Alabaster problems

[Monty]

In another post I was commenting on how the alabaster I was turning was cracking and chipping at the ends before I press in the parts. Here is a pict of what I'm referring to.

Any suggestions on how to keep this from happening?
Sorry about the bad pict, that's why I don't post many picts.

 

[terrymiller]

Mannie are you using any type of finish or just waxing them. When I made my soapstone pens the finish was chipping off with chunks of stone when removing them from the bushings. I started using a stone sealer that they use on countertops for mine.

 

[OKLAHOMAN]

Mannie,I can only guess what is happening but I had a very simular thing with a celluliod a month or so ago and the problem was the tube was not tight in the blank. In other words when I drilled the blank the hole was elongated at the ends and the celluliod flexed when the scrapper or skew got close to final shape and cracked just like your alabaster. This was because the bit was not sharp and the operator needed to slow down. Are you drilling thru or are you cutting the blank long and not exiting the blank? Check to see if you have a gap between the tube and the alabaster.

 

[Monty]

Originally posted by terrymiller
<br />Mannie are you using any type of finish or just waxing them. When I made my soapstone pens the finish was chipping off with chunks of stone when removing them from the bushings. I started using a stone sealer that they use on countertops for mine.

Terry - This was the second one I tried. After this happened to the first one, I applied thin CA to the ends and let it "soak" in, then gently remilled the ends to smooth them. When I was close to the final size, I applied thin CA as a sealer and then finished to size by sanding.

Originally posted by OKLAHOMAN
<br />Mannie,I can only guess what is happening but I had a very simular thing with a celluliod a month or so ago and the problem was the tube was not tight in the blank. In other words when I drilled the blank the hole was elongated at the ends and the celluliod flexed when the scrapper or skew got close to final shape and cracked just like your alabaster. This was because the bit was not sharp and the operator needed to slow down. Are you drilling thru or are you cutting the blank long and not exiting the blank? Check to see if you have a gap between the tube and the alabaster.

Roy - I was drilling through the blank an the slowest speed on my DP. I'll believe my lathe will go slower, I'll check and drill the next ones on the slower machine. I'll also check for gaps and if I see any, fill with thick CA.

I'll see what happens this weekend.

 

[Ron in Drums PA]

Originally posted by Monty
Terry - This was the second one I tried. After this happened to the first one, I applied thin CA to the ends and let it "soak" in, then gently remilled the ends to smooth them. When I was close to the final size, I applied thin CA as a sealer and then finished to size by sanding.

Is it chipping while you are milling?

 

[ed4copies]

Originally posted by OKLAHOMAN
<br />Mannie,I can only guess what is happening but I had a very simular thing with a celluliod a month or so ago and the problem was the tube was not tight in the blank. In other words when I drilled the blank the hole was elongated at the ends and the celluliod flexed when the scrapper or skew got close to final shape and cracked just like your alabaster. This was because the bit was not sharp and the operator needed to slow down. Are you drilling thru or are you cutting the blank long and not exiting the blank? Check to see if you have a gap between the tube and the alabaster.

EXCELLENT observation, Roy!!!

I have done this, and just realized it!!!

There is a fine-line problem here. Looking at the cap on the gentlemen's pen (I believe), the "proper" bit drills the hole a good bit (pun intended) larger than necessary. I, too, have had it flex (Only I JUST REALIZED that was the problem). BUT, we try to make the hole large enough that, if the wood shrinks, it doesn't crack. So, perhaps we need to adapt our instructions (those copyrighted ones) to use a different size bit for plastics (and stones) versus wood???

INTERESTING, FOOD FOR THOUGHT!!!!!!!!!!!!

Thanks, Roy!!!!!!!!!!!!!!!!!!!!!!

 

[Monty]

Originally posted by Ron in Drums PA
<br />

Originally posted by Monty
Terry - This was the second one I tried. After this happened to the first one, I applied thin CA to the ends and let it "soak" in, then gently remilled the ends to smooth them. When I was close to the final size, I applied thin CA as a sealer and then finished to size by sanding.

Is it chipping while you are milling?

Chipping did not appear until later. Upon hinking about it now, IIRC the chipping appeared after I removed the bushings. Wonder if the CA was sticking to the bushings and caused the chipping when the bushings were removed? I'll have to watch out for that this weekend when I try again.