Core Sound 20 #130

[John Burritt]

Sounds like the sandpaper is gumming up w/ "amine blush."  This can be a by-product of the epoxy curing.  Simple to remove from the cured surface by washing it w/ a liberal amount of water and maybe just a wee bit of detergent.  Scrub - turning/changing cloths frequently, rinse & dry.  If it still feels greasy, wash it again.  Water will bead on the surface before you scrub it; not after, if its well cleaned.  Now sandpaper will last a lot longer w/out gumming up.

[Hirilondë]

Also, I am having trouble with my sandpaper gumming up with what I think is wax from the epoxy.  Does anyone have any tips to reduce the buildup?  I think there are de-waxer products, has anyone used one? 

Are you removing the blush before sanding?  My guess is that you are not.  Clean the epoxy after it has cured with just plain water and a sponge before sanding or the next coat of anything any time you let the epoxy cure. 

You could also hot coat your epoxy instead of waiting for it to cure between coats.  Depending on the brand, the time constraints are different.  But you are looking for the window between set up and cured.  This way each coat forms a chemical bond to the previous and thus requires no sanding between coats to give tooth to the mechanical bond you are creating.  It usually means you have a more serious sanding to do at the end, but if careful it means less sanding over all.  This is the route I try to take for everything I do with epoxy.  It does however require planning for long periods of time from start to finish, but when possible I find it well worth it.

[TomH]

A couple more pictures for everyone.  I am planning on epoxying the bottom of my boat the next couple of week nights.  My plan is one thin coat each night to 3-4 coats.  I am going to try to get it really thin by brushing it on and rolling it smooth with 4" foam rollers.  How did anyone else keep it thin so that it didn't create runs?  Also, I am having trouble with my sandpaper gumming up with what I think is wax from the epoxy.  Does anyone have any tips to reduce the buildup?  I think there are de-waxer products, has anyone used one?  Are they helpful?
Thanks!

Not knowing your experience, a couple of things to consider...
1) I did not hear you mention f'glass cloth on the bottom. Brushing/rolling 4 coats of epoxy might be more $$$, weight, and hours of work than just glassing the bottom -- and the strength that the f'glass adds would likely be much more protection.
2) Gumming sandpaper could also be incompletely cured (or incorrectly mixed) epoxy -- if washing does not remove the stickieness then you have curing problems.
3) A good wide and sharp scraper used for a few minutes is worth many, many hours of sanding. Do the scraping to level the epoxy when the epoxy is still slightly 'green' (not fully cured). You get a very uniform and smooth surface with no sanding at all The scraper also works great to remove the raised edges of fiberglass tape with little effort.

[jshaley]

If the sections are flat enough, you might be able to use "Peel Ply" and avoid some of the sanding. Please note, I have read about it, and read good things from folks who have used it, but have not used it yet myself.

Peel Ply: http://www.clcboats.com/s...ystem-release-fabric.html
John

[Twetmore]

I appreciate everyones input.  I just finished epoxying the entire inside bottom of my boat last night so I will try washing it down first before sanding Thursday.  It seems like the epoxy is sitting really flat and smooth with the foam rollers so I think I will stick with this method.

John - Everything that I have glassed does feel greasy, I will try washing and drying a couple of times before the next time I epoxy.

Hirilonde - I have tried to do hot coating wherever I can, unfortunetly, I don't have the large time blocks required to do the whole thing in one shot which would be nice.

Peter - I appreciate any input since I have very little experience.  I am working with graduated containers so I hope I am getting the mix correct, maybe off by a slim margin of the measuring lines but can't imagine it would be enough to throw off the mix.  The pumps that I received hardly ever work so I have gone to pouring the epoxy and hardener which I am not happy about but still feel is accurate.  I thought that curing was the issue also, however, I waited a couple of days on the centerboard and the centerboard cases at 65 degrees fehrenheit and still had the same issue.  Right now it is in the 80s here which means my upstairs shop is somewhere in the 90s.  I would not think that curing is an issue at that temperature.  Since I started though I have not been really fond of the epoxy I've been using so I ordered some Wes Systems which should be here by the weekend. 

        - Are you saying that spreading the epoxy with a scraper is the way to go?  Do you pour it on and scrape it out flat or am I not understanding correctly?

        - Also, I was not planning on glassing the interior of the boat, only the exterior with 4-6 ounce fabric. Any suggestions on which weight would be the best?  My plan for applying the exterior fabric was to have three guys with scrappers and I would mix and pour the epoxy on.  I am trying to find fabric now so that I can use two pieces the entire lenght of the boat overlapping at the centerline.  Once the fabric is saturated with the scrappers I was going to use a foam roller to try and smooth the rest of the way.  Any input or suggestions would be appreciated.  Do you think the two pieces longitudinal is the best method?  Also, does anyone have a good supplier with a good price?  I have looked at Jamestown and they only sell 50" which would be cutting it close at the widest point.

John - I will have to look into this a little farther but am not sure that I want to spend the extra money, but it may be worth it to save the time.  Has anyone else used "Peel Ply"?  Is it useful?  The bottom of the boat is pretty much all I have left for glassing which seems like a large area to use it on.

[hokeyhydro]

Scraping.  Look up  "cabinet scrapers" to get an idea. I use Red Devil scrapers and an 8" fine mill file to keep the scraper edge sharp. You can scrape all the runs and ripples off while the epoxy is set up but still green, as in you can dent it with your fingernail.  Even after the epoxy is cured hard a scraper is the best and fastest way to get the surface level.  Keep the mill file handy and dress the scraper edge every few minutes. You want a "burr" feel on the edge - fingertip test.

[John Burritt]

If your epoxy cured hard, your mixing ratios are correct.  If it stays tacky & soft, the ratios aren't right.  The greasy feel is the amine blush on the cured epoxy.  Water will remove it.  Check the mixing ratios for the West Systems epoxy - probably different from what you've been using.  By the way, almost all epoxies blush to some degree when they cure.  If its really hot when you are doing your glassing, mix the epoxy in small batches & pour it out of the cup as soon as possible.  Heat will build up much quicker in the cup than on the surface.  

[Joe Anderson]

RAKA.com has a good selection of fiberglass, epoxy, and fillers at good prices and with good service.

I was disappointed with some tape I got from them once but they made everything right after a couple of phone calls.


772 489-4070

[Twetmore]

I haven't posted in a while because my summer has been bogged down with different stuff.  I have done a lot of sanding and epoxying and now have the seat tops installed.

[Twetmore]

Has anyone had any trouble with the epoxy holding the deats to the stringers?  I haven't yet, but I am a little worried about that epoxy joint there.  Is it worth it to try and fillet that corner when I cut the hatches in?

[wkisting]

I don't think that's necessary; however, if you're worried, you could do what we did on our CS20... We rounded the front edge of the seats with 3/8" roundover bit on the router, then glassed the seat tops with one layer of 6 oz. fiberglass and wrapped the 'glass over the seat edge to about 2" down the seat face. We did this to give extra scuff resistance to the seat tops since we found the Okoume to be a bit soft and susceptible to imprinting from hard objects. Then, where the backs of the seat tops meet the hull, we made an epoxy fillet to round that transition for a nicer visual effect and easier cleaning. Looks very nice and our seats aren't going anywhere.

By the way, you can see my write-up of this stage of the build here: http://www.roguepaddler.com/cs20h.htm

Yours is coming along nicely.

[Twetmore]

Thanks Wes.  I have been looking at your site A LOT throughout my build and it has been incredibly helpful.  I had seen that you did that and was thinking about it, seems like an easier solution than trying to slide inside the seats...