How to paint V carve clean

[nick]

Hi Guys,

Here's my story...using HDU 3/4".

Did 2 coats of primer, light sand and 2 coats of base paint sanded after each coat.

I applied conform tape...medium tack. pressed firmly to the substrate.

Used a 1.25" 90 deg V bit with letters 2.5" high.

Dust collector off.

The points around the letters with sharp corners started to peal up and off the HDU.

What is the trick to V carving with tape on the material?

PS...RPM 15000, speed 1"/sec.

Any help / tricks would be greatly appreciated.

Thanks in advance.

[joe]

Nick,

The problems with masking has been posted on many times. And will continue to be discussed since there hasn't been a prefect resolve.

The general rule is, the smoother surfaces allow mask to stick better. However if the mask is too tacky it will pull up some of the paint. What a heart break. Since I make signs on rough surfaces, like cedar, I've come up with different solution

We've called it "Dr. Crumley's Rootin- Tootin Snake Oil Mask".


5662

Once the paint has dried, pour on a nice coat of rubber cement.No it won't hurt the paint. Give it 30 minutes to set up. Then apply a sheet of Transfer Tape and burnish it down with a stiff brush. Route away and paint.

When the transfer tape is removed it will take the rubber cemnet with it.

Joe
5663

Good luck with the project. Please do a test or two before you attempt your final project.

Joe

[nick]

Hi Joe...WOW...that sure worked out well. Is this practice still used by you or have you changed to a paint mask A1828 by Avery which I've heard good things about.

Do you use oil or latex for the lettering.

I think most of my problem is because I used latex interior / exterior bought from Lowes...

Your thoughts?

[nick]

Hi Joe...WOW...that sure worked out well. Is this practice still used by you or have you changed to a paint mask A1828 by Avery which I've heard good things about.

Do you use oil or latex for the lettering.

I think most of my problem is because I used latex interior / exterior bought from Lowes...

Your thoughts?

[ernie_balch]

As others have said a smooth painted surface is necessary for good paint mask adhesion. We use One Shot with hardener. We also like using 2 part urethane paints. Although you can get different grades of tackiness in paint mask none will stick to a grainy, dirty or textured surface.

Joe's rubber cement Idea sounds good, but I never tried it.

ernie

[tuck]

There is a product called "Grip Mask" that comes in liquid form. You can brush, roll or spray it on. It dries semi-clear and peels off easily enough once you're done cutting and painting your copy. It's water soluble to boot. My problem is, I can't remember who makes it or who carries it. Attempts with Google have led to frustration. Anybody know?

[xbinbc]

Spraylat corp. Look under stripable coatings under signs. I recently used joes rubber cement idea and it worked fantastic on cedar. I first coated out the cedar with a clear flecto finish , applyie rubber cement and then applied mactac paint mask vinyl. I was shocked at how well this worked. Zero bleeding. Spraylat would work well.

[joe]

Thanks Nick,

Latex is fine. That's what we use since we can get a flat, medium gloss, or high gloss and it lasts without fadeing. I've about given up on any enamels.

The computer masking products I know of are vinyl. When your bit is cutting, it's trying to lift the mask off it's surface. So it's a deliclate process. The amount of tac verses smoothness of surface. Dicey stuff. Too much tac and up comes the paint. Not enough a we have edge bleeding. There is another technique that also works well.
Lay down the mask over your painted area and carve away. Then spray a little shellac in the fresh wood area. This will reduce paint absorbtion. Now brush the letters with the same color as the background. This seals off any gaps. Any bleeding won't show. Last comes your letter color.

The only fly in the ointment comes when you lift the mask. If you painted too thick a coat for an under layment, you can get a a rough edge. Not very bad though.

Perhaps you'd give my "Dr. Crumley's Rootin-Tootin" method a try. It's down right fun too.

What Mark's refering to is "Grip Mask" is made by Spraylat. It's been around for years and shows promise for masking. I have a fresh, unopened can. I believe it cost about $25.00

Ernie, you might give this a go. I purchase Rubber Cement at lowe's for about $7.00 a pint. A pint will do several signs. After all you need to apply it in the letter area's

Please let us know how you do.

I took the photo's yesterday since we are having great weather. I'd completely forgotten about that projcect. It went up five years and two months ago. On the way to a little saw mill 20 miles south, it popped up in front of me and I took the opportunty to give her an inspection. All looked well. Very little color fade and the gold is standing well.

