My first resin cast.  Out of the vessel, it looked great.  Clear, no pores.  While turning I exposed some pores and wondered how that happened.  Then I turned some more and began to think...maybe it's not porosity.  Maybe my tool is chipping...sort of like tearout but since the plastic is so much more brittle, it chips out.

Anyhow, that came to mind when I got a catch.  See the bottom rim all broken out?  That happened when I got a catch.  So again, I was thinking, maybe those pores aren't pores...as some adjacent areas look pretty darn smooth.  Anyhow, can somebody help me diagnose the issue by looking at this pic?  Thanks for the help!

Ahhh, can those be refilled on a 2nd cast? 

Also, are you saying standard gouges, scrapers, etc, don't work well on resin?

I have had better luck with standard gouges than with carbide tools, but that's  just me.  They have to be sharp and you have to take very light cuts. 

Make sure you have the guard down on your guard in place when you're turning it.  If it comes apart, it usually separates explosively.  Have a good friend who had one come apart and hit him in the face.  Now much of the bone in his face is titanium.  A face shield is not designed to deflect chunks, only chips.  After his accident, I convinced the local police department to let me buy a riot helmed from them with a metal cage and lexan screen behind it. 

I have thought, more than once, that NFL helmets with the lexan face shield would work fine for turning, and you could probably mount a positive pressure dust filter to it...

robo hippy

Steve Kniffen wrote on Jan 26^th, 2021 at 10:09am:


Steve, can you provide more details of his accident?  Was he wearing a face shield?  Was the shield rated as Z87+? What was his RPM?   How big was the turning and how big was the chunk that hit him?  Was he standing in the line of fire?  I ask because I am trying to collect data on lathe accidents and protective equipment.

Mike Nathal wrote on Jan 27^th, 2021 at 11:53am:


This accident was a combination of errors.  He took a bunch of 1-2" sticks and stood them on end in a cut off 5 gallon bucket.  Then he poured resin around until they were covered.  The finished blank was 6" high and the width of the bucket in diameter.  Probably weighed 20 lb or so.  He put it between centers and turned a tenon on the bottom then mounted the tenon in a 4 jaw chuck, have no idea what size jaws on the chuck.

Since it was round, he started hollowing.  He had removed the headstock guard.  The blank was not supported by the tailstock.  He was turning at 2100 rpm.  He was wearing a face shield.  He said he got a catch and the blank broke into multiple large pieces.  One of them hit him square in the face.  He woke up on the floor, couldn't see because of the blood, and couldn't find his phone to call his wife.  He has no idea how long he was on the floor before he found the phone and got her to the shop. 

The first problem was the design.  Pieces of limbs encased in resin were not a very stable medium to begin with.  He'd done multiple bowls with pieces of colored pencils and thought this would just be a step up from those.  He failed to take into account the mass of this blank.

Taking the headstock guard off elminated any chance of the chunks being stopped before they got to him. 

The manual on the chuck he was using clearly stated a max rpm of 600 when not supported by the tailstock.  He was turning at 2100.

He trusted a face shield to provide the protection of a helmet.  NO face shield is rated to stop chunks, not even AirShield.  After several serious turning accidents they started stating that specifically on their website.  Face shields are designed and tested to withstand splashes and flying chips.  They are secondary protection and must be worn over safety glasses.  They are not designed to provide head protection like a helmet. 

In 2012, Lynne Yamaguchi had a serious turning accident.  She wrote an excellent article in the June 2014 American Woodturner magazine.  She went into the OSHA requirements as well as the math behind the energy involved the piece that hit her.  Even a police ballistic riot helmet would not have been stressed to deflect the amount of energy in the piece that hit her.  A police helmet would have reduced the damage to her head and face though.  It's a great read if you haven't read it.

That's why I got the police helmet.  My friend is back turning but he has a hockey helmet with a steel grid mask and a lexan mask under it.