Getting a lot of failures

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I think the most probable cause would be wrong glue and/or bad technique.
Can you explain your process so that we can help you get to the bottom of the problem.
 
Hi Dave,
It could be any of many reasons;

1. Too aggressive a cut
2. Dull tool
3. Tool operator error. Angle, distance between rest and work
4. Bad glue or not enough or not set
5. Tube not de-greased or scuffed to provide glue key
6. Loose grained wood

I'm sure there could be many more though:wink:
 
skiprat said:
Hi Dave,

It could be any of many reasons;



1. Too aggressive a cut

2. Dull tool

3. Tool operator error. Angle, distance between rest and work

4. Bad glue or not enough or not set

5. Tube not de-greased or scuffed to provide glue key

6. Loose grained wood



I'm sure there could be many more though:wink:
Click to expand...



I am leaning towards bad glue ,


Sent from my iPhone using Penturners.org mobile app
 
Skiprat's list is good. Review all. Don't try to find any single cause - because it can be a combination of two or three.

Is your tool edge sharp enough to shave hair off of your arm?
Are you cleaning & scruffing the tubes with Sandpaper?
Are you using medium or thick CA, or epoxy? are you coating the inside of the blank well?

One other suggestion: once the blank is rounded, soak it in CA and let it set for a few minutes. This is a little like stabilizing and works well on course/porous/knarly wood.

I don't like using sandpaper personally in most instances, but do suggest at times to use 320 (or medium fine) to sand it down to close to size and then finish sanding with 400 or better.
 
I have seen more people have problems with CA glue than all other glues added together. I know there are people that use it without problems, but for peace of mind, I think epoxy is a far better option.

Scuff the tubes well, make sure there is enough clearance between blank and tube, coat both the inside of the blank and the tube with epoxy, insert tube with a twisting motion . Give it sufficient time to cure. Goodbye problems.
 
I also agree with Skiprat's list & what other's have said. Most times when I see a failure, it's because of lack of glue coverage. It's funny to me that we will spend from $10 to $50 on a kit, plus $4 on up for a blank, but won't spend an extra 10¢ on a liberal amount of glue. I don't know if this might be your problem, but I've seen it many times, including my own failures. :frown:

Or it could be a problem not already mentioned. Sometimes we just mistake firewood for turning wood. :biggrin:
 
I always use thick CA glue. I squeeze a little into each end of the blank and then liberally apply all around the tube. Then just push the tube in. I don't worry about wasting any, it'll turn off anyway. (Knock on wood) I've never had a tear out or anything.
 
I agree that the list is a good starting point, but before going any further, we need to know if the problem is occurring while turning the pen, or while sanding it.


If its while sanding, then I would add excessive heat to the list. If the failures are due to heat, then the root cause could also be incomplete gluing (leaving an air pocket between the tube and the blank where the air can expand when its heated), or excessive moisture in the blank.
 
I will repeat a few things people have been saying and even what Skip said (boy I hate to admit when he is right:biggrin:) But glue is the very first place to start. remember wood is a product that will always move due to moisture and atmosphere conditions and people forget this. we try to encapsulate with CA finishes but they are so thin and the finished turned piece of wood is thin. I hate CA for gluing wood to a metal tube. With CA it is a brittle solid form off glue with no give unless you use flex CA. I prefer to use epoxy because it will have some flex to it even when cured and it is strong and sticks to everything.

Tools are next. Sharp is the word plus proper technique presenting to the project. Learn to use your tools properly and learn to sharpen.

Next is tool rest and the proper distance from project and proper height. Too far away you cause vibration from tool to wood and that is not good. Need to be sure the mandrel if using one is true and the blank spins round and no humps in it.

Next is controlling the amount of cutting action and not be in such a hurry. learn to ride your tools smoothly and evenly across the rest. Some woods are heavy grained and will give different feel as they spin because of the hardness in the parts of the wood. Learn to read the wood. and adjust. Good luck.
 
Try using Gorilla glue- - -it has served me well for 5 years with ZERO failures
Click to expand...

For those who use gorilla glue, my experience is that it tends to foam (expand). Do you seal the end of your tubes?

Seven
 
It's that damned brittle Aussie wood that you are using !!!! :biggrin::biggrin::biggrin::biggrin::biggrin:
 
I use volunteers to tube my blanks, and this is how I have trained them to do it. We use epoxy when there is time to let it dry overnight, or thick CA if we are going to need the blank the same day.

I have them plug one end of the blank with play dough, then put an insertion tool in the other end. They mix the epoxy on a piece of paper (I use old PSI catalogs LOL) and when it is mixed they spread it out in an area big enough to roll the tube in. They roll the tube in the glue, then insert it in the blank, rotate it, pull it back out and roll it in the glue again and insert it and rotate it then pull out the insertion tool. We use 15 or 30 minute epoxy because we are not going to use these for at least 24 hours. This allows them to mix up enough epoxy to tube ten blanks or so at a time before the glue begins to set. Rolling the tube in the glue makes sure there are no blank spots on the tube, and doing it twice makes sure there is enough glue in the blank.

We do basically the same thing with thick CA, but only do one or two blanks at a time, putting a strip of thick CA on the paper long enough to roll the tube in, except we don't pull it out and reinsert it with the CA.
 
I lean more to the first three on skiprat's list. It is possible to turn a blank without a tube in it at all and not blow out chunks.
 
Sharon,

Thanks for posting your method ... It sounds excellent and I am going to try it ...

But where you say "I have them plug one end of the blank with play dough", do you actually mean to say ... the brass tube ... ?
 
studioseven said:
Try using Gorilla glue- - -it has served me well for 5 years with ZERO failures
Click to expand...

For those who use gorilla glue, my experience is that it tends to foam (expand). Do you seal the end of your tubes?

Seven
Click to expand...

Yes, it expands, and yes we plug the tubes beforehand. Expansion - That is the point of using gorilla urethane glue. Even If you fill the hole in a blank with epoxy or thick CA, plug the end of the tube so that no glue gets inside, then insert the epoxied or CA'ed (thick) it will not make full contact all the way down. Air is trapped and often pulled into the space between the tube and blank, creating weak spots. It is not a problem most of the time but on special blanks, that space will rear it ugly head.

For this reason, some use gorilla glue because it will expand and fill ALL of the "space". The one problem with (well two) with urethane glues is that if one is not prepared or inexperienced, the expansion of the glue will "push" the tube toward one end and harden beyond repair with the tube sticking out of the end of the blank. Problem 2: Much more sticky on the hands and what it touches than CA or epoxy.
 
When I glue my tubes, I always use thick CA glue and have not had any problems with it. I always coat my tube real good and twist it as I'm inserting it into the blank to insure it is spreading the glue all around.
 
I use thick CA glue, put one end of the tube into one end of the blank, turn a bit and insert the tube in the other end while turning the tube. Can't use anything to plug as I made an insertion tool from a piece of HDPE.
 
magpens said:
Sharon,

Thanks for posting your method ... It sounds excellent and I am going to try it ...

But where you say "I have them plug one end of the blank with play dough", do you actually mean to say ... the brass tube ... ?
Click to expand...

Yes. The tube. Senior moment.
 
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