How do I repair/stabilize a cracked blank

[spork]

Howdy folks. I did try and search for this, but couldn't find an answer - I promise.

I was turning a pen today and had a blowout. I glued the chunk back in place with C/A, but I noticed a very serious crack on the other side of the blank as well. What's the standard procedure here if I want to continue? Should I try and fill the crack with C/A, epoxy,...?

Thanks.

 

[farmer]

Cracked

Who wants a cracked pen ?

The cracked portion of the pen blank is junk............................

What you can do with what is not cracked is up to you...

In other works once you get to the point of segmenting pens then you might be able to salvage what is not cracked and use the good parts mixed in with wood or another piece of acrylic pen blank..

 

[jttheclockman]

Hello Rick and welcome to the site. What has occurred for you is not new and happens on occasions. There are a few ways to deal with it. At times it depends on the material you are turning. All is not lost. Sometimes just hiding a crack under the clip solves the problem.

I will go out on the limb here and assume it is a wood blank. But You will have to supply a little more info or maybe a photo. Many times when you get blowouts and cracks people just glue back with CA and continue on. When you get cracks you can drizzle thin CA over the crack and it will secure it. Sometimes people will celebrate defects like this and enhance them by filling with colored epoxy or inlace or even coffee grounds. It gives the blank more character and it makes it look like it was meant to be. Then there are times when it just does not pay unless it is an expensive blank. They just turn it off the tube and start over.

You will get these things with burls alot because the grain and stability of the wood is stressed. Many people have been stabilizing these type blanks with vacuumed resins. That is a story for others to tell. I do not do that.

One thing that is paramount though when working with blanks that are fragile and that is use sharp tools and light cuts. You have to be able to finesse your tools. Let them do the work. Sometimes and not alot you just have to resort to sandpaper and leave the tools alone. But another suggestion is if working with fragile blanks to continue to add thin CA every so often to the blank and let it soak in. This will help stabilize it without doing the vacuum thing.

Anyway hope some of this helps and i know others will chime and help also. Good luck and again welcome to the site.

 

[spork]

Thanks very much for the tips and suggestions. This is only my 10th pen, so I'm still on the steep part of the learning curve. I'm not inclined to throw it away, because every pen is practice at this point. I like to see what can be done to salvage them when I mess up.

I've attached pics of the two problems. As mentioned, one problem was a complete blow-out. I just knocked a huge chunk of wood off and glued it back on with thick C/A.

The other problem is a natural defect that I'd like to stabilize before it becomes a problem. Unfortunately I don't have any thin C/A at the moment - only thick (because that's what the guy in the video was using to finish pens). I can't decide whether to try that in the crack or some epoxy.

If I use epoxy I'm tempted to squeeze it in the best I can and then hit it with a heat gun to make it flow.

 

[jttheclockman]

Rick thanks for putting the photos up. No do not throw the blank away. You have the right idea. Learn from these things and see how well you do. You do see where it blew out. That is the heavy grain of that blank. That is a weak point.

If i may make a suggestion. Do yourself a favor and get some CA, thin and med. Thick CA is good for gluing in the tubes but not much more than that. You will eliminate alot of finishing problems. The thin will flow in the crack better.

When going to finish, put about 3 coats of thin CA on and let it dry. This will now seal the wood. Now put 4 to 6 coats of med CA on and then polish and sand out as normal.

This is the glue I us and they are a vendor here. Satelite glues. very good product. CA Glue from Satellite City Instant Glues- Cyanoacrylate Glue

Now if you want a quick glue to fix that crack and use as a thin CA, just go to the home depot and get a package of their CA glues. Thy will work for now. Good luck.

 

[spork]

thanks for putting the photos up.

Thanks for taking a look and offering tips.

No do not throw the blank away.

It was never an option. At this point if I can find the sawdust I'll glue it back in and keep going. I'd just as soon throw the finished product away if turns out awful. This is just a hobby, and there's only about $3.00 invested in each try. Of the 9 pens I made so far I feel pretty good about giving 4 or 5 of them away (and I can give the others away with a slight disclaimer).

Do yourself a favor and get some CA, thin and med

Definitely. I did some more reading and YouTubing on finishing and found exactly what you're suggesting. Funny that the first video I watched said to finish with thick CA - so I made sure to get thick.

I'm becoming somewhat proficient at finishing with the thick, but I'm guessing your approach will be easier and more consistent.

Here are three of my recent efforts...

 

[nativewooder]

Many times, "blowouts" have one of two causes: improper application of glue holding the blank to the tube, or, dull tools which need to be sharpened. If you are using carbide tools, then you have a continuing problem which will require that you change your technique.

 

[spork]

Many times, "blowouts" have one of two causes: improper application of glue holding the blank to the tube, or, dull tools which need to be sharpened.

Thanks. Both are entirely possible. On this particular pen I managed to break both tubes loose while milling the ends of the blanks. Never had that particular problem happen before. But I have had to remove and reposition a tube once or twice, and my experience was that the C/A goes off extremely fast when there's already C/A in the hole. So when I remounted these tubes I didn't do the spinning and plunging I normally would. I just covered the tubes with C/A and slammed them in there *fast*.

On the tool side, I'm doing all this at the "TechShop". It's like a tool commune. So you're never sure what you'll encounter day-to-day, and I'm not sure I'm all that good at assessing when the tools need sharpening yet. There is a wheel right next to the lathe, so I do sharpen the tools, but I'm sure I wait too long sometimes. Also, I've got a big box of hardwood scraps, so I've generally been turning different wood each time. I'm coming to learn that they have significantly different properties when cutting, and different rates at which they dull the tools. All part of the fun.

If you are using carbide tools, then you have a continuing problem which will require that you change your technique.

These are not carbide tools, but there's no doubt my technique needs further improvement. Interestingly this was my first blowout though.

 

[Kragax]

I just cracked a nice piece of mesquite. I have filled the crack with ca and it has been setting overnight. Will sand and finish later today. This has worked for me in the past but not always. Like someone said above. "it happens". I have to start segmenting. My biggest thing is deciding what woods look good together.

 

[spork]

I filled the natural crack with thick CA (because I don't yet have any thin on hand). I worried that it wouldn't get into the crack, but it soaked up the CA like a sponge - so much that I added a second application. It soaked that up pretty well too. I plan to turn in today. I'll post my results.

I also added a bit of CA where I had blown a piece out and glued it back. But it didn't take the CA like the natural crack did.

 

[spork]

Here's a pic of the pen with the cracks. To be fair I kind of hid some stuff with the clip and there's a bit of other stuff on the side you can't see. I think I would have done better repairing the crack with epoxy rather than C/A. I'm actually thinking about trying to cut out the imperfections with an X-Acto and re-doing it with a bit of epoxy. We'll see.