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Nov 09, 2017, 08:24 PM
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Daren71's Avatar
Discussion

Laser cuts not completely burned thru


I am building a kit, something I haven't done in a long time. The plywood laser cuts aren't burned thru. As a matter of fact, I can't see them on the opposite side. So far, I've tried drilling holes, and cutting the remaining wood out, or using a chisel, then cleaning up the holes as needed.

The inside pieces won't break out, I'm afraid of breaking the piece I'm working on. Does anyone have any better ideas? I don't own a scroll saw, and I have no room for one, so that's not an option.

Any tips or hints are greatly appreciated.

Thanks, Daren
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Nov 09, 2017, 08:31 PM
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DGrant's Avatar
What kind of wood... I guess you did say plywood though... but is it light-ply, hard-ply?... Thickness? etc... You give little information as it just might be a case where you have to break out the knife... or saw... Much can be done by hand also. Depending on the wood itself... plywood can be hand cut, although it's much more labor intense... that's sometimes part of building... especially if you don't own/or have room for a scroll saw. A hand-saw, or coping saw can make quick work of cutting parts also... It's part of the craft of the hobby. Someones got to cut it... might as well be you. Outside of that.. I would say get a bigger place so you can get a saw.

Seriously though, what kit are you building?... You might get someone with actual experience on it to respond. Imagine that. The more info you give, the more you usually will receive.
Nov 09, 2017, 08:51 PM
Obviously I'm a "Minus Member"
buzzltyr's Avatar
You could try sanding the back side of the parts sheet. The laser cuts sometimes are close enough to the back surface of the wood sheet that some sanding connects to the existing cut line. It is easier to do with balsa than ply, but it might work. I would definitely use a sanding bar to try it.

Mark
Nov 09, 2017, 09:20 PM
Still circling in sink...
If it's thinner plywood, say 1/16" or less, you can use the heavier duty X-acto knife handles and blades - line them up on the cut and just crunch on through. Get a real cutting mat to lay the plywood on and you'll get a decently clean result.

For thicker plywood, I'd suggest using a saber saw to cut just outside the part's outline, maybe 1/8" outside the line. Then use the heavy X-acto to chip or pry away the layers of ply that were burned through. The un-burned layers should now be thin enough to trim fairly easily.

For the inside pieces, if you can drill a bunch of holes close to the cut line, then chip away the layers, that's probably as good as it's going to get. Masking tape on the back side will keep it from splintering. A rounded diamond file (not that much $ from MicroMark) will then clean up the hole nicely.
Last edited by tom1968; Nov 09, 2017 at 09:27 PM.
Nov 09, 2017, 09:23 PM
Still circling in sink...
The scroll saw is a lovely piece of equipment for modeling if you can possibly manage it. But I was probably 56 yrs old/kids out of college before I could justify buying one so I feel your pain.
Nov 09, 2017, 11:12 PM
Registered User
Daren71's Avatar
Quote:
Originally Posted by DGrant
What kind of wood... I guess you did say plywood though... but is it light-ply, hard-ply?... Thickness? etc... You give little information as it just might be a case where you have to break out the knife... or saw... Much can be done by hand also. Depending on the wood itself... plywood can be hand cut, although it's much more labor intense... that's sometimes part of building... especially if you don't own/or have room for a scroll saw. A hand-saw, or coping saw can make quick work of cutting parts also... It's part of the craft of the hobby. Someones got to cut it... might as well be you. Outside of that.. I would say get a bigger place so you can get a saw.

Seriously though, what kit are you building?... You might get someone with actual experience on it to respond. Imagine that. The more info you give, the more you usually will receive.
https://www.rcgroups.com/forums/show...re%20SHARK%20E

This is the plane. Its 1/16" plywood, I would say its hard, its very difficult to cut into with a new exacto blade. Using a saw isn't possible, the parts I'm having trouble with, are inside lightning holes. I have been drilling and using a chisel to knock out pieces, then finishing it later with sand paper.
Nov 09, 2017, 11:14 PM
Registered User
Daren71's Avatar
Quote:
Originally Posted by buzzltyr
You could try sanding the back side of the parts sheet. The laser cuts sometimes are close enough to the back surface of the wood sheet that some sanding connects to the existing cut line. It is easier to do with balsa than ply, but it might work. I would definitely use a sanding bar to try it.

Mark
I will experiment with this on a piece that isn't very structural. I have a decent sanding bar.

Thanks.
Nov 09, 2017, 11:18 PM
Registered User
Daren71's Avatar
Quote:
Originally Posted by tom1968
If it's thinner plywood, say 1/16" or less, you can use the heavier duty X-acto knife handles and blades - line them up on the cut and just crunch on through. Get a real cutting mat to lay the plywood on and you'll get a decently clean result.

