JMetzner Posted January 31, 2003 Posted January 31, 2003 At the risk of sending Capt. Jake into fits of apoplexy, I'm going to ask some epoxy sanding questions. I'll be rolling the weekender over tomorrow and expect to get to the epoxy sanding stage by the end of Feb. I'm looking at buying sanding supplies in bulk, mailorder or from the web. I figured I'd be using my random orbit sander and probably a long board. I didn't figure I'd be using the belt sander, I thought it'd be too aggressive. So, do I only need stuff for the ROS and long board? What grit range 80 to 150 or so? I haven't worked with epoxy before, so I have no idea how fine a grit I really need to go down to. Thanks, John M. Quote
Mike Donlin Posted January 31, 2003 Posted January 31, 2003 I think I used from 80 to 150 grit on the ROS, but I never intended for my boat to look like a floating piece of furniture. I was striving for the workboat look and I think I achieved it quite nicely. We used Kevlar on the keel and chines and without lots of fairing with microballoons and silica those areas were rough looking. A good tip to save lots of sanding is to go over the epoxy the next day with a sharp wide chisel or scraper to cut down the drips, blobs, and ridges that didn't get leveled out with the squeegee. I can't remember who said that his boat looked pretty from 20' away but up close it was "rough as guts" That would pretty much describe my finish. Quote
Charlie Jones Posted January 31, 2003 Posted January 31, 2003 A good ROS machine and the long board should do nicely. I also use a redwood concrete float with sandpaper wrapped around it. Has a nice handle and is pretty easy to use one handed or two. You will also find good use for a cabinet scraper. Used correctly it can save you tons of elbow grease :wink: Sanding the epoxy, 80 through 150 should do all you need. I never go finer than 150 on any surface to be painted anyway. Even in my woodshop, prior to staining furniture we never sand beyond 150, and usually stop at 100 grit. After the finish is on, that's a different tale. THEN we go to what ever grit is needed for the finish, within reason. Quote
capt jake Posted February 2, 2003 Posted February 2, 2003 Send me into fits!!!! Sheesh, I am going to have to change that!! They said all that need to, except, I sanded to 220, and then 320 for the final spray job (per the painters recomendations!!). Brightwork will be my downfall!! Floating furnature LOL is right!! I hope to achieve that!! It will be close, I hope!! Quote
Brent Posted February 7, 2003 Posted February 7, 2003 I am building a core sound 20, but if you will allow I occassionaly check this forum for useful information. I would like to get a very smooth hull surface, but dont have a great deal of experience on the subject. I would like some input on how best to build up to that. I am thinking of using six or seven coats of epoxy something like this: *sealing coat of epoxy *epoxy thickened with microspheres/cabosil mix applied with notched trowel *sand *epoxy thickened with microspheres/cabosil mix applied with smooth trowel *sand *epoxy *epoxy with color tint *epoxy with color tint *sand with progressive papers What is your experience and recommendation? Quote
capt jake Posted February 7, 2003 Posted February 7, 2003 What is your experience and recommendation? My recommendation??? You can take the sanding torch and go forth!! :D Your layup sounds good to me, but then again I sand too much!! Go forth and SAND!!! I will try the grooved trowel technique next time. Seems that it might work quicker and easier. Quote
Frank Hagan Posted February 9, 2003 Posted February 9, 2003 I am building a core sound 20' date=' but if you will allow I occassionaly check this forum for useful information.I would like to get a very smooth hull surface, but dont have a great deal of experience on the subject. I would like some input on how best to build up to that. I am thinking of using six or seven coats of epoxy something like this: *sealing coat of epoxy *epoxy thickened with microspheres/cabosil mix applied with notched trowel *sand *epoxy thickened with microspheres/cabosil mix applied with smooth trowel *sand *epoxy *epoxy with color tint *epoxy with color tint *sand with progressive papers What is your experience and recommendation?[/quote'] The "putty" consistency mix you make and apply with a notched trowel is for hulls where you have to make a lot of corrections (usually planked hulls). With plywood, you may find that the hull starts off pretty fair, with few (if any) ridges or low spots. If the hull looks pretty good in that respect, I would just opt for multiple coats of unthickened epoxy ... roll it on like paint ... and plan on using 5 to 8 coats (or 10 - 12 on vertical areas, where you can't put it on very thick). A cabinet scraper between coats is great for little uneven areas. You need about 3 coats just to fill the weave in the cloth, and the extra will really make it smooth. I found that sanding with aluminum oxide sandpaper discs on a random orbital sander was the best way to sand the epoxy smooth. As a last step, I used unthickened epoxy and a plastic auto-body spreader to fill in little scratches and nicks in the surface. Quote
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