Coloring Intricate designs

[Harry Radaza]

In the past I have not included colors in my line of services but lately have been approached to do laser engravings with colors on them.

The volume of the orders involved if I can accomodate them behooves me to explore coloring further.

The designs are normally of the flowery type. With leaves and other fine intricate designs. Some symmetrical. Others of the Victorian type. I will post pictures as soon as I get a chance.

Materials involved are shell, wood, MDF, acrylic.

We experimented with putting regular masking tape over the material. Engraved it and then applied color using an airbrush. This method turned out ok, however, there were always bleeding under the masking tape. If we let the paint dry too much, the masking tape would sometimes pull of parts of the paint. If we let it dry too early, the bleeding would get worse.

We tried using the wipe off method (acrylic and shell are shiny). This was not consistent especially with shell since the depth would not be consistent throughout and thus giving us unacceptable results.

My sample Transfer Tape (i heard much about this) will come in tomorow so I can play around with it. If this works out, I guess I will be fine.

Does anyone have any other ideas on how to do this ? What the process is or how to be able to paint color onto the substrate on the engraved areas only. The designs can sometimes be as small as 3mm - 5mm.

[Mike Null]

Harry

I've always had to seal the wood after engraving with some sort of clear coat (lacquer, acrylic) or the open grain invites the capillary action that will stain and ruin the engraving.

[Harry Radaza]

agreed. the only problem is with the wood pendants and beads that we are working on, the clients want it to be a natural finish. Sealing it with laquer would give it a shiny / glossy finish which goes against their natural effect that they want.

And if so, that would only solve the wood problem. With shells, I'm still stuck with bleeding and smears.

Any other ideas anyone ?

[Mike Null]

Harry

I didn't make myself clear. When you engrave through the transfer paper then spray the engraved area. The transfer paper will mask the rest and it will have a natural finish.

I hope you have a fairly aggressive transfer paper.

Can't help on the shells.

[Harry Radaza]

transfer paper.... you mean transfer tape (like the ones used by vynil sticker shops?) right?

By aggressive... you mean tacky ?

[Doug Griffith]

Has anyone tried liquid frisket instead of masking tape/paper. I used to use it when airbrushing. It's brushed on as a liquid and dries as a thin rubbery surface film that can then be peeled up after painting. It solves bleeding issues but there will still be problems if peeled too early.

[Mike Null]

Harry

Yes and yes.

[Harry Radaza]

Doug . Liquid frisket sounds like something i want to try. Where can i get em? We use air brush too

[Doug Griffith]

I found it at art supply stores. Haven't used it in a few years but am sure it still exists. Google is your friend. "masking fluid" is another name for it.

Cheers

[Mike Null]

Just another opinion. I doubt that liquid frisket will solve the capillary bleeding problem. The reason is that it must be removed and doing so removes the colorfill within the engraving. It will probably solve the surface bleed. It is primarily used by water colorists to mask areas of a painting.

[Doug Griffith]

I'm thinking:
1) apply liquid mask
2) dry
3) laser (possibly a solid fill pass to remove mask, another to etch substrate)
4) color fill
5) almost dry
6) peel away mask

It would definitely be an experiment.

[George D Gabert]

could you mask with. laser. clear coat laser area. color fill. and then remove mask.

clear sealer will seal pores and will not show. this should solve the problem of the color blead.

[Dee Gallo]

I do a lot of small carving and color filling. Here are samples about 7/8" wide x 1 1/4" long. The lines are usually hairline or slightly thicker, sometimes filled shapes with no line . Bone and ivory act a lot like wood, since they are porous and capillary action makes the paint run inside. This is not a fast process, but very effective for the restoration work I do. Picture #1 is original design acrylic, #2 is bone (my repro w/design change is on the right) and #3 is ivory (my repro is on the left).

The technique I developed through trial and error is to do the engraving using transfer tape to avoid burn or char on the surface. Wash the piece off with running water (dish soap if needed), tape still on, and a toothbrush but quickly to avoid too much water. The soot will stick to the tape and then the tape will come off. With bone I have to scrape out the charred bone, but you probably won't have to with your materials. Dry it on a towel.

