PMD - Take Apart Cutting Errors


I need some help recovering from cutting errors on my PMD.  I failed to hold the saw straight and cut swoops (approx. 1/8 to 1/4" deep) into the top and bottom (as depicted). It makes for a gap at the top of the seat and on the bottom of the hull.  I am hoping that others might have encountered this before and have some advice?  A few specific questions:

Question 1 - Should I fix this, and how?  Laminate one or two layers of veneer and epoxy over it?  Try to build it up by making a form and pouring thin-ish epoxy in?

Question 2 - Should I glass the outsides of the bulkheads for extra strength?  It seems worryingly thin when, for example, my 5 year old might run up to the front and jump up and down.

Question 3 - Now that a 3/8" strip is missing from the hull, there is a ridge where the two parts meet, because the back half is larger.  Any suggestions on dealing with this?  I'm planning to just plane / sand it down so the ridge is not that pronounced but the hull isn't super thick so don't want to over-weaken it.




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RE: PMD - Take Apart Cutting Errors


RE: PMD - Take Apart Cutting Errors


We had some similar issues, some of which got into the inner faces of the two bulkeads through at least one layer of vernier.  You do want to fix it as best you can.

We leveled out tha affected areas with epoxy thickened with wood flour, same as we used for all the fillets.  This happened in multiple stages.  Ultimately, we ended up filling the low spots, covering with wax paper (taped into position as needed, and mated the two halves of the boat back together (without the gasket) to get a good "fit" without sticking the boat back together.

You'll also want to fill in any gaps and divots along the plank edges and work thickened epoxy between the blanks and the bulkheads all along to make sure there aren't any gaps where the material from the fillet may not have gotter all the way through from the other side.

If you restore all the places where the "over-sawing" got into the outside of the planking to the original profile, she should fit back together once the gasket is in place with the plank edges not looking too whopperjawed over the gap which the gasket makes.

After a few years of use, we've had no reason to doubt the strength of the bulkheads.  The joint seems pretty sturdy.  I wo put some large flat washers over the protruding bolts before tightening down the star nuts to spread the load out some and to keep the nuts from pressing into the plywood.

Hope that helps.  Thickened epoxy is your friend...and so is paint!



RE: PMD - Take Apart Cutting Errors

I should have added that you want to make sure everything on the inner faces of the bulkheads (which may have been abraded by the sawing) and the exposed plank edges get a couple of coats of unthinned epoxy to make sure everything is well sealed up.


RE: PMD - Take Apart Cutting Errors


Michael (as ususal) gives excellent advice.  I just cut my PMD this last weekend and managed to only miss by a little bit.  But I will share your pain.

The instructions for this part of the (de)constuction are woefully inadequate.  I started to cut then realized once the visible part of the cardboard is gone, you are on your own.  I was guided by the "tabs" from the bulkhead knowing that the cardboard must be just aft of the tabs.  That allowed me to get a decent line underneath along the hull.  But it took hours of measuring and hoping to get it right.  And excellent last post by Micheal because the instructions don't say anything about adding a coat or two of epoxy for the exposed bulheads.  But they will clearly be exposed to water. 

One question I have (I haven't sanded the edges yet) is the slight overhand (or leftover) I have from the hull on one side.  Do I take a small saw and remove it?  I seems like I will have a bit of a gap if I do. 

Good luck moving forward.


RE: PMD - Take Apart Cutting Errors

I believe you'll want to cut the ends of the planks flush with the mating faces of the bulkheads.  These need to be flat and true so the two "halves" will come back together plumb.  We used that slick Japanese-style saw (purchased from CLC) for all such "cutting flush" operations, for which it seemed well suited.

The idea here is to restore the mating faces, all the way out to the edges to what they would have looked like if your saw hadn't wandered.  A long straightedge is handy for this.  Assuming your buikheads weren't located too far apart or off plumb, the whole thing should come back together without much gap beyond the thickness of the gasket.

We had to fuss around quite a bit to get a decent looking fit, re-assembling and dis-assembling the boat to check at each stage and then applying more thickened epoxy and smoothing until we achieved clean edges and flat surfaces.  At times, we bolted the boat back together with waxed paper taped over the uncured epoxy to squeeze things flat at some stages.  The epoxy/woodflour is quite hard when cured, and we've not had any issues with chunks of it falling out.

We ended up with a not quite perfect match, but from five feet it doesn't look bad at all.  I've got some photos I could share if that would help.  The final appearance was helped by runing the topside paint around the "corners" of the mating surfaces for the thickness of the planks or maybe a bit more.  From the right angles, in the right light, the gap almost disappears.  I think CLC put some of our photos (I keep trying to win that $1000 prize) in the standard PMD gallery instead of the take-apart one, I assume because the gap wasn't so obvious...from a distance.

Keep filling and smoothing and reassembling to check.  It won't be perfect...but that's what paint is for!


RE: PMD - Take Apart Cutting Errors

   Thanks, Michael.  Always nice to hear that it is often much more nuanced than how it appears in the instructions.  I don't have a deadline, but between the sanding and finishing, the project has slowed to a crawl.  At least as far as visible changes go.

When the project was started I had a boat-looking structure in 10 hours.  Then I got to the sanding....

RE: PMD - Take Apart Cutting Errors


Yes, it can seem a long haul, coming down the stretch after you get to this point.  Hang in there with it, and keep your mind focused on the ultimate joy of having her ready to splash.

Make sure you've got a "moaning chair" available--a comfortable place to sit with good light and a good view of the work so you can have a cup of coffee while you paw through the manual, look at the boat, and figure out what to do next.  Save the stronger beverages for later, though a wee dram of Maker's Mark, for medicinal purposes, of course, and after the workday is over, can ease the physical and mental pain of seemingly endless sanding.  <;-)

Wishing you light at the end of the tunnel....


RE: PMD - Take Apart Cutting Errors

Thanks all for the suggestions.  I think I'm mostly repaired here.

I first sanded everything smooth so I could see how bad the dips were.  Some of them were thick enough that I thought I could squeeze some thin pieces of wood in there, so I ripped a few strips from a chunk I had sitting around ( I think it may have been part of the packaging for this boat kit) and epoxied them on, then added some more to smooth the ridges, and started sanding. Now, the top mating surface lines up quite well. The bottom still needs a bit of work, I think I will give it one more layer of paste, then sand it flat and paint it.

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