dscm1
Member
Why am I having such a hard time with blowing out acrylic blanks? I am 2for I have sharp tools and I am going slow with a light hand. Could the cold temp in my garage be causing it? What am I doing wrong?
Blow out problems
- Thread starter dscm1
- Start date
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Marc Phillips
Member
Can you add some more info? ... what tool are you using? .... what speed is the lathe turning? ... When is the blank blowing out... at the initial roughing out stage or later on as the blank gets rounded?
dscm1
Member
I am turning at high speed, I am using a gouge and it is blowing out during the rough stages before it is completely round.
doddman70
Member
Is it actually acrylic or some other type of plastic? not all the plastic blanks out there sold are acrylic. and some are very brittle.
Monty
Group Buy Coordinator
First of, check the blow out to see if you have glue coverage, if not, you may need to modify the way you glue in your tubes.
Second, your gouge is probably catching the rough edges of the blank. Try a lighter touch and don't try to take too much off at in one pass. One thing that has helped me is to sand the sharp edges of the blank down (partially round off the blank) using my belt sander.
Second, your gouge is probably catching the rough edges of the blank. Try a lighter touch and don't try to take too much off at in one pass. One thing that has helped me is to sand the sharp edges of the blank down (partially round off the blank) using my belt sander.
Sand the sharp edges so they are rounded off just a little.
PUt the gouge down and use a skew, even before it gets fully round. And use the skew properly; as a angled cutter, not a flat scraper.
Fast spin on the lathe and sharpe tools.
After a while you will develop a consistent light touch to allow you to do it with a gouge, but it takes some time to get the feel for that.
PUt the gouge down and use a skew, even before it gets fully round. And use the skew properly; as a angled cutter, not a flat scraper.
Fast spin on the lathe and sharpe tools.
After a while you will develop a consistent light touch to allow you to do it with a gouge, but it takes some time to get the feel for that.
jwoodwright
Member
You can also sand the edges on the lathe by using 60 or 80 grit paper. Sounds also like a lighter touch is needed. You should get ribbons of material shooting all over... Wipe your lathe and tools 1st with a new dryer sheet; that stuff is messy. Also you want to angle your gouge to engage it in cutting mode, not scraping...
ed4copies
Local Chapter Manager
EXACTLY what material are you trying to cut?
Source and product name would help./
Source and product name would help./
dscm1
Member
THANKS! I will try all these ideas and hopefully it will TURN out well.
dscm1
Member
Held gouge at different angle and worked great. Thanks!!!!!
Aderhammer
Member
A little late on advice, but just like they said, blow out problems = lighten touch and increase angle to make a shearing cut.
jwoodwright
Member
Alright Darren! Looking forward to seeing the completed pen!
alamocdc
Member
The first thing that caught my eye is that you are using a gouge. Except for spindle work (wood only), and bowls (using dedicated bowl gouges), I've not had good luck using a gouge, especially on synthetics. My one exception to this is my 1/2" detail gouge, but it's shaped more like my round nosed scraper so a smallere surface area contacts the blank. If you don't trust yourself with a skew yet, you can use a round nosed scraper to rough the shape in. Light cuts, sharp tools and let the tool do the work. Don't try and force it.
ed4copies
Local Chapter Manager
A gouge will work fine for roughing. (The larger, the easier)
You CAN make the pen with a gouge too, but that's trickier.
You CAN make the pen with a gouge too, but that's trickier.
jwoodwright
Member
Wow! Before I was scared of the skew, it "chunked" out material and always was hungry for blood, mine.
So I used a gouge, regular 3/4" and sharpened it and as I was moving it I kinda rolled it so the lower part of the lip was cutting. The instant I hit the joy spot, a cascade of stringy material was shooting all over... Thus I continued and damn near didn't need to sand.
So I used a gouge, regular 3/4" and sharpened it and as I was moving it I kinda rolled it so the lower part of the lip was cutting. The instant I hit the joy spot, a cascade of stringy material was shooting all over... Thus I continued and damn near didn't need to sand.
Since dscm1 commented that changing the angle on tht gouge helped, it sounds like he may not have been rubbing the bevel when cutting when the bowouts were occuring.
This may be repeating the obvious but it is a good idea to initialy present the cutting tool to the material with the bevel below the blade edge rubbing material and a slight gap between the edge and the material. Then slowly lift the handle which will drop the edge into the material.
The angle statement may also mean that you were cutting on the wrong arc of the gouge. If you look at the gouge on the toolrest and imagine a line from the toolrest to the cutting edge, that line should be along the lowest point of the tool. If you dont do this you risk a catch which will twist the tool and cause a blowout.
Google "laws of woodturning)
This may be repeating the obvious but it is a good idea to initialy present the cutting tool to the material with the bevel below the blade edge rubbing material and a slight gap between the edge and the material. Then slowly lift the handle which will drop the edge into the material.
The angle statement may also mean that you were cutting on the wrong arc of the gouge. If you look at the gouge on the toolrest and imagine a line from the toolrest to the cutting edge, that line should be along the lowest point of the tool. If you dont do this you risk a catch which will twist the tool and cause a blowout.
Google "laws of woodturning)