For thicker plywood, I'd suggest using a saber saw to cut just outside the part's outline, maybe 1/8" outside the line. Then use the heavy X-acto to chip or pry away the layers of ply that were burned through. The un-burned layers should now be thin enough to trim fairly easily.

For the inside pieces, if you can drill a bunch of holes close to the cut line, then chip away the layers, that's probably as good as it's going to get. Masking tape on the back side will keep it from splintering. A rounded diamond file (not that much $ from MicroMark) will then clean up the hole nicely.
I will look for some heavy duty X-acto blades. I have a life time supply of #10's, so I've been using new, sharp ones today, without much success. Drilling holes seems to work, I was hoping for something a little cleaner and less "cave man" than hammering this lovely ply with a hammer and chisel.


Thanks, Daren
Nov 10, 2017, 03:39 AM
Registered User
DGrant's Avatar
It sounds like it's just all about some "elbow grease" to get it cut. 1/16" really isn't hard to cut, It sounds like what's making it challenging is the circle/lightening holes... and that curvature... which does add some difficulty I'm sure.

The plane isn't that big, which tells me the holes aren't either, so you've got some fairly tight curves. A thinner blade, like a #11 X-Acto would be easier to cut the curves, whereas a fatter blade makes it tough. Any blade that's rounded though won't work for this... so if your blade is rounded therein might lie your problem. I would get a whole box of brand new #11 blades, and carefully start with light pressure, as the #11 blade tips are easy to break.. know that you will break a few... but they're sharp, and with minimal pressure will cut.. albeit it will take several passes through ... but yeah.. I think it's doable about like that.

Patience is key though.. know it won't get cut in one swipe with any knife blade. If it takes 10 or 20 swipes to get a clean cut... guess what?... you've got a clean cut. Good luck.

PS... I did just read you're using #10's... those blades aren't meant for the type of cuts you're making... go with the #11's.. and a gentle touch on the tip... I think the blades you're using are a big part of your problem.
Nov 10, 2017, 03:39 AM
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Norm Furutani's Avatar
I would let the manfacturer know, and hopefully they would replace the poorly cut parts.
Norm
Nov 10, 2017, 07:29 AM
Registered User
Quote:
Originally Posted by Norm Furutani
I would let the manfacturer know, and hopefully they would replace the poorly cut parts.
Norm
I agree. I would be very dissatisfied with what you are describing from any laser cutter. The point of a cut kit is to not have to cut all the parts by hand, which you are kind of doing. I would be expecting replacement parts.
Nov 10, 2017, 11:48 AM
Registered User
Daren71's Avatar
Quote:
Originally Posted by DGrant
It sounds like it's just all about some "elbow grease" to get it cut. 1/16" really isn't hard to cut, It sounds like what's making it challenging is the circle/lightening holes... and that curvature... which does add some difficulty I'm sure.

The plane isn't that big, which tells me the holes aren't either, so you've got some fairly tight curves. A thinner blade, like a #11 X-Acto would be easier to cut the curves, whereas a fatter blade makes it tough. Any blade that's rounded though won't work for this... so if your blade is rounded therein might lie your problem. I would get a whole box of brand new #11 blades, and carefully start with light pressure, as the #11 blade tips are easy to break.. know that you will break a few... but they're sharp, and with minimal pressure will cut.. albeit it will take several passes through ... but yeah.. I think it's doable about like that.

Patience is key though.. know it won't get cut in one swipe with any knife blade. If it takes 10 or 20 swipes to get a clean cut... guess what?... you've got a clean cut. Good luck.

PS... I did just read you're using #10's... those blades aren't meant for the type of cuts you're making... go with the #11's.. and a gentle touch on the tip... I think the blades you're using are a big part of your problem.

They are #11 blades, I went and checked. It was the whiskey talking last night. Multiple cuts seem to be doing it. The small inside round cuts are tough, I'm trying not to be an emergency room visitor.
Nov 10, 2017, 11:51 AM
Registered User
Daren71's Avatar
Quote:
Originally Posted by Yoda466
I agree. I would be very dissatisfied with what you are describing from any laser cutter. The point of a cut kit is to not have to cut all the parts by hand, which you are kind of doing. I would be expecting replacement parts.

I'm not too worried about it. Winter just started here last night. I've got some time before outdoor flying is going to be happening. On the other hand, we have indoor flying tonight. Yaaaaa

Thanks, Daren
Nov 10, 2017, 12:17 PM
Registered User
DGrant's Avatar
Quote:
Originally Posted by Daren71
They are #11 blades, I went and checked. It was the whiskey talking last night. Multiple cuts seem to be doing it. The small inside round cuts are tough, I'm trying not to be an emergency room visitor.
I like whiskey... totally understandable, it's my favorite adult beverage!

