HELP!!! Computer board blow out

Signed-In Members Don't See This Ad

ROOKIETURNER

Member
Joined
Feb 26, 2010
Messages
282
Location
Naperville, IL
HELP!!! I am very new to this. I have turned about 12 wood pens and 3 acrylics. So I am very very green.

I fell in love with acrylics, so I purchased a number of blanks and turned a few.

WOW! What an awesome look and feel. So of course I jumped head first and purchased a blue and green computer board pen kit frmo WOODCRAFT. I have watched 2 of them being turned by a much more seasoned turner.

Under his watch, not that careful because he was helping 2 other rookies, I began to roundout the green pen. All was good, when BOOM!!! A huge chunk came flying at me. I stopped, wanted to tear up, and removed the blank. A chunk down to the board was missing. Even tore a resistor off with it.

Oh well, there is always to blue kit. I milled it and put it on the lathe. Rounding began and all was good. I was able to fully round the blank (15 minutes of timid and sweat filled turning). I then began to shape the blank into a nice soft curve. BOOM!!! This time a band of cracks and pits rattled off the blank. I stopped it, and sure enough several of the pits went all the way down to the board.

What the heck am I doing wrong? Tools are sharp. Speed right around 1200rpm. Soft gentle touch. HELP!!!

Also, not having worked with PR, can someone help me with the recasting?

Thank you!

Rob
 
Signed-In Members Don't See This Ad

wb7whi

Member
Joined
Aug 29, 2008
Messages
304
Location
Spokane WA
cant you just put everything back together with CA and finish the blanks?

I recently turned a circuit board pen and one end blew off. I clamped a small piece of wood and wax paper to the end and filled it with CA. The next day it turned just fine. Cant tell where it was filled.

If you are new to this exotic form of torture then I suspect your tools may not be very sharp. Get with a mentor (you must have a wood turning club in the area) and let him show you the tricks.
 

ROOKIETURNER

Member
Joined
Feb 26, 2010
Messages
282
Location
Naperville, IL
cant you just put everything back together with CA and finish the blanks?

I recently turned a circuit board pen and one end blew off. I clamped a small piece of wood and wax paper to the end and filled it with CA. The next day it turned just fine. Cant tell where it was filled.

If you are new to this exotic form of torture then I suspect your tools may not be very sharp. Get with a mentor (you must have a wood turning club in the area) and let him show you the tricks.


I am turning under the direction of Dave a.k.a CHICAGOHAND. So I am in good hands. My tools are sharp. I think that was lesson #2 after, lesson #1: Metal end towards lathe.

As far as trying CA, that was our first thought. However CA and PR are not the same material and I did not want to experitment. If I could recast in PR I would rather do that. I was not sure if the PR would stick to the PR.
 

mtgrizzly52

Member
Joined
Feb 24, 2008
Messages
326
Location
Kalispell, MT, USA.
My first circuit board pen started out like yours did, and I ended up popping out some components and had little pits all around the blank....heavy handed with the skew. After the right amount of positive swear words and I'm sure I threw something or another, I grabbed a bottle of medium CA and started putting things back together. You couldn't or to this day can't tell where I repaired it. Once I was done with the repair, I then started using the CA as a filler for the pits, similar to Russ Fairfield's technique in filling wood blanks. By the time I was done, it was just like having a brand new blank.

Finished turning it CAREFULLY, and with the CA bottle close by, and it turned out wonderful.

Give it a try!

Rick (mtgrizzly52)
 

randyrls

Member
Joined
Feb 2, 2006
Messages
4,821
Location
Harrisburg, PA 17112
I got a few of these at the recent Woodcraft two day sale. Have not turned them yet.

Couple of tips. Use your skew as a cutting tool, not a scraper. The long point of the skew needs to be above the blank. You should be getting fine ribbons off the blank. Little nits are not good.

I try to sharpen my skews with a flat grind bevel, not a hollow grind.
 

Rchan63

Member
Joined
Apr 17, 2009
Messages
672
Location
Framingham, MA
You should sand off the corners first with belt sander or a piece of course sand paper on a flat surface. Without the corners the turning is much easier. Sharp tools and take very light shavings will go a long way. After my first two blow out I learn my sharp tools are not sharp enough and the light cuts are not light enough.
 

NewLondon88

Local Chapter Leader
Joined
May 15, 2008
Messages
5,077
Location
Claremont NH
lesson #1: Metal end towards lathe.

*chuckle*
As far as trying CA, that was our first thought. However CA and PR are not the same material and I did not want to experitment. If I could recast in PR I would rather do that. I was not sure if the PR would stick to the PR.

