Need masking advise

[Steve_mi]

I have a CNC router and am just getting into smaller signs. Machine only has a surface area of 16" Y by 24" X. Z is 4". Signs are for residential settings.

One of my biggest hurdles is mask to put over the surface so I can paint the routed segments. I use pocket milling to create the routed segments. I also use end mills and not v-cutters.

My normal 1/8" diameter mill is a Whiteside router bit with upcut. I know that upcut is probably my first mistake and will change that next week.

I use a 0.05" endmill quite extensively.

I have tried shelf liner, blue paint tape and a product called "Stickey Mickey" used by body shops for custom paint masking. I have heard that Avery makes something, but don't know a number or place to buy in southeast michigan.

My problem is that the edge is always ragged and in smaller parts it pulls away from the material being routed. With exception of the blue paint tape all of the stuff that I tried has a glue like layer that gets pulled by the router bit. Something more paper like the blue painter tape seems what I need.

Most of my work to date has been in hard maple, basswood, cabinet doors and corian. I attached a cabinet door and corian project pictures. For the corian, I ended up just painting after the fact then sanding the surface spray off. Cabinet door used shelf liner for the ford emblem, but the lettering at the bottom had to be hand painted due to pulling up of the shelf liner.

I want to start using MDO, but want to resolve the mask issue at the same time.

Steve.

 

[sinetist]

Have a look at this thread on a cnc forum.

http://www.talkshopbot.com/forum/messages/315/31314.html?1213286013

 

[Techman]

nice work..
I do not know much about masking for routers so I do not have a real good answer.
however,,,
How far are you from Grand Rapids?
I represent your area on this board..
If you would.. Please get me a PM with your contact info.
Thank you

 

[sinetist]

....and definitely get a downcut spiral bit. I don't have a CNC machine but I do route a few signs. A downcut bit will greatly reduce any chipping.

 

[steve b]

Maybe just forget the mask and just paint the whole sign first, and after that has completly dried, paint your routered areas as careful as you can.... just have some thinner around to clean up any mistakes. That works for me with my sandblasted signs.

Best Of Luck,
steveb

 

[Steve_mi]

Sinetist - I am going to try "Dr. Crumleys Snake Oil Mask" in next day or two. Lot of thanks for the tip. I've been to shopbot before during google searches and think that is where I saw the shelf liner tip. Sure wish I had a budget for a bot.

Steveb - Many of my signs are smaller (less than 12" square) and 18" to 36" from the person, so the edges of the letters are really visible. Not to mention that my painting skills leave something to be desired.

 

[J Hill Designs]

I would maybe try (just a suggestion, never actually tried it...) sandblast mask - maybe the fact that it is rubber will ease in cutting instead of tearing?

just my 2¢

 

[Jackpine]

Use high quality sharp bits like www.hartlauer-bits.com or www.onsrud.com. A spiral up is to remove the chips. I use Gerber vinyl mask. It takes the heat and is easily removable. Your feed rate may be a bit fast also.

 

[Steve_mi]

Use high quality sharp bits like www.hartlauer-bits.com or www.onsrud.com. A spiral up is to remove the chips. I use Gerber vinyl mask. It takes the heat and is easily removable. Your feed rate may be a bit fast also.

Jackpine - I am a Whiteside router bit guy. If anything my feed rate is probably slow as I usually have router burn on the wood when I cut through.

It almost seems like the materials I have been using as masks that I have tried are melting instead of being cut. The melting causes the mask to then stretch what is stuck to the material I am cutting. Does this make any sense?

sinetist - Just got back from the Woodcraft store with downcut Whiteside router bit (RD1600 / 09I17) and going to try it. We are 90+ degrees today and 100% humidity, so we'll have to see my ambition once I get in the garage.

All you guys in your air conditioned shops are my envy.:ROFLMAO:

Steve.

 

[Steve_mi]

"Dr. Crumleys Snake Oil Mask" Update

Found the elmers in a quart at Office Depot. I used some popsicle sticks to spread the glue. This is kind of an art and sure that I could get better over time.

First small trial with two different masks on different sections was good and bad. Shelf liner mask helped in some places and frayed significantly in others. The pinstriping mask seemed to be pulled by the router bit and then retracted behind the line I wanted to keep.

Reading about the method, it seemed the mask was only necessary to help with getting the glue off, so I decided to go naked on the next larger experiment. Let the glue dry overnight and then route.

I am using a router, 60 degree bit and dust collection (shop vac) behind the router bit. The vacumn pulled the elmers for about 3/8" around the bit. No value to the glue in masking for paint.

Running without the vac isn't very practical due to the debris that gets on the mechanisms, which then requires an hour of cleaning and regreasing.

So, can anyone recommend a commercial masking product?

I can lightly sand or wipe with denatured alcohol after removing the mask since I usually put on a clear coat of shellac or polyurethane afterward. Wouldn't want the mask to pull off any paint though.

Steve.

 

[GB2]

The tools you are using, the materials you are using, the suppliers you are using are all arts and crafts hobby grade. I doubt anything could be recommended to you here. You should search out information from areas that deal with similar equipment and procedures. See if you can find a forum for your routing machine or look for hobby type practices. Ask for their recommendation wherever you bought the stuff.

 

[Just Another Sign Guy]

many years ago i spent a huge amount of time trying to streamline production of the finishing of routed signs. ultimately what i decided was best for me and the products that were leaving my shop (with my name on them), was not to cut corners. there is no fast easy way for putting out high quality work.

route the sign. remove all dust. prime the entire sign. if overall design of the sign will allow spray entire sign the color of the deepest routed level. from this point paint the sign by the next highest routed level, continue.

what i am understanding from your posts is that you are wanting to paint sign blank prior to routing, then mask the sign, route the sign blank (which would leave you with the face of the sign masked, allowing you to spray the reliefed/routed area, and then remove the mask from the faces of the sign and be done.

the only materials i have had acceptable results with this method is acrylic and expanded pvc. but even with those there is still some touchup needed. and for masking i used plane old high quality transfer tape. what we used to use was transferite 6792 (heavy paper/heavy glue) but it is no longer available and i have never found a product that works as well.

in regards to using vinyl paint masks i have never achieved acceptable results for relief routed signs, however, i have regularly masked the face of many different materials, acrylic, dibond, aluminum, pvc, etc. and placed the sheet face down on the router table and routed out dimensional letters in reverse. allowing me to spray the sides of the letters another color then remove the vinyl off the face and be done with them. this also works well for laminate dimensional letters, for example brushed aluminum faces mounted to pvc, where you need the sides of the letter to be a custom painted color.