Stern Twist

I glued my C17LT this weekend and have been cutting wires and filing smooth this evening.  As I got to the stern I noticed the bottom panels have twisted 1/4" to the left from center.  The sheer clamps are level and the twist seems to have been caused by the bottom panels not being perfectly aligned.  

The curve occurs along the last 4-5" of the keel line.  My instinct is that this will cause tracking problems.  Since the glue has set there is clearly no twisting it back.  Should I try to cheat a little and sand one side and try to build back the right side with a wood flower & epoxy mix?  I guess another option is to change the shape of the stern a bit to get it out of the water quicker.   


6 replies:

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RE: Stern Twist

You could cut through the offending seam(s), force back to the right shape, then re-epoxy.  Or try the heat gun approach to soften the epoxy and push the panels into alignment.  If you're afraid you'll cause a bigger mess by cutting or setting your hull on fire with the heat gun, use your cheating option.  My preferred order for a fix would be the heat first, then a cut, then a cheat.  Maybe CLC or someone who has done the heat treatment recently will chime in.  Remember though, if the final results aren't museum quality, tell anyone who asks that you were up to your ears in alligators when that damage occurred and that only through quick action on your part was further damage avoided.  Then change the subject.  :)

RE: Stern Twist

I had a similar issue building my WD12, I used a propane torch to heat a chisel and that worked amazingly well (aka luke warm knife through cold butter). 

I was using a 1" chisel.  You will only be able to a little bit before needing to heat up the chisel but I found that actually helped.

RE: Stern Twist

Ouch! Hope you have a spare chisel for actual chiselling.

Laszlo

 

RE: Stern Twist

I'll give the chisel a try.   

I agree with you Laszlo, I think I'll stop by Harbor Freight to get a nice Tiawanese chisel worthy of this specific task.....

  

RE: Stern Twist

I think you're on the right track. Epoxy is a thermoset plastic and heating will help. You can do some amazing things with epoxy when it's warm and soft!

If you're clever, you can heat it to just the right temperature and it may peel right off the wood. But be sure to get it the first time. If you let it cool and try again, the epoxy will have "tempered" to a much higher strength and may not peel off quite so nicely. Also try to do it before it gets to that 7 day, fully cured state, assuming warm temperatures are the norm where you live. If it's been freezing, you may still have plenty of time.

I'd use a heat gun and play it on and off the section of epoxy you want to remove until it gets soft enough to lift with a putty knife. Continue working down the seam in a progressive manner until you've removed it all from the seam you want to adjust. If there is too much fillet to work with effectivly, grind most of it away before trying to peel the remainder off.

 I hope this helps!

RE: Stern Twist

Well guys I gave both the heat gun and the chisel a try.  I'm not sure I got either hot enough to get the job done.  I got a bit scared when the chisel seemed to be burning more wood than softening glue so I backed off.  

Either way, after all that I went back to my father's method.  "Measure once, cut once, SAND."  (God love him)  Not perfect but certainly straight enough that I'm not worried about tracking problems any longer.   I'm still going to go with a clear finish on the bottom panels so the mistake will become a talking point.  

 I'll blame the alligator attack for sure!  

 Thanks for the advice.   

 

 

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