View Full Version : butt joint fiasco

05-02-2003, 03:33 PM
Well after spending all day yesterday setting everything up by laying out the floor with two butt joints and keel and both side panels with two butt joints a piece. I fussed, talked with the board about small gaps on a couple of joints, and basically got everything ready, measured and marked.

Today, I spent another hour fussing with the layout and double checked reference lines and such. I mixed my first batch of epoxy/hardener (glen-l -5 to 1) and when I got to the second butt joint and started trying to get the epoxy to fill the gaps, which it simply oozed on through. Then like an idiot, I grabbed some tape to tape the underside (saw this in a video) that of course put the whole panel out of alignment. While fussing with this precious time went by and I looked over to see my tin can full of hardening epoxy smoking and caking up. I hurriedly slapped some epoxy on the one corner I hadn't gotten and slapped the butt in place and put weight on it. The can of epoxy (smoking badly and barely able to be handled) was hurriedly tossed in a pile of dirt.

I mixed the second batch of epoxy in a flat pie tin with aluminum foil and just generously coated the panels and butt joints over the next half hour and used the rest to encapsulate one section and done.

Now I'm more than a little concerned about the panel that had so much run through the seam. I figure it's going to be a complete mess on the other side.

I used about 500 ML (a pint or so) to do four butt joint plus a 13'x 4" keel on the centerline. Does this sound about right?

I think I now understand and assume that instead of trying to get the epoxy glue to fill the voids during the butt joint stage, I instead need to use epoxy putty to fill and fair when I do the stitch joints and FG. Right?

Any input on the overall impression of this fiasco is appreciated. Does it sound like I recovered and did the process right and that my main carry over problem is a lot of epoxy sanding on the one joint that I kept over applying?

gary porter
05-02-2003, 04:26 PM
swhite, welcome to the world of epoxy. First, don't mix too much at once, do one or two joints at a time. A good methode for making butt joints or scarph joints is to use scrap plywood pieces, visquene (poly sheeting), and sheetrock screws to use for temporarily fastening them in place. use the visquene over the joint then the scrap and screw the whole mess together, you can fill any screw holes later. First coat you pieces with fresh unthickened epoxy and let soak just a bit , the plywood or wood will soak up the epoxy and you;ll want to recoat so as not to have a dry joint. The second coat can or should be thickened a bit with Cabosil(silica thickener) or even a bit of wood flour,,then put the pieces together. Its a bad idea to try and quickly slap some epoxy on thats started to set as this will not penetrate and thus won't form a reliable joint. Take your time, dry fit, don't mix too much at once, and don't worry about small crack or disscrepancies, you can fill them later. Next day when you undo the scrap, visquene and such you can sand the joint and fill any voids. Don't mess around trying to get everything perfect at first,, get at it and have fun.

Mike Vogdes
05-02-2003, 05:30 PM
Well... its time to fall back and regroup.
I know Glen-L is a good reputable company and probably sells good stuff, however that said, I think you should find and buy Sam Devlins book on stitch and glue construction. Its full of illustrations, tips, recomendations and is by far the most usefull book on this type of construction. I see it for sale at Barnes & Noble and Borders and such. You will gobble it up in an evening or two and it will answer lots of questions you havn't even thought of yet.

Now about your imediate problem. If its in the buget maybe it would be best to use those panels that went bad for other parts in the boat and go about building new panels out of sheets of plywood properly joined. It would be better in the long run and theres allways use for the scraped panels, floors, bulkheads, outdoor toy box for the kids?

05-02-2003, 09:00 PM
Thanks guys.

I hate to over-react and discard several hundred dollars worth of marine ply and 30 hours of work.

I guess at this point I feel I'm okay and I don't think that the joints are dry. The one joint that set this all in motion did get plenty of epoxy, I just kept applying over the seam and I'm sure there is a lot of epoxy on the other side. The second batch of epoxy was right (well mixed and did not thicken while I worked with it) and I applied it liberally to all of the joints. The batch that was thickening was immediately discarded and that joint was liberally saturated.

Everything is in perfect alignment matching up with all of my reference lines during dry fitting.

Although I have been studing this process I have no reference in experience to fall back on. There's nothing like actually doing it. Ireally apreciate this board for the advice and words of wisdom.

Paul Scheuer
05-02-2003, 10:45 PM
Although I have been studing this process I have no reference in experience to fall back on. You do now.