Shattering blanks

[areyouhappydad]

Hi all, first posting!
Having a problem with shattering blanks, both wood and acrylic. Have turned a number of pens without this problem, don't think I have changed the way I do things or provider but have blown 5 out of last 8 and getting frustrated!
Any advice will be greatfully received.
Cheers
Stuart

 

[NikNak]

shattering as in 'boooff' they disintegrate off the lathe while working on them..?

a few pics or what you were trying to do might help a little




Nick

 

[areyouhappydad]

Hi Nick,
The blanks are breaking in chunks from the brass tubes glued into the pen blanks. At times I have nearly got to the bushing and then a chunk has broken off. Don't think I am rushing.

 

[NikNak]

ahhh.... pens, sorry i was thinking along the lines of bowl blanks #-o

You've glued the brass tube in the wood, right..? using C.A. (super glue) i bet..?

I've had this problem too (in the past) have you recently changed the 'type' of glue used..?



N

 

[Steven]

Is it blowing out from the opposite end from were you insert the blank? If it is, the glue is will not be spreading all the way down the blank.

Things that helped me. Putting a drop of glue in the blank so the tube pushes it in as it goes, sharp tools especially on acrylics, lighter cut nearer the finished size, taking one less cut and a bit more time with the sandpaper (until at least you find out what it going wrong) and can I take it you are putting a key on the tubes before gluing.

 

[areyouhappydad]

Thanks for the replies. I have changed glue recently which may be a factor, it is noticeably thicker ca glue than my previous one. Will try out adding some to the hole first e
And ensure I have left it longer before working.
Thanks

 

[myturn]

I use thick CA glue too.

Rough the tubes with coarse abrasive first.

Put plenty of glue on and twist the tube as you insert it into the wood so the glue spreads. I use a home-made insertion tool that allows me to control the depth of insertion whilst twisting.

If you dont twist then there is a risk that some part of the wood will not be stuck and this is one reason for breakout.

Sharp tools are a must, especially as you get to the thinner stage. A skew is generally best, but towards the end sandpaper is easier, takes less off and I am not too proud to admit to using plenty of it for the final shaping and finishing.

 

[areyouhappydad]

Thanks Mick. Reckon the glue process may be the key. Will post some pics of pens turned if I can figure out how!

 

[NikNak]

Stuart,

the problem i had was when i changed from a 'thickish' glue from one of those small metal tubes, to a very thing CA glue from a plastic bottle (it was cheaper to buy as it was a larger quantity), but didn't notice that it was incredibly thin and water like. when i applied it to the tube and slid tube into hole, it was almost immediately soaked up into the wood, leaving virtually nothing to hold tube in place. It took several 'mishaps' before i realised what was wrong.....

I now 'prime' the hole first with a generous amount of the watery stuff, then apply more to the tube before sliding it in. Touch wood (ha ha...) it's worked so far (got several more bottles left... )

However, when ever i do a pen from a kit that's cost me a bit more lets say... i still use epoxy 2 pack.


Nick

 

[areyouhappydad]

Have never tried epoxy. Does it make a real difference?

 

[Blister]

When I make pens I always use a cotton wool bud soaked in superglue

then also squeeze some superglue inside the wood blank , insert the bud and use it like a barrel cleaned running it up and down inside the blank

Making sure all the inside is covered , then run glue along the pan blank brass tube , When inserting the tube rotate it with a twisting action as it slides in

Also a little note , only do this when the pen blank is cold not straight after drilling as the heat caused by drilling makes the glue go off quickly sometimes before you get the tube all the way in

:wink:

 

[Jonzjob]

I always use 2 part 5 minite epoxy too. The one time I used cyano I had a break so I don't use it any longer. Great for radio controlled gliders, but not for me on pens.

I made a few small bamboo spatulas and use them to put a fairly generous amount into the hole. I also plug the end of the tube with some absorbant paper to stop the glue getting into it and, belt and braces, after I have twisted the tube almost right in I put some on the last bit of the tube. No failures doing that even when I have put Celtic knots on the top barrel.

 

[Melinda_dd]

I use the epoxy too. Mainly coz it takes that bit longer to set (gives me more time to maneuver the tubes).... the one time I ran out and used CA, I was covered and took days to get hands that resemble skin back and not sandpaper!... and I was using gloves!

I smooth some in the hole first, then coat the tubes with plenty... twist in and remove any excess.
Epoxy all the way!!!

 

[Dalboy]

I use polyurethane glue and block the tubes with potato again as many do I put some in the drilled blank and also a little on the tube slide and twist the tube as you insert it then cover the ends with paper towel and put clamp on as sometimes the tube can get pushed out had no problems doing it this way