 16oz because the 16oz is just the resin (you also need hardener). I've been quite happy with their epoxy and I have used it specifically for refinishing EPO rudders. As far as not using it up, you will be amazed at how many applications you find for epoxy once you start using it. sm |
Author: | Tri_X_Troll [ Wed May 13, 2015 9:41 am ] |
Post subject: | Re: EPO rudder refinish problems |
It looks like the 16oz resin + 8oz hardener is what I'm looking for and should result in 24 oz mixed. I'm assuming that by the time I add my graphite that I should have enough to get a set of EPOs done. Do you use the thick or the thin when you've used the USComposite kit? |
Author: | srm [ Thu May 14, 2015 6:16 am ] |
Post subject: | Re: EPO rudder refinish problems |
I use the standard thin laminating resin. I just used the straight resin, never added any graphite or thickeners. I painted it on with a brush, let it cure, lightly sanded, painted on a second coat and then final sanded and painted. If you wanted, you could probably just paint on one coat, let it partially cure, and then paint on a second coat an hour or two later (once the first coat goes green). sm |
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