While still "dampish", the water fills the pores a bit, coat the piece with clear nailpolish mixed 50/50 with nailpolish remover. This seals it with a very thin penetrating coat.

Paint as you wish and let dry. Scrape the dried extra paint off with a razor blade. Buff with micro sanding pads from 1500 through 4000 grit. I use a white diamond buffing wheel instead if I have a hundred to do, since it's faster and easier. This removes the extra paint bits, nailpolish and leaves a nice surface.

Painting plastic is a lot easier but the painting process is different. I have a comprehensive tutorial if you want it, it's kind of long winded. PM me and I will email it to you.

HTH, dee

[Larry Bratton]

I'll post this again at the risk of being redundant.

I get a product from Piedmont Plastics Corp. called P-flex. It is a very thin (2mm) I think, polyester film. It has adhesive on the back and is clear in color. They will cut it into sheets for you. I buy it to fit my laser table size, 24x36. It is about $2.50 a sheet. It makes a great mask for anything you want to use it for. I sell a ID plate for apartment unit doors. I make them from 1/4" mdf core melamine. I have a template made on my cnc router that takes 24 ea. 6"x4" plates. I cover the whole thing with P-flex and engrave the numbers etc. Then when finished, I remove the template and paint fill the engraving. When dry, I pull off the remaining P-flex mask and I have 24 finished plates. It also makes a good mask to keep residue off wood. I engraved some raw basswood plaques the other day and masked them with it and it worked perfectly. http://www.piedmontplastics.com/
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[Dee Gallo]

BTW- liquid frisket is probably not a great idea - it is not normally clear and if any goes into the grain, you will see it like old car wax. It's rubber and sticky, so dirt will stick to it. To remove it, you would have to use something strong like rubber cement remover which will discolor and dry out your wood.

One more thing about airbrushing: if you are doing it correctly, the paint should dry exactly as it touches the piece, so there should be no seepage unless your mask is loose. Work on your techniques for amount of paint applied in relation to the distance your airbrush is from the piece. Several light coats are better than soaking to cover.

just my 2 cents on that subject, dee

[Mike Null]

Dee

Very impressive work.

What kind of paint are you talking about that dries as soon as it hits the surface? (air brush)

[Dee Gallo]

Airbrush paint should be "touchable" as soon as it hits any substrate, although it might take a little while to harden or cure. "Dry" is a relative term, but the main thing is that the paint is not running under the mask or so wet that it saturates the mask. If you are getting "caterpillars", you're using too much paint for the distance from the surface. Spray dry!

That said, I've used acrylic, enamel, lacquer, watercolors, textile, nail and specially formulated airbrush paints both water and solvent based. They all do the same thing, although lacquer dries hard faster than any others on non-porous surfaces. I've done custom metal fishing lures that are wicked cool with flourescent lacquers. Even if the paint is delicate for a little while (scratchable) it should NEVER run under your mask if you are spraying correctly. In fact, there is a technique called sgrafitto which is used to scratch texture into airbrush paint since it's usually too smooth for realistic surfaces like skin.

cheers, dee

[Harry Radaza]

Doug,

I ruled out liquid mask as of the moment since I am in the Philippines and importing it would not be practical. Unless I find a local substitute for it.

Well my transfer paper came. And I think it went.... first 2 passes on transfer paper on wood and the transfer paper seems to have melted on the edges where there was engravings. Could have been the fire from the mdf with laser.

I also tried regular clear packing tape and this turned out better with out the melting in the edges. However, I am worried with the extra strong adhesive that it will leave traces on the substrate.

still trying transfer paper on shell too. And will experiment with it on wood.

Anyone have any suggestions regarding the use of transfer tape? I know it has been discussed extensively in other threads...

[Harry Radaza]

Dee,

Wow I am amazed at your work. Although your description sounds like it is a long process but I am interested in trying it, especially with the results you have posted.

My question with your process is this...

1) when you use running water to clean the material, doesn't the transfer tape come off?
2) At what stage exactly is the transfer tape pulled out? I would assume after painting the engraved area right?

