Turning Snakeskin Blanks

[BassBlaster]

So, I think I have this casting snakeskin thing down. Now I just need to figure out how to turn them. More specificly, how to mount them on the lathe. I have tried using the mandrel and tried between centers, both gave the same result. The PR is seperating from the skin. I believe the reason is from bushings putting pressure on the resin. Today, I went through a process of making sure everything was perfectly square with my end sanding process using a digital angle box so I could rule out unsquared ends. When mounting on the lathe, I'm only using enough pressure to keep the blank from spinning so its not from excessive pressure. Any suggestions? I need some help.

I'm considering just mounting up my bushings and sanding the inside edges back just enough that they are only putting pressure on the brass tube but I dunno if that will help or not.

I am also willing to send someone that casts and turns these regularly, one of my blanks just to rule out a casting issue, allthough, I really feel like its not a casting issue. I have followed everyone heres tutorials and advice perfectly and they look perfect when they come out of the mold.

I should also mention, the blank I attempted today was cast at least 3 weeks ago so its not an issue with the resin not being cure.

Please give me your thoughts. I can post a pic if need be, but everyone has seen resin seperate and knows what I'm talking about.

 

[mikespenturningz]

When you square off the blank you are squaring all the way to the brass tube right? You don't want to put pressure on the casting it will do bad things!

 

[seamus7227]

hey Dennis,
It sounds like you have covered everything up to the point of turning with a tool. Are you making sure your tools are super sharp? When i turn my snakeskin blanks, i use a roughing gouge to get them round and then a skew the rest of the way down and have no problems. However, if i get greedy when turning and try to remove too much resin in one pass across the blank, I run a risk of chip-out if i am not careful with the angle of my tool. Any one particular tool "grab" (so to speak) can cause some separation, or so has been my experience. I typically tell people when turning my blanks to use sharp tools and light cuts. Take your time! I hope somewhere in all of my rambling you are able to get something useful out of it!

 

[BassBlaster]

When you square off the blank you are squaring all the way to the brass tube right? You don't want to put pressure on the casting it will do bad things!

Yes

hey Dennis,
It sounds like you have covered everything up to the point of turning with a tool. Are you making sure your tools are super sharp? When i turn my snakeskin blanks, i use a roughing gouge to get them round and then a skew the rest of the way down and have no problems. However, if i get greedy when turning and try to remove too much resin in one pass across the blank, I run a risk of chip-out if i am not careful with the angle of my tool. Any one particular tool "grab" (so to speak) can cause some separation, or so has been my experience. I typically tell people when turning my blanks to use sharp tools and light cuts. Take your time! I hope somewhere in all of my rambling you are able to get something useful out of it!

I'm not skilled enough with a skew to use it on a project yet. Ive been playing around with one but only on practice blanks.

I used a freshly sharpened spindle gouge to round the blank. As soon as it was completely round, I switched to a freshly sharpened and razor sharp carbide tool and took very light cuts. Light cuts to the point that it took me close to a half an hour to get the blank down to a point that it was ready to sand. I didnt get any chip out at all. the blank stayed nice and smooth all the way down.

I also read somwhere that these blanks can be turned with a bastard file. An earlier attempt was with a file and I recieved the same result.

This is definately coming from the pressure on the ends of the blank and not the turning portion itself. Maybe I should purchase new bushings, I dunno. Isnt there a company that uses CNC to machine perfect bushings?

 

[Joe Burns]

I use a carbide cutter that works just fine on acrylic blanks. Using a very sharp cutter and take light bites should give you no trouble.

Using this method I recently turned a diamondback rattle snake Zen this month that went smooth. The blank was already squared with the tube when I got it though.

Joe

 

[Rodnall]

I just posted on another thread a link to capn eddie that shows another way to grind your skew that helps avoid catches. Since I changed my grind it almost looks like I know what I'm doing. Here's the link shaprskew.avi - YouTube

Good luck
Rod

 

[BangleGuy]

It seems like you want the bushings to be putting clamping pressure on the PR and not the brass tube. If you drive the brass tube, you will be putting a lot or torsional shear on the snake skin, if you drive the PR then the skin is out of the equation...

Could it be heat related? An interesting problem for sure.

 

[BassBlaster]

I just posted on another thread a link to capn eddie that shows another way to grind your skew that helps avoid catches. Since I changed my grind it almost looks like I know what I'm doing. Here's the link shaprskew.avi - YouTube

Good luck
Rod

Thanks, that video is the one that convinced me to pick the skew back up. I sharpened both of my skews to his grind and have been playing around. Havnt had a single catch with that grind yet but I still dont have the confidence yet to use it on a project. I'll get there.

