need help

[rickry6092]

I am having trouble with blowout when turning blanks.
It seams that when I get close to the finished diameter I chip the wood.
I don't get this problem when I work with plastic.
Any help would be apreciated.
Thank You
Rick

 

[nativewooder]

In my experience, the two most likely culprits are dull tools or punky wood. Only the "Shadow" knows!

 

[Ruby pen turning]

Dull tools or the blank may not have been glued good to the tube in that spot. I have looked at the tube when that has happened to me and could see that I had not glued the tube in very well, as in no glue on chipped off piece or tube where it broke.

 

[JessPens]

Hi,

I am fairly new to pen turning but I will throw in my newbie experience for what it's worth. I have had the same problem and all I can do is add three things I have tried.

First, is this happening on the end of the blank? I found that for some reason I was not getting enough glue on one end of my blanks so now I take a q-tip and thouroughly swab glue thru the entire blank. Make sure you sand the brass tube, I forgot this once and every blank blew out when turning. :frown: I then roll the brass tube in glue and insert it half way and spin it around. I then remove it and roll it in glue again and insert it from the other end twisting it as I insert.

Second, for some woods that seem to be more brittle I turn less and sand more. I get the basic shape of the pen pretty close but leave enough room to sand. I found that I was trying to save sanding by turning but this wasnt working out well for me.

Third, be very patent when drilling to clean out the brass tube and square up the edges. I found that my bit was heating up enough to melt the epoxy glue, I am not sure what this does to the strength of the glue after it dries but it made me nervous and I have slowed this step down to avoid having this problem. I want to switch to CA glues after I use up my epoxy.

I hope this helps...

Jesse

 

[kovalcik]

"I found that my bit was heating up enough to melt the epoxy glue"

I have seen a few different people on various threads mention that the barrel trimmer was heating up enough to melt the glue, and this really has me puzzled. It takes me about 5 seconds with my hand drill at medium speed to square the end of a blank. Hardly enough time to heat up the bit enough to melt glue. If your trimmer is getting that hot then you need to change how you are using your trimmer.

1) Is the trimmer dull? Sharpen it. It is quick and easy and makes a huge difference. If you don't want to sharpen, buy a new one.

2) How much material are you removing? If you are consistently removing more than 1/8" then trim the blank down on your bandsaw before squaring. I try for around 1/16".

3) If it is heating up because you are trying to remove glue from the tube, then either plug the ends of your tubes with putty or wax or use a rat tail file to remove the glue by hand.

These suggestions should remove any threat of heat from the barrel trimmer and give you better results. I find that if a tool is getting too hot or making weird noises, then I am probably using it incorrectly. Then it is time to stop and rethink what I am doing (or post to IAP and ask a question )

 

[leehljp]

I will add another potential problem: Speed. While the likely culprit is dull tools, too slow of a speed is another. On occasion, people equate bowl turning with pen turning and run at the same speeds. The speed of the surface of a pen at 500 RPM is MUCH MUCH less than the surface speed of a 10 in bowl at 500 RPM.

Slow turning is more prone to catches.

A second help will be this - when getting close to size, coat liberally with thin CA, turn a little, coat with CA again, turn a little, more CA.

A third problem, if the wood is not seated WELL with glue, it will have a higher chance of a blow out. HOW to TELL if this is the problem: look at the blow out. Does the section that came off have a full smooth impression of the tube where it separated? Or does it show glue but obvious that it was not making contact with the tube.

 

[JessPens]

Does the section that came off have a full smooth impression of the tube where it separated?

This is what I was experiencing causing me to slow down my glue-up process and ensure a good bond between the blank and the tube.

 

[JessPens]

BTW Rick, don't give up on those blanks. This is a hobby for me and I cant afford to throw blanks away LOL I had some stabilized colored maple and elder that I had this problem. I picked up all my really fine sawdust from that color and mixed it with epoxy. I used many parts sawdust to one part glue and made it a really thick paste. I filled the gaps and built it up above the surface of the pen and then put it in my lathe to sand. I made sure the end that blew out would be the clip end and I put the clip on over the patched piece, it actually came out quite nice. Depends on the grain of the wood I guess.

Also, I had a couple that I had most of the piece that blew out so I glued it back in and then sanded it on the lathe Again, I put this end up at the clip and you cant even tell.

Just a thought,
Jesse

 

[rickry6092]

thank you for all this great info

 

[jcm71]

Another tip is to listen and feel. Sometimes when I get down close to the bushing something either feels or sounds hinky, a sure indicator that I didn't do a good job gluing earlier. When that happens, I put the chisel away and sand down to the bushings. Another thing that helps is to "seal" the ends with with thin CA before you start turning.

 

[Jgrden]

You should have seen what I did to a pine cone blank today. Sheesh. I could not even find the parts. This was after I had sharpened the gouge. Even after I patched it with saw dust the sand paper (and I knew better) threw it off center. What a friggen' mistake. Should have stayed in bed.

 

[ed4copies]

One other possibility: Are you drilling the hole quite a bit larger than the blank? Some instructions call for a bit that is too large, based on the finished dimension of the pen.

Also, if you douse your ends with thin CA before mounting the blanks to turn, it will reinforce the wood--particularly at the ends--where you need it.