Puzzle joints and heat gun

Hi there,

Am building my first CLC boat (Cester Yawl). Assembled all the puzzle joints (12) and used boards and screws to compress them. For efficient use of space I made a couple of layers with plastic inbetween.

There 1) was certainly excess epoxy and 2) some of the joints are not completely flat.

Having read other threads, I first tried scraping, then tried a heat gun followed by scraping.

1) A heat gun has made scraping the excess epoxy quite doable.

2) What to do with the joints?

a. I could now scrape/sand sand the wood on both sides of the puzzle joints (high spots on both sides). This would result in slightly thinner wood at the joints. At some point I would think that this impacts strength of the joint.

b. I could fill in the low spots either before or after assembly. (This has raised some questions about appearance on the varnished interior in other posts).

c. If I keep using the heat gun, will the joint become soft enough that the "high" puzzle pieces can be pushed down flat? Am I correct that both sides of the joint would ned t be heated?

Many thanks!


4 replies:

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RE: Puzzle joints and heat gun

i would try your option c first.  but yes, you will need to heat both sides of the joint to get it hot enough.   just use caution to not burn the wood:)

if you are finishing bright, you can tolerate a little misalignment with no real need to fill as long as the sanding does not go through the veneer.


RE: Puzzle joints and heat gun

   I had the exact same situation with you with my NED. The table that I screwed the board above the puzzle joint in my bottom panel had a bend to it. And eventually so did my bottom panel. 

I always planned on painting, so aethetics weren't a major concern, as long as it was strong. 

I used a cabinet scraper to get as much off as I could. Then I sanded down the high parts of the joint, and put thickened epoxy on the low parts. Another round of sanding and it and it was good-to-go. 

The result is a milky looking joint because of the filled in sections with the thickened expoxy, but it is smooth and strong. (well, I'm just assuming the strong part. It hasn't been tested in the water yet. 

RE: Puzzle joints and heat gun

Thanks for the input. I would like to "make it right" if the heat gun (option c) will truly loosen up the puzzzle joints enough for me to push them together for a smooth joint.

The wood was certainly getting dry and hot as I heated and scraped the excess epoxy.

Just want to confirm that further heating should soften up the epoxy within the joint.


RE: Puzzle joints and heat gun

I had a similar problem at one butt joint in the deck of our MC 16.5. 

I just built up the low side with multiple coats of epoxy until it was as high as the other side. Now, I'm not even sure which of the 4 butt joints it is (or was).

 Assuming you don't have to buid it up too much!

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