Thanks Thanks:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Page 1 of 3 123 LastLast
Results 1 to 15 of 42
  1. #1
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default Refinishing our Eureka

    A bit of background first on our Eureka. It was a rushed and rough build over 8 days for my son’s 13th birthday in Nov 2011, using whatever I could find from local hardware stores. Choice of materials was dictated by local availability of materials and time constraints rather than an attempt to save money. Though as I go about this refurb any previous savings are out the window. Lack of experience comes into play of course. Since this was my first boat build I made some poor choices against good advice or instructions and as I’ve stripped paint and epoxy back I’m left shaking my head at some of my handiwork, muttering to myself, “what the hell were you thinking”.

    The need to refinish was brought about by cracks appearing on both sides of the hull, but particularly on the bottom panel and then bilge panels after a year of service. To my mind it’s directly the result of the use of inferior ply and poor application and choice of epoxy.

    Firstly the ply was 3ply 4mm CD bracing ply instead of 5 or 6mm marine recommended. Apparently it does have an A type bond but didn’t last the boil test, a small piece delaminating within an hour from memory. Regardless of bond type, you can imagine that voids or defects in any of the plies reduces it’s thickness by a third and subsequently its strength. Although the canoe is solid, certain areas of the bilge and bottom panels in particular have been able to flex enough under stress to crack epoxy. Water has subsequently penetrated and contacted the ply

    Secondly, the epoxy I used was the kind that requires a few drops of hardener for every 100mls rather than a 2:1 or 5:1 type epoxy system. My main issue with the former is it’s a pig to sand, clogging up any kind of abrasive I’ve tried to use on it. It also produces amine blush and the smell is overwhelming. The Mrs can’t stand it but I don’t mind it. Doesn’t make me dizzy but at the same time it makes you think it can’t be good for you. The BoteCote I bought is completely different. 2:1, no real smell, sands easily and cure time’s not so fast as the hardware store bought stuff. Really enjoyed using it.

    Regarding improper application of the old epoxy – too thick on non glassed areas. I taped seams only and encapsulated bare wood with three coats, but my method of coating was like using pour-on-gloss. Even when spread about, the three coats ended up too thick compared to what one should do. At it’s thinnest it was 1mm, from a post from PAR some time ago, 0.5mm should be a maximum. After some early cracks appeared I rubbed back and applied some epoxy as repair and painted the external hull with a thick layer of external vinyl paint. But the cracks returned, showing up through the paint and water contacted the ply in a few spots.

    Cracks showing through the paint





    Gunwales have been knocked about a bit too from the oars and from being stored inverted. Just needing a sand and recoat, no real damage.


    Just one of a few areas that've been affected by water ingress. No real damage apart from staining.







  2. # ADS
    Google Adsense Advertisement
    Join Date
    Always
    Location
    Advertising world
    Posts
    Many





     
  3. #2
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    Stripping epoxy is the pits. I started this refurb in June or July, I forget. And the canoe hasn't touched water since February. I circled areas where cracks were and was going to just repair them but this vinyl paint seems impossible to remove without taking the epoxy with it. It wouldn't sand off and when using a heat gun, you could scrape some paint away cleanly then within a second or so the epoxy would heat up enough that the scraping knife would sink in. I decided to strip the exterior completely which in hindsight, I'm glad I did.








    The decks are another story, a bit embarrassing really. They did have a single thin coat on for the launch and wasn't quite water proofed. A few more coats a week or so later I poured on a couple of thick layers with the view of sanding then varnishing. Well I neglected to varnish before the decks were subjected to direct sunlight on a 37 deg day and they began to go white. I left it with the view of stripping and recoating but left it until now. The overly thick sun damaged epoxy was fairly easy to remove.




  4. #3
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    The bottom panel had the worst cracking of epoxy and seemed to flex too easily. I bought some CC 4mm brace ply and using a template, traced the shape of the bottom panel to laminate the entire section. Rather than having two mirror parts butt jointed at the middle, I covered the middle joint with a large piece with two smaller pieces extending to the end. I used thickened epoxy, sawdust and botecote and stapled the panels on. Prior to glassing this now 8mm thick section is very strong. I cut the pieces oversize then trimmed with a block plane at a bevel to match the angle of the bilge panel. I also cut out the previous stem filler and reapplied using botecote and DIY sawdust.











    Sanding, filling scraper marks and gouges plus chines, then more sanding followed prior to glassing.







  5. #4
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    With the external hull ready I decided not to tape seams again. I've read before and recently about glass adds abrasion resistance moreso than strength and that 2oz cloth is enough for sheathing the hull. I wanted strength and abrasion resistance so went a bit heavier with the glass and used 125gsm/4oz 1m wide cloth to cover it. It was a heavy canoe to begin with but I never weighed it before. I should be able to tell if feels heavier particularly if I completely glass the interior.

