I recently received a 1/3 scale Bücker Jungmeister short kit that was laser cut. The cutting accuracy is great. What I would like to know is how much of the black surface on the edge of the parts should I remove. The 1/4" ply pieces have the most. I plan to use CA and epoxy.

Ken

Ken...I just sand of the tags that keep the pieces in place on the sheet and build as is...I may be doing this wrong but I have not seen any probs. from it.

I've heard people say that the "charred" edge won't accept glue as well, so I usually just hit it lightly with sandpaper. Be careful not to sand it much, you can ruin that great fit.
Dennis-

for what it's worth the instruction manual for the sig se flat out tells us not to sant the charred edges.

I second the idea that you aughta just sand the tags and set it together

Same here, I don't sand them.

Thanks a lot for the advice. That will save me a lot of work.

Ken

Nobody cared to make a strength test between charred wood glue joints as opposed to regular saw cut one?

I have never sanded any laser cut part on planes that I have built and have not had a glue joint failure yet. I have also tested glue joints on laser cut parts vs parts that were sanded and have not found a difference in glue strength.

Mike Grey
Skyshark R/C

I've only built one laser kit and I beat the crap out of it. No sanding and no glue joint failures.

BTW - I never use CA for general construction - always Carpenter's glue.

Herr Pitts Special

I never sand and I've never had a joint come loose,I use all types of glue in building.

Good enough for my information, thanks for the input.

I dont sand them either and have found no problems yet. I think the charred surface absorbs the ca glue easily down to the good wood underneith.

I would test the joint strength but I haven't been able to get one to fail so I can examine it. ...JIM ...The opinions expressed here are not necessarily those of anyone in his right mind.

Newcomers welcome! Volunteers needed to crash test their airplanes that use laser cut wood, we need direct reports on how the joints are able to withstand direct and/or indirect impact. This is your chance to step into the Hall of Fame. Apply within!

Sadley to say I have crashed a laser cut plane,nose first and I repeat my above statement,using different types of glue,ca,epoxy,yellow,I still haven't had a glue joint fail or come apart,I did have a large amount of wood break when the earth gods spanked my plane.[:-]

Easy test take scrap balsa from kit , glue to sanded peaces together , and to laser peaces to gether and let set. The other test I tried all I have left was the tail SE from wing tubes back!!!!!

The only time I've sanded any laser-cut parts (other than the tabs) is when the plane is going to be covered with clear/opaque covering because the black lines show through. Otherwise it's not worth the work just to loose the great fit.