Yes... multiple passes with the blade will do it. By the time you approached the kit-cutter(or whomever lasered it)... you could probably have everything cut out and done 5 times over. I got a good look at that plane... and it does resemble the GLH plane of years gone by... and they were fast. If I had to guess it wasn't done by a main-stream manufacturer.

Here's a tip that might, or might not be of use... knowing that you're using a #11 blade.. and those tight curves are tough to cut without breaking a blade tip... and it's the tip of that blade that contacts the wood... so the best thing you can do is keep it sharp sharp...

I've had a sharpening stone on my bench for years, and I've used it hundreds of times for these very same blades... a few swipes of the blade on the stone every few passes makes a big diff. When a blade is fresh, you don't have to sharpen it for a while.. but once the blade starts wearing, you can extend it's life dramatically by just a few swipes on each side of the tip on the stone every few cuts/passes...and for this small wood it seems to help cut it.... as it's only that very tip that contacts the wood, especially when cutting small curvatures.

I've worn out my stone very little in the 20yrs it's been on my bench...but I've probably saved alot of blades. I have a few handles ready with blades... a rough cut handle... and a fine cut handle(usually has a new fresh blade).. I just switch them around a bit.. as it's easy to tell which blades I've beat up, and which one is fresh.. just something I do.. saves a little time, but seems to make the job easier as well.

Even if you bust the very tip, take it to the stone and sharpen what's left, and it will continue to cut decently for what you're working with...but that's up to you.. blades aren't exactly cheap these days.. I'm not cheap... but if I can get a little life out of a blade, why not.

This is how I roll... and just a suggestion... of course there's nothing like a new blade... but I try to use a blade as long as possible... and really the finish edge comes from a quick touch (sometimes a slow touch too) with sand-paper or block anyway... not from the knife blade... at least in my shop.
Nov 10, 2017, 03:34 PM
Registered User
Daren71's Avatar
Quote:
Originally Posted by DGrant
I like whiskey... totally understandable, it's my favorite adult beverage!

Yes... multiple passes with the blade will do it. By the time you approached the kit-cutter(or whomever lasered it)... you could probably have everything cut out and done 5 times over. I got a good look at that plane... and it does resemble the GLH plane of years gone by... and they were fast. If I had to guess it wasn't done by a main-stream manufacturer.

Here's a tip that might, or might not be of use... knowing that you're using a #11 blade.. and those tight curves are tough to cut without breaking a blade tip... and it's the tip of that blade that contacts the wood... so the best thing you can do is keep it sharp sharp...

I've had a sharpening stone on my bench for years, and I've used it hundreds of times for these very same blades... a few swipes of the blade on the stone every few passes makes a big diff. When a blade is fresh, you don't have to sharpen it for a while.. but once the blade starts wearing, you can extend it's life dramatically by just a few swipes on each side of the tip on the stone every few cuts/passes...and for this small wood it seems to help cut it.... as it's only that very tip that contacts the wood, especially when cutting small curvatures.

I've worn out my stone very little in the 20yrs it's been on my bench...but I've probably saved alot of blades. I have a few handles ready with blades... a rough cut handle... and a fine cut handle(usually has a new fresh blade).. I just switch them around a bit.. as it's easy to tell which blades I've beat up, and which one is fresh.. just something I do.. saves a little time, but seems to make the job easier as well.

Even if you bust the very tip, take it to the stone and sharpen what's left, and it will continue to cut decently for what you're working with...but that's up to you.. blades aren't exactly cheap these days.. I'm not cheap... but if I can get a little life out of a blade, why not.

This is how I roll... and just a suggestion... of course there's nothing like a new blade... but I try to use a blade as long as possible... and really the finish edge comes from a quick touch (sometimes a slow touch too) with sand-paper or block anyway... not from the knife blade... at least in my shop.
So after a bit of experimenting, I think I've found out what works. Doing multiple cuts on the straights, and pushing the tip thru in the corners. Flip the piece over, and connect the dots in the corners. So far 3 pieces have come out pretty clean. Lots of work, but at least its working.
The guy that designed the plane is from Ottawa. I bought the same kit years ago when it came out. The airplane didn't make it past the maiden. I really liked the looks, so I repaired the broken one to non-flying status. I was also a much greener RC flier those days. I wanted an easy build for the winter, and I have most of the electrics, so it won't break the bank.

Thanks for all the suggestions. Daren


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