    I paid much more attention to applicator force and spreading the epoxy. I love the way FG wets out but before I decide on varnish or what type of paint, I really want to be able to fair the outside smooth. One of the earlier photos in the first posts show the painted hull with roller applied finish. A lot of drag I'm guessing but it was to hide imperfections in the other epoxy which was too hard to sand and fair.





    1st coat


    2nd coat



    After 3 coats




    Glass was trimmed at the stems then later tape was apllied and 3 coats applied. The first photo shows sanding prior to taping the stem. I'll have to add a decent before and after stem photo.

    I then started some sanding just to see how botecote behaved and how well it could be faired, particularly around the stems which had plenty of runs and around the centre section of top panels where the FG doesnt go all the way to the gunwales. I was really impressed. Getting a smooth finish for a high gloss slick surface looks a goer.







  6. #5
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    I left the external sanding for later cos I'm not sure how I want to finish the outside. But with the outside fully glassed and cured I thought it would be safe enough to remove internal fillets and taped seams without joints moving. This is where I really began to think how dumb some of my craftsmanship was. Apart from loathing having to strip the enitre interior, bar bulkheads, I was faced with materials that seemed impossible to remove. Why on earth did I use Sikaflex for filleting. I dunno. I was really doubtfull about the idea of using epoxy as glue. It was a foreign concept at the time and everything I've built before has been screwed, nailed, welded, bolted. Never glue by itself. I was ignorant of the facts in the instructions and other peoples testominies in other builds. I couldn't grasp the concept of FG tape and epoxy holding together two pieces of bent ply joined at their sides. But it does. I thought it would need extra stuff so I used sikaflex and some commercial filler which did nothing other than occupy space below the tape. The filler fell out easily enough with heat but the sikaflex has had to be cut out then scraped.







    It took ages to clean the interior up, but on to filleting. Just used epoxy thickened with wood flour made with a belt sander. As with the stems I noted the fillets were rough, not smooth and a lot of sanding would be needed to smooth them. However, one thing I learnt from a youtube vid was to use alcohol (metho) and a gloved hand to smooth down the fillets. This was brilliant, I'd never heard of it before. By the time I saw this handy bit of info the fillets were well on their way to curing but still tacky and kind of pliable. If I got to them sooner the result would've been much better but as is, the required sanding is been dramatically reduced. Some comparison pics. The first one, although out of focus shows smoothed section on the left.






  7. #6
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    I sanded the interior as best I could. I decided not to glass the interior, partly due to my epoxy supply running a little low and I figured the fillets plus external glass would be strong enough. The result after three coats on the interior was that a fair amount of sanding will be required to smooth it out, but all imperfections were filled. I applied the epoxy with metal blades as with the exterior, but the epoxy seemed harder to control. The metal blades are fine for working epoxy over glass but not over bare wood. I wish I had used foam brushes instead. I've laminated the decks by using ply strips and three coats of epoxy applied with foam brushes and they turned out really well.

    The first pic shows half of the first coat. The next two is after three coats. Much work to be done still prior to varnishing but with a couple of cold nights delaying sanding I turned my attention to reworking the decks.






  8. #7
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    Of the many aspects that make wooden boats look appealing I've always loved the look of veneered decks and wanted to try it on something smaller before I one day build a runabout. I've left the original deck intact than applied veneers using two shades of 4mm CC brace ply that I bought earlier. I used unthickened epoxy to glue the veneers and 10mm staples to keep them down. Fairing was done by hand with 80 then 120 grit on sanding boards. Trimming of the veneers was with Japanese saws, chisels, block plane, spokeshave and a bastard file was used for smoothing and shaping the cutouts towards the interior. The 48mm wide veneers were cut by hand with a Japanese rip saw to avoid tearout.

    Three coats of epoxy were applied using foam brushes and the result so far is fantastic. All that's needed now is fairing, filling the seams then varnishing. I'm not sure what I'll use for seams. Most likely sikaflex but no idea what colour I'll choose; black, white or tan.

    Original deck stripped and sanded.


    Marking centre line. I had clamped a string line from stern to bow, made a few marks, eyed a straight line then used a long metal rule to mark it. After it all came together I was pleasantly surprised to see both kingplanks line up. Given that the canoe isn't entirely straight it was a minor miracle.



    Veneers laid out, spaced with 4mm ply offcuts then trimmed.




    Registration marks were made against the deck, kingplank and outer veneers then all was removed for glueing and stapleing.

