Spray masking techniques

[mjg]

So, I think I'm almost at the end of the priming, and getting ready to put some colour spray on.

The finish will have red on the edges, black on the top. Hoping for a nice clean line between the two.

What approach do people use for masking off areas while doing other colours? Do you mask when spraying the first colour? Or do you just spray the first colour, knowing that it will get covered with the 2nd colour?

I've been experimenting on a bit of scrap, and found that if I mask off and spray red, then remove the tape, mask off the other side and spray black, then I will get an obvious line where the edge of the red paint was. It leaves a raised ridge - I guess the red paint has raised up a bit where it can sit next to the tape while drying.

Should I have lightly sanded down the edge of the red to remove that ridge before spraying the black?

Or should I just not mask when spraying the red edges, let that dry, then mask off the bits I want to keep red and spray over with black.

Any opinions welcome.

The tape I have is professional painters tape, for use with spraying, varnish, lacquer, etc, with 10 day clean removal. It sounded convincing to me anyway.

[stan]

Skinning cats mate, many ways...
I think if you mask both ways you will still get an edge, and if you sand it you may end up with an imperfect meeting of paint lines.
Just me , I'd do the red first and then mask it for the darker stripes, gently sand any obvious ridges and clear over to blend it all in...

[mjg]

Thanks Stan. I'll try that out on my scrap and see how it goes.

Here's the plan for the colours (assuming minds aren't changed before then...)

[stan]

Very wise, plan on scrap. That will look great

[B'Lark]

When I did my MB-1 colours, I did my lightest colours as my base coats, and went darker as I got closer to the top (barring a couple of small spots that were for little details.

In terms of how I masked, I used 3mm Vinyl tape (3M brand if that matters, idk how many brands make the stuff) to do the edges, then used some form of painters masking tape to cover the areas around it, and if I had a massive space to cover, used some masking paper over the big parts so that the whole thing wasn't covered in tape.

There was a tiny bit of bleed on some of the tighter corners, but nothing that a bit of careful scraping couldn't deal with.

Masking:


Result:


Oh and with the edges: Yea also had a bit of an edge, but carefully sanded that down, not totally flush, but close enough that some clear coats would fill that out a bit

[mjg]

Thanks B'lark, awesome looking example.

If most of my build is black, with a small amount of red, could I do black all over, then cover with red? Or is the black underneath going to affect the red colour too much?

I was spraying some scrap pieces today to test, but didn't prime the scrap first. I can now see why primer is important...the red peeled straight off the scrap wood! (Was using some old kitchen laminated MDF for test scrap.)

More testing on scrap tomorrow planned, with primer first this time!

[Thigg88]

Red doesnt usually cover dark colours well in my experience. A grey or white is best for a bright strong final colour. I would spray the red first then mask it to spray the black. A easy way to minimise your tape bleed it after you mask spray a light coat of the masked colour(red in this case) around the tape edges. This kind of seals the tape with little bleeds of the same colour. Really works well to make your contrast colour line clean

[Simon Barden]

A easy way to minimise your tape bleed it after you mask spray a light coat of the masked colour(red in this case) around the tape edges. This kind of seals the tape with little bleeds of the same colour. Really works well to make your contrast colour line clean

Great tip there, Thigg!

[mjg]

Thanks Thigg, I just re-read your hint and realised what you meant (think I was tired last time!). That is a great idea.

Next question... in my testing on scrap, I found that cheap electrical tape worked better than the expensive professional painters tape, when doing curves and corners. The electrical tape is slightly stretchy so I could curve it around in one piece and get a much nicer finish. With the painters tape, I had to cut out lots of tiny little fiddly bits of tape to go around corners, and the finish looked a bit crap.

Does anyone have any good/bad experience with using electrical tape for masking? I've only done it once or twice on scrap, so don't know if I'm going to cause problems by using it on the guitar.

[Dedman]

you can get pvc pin striping tape from panel beaters supply and I've found that to be very good, I also use some very fine fibred paper tape used in scale model building