It seems like you want the bushings to be putting clamping pressure on the PR and not the brass tube. If you drive the brass tube, you will be putting a lot or torsional shear on the snake skin, if you drive the PR then the skin is out of the equation...

Could it be heat related? An interesting problem for sure.

Its definately not heat. I stopped several times to feel the blank and it never even got warm.

Interesting thought about driving the PR rather than the tube. I have always thought the other way around but your thought makes sence.

 

[BassBlaster]

So, interesting side note. After turning said blank yesterday, I brought it up and laid it here on the computer desk. I just picked it up and it looks perfect. What gives? The others I have turned still look horrible but this one seams to have repaired itself somehow. I dont get it.:ghost:

 

[BassBlaster]

The blank on the left was one I turned a couple weeks ago, you can cleary see the seperation. The one on the right is the one I turned yesterday. It looked like the other one when I started this post. Not as extreme but a very clear seperation specifically on the ends. Now you can see, it has somehow fixed itself.

So, I went ahead and pressed it together and we'll see what happens with it. Worse case scenario, Sierra's disassemble in about 5 seconds!! Sorry about the horrible pics, someday I'll learn how to use a camera.

 

[Old Lar]

I turned one of my cast rattlesnakes tonight myself and had the same results. Separation... Mine has not repaired itself though.
This discussion has given me new life, because after the one tonight, I was ready to quit snakes. Now, I guess a few more wouldn't hurt.

 

[its_virgil]

Did the blank look like that prior to turning? Could you tell? That look, which I have seen a few times (liar liar:a lot of times) is a casting problem not a turning problem. The gunky look on the skin was probably there before you stated turning. The curved surface of the polished blank is a magnifying glass and all small imperfections will show big time once polished. That are my thoughts on what i see.
Do a good turn daily!
Don

 

[tim self]

I've also learned it depends on how the skin was tanned and how much oil is left in the skin. I had the same issue when I started casting. Since I soak them in alcohol before wrapping tubes. Just my experience.

 

[its_virgil]

Agree with Tim. Clean the skin prior to wsrapping onto the tube. Tanning chemical residue on the skin needs to be removed.
Don

Sent from my Samsung Epic using Forum runner

 

[jimskio]

Just my $.02...
Looking closely it seems I can see some dead scales still on the skin. When you think you have all of the dead scales off the skin, do what ever you do to get them off again. You will be surprised how many of those things just do not want to come off the skin.
Also the skin can never be clean enough, I clean all of my skins at least three times before I cast. It could be some leftover of what you tan the skins with. I have a box full with issues like this.
As far as it "fixing" itself it could be an issue while you sanded the skin to finish it the heat built up enough that the PR pulled away from the skin but as it cooled it contracted back to size. While sanding you can get these, or any other, blanks pretty hot. I have also had the issue pop up a time or two on the ends of the finished tube. If your bushing is tight and you have to force it out this could also create this problem on the end. But I have had blanks that I thought were trash but I turned them anyway and they seemed flawless after turning.
I have learned a lot about casting snake skins from IAP members, especially Don, so if I were you I would follow what he says to the letter.

Good Luck
Jimmy

 

[its_virgil]

Remove the scales...all of them. Clean skin's surface. Coat the skin with thin CA and allow to cure for at least a day.
Do a good turn daily!
Don

Sent from my Samsung Epic using Forum runner

 

[BassBlaster]

Okay, lots of replies. I'll try to respond to all of them.

The blanks looked perfect before they were turned. The one on the left was destroyed on the lathe and I know what I did and why not to do it again. I just used that one for a side by side comparison. The only one I'm questioning is the one on the right. I have a few others, they just arnt pictured here. As for the casting, Everything I have cast so far has looked perfect when it came out of the mold. They have all been destroyed by me or the wife afterward.

There were no scales left on these skins. I checked and checked and brushed and brushed and feel 100% confident all the scales were removed.

I did follow Don's tutorials and updates and any other info from him I could find before I ever started casting. The only thing I didnt do, is clean the skins with alcohol. I hadnt read that prior to now but will clean them from this point on. Even though I didnt clean them, they were coated with CA prior to casting so the PR bonds to the CA, not the skins, correct? This is an issue with the PR seperating not the CA.

I'm still thinking this has something to do with the way I'm mounting it to the lathe or maybe I'm not getting the ends as square as I think I am. I set my sander up with a digital angle box though. I dunno, I'm confused.