  9. #8
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    After staples removed I started fairing. Sawdust filling the seams gave an idea on how tan coloured seams might look compared to darker when vacuumed.




    All trimmed and ready for epoxy


    Three coats of epoxy later and the result is brilliant. Staple marks are evident in the lighter veneers but I'm not too concerned. I only notice them close up and the overall effect takes your eyes away. Can't wait to fair, seam and varnish over the next few weeks.




  10. #9
    Join Date
    Feb 2008
    Location
    Eustis, FL, USA
    Posts
    2,270

    Default

    Traditional deck seams are done with two part polsulfide, though veneer decks usually employ polyurethane. If you use black, over coating with varnish will not affect the seam color all that much, but white will tend to yellow. You could tape off the seams, but once you do this, you'll probably never do it again.

    On a veneer deck, the seam goo is an aesthetic consideration only, so you can just tape the seams, apply goo and call it a day. Usually you'll need a significant film thickness of epoxy on the surface, so you can something to knock down, after the seams are done. Simply put, no matter how careful you are, the seams will need to be sanded flat, for that show boat finish. So, most over fill the seams, then belt sand the crap out of the deck, after it's good and cured (a few weeks), before varnishing.

    You could kill two birds with one stone by filling the seams with epoxy. A pigment of the color you want will work and it's a lot easier to get a clean, smooth result. Some use graphite powder to make black seams (I use p[pigment), which does offer a level of UV protection (not as much as some suggest), but it'll get over coated with varnish or poly anyway, so I don't bother.

    If going this route (colored epoxy) I use plastic packaging tape to define the edges of the seams. You can use "fine line" vinyl tape too, but this is usually thicker. I use these tapes because they're smooth, unlike crepe tape, which makes it difficult to smooth out the seam. Electrical tape also works, but some brands can leave a residue, which is easily removed, unless under the goo.

    Good luck and it looks great.

  11. #10
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    Thanks PAR, that's given me more food for thought. I never contemplated coloured epoxy and am tossing up between that and polyurethane now. The dark colour provided by my thickened epoxy mix might do the trick. Well mixed with black oxide even better. Another consideration here is that I had in mind grooved seams rather than a perfectly flat deck as I prefer the slight grooved look. Either way I've got time to decide. I need more epoxy and need to purchase varnish which will have to wait for a couple of weeks. Plenty of time for sanding in preparation.

  12. #11
    Join Date
    Feb 2008
    Location
    Eustis, FL, USA
    Posts
    2,270

    Default

    I too prefer a slight concavity to the seams, instead of a dead flat mirror. It also helps hide flaws. Epoxy will shrink slightly as it cures, so you naturally get this when you apply it in the seam and putty knife it flush. Instead of pigments for black, I use plain old photo copier toner (laser printer, photo copier, etc.). It works well, is essentially burned iron fillings (powder), so is quite effective as a UV blocker and dramatically toughens up the surface too.

    On show boats where they expect each seam to be dead on perfect, I use a cute little trick. After I apply the thickened goo to the taped seams and mash it down into them, I cover the seams with clear plastic sheeting, like the stuff they use for painter's drop cloth. I push the plastic into each seam, working out wrinkles, then I use a ball, yes a ball. I use plastic balls from the local craft store and depending on how deep you want the concavity of the seams, governs the size of the ball. A deep seam uses a small ball, shallower a larger ball. This takes some experimenting. Put the ball on the seam and drag or roll it along the seam. It'll follow the seam easily and pushes down the goo. You must wait for it to fully cure, before removing the plastic, but this trick makes dead nuts perfect concave seams. Once the plastic is removed, you can pull the tape and finish sand as you like for clear coats.

    For a 1/4" (6 mm) seam a 3/4" (19 mm) looks nice. A 1/2" (13 mm) ball makes a deeper seam.

  13. #12
    Join Date
    Sep 2012
    Location
    NSW, Australia
    Posts
    474

    Default

    Nice tip there. I like it.

  14. #13
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    Quote Originally Posted by PAR View Post
    Instead of pigments for black, I use plain old photo copier toner .
    Just so happens we had a delivery of cartridges to work the other day...Mwahahaha! That's an interesting idea regarding toner but I don't think I'll go down that route though I am leaning towards a darker or black filler for the seams. The ball bearing idea, great too. I thought I'd use the bottom of a plastic spoon as I'd seen posts previously of someone achieving smooth concave seams on polyurethane filled seams but there's a chance of unevenness due to the changing radius of a spoon compared to a ball bearing.
    There is another issue. It seems clear that I should've spent more time matching the cut profiles between planks and cover boards because the 4mm gap isn't uniform between some of them. Although I saw it happening I didn't address it at the time of cutting and before final fitting. Using a spoon or a ball bearing will create a difference in depth of the seams in those areas but hopefully varnish coats will smooth the undulation to make it less noticable. I think too that a darker seam will not contrast as much as a lighter seam that might highlight these uneven gaps. I could router or trim the seams a bit wider but I don't have the equipment plus it's a not too big a deal for the canoe but a valuable lesson for a future build to be more precise. Whilst I fair the epoxy coat you can see difference in gap width.