This kind of work, on rough cedar, can't be masked with viny. Too textured.

Joe

[nick]

Joe,

How do you think these methods work on high density urethane?

About grip mask...does it completely fill the routed area and level off at the top plane where the flat surface is...don't quite understand how it works.

Thanks

[andyb]

Mark,
I think this is your answer to the Grip Mask question and their in our backyard.

Akzo Nobel Coatings Inc.
5555 Spalding Drive
Norcross, GA 30092
USA 1-800-618-1010

MSDS with contact info - http://www.signfinishes.com/store/65404/MSDS%20English/MSDS%20-%20386310%20Grip-Mask%20Trans%20GL%20Eng.pdf

Andy B.

[tuck]

Thanks Andy! "SPRAYLAT!" I couldn't remember that for the life of me! (gettin' old!) I use to use that stuff on occasion when I worked for others. It's a very effective masking agent. It's water based and water soluble, so after you're done v-grooving you would want to use an oil based enamel paint like One Shot to paint your lettering and not a water based latex, lest you compromise your mask. Let that dry, then peel up the Grip Mask and your done. If you have a problem peeling it all off, just take a water hose to it! I remember doing just that, .....years ago.

[joe]

Nick,

Yes, either of these techniques will work just fine on HDU.

Routed, V carved letters, will need to be primed. A spray can of Kils will do the job. Don't worry about the Spraylat being softened by water. It won't go back into solution. Any little pieces left behind can be picked up with masking tape.

[tuck]

Are you sure it won't go back into solution, Joe? I seem to remember it would, but it was at least 10 years ago since I've used it and my memory ain't what it use to be. At any rate, great stuff and a one-step process, I remember THAT much! I'm gonna order myself a gallon tomorrow...

[joe]

Mark,

When using Spraylat it's best to get it on thick. More failures occur when it's very thin and attaches itself to the surface. I try to get a thickness of a business card. That way when you pick up a corner it won't tear apart. It will come off much easier.

My best results are with spraying it on. That way it's very smooth and even. Apply light coats. Use a fan to dry between spraying. Five or six coats is normal. It you get it on too thick, in one application, it takes for ever to dry.

I bet we're the only group in the world shareing this kind of info.

Joe

[tuck]

Joe,

Haha, I'll bet we are too!

I have a furnace fan that a friend gave me some years ago. It puts out an enormous amount of air but isn't very big, nothing like a shop fan. I built a stand for it, mounted the fan to the stand and put casters on the stand base so's I can roll it around my small shop and get it out of the way when I don't need it. The purpose of the stand was to get the fan high enough and at the right angle to point at my work/paint table. I use it when I'm spraying coats of latex enamel for a base coat on larger signs. Between coats, I plug that sucker in and BOOOOM,...dry paint, ready for the next coat. It don't take long. With water-based paints and agents, it's all about air circulation (+ temperature & humidity), as far as drying times. The fan seems to have little effect on oil based stuff. Anywhooo, I'm sure it will work great on Spraylat Grip Mask, even with thick coats. I'm fixin' to find out in a week or two!

[jamesgilliam]

Joe and Everyone, I have tried the rubber cement and transfer tape mask and it is the best I have tried so far. Most times I usually still cut the text or design a little deeper and sand though. Joe, if you have a leather craft store near you they also carry rubber cement by the gallon, alot cheaper buying it that way.

[blackhawk]

What specific type of transfer tape do you use? I am just getting started and I am not familiar with transfer tape.

[jamesgilliam]

I am not sure of the brand I have, it was given to me by a friend, Joe would be the expert in this area.

[joe]

Transfer Tape:

The difference between masking tapes and transfer tape is the adhesive. The latter has a rubber cement adhesive. This will pick up the rubber from your panel like majic.

Woops, Now I'm gonna have to call it "Dr Crumley's Magic Rootin-Tootin Snake Oil Mask".

It's availabe at any sign supply. You could probably get some to try at an quickey sign shop. Some times called Application Tape.

Life is grand!

Joe

Joe

[mccoy178]

Guys, thanks for the info! I just put a shopbot in our high school and was wondering about some cheap solutions for the students. The rubber cement route sounds like the way to go! I appreciate you guys sharing inside information, as it really helps resolve issues.

[tuck]

That's what we're here for, Ben.

(p.s. , the grip mask solution I mentioned above in this thread is less trouble and expense over the long run, but don't tell Joe that, ok?)

[joe]

Mark,

The rubber cement method is must faster than Spraylat. Students could apply the rubber cement and route within the one class period.

