CA Glue Failure- Suggestions?

[woodtreker]

I am having some issues with failures on tubes glued in using CA glue... I take the tubes and rough them using 120 gift paper (on the lathe) and then put liberal amounts of CA glue on the tube on at least two sides... Turning the tube as it is being inserted to be sure to spread the glue around... I let it cure overnight or longer... The percentage of failure is too high...

Any ideas??? Suggestions??

 

[leehljp]

Three suggestions:

1. Use Epoxy or Gorilla glue

2. Make sure the chisels are VERY sharp; Take smaller bites.

If that happens once or twice, that could be considered normal. If it happens several times in a short time period, it means something in the technique of applying the glue and/or something in the technique of turning.

3. It is possible that the CA is bad/old.

 

[IPD_Mrs]

When gluing in tubes we use thick CA. We squeeze some out on a plastic bag that the pen kits come in and use a chop stick to apply it inside of the blank. Once the inside is fully coated we will hold the tube by the very end and roll it in the CA on the bag. We then start to put the tube in twisting back and forth. We pull it out then insert from the opposite end while twisting. Word of caution do not try this with thin or even medium CA. Know your work time with the CA. it has been a long time since we have had a failure.

Mike

 

[ed4copies]

MLK is correct, but let me add - wait for the blank to cool from drilling. A hot blank can make even thick CA set while inserting the tubes.

 

[brez]

I am having some issues with failures on tubes glued in using CA glue... I take the tubes and rough them using 120 gift paper (on the lathe) and then put liberal amounts of CA glue on the tube on at least two sides... Turning the tube as it is being inserted to be sure to spread the glue around... I let it cure overnight or longer... The percentage of failure is too high...

Any ideas??? Suggestions??

The procedure you describe should not creat a lot of failures. You might have some bad CA.

Mike

 

[IPD_Mrs]

MLK is correct, but let me add - wait for the blank to cool from drilling. A hot blank can make even thick CA set while inserting the tubes.

Ed is the only one I know that is so quick and time conscious that he can get to gluing before his blanks cool down from drilling, which should not be too hot to begin with. :foot-in-mouth:

The other thing to consider is a dull tool will heat up a blank enough to cause CA to fail. (damhint)

 

[redfishsc]

I've had hit-or-miss success with CA glue (I only use thick if I use it).

I've found 5-minute epoxy to be nearly as quick and more reliable. Just messier.

If I'm gluing up a lot of blanks, I use 30-minute epoxy (the stuff Monty sells) instead, gives me more working time and I suspect it's even stronger.

 

[RussFairfield]

There are several reasons for the blanks either spinning loose from the tubes or breaking, and not all of them are because of a bad glue joint.

I think the biggest cause of CA glue failure is having too much space to fill between the hole and the tubes. I was drilling 9/32" holes for a 7mm tube when I was using epoxy or polyurethane glue. The was too large a gap for the CA glue, and I had a lot of failures until I started drilling with a smaller 7mm or "J" drill.

Someone already mentioned "old" glue, and how old is old depends on where you live. Hot and humid is not good for CA glue.

Another problem is with over trimming the ends of the blanks and leaving the tubes sticking out from the ends of the trimmed blank. When this happens, the bushings are squeezing on the tubes rather than the wood. The unsupported wood is more likely break loose from the tube than it would if it were in the grip between the bushings. The solution to this is to stop trimming just as the trimmer is starting to cut the brass, and leaving the brass flush with the trimmed end.

Another problem is that CA glue just doesn't stick very well to some woods, or wood that was burned during drilling. The glue joint isn't strong enough to take the banging of the intermittent cut when going from square to round. The solution is to take lighter cuts with the tool and make sure the tool is sharp when turning the square; or rough turn the blank to round between centers before drilling the hole.

And, some wood species naturally have internal cracks that don't show themselves until the tool is in the wood. I like Pistachio wood, but 2 out of 3 blanks break apart during turning. That 3nd one is nice enough to make up for the loss of the other 2.

 

[wdcav1952]

MLK is correct, but let me add - wait for the blank to cool from drilling. A hot blank can make even thick CA set while inserting the tubes.

Ed, you simply do not get enough credit for all the wonderful input you supply to this forum!! You know more than anyone else I know about how to make mistakes. I think it is truly wonderful how you share all the different ways to screw up with everyone!!

With my greatest admiration,

:tongue:

 

[timberbits]

I find also that when turning cross cut timber or poor quality burls that have not been stabilized, it leads to high failure rates as well.

To over come this, after drilling stabilize the inside using thin CA, allow to dry, re-drill then glue in the brass tube using thick CA. Also spreading out the thick CA with a cotton bud before pressing in the brass tube helps.

 

[rherrell]

I use nothing but medium CA for tubes and I don't have any failures, (well almost never!).I squirt some in the blank while turning it until a drop comes out the other end, then I put a line on the tube and insert it with a twisting motion. I spray it with accelerator and remove the excess glue IMMEDIATELY. After I mill the ends it goes on the lathe, maybe 5 min. dry time at most.
Another thing I do is drill a hole as close as possible to the tube size. The recommendations the instructions give for drill size are fine for poly or epoxy but CA won't fill gaps.
Also turning technique has alot to do with failures. Use a sharp skew, don't take big bites and be extra careful with the ends. Try to cut from the center out towards the end, not from the end towards the center.:wink:

 

[randyrls]

I think the biggest cause of CA glue failure is having too much space to fill between the hole and the tubes. I was drilling 9/32" holes for a 7mm tube when I was using epoxy or polyurethane glue. The was too large a gap for the CA glue, and I had a lot of failures until I started drilling with a smaller 7mm or "J" drill.

Another problem is that CA glue just doesn't stick very well to some woods, or wood that was burned during drilling. The glue joint isn't strong enough to take the banging of the intermittent cut when going from square to round. The solution is to take lighter cuts with the tool and make sure the tool is sharp when turning the square; or rough turn the blank to round between centers before drilling the hole.

Russ; You are correct. I often use a different drill bit than the recommended bit. I commonly use the "J" for 7mm tubes. After I determine which bit to use, I write that on the instruction sheet. If I have any qualms about rounding the blank, I give it a trip on the drum sander to round the corners.

I have both a $50 cheapie set 115 piece bits and a GOOD bit set. A good investment in any case.

I went to the local Woodcraft store this week and they were just stocking the lastest "Woodturning Design" YES!!!!

 

[woodtreker]

WOW!!! Thanks

Such GREAT Suggestions... I really appreciate them all...

Here is what I have done: (tries to use most of your stuff... they all were awesome...)

1. Slowed down my drill press to 500 rpm so as not to burn when drilling
2. Used a new bottle of CA glue
3. Going to secure some poly or expoy glue for more porus or questionable blanks
4. Make sure the brass is not sticking out of the blanks so as the bushings catch on them
5. Change my gluing techniques... (The bag was too messy but I did an alternate method)
6. Used 100 or 120 grit to abrase the tubes... Nothing higher...

Thanks to all of you!!!! It was really needed... I have been on many woodworking forums but this one has been quick to respond with valuable help!!!

 

[Petricore]

The only time I ever had problems with CA is when I didnt have coverage all over the brass tube. Instead of doing just 2 sides I usually would take the thick ca and spread it with a chopstick or piece of bamboo (or anything flat and disposable) I could even use accelerator and turn them the same night.

FWIW I only use gorilla glue anyhow (and so should you if you let them cure overnight anyhow) its alot more flexible and I see less cracks from wood movement with the gorilla glue.