  15. #14
    Join Date
    Feb 2008
    Location
    Eustis, FL, USA
    Posts
    2,270

    Default

    Having used a router (usually a laminate trimmer with a flat bottom router bit) to clean up seams, I can tell you it's a bitch. The best way is a double batten system (to guide the router/laminate trimmer) and a bit that is much narrower than the seam's width, so you don't touch both sides at once. Tedious is a forgiving term in this job.

    If you don't want to fool with the sppon or ball method, one I use is a plastic applicator (like an automotive bog spreader), but I bend it as I use it, usually with my thumb as I draw it along the seam, applying thickened goo. It will leave bumps where any irregularities might be along the seam edges and at joints, but I go back and very carefully, with a gloved finger and clean up these irregularities. It's not perfect, but you can get close enough. If you combine this with the plastic sheet trick, you can finger smooth much of it to an acceptable level.

  16. #15
    Join Date
    Nov 2011
    Location
    Riverina NSW
    Posts
    211

    Default

    I had a close look at the seams and regardless of seam width variances there was a bunch of high epoxy spots on the edges of some seams where staples were. I should have wiped the epoxy out before it cured but to clean them out now was not worth the effort. I'd have to pare away with a chisel which was too risky and with no trimmer or router I just went ahead with filling the seams. Come to think of it, I could've used files to remove some dried epoxy but it's a bit late now. I started to tape the seams beforehand using blue Scotch brand tape but you were right PAR, my patience wore thin very early on, trying to cut to the seam edges with a Stanley knife and new blade, I barely finished two seams when I ripped it all away.

    Sikaflex 291 black was squeezed into the seams from a caulking gun then smoothed using a spoon, though I forgot how sticky polyurethane is. Your plastic sheet idea PAR or maybe grease proof paper would've provided a better way to smooth out the seams.


    I scraped up waste with a metal 4" blade then used turps liberally and lots of rags cut from old bed sheets to remove the extra. Considering the deck veneers are epoxy coated and the poly and varnish clean up with turps I figured turps was safe to use to clean left overs so long as the turps/poly wash doesn't contact and stain exposed timber.


    Finally I used smaller amounts of rag over a gloved hand to wash and wipe the excess polyurethane over each board. This worked really well though my first attempt at removing excess poly removed too much out of the seams, just through rushing and carelessness. The second deck ended up much better with more care leaving fuller smoother seams.


    After a few hours to cure I hand sanded with 320 grit then put the first coat of Feast n Watson Spar varnish on using roll and tip. It's the first time I've tried to roll n tip any kind of paint or finish and it worked really well in providing an even coverage. Though I was a bit carless in preparation too. I didn't tack rag properly after sanding nor did I rub the shortnap roller down to remove any loose mohair. So the finish has some dust and impurities but it's a solid base to build on.


    Lastly, whilst the poly was curing I set about sanding the hull which is nearly done. It provided lots of epoxy dust which I kept and used as a filler for a couple of minor gaps around areas such as deck edges and gunwale/inwale/hull joins. I don't know if epoxy flour (if I can call it that) is recommended or used as a filler or thickener but was pretty good to use and provides an off white colour and should sand easily.
    Last edited by Canoath; 11th October 2013 at 12:12 PM. Reason: Create paragraphs

Page 1 of 3 123 LastLast

Similar Threads

  1. Coo Koo Clock Refinishing
    By Ken Weekes in forum RESTORATION
    Replies: 0
    Last Post: 10th August 2009, 04:14 PM
  2. Stripping and refinishing......
    By Kea5 in forum WOODTURNING - GENERAL
    Replies: 4
    Last Post: 28th July 2007, 03:22 PM
  3. refinishing planes
    By kiwioutdoors in forum FINISHING
    Replies: 9
    Last Post: 11th October 2006, 04:36 PM
  4. Help needed refinishing
    By brit_in_oz in forum FINISHING
    Replies: 0
    Last Post: 22nd October 2005, 06:22 PM
  5. refinishing kitchen
    By Ozcruiser in forum FINISHING
    Replies: 0
    Last Post: 6th September 2005, 09:20 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •