Best bit for King Colorcor?

[JohnG]

Can anyone give me a bit recommendation for this material? My finished sign will be 2' x 8' with fairly large lettering.....The stroke is really wide, so I will be hogging out a bunch of material.

Any other cutting tips would be greatly appreciated. Someone told me it didn't look good to "V" carve......has anyone else given this a try? The sheet I purchased is 3/4", so I'm thinking of going 1/4" depth. Also heard its hard on bits?

Thanks in advance.

[chuckster]

I cut Colorcore with a 1/4" upcut bit. Colorcore is a soft material, I havent had any issues with it being hard on my bits. When carving letters I typically use a ball nose.

[bleeth]

For flat pocketing in color core you don't really need to go any deeper than the top face depth plus a little allowance for possible table flatness issues.
I have v-carved it. If the bit/feed/speed isn't pretty much just right you can get a lot of fuzzies to clean up.
Couple of guys here have done quite a bit of it. Perhaps they'll chime in.

[JohnG]

Here is a sample layouts I've been working on. The stroke on Historical is approximately 2.5" wide. Chuck, you would use a ballnose for something like this?
(sorry for the blocked out name. I typically don't post customer info)

[tappsman]

I have cut colorcore and love the way it cuts. I usually use a 1/4 inch straight bit or upcut. On a sign this large you'll probably want to make a rough cut with a larger bit to reduce the cut time. In my opinion you may have some issues with the fine detail on your sign.

Another thing to consider is that colorcore material warps greatly when it is cut and if not held down securely can screw up your cuts. The warping is also a consideration when mounting the sign.

[JohnG]

I have cut colorcore and love the way it cuts. I usually use a 1/4 inch straight bit or upcut. On a sign this large you'll probably want to make a rough cut with a larger bit to reduce the cut time. In my opinion you may have some issues with the fine detail on your sign.

Another thing to consider is that colorcore material warps greatly when it is cut and if not held down securely can screw up your cuts. The warping is also a consideration when mounting the sign.

Thanks for the feedback Dennis....
I guess a couple ways to handle the fine detail, is to either beef it up a bit......or, whats your thoughts on using a "V" bit? I had someone tell me the colorcore doesn't look good v-carved. Any input on that?

Now for a bigger concern....
I do not have vacuum holddown. Are you telling me that clamping the edges will not be enough? I'm surprised the 3/4 material would warp that much??!!

Moving right along to the most troubling issue.....Warping after its installed!!
Are you talking actual warping (as in bowing and twisting), or are you referring more to the expansion and contraction of the material?

This is to be mounted 5ft above their entrance door. I'm beginning to think I made a bad material choice.

[Chuck Keysor]

John, since you don't have a vacuum hold-down, I would suggest that you look at one of the available pressure hold down feet that are available. I purchased one from Widget Works and have used it successfully for holding down 1/4 MDF sheets for V-Carving.

Any flexing or bowing up of your material will be detrimental to your results. So the pressure foot is highly recommended if you don't have a vacuum hold-down.

Good luck, Chuck!

[tappsman]

John
If you forward your email address I'll send a picture of a sample of v-carved colorcore, I don't know how to attach a pic in this reply. However, I don't think that v-carve is appropriate for your sign design. The surface layers of colorcore are approximately 1/16" thick and when you v-carve the detailed areas may not go through the outer layer.

As for warping, I don't know how badly 3/4" material will warp as I have only used 1/2". The largest sign I have made is 24" x 32" (the size of my Buddy) and on those signs I had the purchaser screw directly to the building with 3 screws both top and bottom.

What I have done for hold down is to use a lot of double back tape making sure that it is sticking well to the spoilboard.

[chuckster]

Good Idea! The pressure foot is a huge help as far as hold down if no vacuum is available. I would not use a ball nose for this kind of sign, I would do a 1/4" upcut to hog out the larger areas, then use a v bit for the inside edges.

[blackhawk]

John,

This past week I just cut a 3/4" thick colorcore sign that was 40" x 90". Believe me, that material is so heavy at that thickness, you won't have any trouble with hold down. I clamped the 4 corners and then put a screw at the top and bottom in the middle of the sheet. I have cut about 10 colorcore signs and have never seen them warp after cutting, just my experience. Colorcore will expand and contract with temperature. When you mount it, you just want to allow for this. I normally use oversize or slotted holes and do not fully tighten the colorcore to the wall, posts, etc.

I cut the large sign above with a 1/4" downspiral FEM bit from Centurion tools. The FEM style is meant to give you a smooth flat bottom and it does work. On the 3/4" material I cut .100" deep to get through the colored top layer. (.100" was the top layer thickness based on eyeballing with my calipers.). A downcut is no problem when only cutting .100" deep. I cut at 2.4 IPS and 16,000 rpm with my PC router.

Centurion makes a special V bit for colorcore. I bought one a couple of years ago and tried it. It cut the edges decent, but the tip broke on the first sign. Standard V bits leave a lot of fuzzies on the edges. CMT has a 60 degree laser point bit that does pretty well. But overall, I haven't found any V bits that give good results. Now, I only cut with spiral endmills. I have used 1/2", 3/8", 1/4", and 1/8" spiral downcut endmills with good success.

If you are cutting out the profile of the sign and cutting through the full 3/4" thickness, you definitely want to use an upspiral endmill. If not, the chips will pack in there so tight, it will bog down your router.

I love colorcore and it cuts like butter for me. I just wish it cost about 25% less than it does.

Brad

[kurt_rose]

Hey Brad. Can you tell tell me how thick the outer skin is on CC. Just trying to wrap my head around V-carving the stuff and if the thickness of the skin would affect the look of the font.

[bleeth]

The "Estate" in this sample I did a while ago was v carved. The rest was cut on vector with an endmill (I don't remember which one I used but I think it was either an up or a down cut) Both were some pretty well used bits and there were lots of fuzzies (some still there) to clean up. Feeds and speed are also lost in the depths of my memory (also somewhat fuzzy at this point) but I know it was before I knew what I do now.

http://www.shopbotblog.com/wp-content/gallery/2013-florida-camp-shopbot/daves-color-core-sign.jpg

[JohnG]

Hey Brad. Can you tell tell me how thick the outer skin is on CC. Just trying to wrap my head around V-carving the stuff and if the thickness of the skin would affect the look of the font.

Someone said .100 thick. I'm not at the shop right now to check......but assuming that is correct..... (from memory, I'd say it wasn't any thicker than that).

What if you were to V-carve (the smaller lettering in my example), then do an inside profile pass, going .015 deep, with a 1/8 bit? It looked pretty decent in the software preview anyways.

[JohnG]

The "Estate" in this sample I did a while ago was v carved. The rest was cut on vector with an endmill (I don't remember which one I used but I think it was either an up or a down cut) Both were some pretty well used bits and there were lots of fuzzies (some still there) to clean up. Feeds and speed are also lost in the depths of my memory (also somewhat fuzzy at this point) but I know it was before I knew what I do now.



Dave, please don't take offense, but..... I hope you threw those bits away!!??

I just ordered 4- 2flute spiral upcut bits (flat bottom)..... 1/8 - 1/4 - 1/2 - 3/4

[bleeth]

None taken-long gone!!

[blackhawk]

Kurt - I measured the 3/4" colorcore to be about .100" thick on the top layer. I would gues that the 1/4" and 1/2" thicknesses have a thinner top layer. I would just call King Colorcore and ask them.

I think just a pure v-carve strategy would not look good in Colorcore. If you are set on v-carving at all, I would do v-carve with a flat bottom.