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Thread: advice on mirror dinghy repair

  1. #1

    Default advice on mirror dinghy repair

    I am very new to this, and would very much appreciate advice.

    I am the proud owner of a 1970's wooden mirror dinghy, my first boat and I have a little work to do though before I can take it out sailing however. First stage has to be to strip and revarnish all the inside surfaces, as the boat has been allowed to fill with water, and the ply is a little damp. No immediate sign of rot though. I was intending to use West Epoxy and then varnish over.

    Some of the tapes have come completely off, so I need to replace these, and there are some tapes in the process of coming away. I was thinking to use epoxy/filler mix and stick these down, maybe taping over with wider fibreglass tape just to make sure...

    Suggestions for suitable varnish over epoxy much appreciated. (I am in the UK...) I would like it to last as long as possible, so I want to do the best job.

    There is a hole in the bow, on the deck line, where the wood section holding the painter metal fixing has come away, splintered edges, about 6cm diameter round max.

    Do I cut out a section of the ply (which would allow me access to the front bouyancy compartment to check for rot/damp and to dry and seal if necessary) and replace it, fixing using epoxy/tape, or should I use epoxy mixed with filler to fill the gap? The forestay is attached to the other side of the ply where the painter wood goes... So it seems like this is a stressed area. Husband was thinking to add all sorts of extra bits of wood for strengthening, but I am not sure.

    How thick should this ply be?

    Ideas and comments welcomed...

    ta.

  2. #2
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    Default Re: advice on mirror dinghy repair

    Ahh, something on which I have some experience (Mirror 16) - a long story, but suffice it to say that my father and sister conspired to blow a significant portion of her bottom out...

    Pull up the tape. Probably all of the tape. Redo it with epoxy and it will stick better. Remember the joints are taped on both sides. My experience was that the tape 'within' was better than the tape 'without', and most of the visible tape would peel off with less stick than friction tape.

    The surface veneer on the ply is really, really skinny. DAMHIKT. Be very, very careful if you sand it.
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  3. #3
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    Default Re: advice on mirror dinghy repair

    Welcome, but be prepared to engage with people who are truth-tellers. These folks have made all the mistakes that can be made and you can benefit from their misfortunes if you are not too faint of heart to accept extremely straight discourse.

    If the boat was built in the '70's it may have been glued up with POLYESTER RESIN. POLYESTER RESIN is not noted for it's longevity. A boat built with POLYESTER RESIN may not be safe any more. Since it is glue that hold this hull together it cannot be overstated , the resin /glass tape is what your existence on the water depends on. You may have to replace more than the tapes that have come loose. Only someone who can examine the joints up close can make that determination.
    Forget about what you will paint this boat with for the time being. You may be a long way from that stage.
    The wood has to be dry to bond to epoxy. I do not know how long it will take in the British climate but it is important. Getting the boat inside a heated building will help greatly. That is a stumbling block for many of us.
    Besides rot, plywood can fail by delaminating. Thumping, twisting and shaking are necessary to make certain you have discovered all the bad spots.
    The Mirror Dinghy is the mother of all Stitch and Glu....., excuse me, Tack and Tape boats. It is a kind of monocoque construction that derives it's strength from having everything glued to everything else. It didn't contain much dimensional lumber and if the ply/glass/epoxy are all proper and correct it shouldn't need any additional lumber. Since their are many Mirriors still afloat a potential buyer would readily see your boat has been modified. If saleabilty later on doesn't bother you what you do to the boat will not matter.
    Good luck.

  4. #4
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    Default Re: advice on mirror dinghy repair

    Do not forget to specify e glass tape for use with the epoxy resin, you had best buy both from the same supplier.
    I would scarf in a patch to replace the damaged bit of bow transom. Square up the hole, then taper the edges back six times the thickness of the ply. Make the patch to fit and glue it in with thickened epoxy resin. Wrap a piece of scrap wood or two with packing tape and screw them across the patch to hold it in until the glue sets. Do a dry run before you mix the glue so that you can sort out any issues before covering everything (and you) with slippery glue. When the glue has set up the packing tape will allow you to remove the clamping pieces. If you are not familiar with epoxy, the suppliers will probably have some instruction pamphlets, ask them when discussing buying the tape and resin.
    It really is quite difficult to build an ugly wooden boat.

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  5. #5
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    Default Re: advice on mirror dinghy repair

    Easiest if you can find someone with experience in marine ply. I'd check out all the joint and bottom areas with a sharp knife -- poke around and look for soft spots. Any ply that's soft should be removed, as that means it is rotten. Rot spreads very rapidly through ply, as it moves along the plies much faster than it would through solid wood.

    As above, dry it all out first to see what you've got. Then check for rot, replace any ply that is soft or has holes through it. THEN you can think about varnish and paint.

    Good luck!
    "The enemies of reason have a certain blind look."
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  6. #6
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    Default Re: advice on mirror dinghy repair

    Do a search on this forum " an update on the mighty Pippin", posted by a fellow Mirror owner who did a major rebuild.

    Great boats! I sailed a Mirror for years in all types of wind and weather and have some great stories and memories.

  7. #7

    Default Re: advice on mirror dinghy repair

    Thanks for suggestions. I am mightily impressed and overwhelmed by Pippin! Fortunately my boat doesn't require anywhere near as much work, but seeing the repair techniques used is extremely helpful.

    Does anyone have any other comment about the forces that are going to be on the repair to the front of my boat?

    Drying out in the garage starts quickly once the varnish is off and as soon as this is complete (yep, VERY CAREFUL!) I am going to bring the boat in to the house to complete the drying.

    Is it right that layering epoxy as a sealer on the cleaned off bare ply will provide a bit of fairing to some of the dinks and scratches, or should I tape over these? Looks and saleability not important here...and I don't think I am the racing type.