CA will work just fine and if done right, it won't show. PR to PR will also
work and that's one of the things the ResinSaver molds are good for.
(not plugging my own mold, but this is something the mold is good for)
 

Bree

Member
Joined
Jun 19, 2009
Messages
1,736
Location
Buffalo, NY
Sharp to one may be dull to another. Sharpen your tool until is is hair splitting sharp. Make sure the edge of that skew will slice paper with no catches just like a hot knife going through butter. Then give it a few licks across a hard Arkansas stone. Get a piece of leather, some jeweler's rouge or white rouge and some honing oil. Rub the rouge on the leather and oil it up a bit.

Then get it on the bevel and PULL it across the treated leather several times on each side. Your bevel will start to get mirror like and your edge will be extremely sharp.

Now turn the acrylic. See what happens. Use shearing cuts not planing cuts. Go lightly, slow, steady, and you will git er done!
:wink::wink::wink:
 

jttheclockman

Member
Joined
Feb 22, 2005
Messages
19,082
Location
NJ, USA.
I have just seen the photos of the blanks you are showing with the blowouts. My thoughts are you are either using the wrong tool or the angle on the tool is wrong for what you are doing or your use of it is wrong in that your approach with the tool is too steep.

You know about the tools being sharp and this maybe ok, only you will know for sure. But from your photos and all the chatter glass look means you either are using a wrong tool or the angle of approach is wrong. You are presenting the tool on too sharp of an angle with the material. You need to have the bevel of the tool ride on the material and then gently raise the back end of the tool up to start cutting. Do not just left or right with the tool. Ed Davidson has a good video on cutting acrylics and I think it is either here in the library or on his web site. He cuts an orange acrylic blank and shows you what to do and what not to. Check it out and it will help. Ed Davidson, AKA YoYoSpin
 

lawry76

Member
Joined
May 5, 2005
Messages
46
Location
Peoria, Illinois, USA.
I'm duplicating what was said above. My first one I blew the daylights out of it. CA glue helped but it was way too noticeable. Second one I sanded it down so that it was round when I put it on the lathe. I made sure I made small cuts and even dry sanded a couple of times in the process to keep it round with no rough places to catch the tools. And sharpened tools twice while doing it. I can sure empathize with you. Just broke my heart when it flew apart. Made me feel like a rookie again. Oh well.
 

mywoodshopca

Member
Joined
Nov 3, 2008
Messages
1,123
Location
Charlottetown, PEI Canada, Derby Kansas and Canyon
Sure looks like the result of dull tools to me..

I always thought my chisels were sharp until I started using the carbide inserts.. now I rarely use chisels and do 99.9% of the stuff using the carbide insert tool.

I blew a few blanks out with the chisels but none so far with the carbide.
 

ROOKIETURNER

Member
Joined
Feb 26, 2010
Messages
282
Location
Naperville, IL
Here are the pics:

1_Blowout2.jpg
1_Blowout1b.jpg
1_Blowout1.jpg
 

wolftat

Product Reviews Manager
Joined
Aug 19, 2007
Messages
5,377
Location
Fairfield, CT, USA.
You can sharpen the tools to a razor edge but they still take some time to get used to. I would just keep practicing whenever possible and sooner or later you will find that they become like an extension to your hands, until then just go easy and take very light cuts.
 

PJT

Member
Joined
Jan 13, 2010
Messages
41
Location
Southern Ontario Canada
I agree the tool was likely sharp , you may have changed the angle of the tool down just a tad and had a catch ( talking from experience) I try to remember A address B bevel C then cut . especially with brittle resins.
My first one of those computer blanks was also rebuilt with CA
Keep trying you will get it , before pen turning my motto was "patience if I had patience I would be a Dr." well pen turning is helping
Pete
 

thewishman

Member
Joined
Mar 9, 2006
Messages
8,181
Location
Reynoldsburg, Ohio, USA.
I do almost everything the opposite way of other turners, my skew is "upside down" I use planing cuts on acrylics...

1. Speed your lathe up to at least 1800, faster would be better.
2. Practice on other acrylics before you use a $20 blank.
3. Practice on inlace acylester once you are comfortable with other acrylics.

When you are comfortable with acrylester, you can turn the circuit boards with confidence.
 

ROOKIETURNER

Member
Joined
Feb 26, 2010
Messages
282
Location
Naperville, IL
Yeah, I know I am being aggressive with trying to tackle this project, but I am trying to find the good in it. I am going to recast them. So I will get some PR experience as well, and I also have a good excuse to buy the materials to cast future projects.
 

nava1uni

Member
Joined
Mar 30, 2008
Messages
4,936
Location
San Francisco, CA, USA.
I would use thick CA and you won't be able to see the repair at all. This is true about repairing most acrylics and lots of wood or other things. CA can be used in its many thicknesses for repairs that, if you take your time, will not show. I also think that you might want to practice a lot more on other types of material and make a lot more pens before spending $$$ for blanks. You have only made a few pens and, in my experience, it takes a lot more time pen turning or any turning to be experienced. Like any skill, practice makes closer to perfect.
 

