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I would welcome any recommendation for self adhesive tape or sheeting to retain, as far as possible, the integrity of the outline being "V" cut. In order to spray colour into the (masked) cavity.
Have tried various green and white masking 'tapes as usually advised, but the result is very poor. Also used s/a heat shrink (useless).
If you have the secret and would share. I would be most grateful.
What exactly you are trying to do? Its not done this way. Is it wood?
I have tried all possibilities and here is my advice if wood, as possibly all other scenarios lead to a fault or mediocre quality:
1.V carve
2.Sand a bit the edges and clean the V channel perfectly
3.Find the best quality and fastest dry impregnation lacquer for outside wood. Best works water based urethane.
4.Paint more or less, paint back if needed, paint sides if needed. Dont care for inside of channel
5 Let dry recommended time
6. Use only 2 component Urethane paint. MIx and paint the channels without caring if you make all thing dirty.
7.Let it dry for a couple of hours
8. Sand directly with 100 and up sander. If you have a good sander thats it. If not sand up to 240.
9. Arm yourself with a sponge and apply finish with careful brushing movements so as the paint or lacquer not to go in the channel
For metal:
use only 2 component base and paint. Sand face down on flat plate, do not use polisher. Or if using polisher, do that after the base , then spray color and then fast clea with acetone very carefully the polished part that need to be seen.
Here is an illustration of the process. In fact exactly what i am doing today:
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Boyan - Thanks for information. I have to paint the whole surface first. Then cut through with the v cutter. Then spray contrasting colour onto engraving. Then remove tape/film. I also use water based emulsions and cover with urethane after removing all remaining film.Quote:
Originally Posted by Boyan Silyavski
Regards
Rod
No, what i am suggesting is more precise. There is no need for tape. Paint will go under the tape and into the wood! hence better is to impregnate wood and then paint channel. Then sand excess. I have that constant conversation with a printer guy friend of mine when he tries to teach me that i have to use tape and me that is better without tape.Quote:
Originally Posted by Leadhead
Plus there's that detail that you have to sand inside channel or clean with flat screwdriver before coloring and priming. The tape will not permit that or will roughen and then coor will go where is not needed in wood.
I have tried all and what i say works 100% perfectly. I don't have more time for experiments... It works also just V cut clean and paint, but then sanding is more time and trickier if you have 1mm grooves like that on picture below. In fact on that images you will see that i used different method for each plate. result was same just i lost 2 1mm lines and had to do them by hand later.
And use bicomponent paint otherwise you could be testing the destiny. Once only i used bad paint on 30 signs and had to repaint them 4 times.
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Boyan - Yes but your Z0 surface is plain. I have to paint my whole Z0 surface first and then cut in. I could then hand paint in the v cavity. But I generally like to airbrush.
Would it be possible to deliberately carve slightly too deep (say 0.2mm for talking sake), paint the cuts, then mill the 0.2mm off the whole surface with a clearing bit?
Yes but, this assumes that you require a natural colour surface. As my conversation with Boyan above. I need a painted surface, which is another ballgame. Currently my method is to paint or spray my base surface (Z,0 surface) then use industrial strength iron-on film over that. A good initial surface is required and a well dried polymer based paint is imperative for good film adhesion. I cut through for my lowest contour first. Iron back the edges to ensure a seal against the painted edge. Then paint or airbrush in the cut. If going for three or more colours, then I repeat the iron on film process as required. (Find a small triangular model film covering iron is very useful.)
I have tried cutting the surface back, as you suggest, and rubber rollering the topcoat. Results where not good.
You could use laminations.
Layer1 would be your top colour
Layer2 would be your cut layer, revealed by the cutting tool.
Layer3 would be the unseen backing layer.
Pieces of different colour could be positioned in layer2 so that many colours would be revealed after cutting.
Of course that would take planning but the machine could cut those out to fit like a mosaic.
Some type of plastic would be ideal for Layer2 or possibly thin wood that had been fully saturated right through with colour.
Problem with solid wood or MDF is that the edge of that laminate has to be painted. Also it would seem to assume that the colour differentiation was on a common x,y (lamination) level. 3D colour changes would be inefficient at best I think. Unless you have a way please?
This is about paint!
You need to paint the top surface with a paint which is resistant to the solvent in the paint for the fill.
If you cannot do this then the solution (no pun intended) is not what you would like it to be.
The polymer base paint I currently use is achieving this. The pita is keeping the film attached to the edges after the shearing action of the cutters. I have it sussed it 95% with the iron on film but my original search request was for a better film to give 100% adhesion and still be removable. I do have that workable compromise currently and with due diligence it is giving me a result. Simply seeking either a better film or method.
Only just come across this could a change of cutter help have you tried a down cut?Quote:
Originally Posted by Leadhead
Phill
This application is for a "V" cutting bit. Not sure if there is a downcutting option. I normally use downcutters for pocketing.
Only option seems to be what was already mentioned- incompatible paints.
What if you paint top layer with automotive/car type solvent based paints, then engrave, then paint recesses with water based paint that can wipe off the top layer? Might even be able to laquor top layer, possibly even with a silicone product that is totally hydrophobic.
Currently doing just that, with water based acrylics for the infills.
For the infills as you call them I think you should use a thick paint because as Boyan said earlier, it will soak sideways into the top grain if thin.
Also I'm wondering about the stuff they 'wrap' cars etc. in ?
The only way i know of, as i said above, is using flat reinforced sponge to do that. As per this sign making video:
https://www.youtube.com/watch?v=ARx1fPoYcvo
I saw this video and stole a really great tip...
If you use vinyl sheet as a mask, it probably won't fray at the edges as badly as masking tape, but even so, you'll still get paint bleeding through from the edge of the lettering onto the uncarved areas. The tip in this video is to paint the letters with background colour first, let it dry, them paint carved areas. The idea is that the bleed colour would be same as background anyway. So...
With gold text carved on black background, for example...
1- paint uncarved wood black
2- apply vinyl film
3- carve out letters
4- paint letters black and allow to dry (seals bleed points)
5- paint letters gold and allow to dry.
6- remove vinyl film.
(I've never done this before- just putting the idea out there)
Here's the video I stole the bleed tip from..
https://youtu.be/NgMoYRDtrUo
Boyan's link is excellent but the results the guy in the video achieved don't look 100%
I don't do brushes and foam, just good masking and spray guns, but I'm from an automotive paint background and I'm really picky about colour and surface finish, I can spot a poor job on a car at 100 yards in bad street lighting on a rainy night :D
There is no automation doing stuff like that. One must be an Artist.
Its impossible to mask anything 3d properly with tape, vinyl or similar.
For perfect result first of all the wood should be chosen to be perfect for the job. IMHO that would be Cedar or similar structure wood.
But if a perfection is desired when painting, then even secondary machining like surfacing after paint is not a bad idea. For example: egrave deeper setting Z0 say 0.5mm deeper, base coat inside, paint inside, trim all 0.5mm, then using flat tool paint rest, right away carefully clean excess paint that went inside across the border. Use flat painting tools, fixtures.
Same like auto body work. You don't flatten a door using 10cm sanding pad, you flatten it using 50cm sanding pad.