Each method has it's strong points.

[tuck]

Joe, I kid, I kid....

Actually I think your method sounds great and I plan to try it. Just ordered a new batch of V bits today!

[gene]

I know that if Joe keeps adding to the name he is going to have to sell it in gallons only. I dont think all that will fit on a small bottle or jug.
Thanks for all the great info guys.. It sure makes the job alot easier when you can get this type of advise from people who actually know ( or sounds like)what there doing.. Great Forum

[tuck]

Oh yeah, one other thing to consider when V carving is the letter stroke. By "stroke" I mean the width of the "parts" of the letters, not the actual width of the letters themselves. This leads to careful bit selection and other considerations. I'll try and explain as best I can:

Let's look at the letter "O" in times roman and say it's a 10" tall letter:
http://i50.photobucket.com/albums/f332/Superfan52/LetterO.jpg

See how the "stroke": of the letter goes from thick (wide) to thin (skinny)? When you V groove, your bit will traverse and cut through the center of the letter stroke in order to "V" groove it. In this case, the widest part of the stroke with a 10 inch tall letter is about 1.5". Your bot will plunge deeper to cover the widest stroke of the letter and raise up to cut the thin parts of the stroke. (It's NEAT to watch!) What this means is, at least to my experience, is that you have to select a bit that will cover the widest part of the letter stroke in ONE pass to begin with. In this case I would select my 1.5" diameter 120 degree V bit which won't give me as sharp of a "V" cut as I might like but will "get 'er done". If I selected my 3/4" 90 degree bit I would have to use multiple passes. That process takes forever and never turns out right. If I can't do it with a single pass, I don't want to do it at all.

But here's the REAL trick: The wider the stroke of the letter, the deeper your bit is going to have to plunge to cut that width. If I V cut that letter "O" with my 120 degree bit but it had to plunge say, 3/4" to cut the wide parts of the stroke and my material is only 1/2" thick, well guess what? I just cut all the way through my material and 1/4" into my spillboard, something I didn't want to do! Material ruined! I get customers on occasion that already have a design for a larger sign with letters that may have a 4" stroke and they say, "We'd like it V cut, please.", to which I say, "You're out of your cotton pickin' mind!" V carving is for smaller signs and plaques in my experience. Others may beg to differ and they are welcome to. I'm just telling you guys what I've learned about V carving. Joe has posted a pic of some large V carved letters in this thread. I could be wrong and often am.

Back more on topic, I am thankful for this thread like I can't tell ya. I had all but given up on V grooving signs because I couldn't come up with a satisfactory mask. I tried the vinyl mask and it bled through when I painted it and never stuck to my satisfaction. I couldn't remember "Spraylat" for Grip Mask to save my life and I'd never heard of Joe's method with the rubber cement and transfer tape.

This is indeed a GREAT FORUM!

[cnc_works]

Mark, you may already know this, but for the sake of others, there is a solution to the "too deep" problem that will work in many situations. Most software packages capable of v-carving will let you limit the maximum depth and spiral cut a flat bottom wherever that depth is reached. You can set the stepover to whatever smoothness is desirable. May not be suitable in the design of all pieces, but I've used the technique successfully many times.

Donn

[tuck]

Thanks Donn, and yes, I already know that. SignLab 5 does it: "Warning, Will Rogers! Warning! Set path is too deep for material thickness! Selected bit too small to cover stroke! Warning! Warning!" lol. Plain and simple, you can't V groove letters with 4 or 5 inch wide strokes in 1/2" or even 3/4" material and it look right and not take a week to cut. Ain't gonna happen. There are limits to everything and this is a good example concerning CNC and practical V grooving. When I say "practical", I'm talking about speed of process and a product that looks like it's supposed to.

Customer: "What's them flat areas doing in the bottom of them letters? You told me this sign was gonna be V grooved!"

Me: "Well, see, you wanted this 2x8 sign routed out of 1/2" PVC for your lobby that says "Sales". I did the best I could considering the material thickness."

Customer: "I'm not happy."

There are many others in here that are more clever than I but I do understand simple mathematics..."If'n it don't fit, don't force it."

[ernie_balch]

Wide Vcut letters in thin material is possible. You can change to a 130 or even 150 degree cutter for wide V-cuts. Make sure your material is flat because you will be doing shallow cuts.

To speed things up just buy a 3" diameter cutter this will limit the number of step over passes.

ernie