Attn Finishing Gurus

[mshilarious]

I tend to keep things simple when I finish an instrument, I have Stew-Mac's violin varnish and that's about it. But I want to do an instrument with a painted figure on it, but otherwise natural finish, so:

- What to use before applying the paint.

- What kind of paint to use for the drawing (regular art-supply oil paints?).

- What to use for a topcoat.

Ideas? I have a spray booth if needed. High gloss finish is not required, as I said usually I am happy with a simple varnish. Wood is mahogany.

Thanks!

 

[ggunn]

WTF are all these ads for "related products" doing in here? First there was the highlighting of key words pointing to sites wanting to sell us stuff, then this. It's getting annoying.

 

[Roguetitan]

WTF are all these ads for "related products" doing in here? First there was the highlighting of key words pointing to sites wanting to sell us stuff, then this. It's getting annoying.

+1 fucken spam IMO

 

[Roguetitan]

I tend to keep things simple when I finish an instrument, I have Stew-Mac's violin varnish and that's about it. But I want to do an instrument with a painted figure on it, but otherwise natural finish, so:

- What to use before applying the paint.

- What kind of paint to use for the drawing (regular art-supply oil paints?).

- What to use for a topcoat.

Ideas? I have a spray booth if needed. High gloss finish is not required, as I said usually I am happy with a simple varnish. Wood is mahogany.

Thanks!

No, you don't want to use oil based paint.
you want to use a laquer based paint.

I use either laquer or poly auromotive paint on solid body electric Guitars
I also use acrylic sometimes depending on the types of wood
you want to use something that is flexible because wood expands and contracts.
Epoxy based paints don't work too well with wood because it tends to crack easily.

if you are wanting a natural finish I would recomend using tung oil or boiled linseed oil before painting the image then after you paint the image color sand with 1200 grit paper, use a tack cloth to ermove dust and particles then spray a clear coat.

what kind of an instrument are you wanting to re finish?

 

[32-20-Blues]

Nothing constructive to add here - although I have painted figures on an off the shelf ukulele before with designer's gouache - but can you post pictures when you're done? It sounds like a cool project.

 

[mshilarious]

Nothing constructive to add here - although I have painted figures on an off the shelf ukulele before with designer's gouache - but can you post pictures when you're done? It sounds like a cool project.

Yeah it's a uke, going to have some local designs done on it by the kids. Should be fun.

Rogue, as it's acoustic I don't want to be using auto finishes, needs to be more natural than that.

 

[Roguetitan]

I tend to keep things simple when I finish an instrument, I have Stew-Mac's violin varnish and that's about it. But I want to do an instrument with a painted figure on it, but otherwise natural finish, so:

- What to use before applying the paint.

- What kind of paint to use for the drawing (regular art-supply oil paints?).

- What to use for a topcoat.

Ideas? I have a spray booth if needed. High gloss finish is not required, as I said usually I am happy with a simple varnish. Wood is mahogany.

Thanks!

prep with 800 grit emory paper then step down to 1200 grit ( always sand with the grain) then
rub in a coat of tung oil with a lint free rag for a base let dry over night, l then lightly sand with the grain 1400 grit wet sanding emory paper, wipe down with tack cloth rub in one more coat of tung oil then repeat the sanding process and wipe off with tack cloth
you can use Acrilic enamel for the art work and not worry about any clear coat.

 

[muttley600]

I tend to keep things simple when I finish an instrument, I have Stew-Mac's violin varnish and that's about it. But I want to do an instrument with a painted figure on it, but otherwise natural finish, so:

- What to use before applying the paint.

- What kind of paint to use for the drawing (regular art-supply oil paints?).

- What to use for a topcoat.

Ideas? I have a spray booth if needed. High gloss finish is not required, as I said usually I am happy with a simple varnish. Wood is mahogany.

Thanks!