ROOKIETURNER

Member
Joined
Feb 26, 2010
Messages
282
Location
Naperville, IL
I would use thick CA and you won't be able to see the repair at all. This is true about repairing most acrylics and lots of wood or other things. CA can be used in its many thicknesses for repairs that, if you take your time, will not show. I also think that you might want to practice a lot more on other types of material and make a lot more pens before spending $$$ for blanks. You have only made a few pens and, in my experience, it takes a lot more time pen turning or any turning to be experienced. Like any skill, practice makes closer to perfect.

I know, but a fool and his money are soon parted. I am one of those guys, that when I see something and I am told that it is too hard, I go for it. I know it is foolish, but I am a fool. :)
 

KenV

Member
Joined
Oct 28, 2005
Messages
4,720
Location
Juneau, Alaska.
Practice practice practice -- no problem taking on hard things, but do expect some failures and learning from them along the way -- Do take time from production to get some consistent technique built.

ABC is a good thought process while developing technique. Get a reliable feel and build on it. A few pieces of 2 by 2 from the lumber yard as warm up exercises before going to serious work will also help you develop the techniques and coordination.

Keep turning and keep trying -- and keep learning.
 

David Keller

Member
Joined
Nov 30, 2009
Messages
1,618
Location
Enid,OK
Good advice so far... My only other suggestion would be to crank up the speed. Faster speeds usually mean fewer catches for me.
 

Mr Vic

Member
Joined
Aug 11, 2008
Messages
1,865
Location
Falcon, CO
Five minute epoxy will work wonders...had a blow out similar to your green one but not as long. Mixed up the epoxy on a glass plate then globed it on...No runnin like CA and you cant even see the repair.
 

CHICAGOHAND

Member
Joined
Apr 1, 2007
Messages
350
Location
SUGAR GROVE, ILLINOIS, USA.
Keep the faith on polyester resin

I was there on the terrible night.
If you notice on the blue blank the chipping only happened in one spot continuously around the blank. My personal opinion with nothing to back it up is that the blank had cured differently in that one area. My first computer blank had the same problem but it did not go all the way to the circuit board. I stopped turning it for the night and came back the next day I thought it may not have been fully cured so I wantet to give it some time to cure some more. Also has anyone noticed when you buy these they are still quite sticky.
Could this be an indicator of it not being fully cured???


ROOKIETURNER, aka my friend Rob you are doing a great job on each pen you turn keep it up. And by the way that night Rob and two other guys from church came over and we had 3 lathes going at the same time, on the same circuit and me in the middle being the referee, it was a good night with a break for dinner and then back to turning.
Thanks to Johnnycnc these guys are getting set up to turn between centers and have come a long way.
One guy was brand new to turning and made two key chains and one European.

SO NOW THAT WE GOT THEM HOOKED WHEN SHOULD I RAISE MY PRICES ON THESE GUYS???
 

bruce119

Member
Joined
Jul 30, 2007
Messages
2,978
Location
Franklin, NC, USA.
I will give my 2 cents sand off the ends to round them off before the lathe. The faster the better I turn as fast as the lathe will go. I do have a mini metal lathe but only use it to round the blanks then I use a 1/2" oval skew. Now I don't use the skew in the traditional manner. I use the point think how a metal tool bit would work and like a scraper straight on. You should be getting fine dusty ribbons or just dust. Absolutely NO chips if you are getting chips you need to adjust your methods. Looking at the photos that was way too aggrieve turning. To me a gouge is a very bad thing with these blanks. Rounding them first on a disk sander then scraping with a VERY sharp skew. You want to start wet sanding at 400 then into micro mesh then finish off with a plastic polish like Novus II.

Now if you blow one up or fracture it. I would clean it up with alcohol and if there are any small fractures just break them away clean it up with alcohol and blow it out. Then just recast the whole thing with polyester resin. These are polyester resin to begin with so it should blend in nicely. Little things mite be fixed with CA like hitting a component and you get a little tear out and no cracks then just fill with CA and finish.

Hope this helps
 

ROOKIETURNER

Member
Joined
Feb 26, 2010
Messages
282
Location
Naperville, IL
Thanks Bruce!!! I just picked up the PR today and plan on recasting this week. Any tips? What should I make the mold out of? Ratio of PR to Catalyst? Tap bubbles out? Vibrate them out? What to use to vibrate?
 