  8. #8
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    Default Re: advice on mirror dinghy repair

    Quote Originally Posted by fish-inna-tree View Post
    Thanks for suggestions. I am mightily impressed and overwhelmed by Pippin! Fortunately my boat doesn't require anywhere near as much work, but seeing the repair techniques used is extremely helpful.

    Does anyone have any other comment about the forces that are going to be on the repair to the front of my boat?

    Drying out in the garage starts quickly once the varnish is off and as soon as this is complete (yep, VERY CAREFUL!) I am going to bring the boat in to the house to complete the drying.

    Is it right that layering epoxy as a sealer on the cleaned off bare ply will provide a bit of fairing to some of the dinks and scratches, or should I tape over these? Looks and saleability not important here...and I don't think I am the racing type.
    Providing you use a 1-6 taper on the edges of the new patch and achieve a reasonable fit, thickened epoxy adhesive will make it as strong as original. If the repair only leaves a border of original transom, it might be easier to pull the tapes off of the transom and replace the entire component, using the old one as a template. If you can post a picture, the other forumites will be able to offer more focused advice.
    You can use epoxy filled with micro balloons as filler to repair dings, they will not need to be taped.
    It really is quite difficult to build an ugly wooden boat.

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  9. #9
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    Default Re: advice on mirror dinghy repair

    Here's another source for information and support.
    http://groups.msn.com/MirrorDiscussionForum
    Old Sailor
    Mirror and Mirror 16

  10. #10

    Default Re: advice on mirror dinghy repair

    Thanks Guys!

    Project going well with the epoxy - tapes replaced where possible and filling in the tight spots. No rot found yet, and a few manky repairs redone with new materials cleanly. Hole at the front sized up, and will be done when we turn her over.

    The daggerboard was in a mess, so I have stripped it back and want to varnish that, as well as mast and gaff.

    Now I am looking to choose a varnish and I am tempted to go for a 1 pack tung oil based spar varnish like rather than a 2 part poly. Candidates on the list include international schooner, epifanes clear gloss or WW Spar Restoration. The ply is water-stained and dinted, so this is a utility repair - not for beauty, and I fancy I will be revarnishing because of physical damage well before UV degradation. Any comments? So far I have found conflicting ideas and am a bit confused.

  11. #11
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    Default Re: advice on mirror dinghy repair

    I saw this thread last night and was in the middle of tapping out a reply and then had a black out! Anyhoo, I said something along the lines of it's great to see another Mirror being restored. Fine little ships they are! all the advice above is good, however, I would be tempted to put a backing plate from the deck up to the top of the prow where the forestay and painter attach to. I would also make absolutely sure there is no other rot while you have the boat down to bare timber. That water staining may have some rot associated with it, so pay attention to these areas. Lastly, tung oil may bee a great product on traditionally built craft, but I'm not sure about its ability to adhere to taping/epoxy. I'm going to use a water based two part poly call Boat Cote which is made just north of here in Queensland, but I'm sure you'd be able find a similar cross-linked type paint product in the UK.

    BTW, I'm overwhelmed that you're overwhelmed!

    It'd be terrific to see some pictures of your work!

    Cheers
    Duncan
    “For masterpieces are not single and solitary births; they are the outcome of many years of thinking in common, of thinking by the body of the people, so that the experience of the mass is behind the single voice.” Virginia Woolf, A Room of One's Own

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  12. #12
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    Default Re: advice on mirror dinghy repair

    Quote Originally Posted by fish-inna-tree View Post
    Is it right that layering epoxy as a sealer on the cleaned off bare ply will provide a bit of fairing to some of the dinks and scratches, or should I tape over these? Looks and saleability not important here...and I don't think I am the racing type.
    A quick second comment on this: I've done layering of epoxy with micro-spheres to attempt to get a slick finish and really feather off the retaped seems and dutchman repairs. If you're not worried about the bumps, hollows and dings then don't follow suit as it is a reasonably laborious process, but one I still feel is worth the end result. I want to get many more years of fun from the ship than I would if I do a quick and dirty repair.

    The one thing I would do is use a heat gun to really warm up 20cm square sections of the hull at a time and paint unthickened epoxy onto in. This will create a barrier coat and help preserve the timber against moisture and the following rot. You will nedd to give each coat of epoxy a light sand to give any other paint/epoxy coat a good surface to bond/adhere to immediately prior to applying the newer coat. Another epoxy product that many here use is CPES which is a very very thin epoxy that will do the same thing as heated timber sucking in the normal epoxy.
    “For masterpieces are not single and solitary births; they are the outcome of many years of thinking in common, of thinking by the body of the people, so that the experience of the mass is behind the single voice.” Virginia Woolf, A Room of One's Own

    The Mighty Pippin
    Mirror 30141
    Looe
    Dragon KA93

  13. #13
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    Default Re: advice on mirror dinghy repair

    Quote Originally Posted by fish-inna-tree View Post
    The daggerboard was in a mess, so I have stripped it back and want to varnish that, as well as mast and gaff.

    Now I am looking to choose a varnish and I am tempted to go for a 1 pack tung oil based spar varnish like rather than a 2 part poly. Candidates on the list include international schooner, epifanes clear gloss or WW Spar Restoration. The ply is water-stained and dinted, so this is a utility repair - not for beauty, and I fancy I will be revarnishing because of physical damage well before UV degradation. Any comments? So far I have found conflicting ideas and am a bit confused.
    If you are only going to varnish the spars and dagger board Epifanes has a good reputation. As the dagger board is going to be out of sight when in use why varnish? Paint is more robust.
    It really is quite difficult to build an ugly wooden boat.

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