Mahogany is opened grain you will need to Prep and fill first. Sanding down through the grades is obvious but how far you go is down to you and experience. I'd recommend at least 400 grit. With some timbers and finishes you want to go further. There are many ways fill. What I would do would depend on the subsequent finishing regime. You have a choice of three easily available fillers that will do the job for you. A general purpose grain filler as sold in your hardware store and sanding sealer. Get a colour that is just a touch darker than the wood when its damped slightly. Lighter colours will not look good. Secound, a Vinyl sealer. You can get these in rattlecans and will work but don't build too much just enough to fill the grain and give one top coat. This stuff is really better shot from a decent gun but will work for you. If you build too much it can "blush under your topcoat. Third you can use Shellac to grain fill. It will take a bit of time but you can rub it on coat after coat and needs only a few minutes between coats. Just about everything sticks to shellac and it it will give you a good attractive deep finish to finish over. There are many other filling options and I've tried most of them from epoxy to natural oils. I'd stick with one of the above on mahogany. If its a one off I'd go with shellac as a filler and base coat. Maybe with a good clear grain filler if the grain was really open. You'll see how well the grain fills when you cut back. Any open grain fill again. You'll be glad you did later.

As to getting the picture or paint job thats a bit trickier. It sounds like you want kids to have a hand in this so I'd want to choose something safe. I've never had this consideration so I can't really advise but I'd be looking for something that will take will give a good solid colour with little or no build. I'd get some old mahogany prep it and start testing everything on it. Felt pens, paint pens, just try everything. Your after something that will look right and not require too much cutting back. also something that will not bleed through subsequent top coats. This is one place where you may be better with a vinyl sealer as you can spray a top coat to protect the artwork. Again test it and test it some more. You want to avoid oils or enamels as they would be hard to level out and cut flat to get a nice smooth finish with and I'd worry about the compatibility of those paints under a top coat adhesion wise. Again you need to test.

Another possibility if is acrylic paints but I'd want to keep them thin. I'm not sure if they will look good on a mahogany base. I had a chat with Rob Armstrong sometime ago about how he does his and he uses acrylic paints but he's working on a white base most times. He does some detail work with oil paint as well. If you do you'll want to add some drier (Liquin) to speed up the drying times. From here he shoots nitro on top. You know my thoughts on that in the wrong hands but if you observe some basic safety measures you'll be OK and if you ahve a booth just make sure it's safe for nlow flash point stuff. Whatever you'll need to build up a topcoat that you can cut flat so you'll want to keep the paint to a minimum and make sure you have enough build so you don't sand through and ruin the artwork. You'll need to 100% sure the oil and acrylic paint has dried. It can take weeks so be prepared if you go that root. I'm not sure what else will sit on top of oil and acrylic paint because I've never done it but I would be confident that the violin oil varnish would. One of the methods used to colour modern violin finishes is with oil paint. I've done that!! I know Rob likes to finish with a slightly less than gloss top coat. Too much gloss can "hide" the picture.

I'll have a bit more of a think about this and see if anything strikes as good way to go. Just remember that even us "pro" builders ALWAYS test a new finishing regime on scrap at every stage, take notes of everything, and preparation early on will be rewarded later.

Once again this is how I'd approach it, but I haven't tried it. I would test at every stage and good luck. Let us know how your thinking of preceding. If I can see any obvious problems I'll chip in...

 

[mshilarious]

That's excellent, thanks. The violin varnish is a shellac base, I also have some sanding sealer around, I'll have to check the color though I think it was for pine. Probably not the best.

I'm not crazy about acrylic arts paint, I mean I rather like it on canvas but it's not the right look for wood. Maybe I should try tempera . . . then safety should just be a matter of choosing nontoxic pigments, the kids are old enough to not purposely eat the paint anyway

Exactly right about the topcoat gloss, so again the varnish seems the way to go.