NewLondon88

Local Chapter Leader
Joined
May 15, 2008
Messages
5,077
Location
Claremont NH
Thanks Bruce!!! I just picked up the PR today and plan on recasting this week. Any tips? What should I make the mold out of? Ratio of PR to Catalyst? Tap bubbles out? Vibrate them out? What to use to vibrate?

Warm the resin and the mold. You can warm the resin by putting it in a jar
and putting that in a pan of warm/hot water. Warm the mold in an old toaster
oven (set on Warm) Warm resin flows better and bubbles clear faster.
For vibration, I put the mold on an old scroll saw table. It works well enough
to move the bubbles out of any hiding places
 

bruce119

Member
Joined
Jul 30, 2007
Messages
2,978
Location
Franklin, NC, USA.
Warm the resin and the mold. You can warm the resin by putting it in a jar
and putting that in a pan of warm/hot water. Warm the mold in an old toaster
oven (set on Warm) Warm resin flows better and bubbles clear faster.
For vibration, I put the mold on an old scroll saw table. It works well enough
to move the bubbles out of any hiding places

Like Charlie said warm it a little not too much 90 or so should be fine. As far as the catalyst with resin it all depends there is a LOT to consider when adding cat. air temp, temp of resin, depth (volume) of resin, manufacture of resin. They all effect how the resin cures. Now I am not exactly sure but what the Cat. dose is chemically heat the resin so it will cure. The more you put in the resin gets hotter faster you are far better off trying to slow down the curring process then speeding it up. So why do we heat the resin it's a double edge sword. It thins the resin out so it will flow into the cracks and release bubbles more easily as Charlie said. But remember heat is what sets the resin off so you would cut back on the Cat. In your case I would use just 3 drops per once.

Now for a mold steel the wife's plastic kitchen cutting board. Cut it to make a box the size you need. Then to hold it together I use duct tape on the outside I don't use screws on anything. Just tape it together now once it is a box you get some "Goop" ,a silicone type glue found at any home stores, now run a bead across the corners on the inside of your mold use your finger to push and spread the bead caulking the seams. It dries very fast and comes rite off your fingers like a bugger (so I was told). Fill your mold with water then pore in a container measure it now you know how much resin to use. When done the Goop just pulls off the plastic cutting board and you can do it again & again. Now your going to need to plug you ends of the tube to seal them I use rubber corks the glue the ends to pop sticks to get the tube up off the bottom of the mold. I put a dab of goop on the bottom of the stick and glue it to the bottom of the mold it stays put.

Oh I do use vibration I have a vibratory ,a vibrating tumbler, I put a top on. Then I use a pressure pot and put the molds under pressure I use 60 lbs. But you wouldn't need that much it depends what you are doing.

Now you can do all that and it cost you hardly nothing or simply purchase one of Charlie's "NewLondon88" resin saver molds for a Sierra and save yourself a lot of time and resin.

003.jpg

Good luck you can always ask if you need help
 

NewLondon88

Local Chapter Leader
Joined
May 15, 2008
Messages
5,077
Location
Claremont NH
Fill your mold with water then pore in a container measure it now you know how much resin to use.

Or you can multiply the length x width x height to get the volume of the
mold. Multiply that number (cubic inches) x .554 (or thereabouts) to get
the weight of the resin you need.
 

bruce119

Member
Joined
Jul 30, 2007
Messages
2,978
Location
Franklin, NC, USA.
Or you can multiply the length x width x height to get the volume of the
mold. Multiply that number (cubic inches) x .554 (or thereabouts) to get
the weight of the resin you need.

OMG my head is going to explode :eek: I hate and failed math can add or multiply worth a crap I'd be lost without a calculator:confused:

.
 

NewLondon88

Local Chapter Leader
Joined
May 15, 2008
Messages
5,077
Location
Claremont NH
OMG my head is going to explode :eek: I hate and failed math can add or multiply worth a crap I'd be lost without a calculator:confused:

.

LOL .. it's easy enough. If your mold is 6x6 and it's an inch deep, it is
36 cubic inches. 36 x .554 = 19.994 ounces of resin.
Round it up to 21 oz just because you never get that last little bit of
resin out of the cup..
 

Mac

Member
Joined
Feb 15, 2008
Messages
532
Location
Bingen, Arkansas
The green one blew on a spindle gouge.

The second on a versa chisel.

SKEW---SKEW--- SKEW and use it like a skew. Yea its slower but write it off as skew practice. You will be thankful when you get in front of a crowd of woodturners to do a demo and pull out a big skew and go to town on a piece of wood. As alot of woodturners are scared of them and don't use unless as a scraper.

Sometimes ,after turning with a skew I can start as high as 600 -800 grit sandpaper. I don't like sanding, I like turning.

PS notice I said woodturners not penturners as most penturners know how and use a skew.
 
Top Bottom