Thread: Problem with my CA finish

my guess would be that it was stuck to the bushings and when the CA let go of the bushings it caused a weak spot which has flaked off

that is only a guess, it happened to me a couple of times

now i made a small well micro skew chisel out of a piece of bed matress wire, the bit that goes around the top edge and holds everything together, after i finish applying my finish with the lathe running i gently run the skew on the bush to the edge of the wood in order to break the glue

just my 2 bobs worth

MIK

Nope not that. I do my CA finish between centres as shown in DJ's tutorial. It was fine up until this morning when I noticed it starting to flake away.

could it be some contamination?

Maybe coming up from under the wood? Like moisture under the CA coating?

Completely ignorant here, but interested....

Between centers, on the bushings .. it could still be the same condition that MIK
described. . it could be that the glue was stuck to the metal and this can cause a small
separation when the blank is removed (from the bushings or the centers) I've now taken
to cutting through the glue with a razor before removing them from either the bushings or
the centers.

Or perhaps something related .. when the blank is removed from the center or bushings,
do you sand the CA back down to the ends of the blanks? If there is any extra length,
the CA will not want to compress as you press fit the parts into the tubes. Since the CA
can't compress it will tend to push outward, lifting from the wood.

Any of this sound possible?

Originally Posted by NewLondon88

Between centers, on the bushings .. it could still be the same condition that MIK
described. . it could be that the glue was stuck to the metal and this can cause a small
separation when the blank is removed (from the bushings or the centers) I've now taken
to cutting through the glue with a razor before removing them from either the bushings or
the centers.

Or perhaps something related .. when the blank is removed from the center or bushings,
do you sand the CA back down to the ends of the blanks? If there is any extra length,
the CA will not want to compress as you press fit the parts into the tubes. Since the CA
can't compress it will tend to push outward, lifting from the wood.

Any of this sound possible?

When I do the finish between centres there is nothing touching the ends of the blanks for the CA to stick to so issues when separating off is not the cause. I do tidy up the ends (not that they need much) with the barrel trimmer before assembly.

WoodHacker, with oily woods in particular, this happens too often and is very frustrating.
1. Get some Delrin bushings off Fred (Big Shed), this will greatly reduce the lifting and the worry about sticking, although you may still need a light touch with the skew for a clean cut, then use a sanding mill for the ends (Fred makes those as well), of course if you want to make your own tools that is fine also.
2. Use less CA on the oily woods, I try one coat thin, one coat medium, one coat thin and try to finish off. I find that with less coats there is less "lifting" of the CA.
3 When putting the pen together, use a little Burnt Linseed Oil on a cotton bud and smear it on the pen part and on the inside of the tube and press gently together, pressing it too hard can also lift the CA.
Hope that adds to what others have said and you get a great finish, Amos

Could be off-gassing from the CA but not normally after 24 hours or so. Did you resand the ends of your blank after the CA? The CA will go over the ends and cause a buildup, then pressing parts against it will cause a crack. You probably still have a mandrel--the perfect sander for that. Buy some 80 grrit stick on sandpaper. Normally come in 5 & 6 inch discs. Draw a bunch of disc [circles] on the back about the size of the end of the mandrel, drill a 1/4 inch hole in center. Doesn't have to be perfectly centered, and cut out. Cut square & clip off corners will do. Stick that to the mandrel & sand the ends of the blanks after all finishing is done. That will re-true up the ends & get a better fit with kit parts, also keep from cracking the CA as the parts are mated with it. Make sure to use the spacers on anything larger than the 7mm tubes. Hope this helps.

Originally Posted by wood hacker

When I do the finish between centres there is nothing touching the ends of the blanks for the CA to stick to so issues when separating off is not the cause. I do tidy up the ends (not that they need much) with the barrel trimmer before assembly.

i am going to take another guess now that you have metioned the barrel trimmer

the barrel trimm could have grabbed the edge of the CA and weakened it which when hit in the wrong way by something in your pocket could have flicked the weakend piece off

just a guess again

MIK

Originally Posted by MBUMIK

i am going to take another guess now that you have metioned the barrel trimmer

the barrel trimm could have grabbed the edge of the CA and weakened it which when hit in the wrong way by something in your pocket could have flicked the weakend piece off

just a guess again

MIK

I think you may be on to something there Mik.

Thanks to everyone for their suggestions.

Amos this one was red mallee burl so I don't think that oiliness was an issue, however I will keep your advice in mind when I do attempt an oily one, also I was thinking about getting bigshed to make me up some bushes to turn pens between centres (mainly cause I keep bending my mandrel) so getting some delrin ones to finish with would compliment those.

Mobil Man I like your suggestion for sanding the ends square sounds good and I will give it a go.

Once again thanks all

cheers
WH

If you did use a barrell trimmer it definitely could have caught on an edge, put the drill in REVERSE , that way it won't grip on the edges and may smooth them a little, Amos