This is a kit instrument so I don't have a lot of scrap wood. Is it OK to test a spot inside the back? I suppose that might affect the tone, but hopefully not too much, or maybe in a good way

This is going to be a fun instrument; I've upgraded a few bits of the kit, I got some nice paua abalone for the soundhole inlay and it looks great. It's much easier to work with than I thought it would be. I have an abalone nut and I'm going to replace the dots with abalone too. There is an inlay on the bridge which was wood, I chucked that, and you guessed it, more abalone!

Although if I was a real man, I'd be harvesting the shells from the beach myself

 

[muttley600]

If you haven't got test pieces of the same timber hunt around for something close in colour and grain. What your really testing for is to make sure that your process doesn't lead to adhesion problems from swapping finish types and also to make sure it gives you amount of tint, dye, gloss your after. It's ALWAYS better to mess up a test than the instrument. Ask anyone who's done any amount of finishing and they'll agree.

Not sure about tempera as again I have no experience with it. Do you mean true tempera egg white based or the modern poster paint sold as tempera, at least round here? Either way I'd test it first. I think you main problem is going to be finding a base that your paint medium will stick to, laying the paint fairly thin so you don't need to build the top coat like a toffee apple, and finding a topcoat that will cover the whole thing. Not impossible at all but just need some thought and test's.

Why not get some scrap and prep up some table mat or coaster size pieces and have the kids make some place mats while you at it? Could be fun and a good learning exercise for all concerned. Good luck. Let me know how you get on. I'd be glad to learn from your experience.

 

[muttley600]

Just a quick note. I hope your making sure that abalone dust is kept out of your lungs. Nasty stuff....If not please do so in future.

 

[mshilarious]

Just a quick note. I hope your making sure that abalone dust is kept out of your lungs. Nasty stuff....If not please do so in future.

No worries there, it's all pre-cut Except I guess I have to cut the nut slots, but I'd have to be pretty sloppy to breathe that dust.

As for the tempera, yeah I mean the real egg thing, if I can find the pigments. The kids stuff is way too primary colored; I need the good ol' fashion pigments, minus the lead and mercury . . . and cadmium . . . and cobalt . . . there are pretty good synthetic substitutes for those in acrylics, hopefully it's the same in tempera.

I think what I might do is get a koa top, that way I'd have the mahogany top in the kit for practice, and some scrap koa too.

 

[32-20-Blues]

As for the tempera, yeah I mean the real egg thing, if I can find the pigments. The kids stuff is way too primary colored; I need the good ol' fashion pigments, minus the lead and mercury . . . and cadmium . . . and cobalt . . . there are pretty good synthetic substitutes for those in acrylics, hopefully it's the same in tempera.

Just to let you know - I've painted with egg white based tempera many times, and it really doesn't go on easily. Imagine painting with something the consistency of nail varnish...

If it was up to me, I'd go for Sharpie markers over a selectively applied white base coat (how you do the base coat is Muttley's part). They'll go on vibrantly, and they're very convenient.

 

[muttley600]

If it was up to me, I'd go for Sharpie markers over a selectively applied white base coat (how you do the base coat is Muttley's part). They'll go on vibrantly, and they're very convenient.

Those are the kind of thing I was leaning towards. The other consideration for the whole paint thing is colour fastness. Some of those pen and fabric paints don't seem to be very colour fast. Again I don't have a huge amount of experience with them. Test, test some more and then test it again. When mixing finishes you always run the risk of poor adhesion, crazing, cracking, pitting, blistering, blushing and a whole host of other potential problems. The compatibility of most finishes is widely understood. The moment you introduce a third medium, in this case the paint you need to be sure it is compatible and colour fast when used with the base and top coats.

Another possibility would be to use a shellac filler and base coat. oil paint and then a tru oil on top. You don't get much build with tru oil but being based on linseed oil it is traditional for protecting oil paint. All of those mediums know are compatible. You main problem would be keeping the oil paint flat so you can level off with the tru oil. Tru oil makes a great finish on guitars by the way. It's more of an oil varnish than an oil, and can be ragged or padded very well. If sprayed you need to keep the coats real thin.