I will also watch over my painter to see how he is using the airbrush... I do remember him painting very wet with the airbrush.

[Harry Radaza]

Ok I'm confused with the transer tape. I tried all kinds of settings and I still get the transfer tape melting along the edges.

Are you guys getting similar results ? Or could this be the type of transfer tape that I am using?

[Mike Null]

Harry

I've never seen transfer tape melt. It will burn away in the area you are engraving leaving a mask over the unengraved area. I suggest that you use a squeegee or a credit card to apply the transfer tape.

Dee

Our problem is with wood and in the engraved area where there is no sealer, capillary action draws the paint into the grain making for a sloppy color fill. The top surface is usually not much of a problem if it has been sealed.

That is why my question on instant drying paint.

[Harry Radaza]

Mike,

melting might not be the best term. Yes the engraved areas are burned away, but edges right where the engraving ends, some areas of the transfer tape is wrinkled up due to the heat.

[Scott Shepherd]

Harry, have you tried paint sticks yet? They work fairly well, but have limited colors.

[Dee Gallo]

Mike-

You'll notice I don't apply the sealer until after the tape is removed. This way it creates a solid seal from surface to cut areas. With wood, it's easy to buff-sand the sealer off. I believe Harry's original thing was to have non-finished surfaces.

If you wanted a finished surface, I would engrave, seal, paint/clean/buff, then seal again.

If you are airbrushing, spray a little sealer into the grooves and then paint, but leave the mask on throughout. This avoids overspray obviously. You must seal the cut areas, since the whole point of wood is the capillary action.. it's what keeps the wood alive!

I imagine if your wooden piece has engraved lines big enough, you could use a brush or ball-tip brush to apply sealer to the grooves only and then paint with no seepage. That would be easy and simple.

[Dee Gallo]

Dee,

Wow I am amazed at your work. Although your description sounds like it is a long process but I am interested in trying it, especially with the results you have posted.

My question with your process is this...

1) when you use running water to clean the material, doesn't the transfer tape come off?
2) At what stage exactly is the transfer tape pulled out? I would assume after painting the engraved area right?

I will also watch over my painter to see how he is using the airbrush... I do remember him painting very wet with the airbrush.

When you start to clean the piece under running water, there is soot that is oily and it smears all over the tape, not your project. Soap helps to remove it from the engraving. After the engraving is clear, the tape comes off by itself from the water and rubbing. I paint after the tape is removed.

You can also spray your sealer through the tape and then airbrush paint before removing the tape. Just make sure the edges of your mask are tight. If you intend to do this technique, I recommend a med. tack frisket film (not liquid) but it's a bear to get right on curved surfaces.

BTW- even though my description is long-winded, it actually only takes about 5-10 minutes start to finish to do the cleaning/sealing/painting/buffing for each tile I do. But this is after a long time working out the steps and long hours of practice to become efficient.

cheers, dee

[Harry Radaza]

Dee,

thanks. I finally understand your process... you paint after taking out the mask. and the blade scrapes off anything on the surface leaving the paint in the subsurface (engraved portion). and the buffing with 1k-4k grit will take out anything left off. This will work for flat surfaces. But for shells with a slight concave to it with some texture, it might not. Will have to consider sealing with the mask on the material, then painting, removing, buffing then sealing again.

Will go through your email tomorow as it is midnight already here. Will try to post pics of the stuff I am doing. WIll also be dealing with a lot of unfinished wood and finished wood.

[Dee Gallo]

Harry,

The bone tiles I work with have slightly concave surfaces. The microsanding pads I use are flat flexible sponges with the grit applied to the sponge, so they can go into curves. The buffing wheel has short linen/cotton threads which also go into the curve easily.

- dee

[Harry Radaza]

i still dont understand why my transer paper is melting in the edges. can any of you guys point me in the right direction as to where to get it (link) so I can compare the pics if it is same as mine?

mine is 12" and 1 roll is about 100 meters.

[Mike Null]

Harry

This is what I use.

http://www.beacongraphics.com/supplies/transferrite.html