filthyPierre's GR-1SF build

[Simon Barden]

I bought a cheap pop-up toilet tent to use as a spray booth outside. Obviously needs decent weather, not too cold, but it's better than spraying in a crowded garage. Provides protection from the wind. I spray with the door open from outside, then zip the flap up straight after spraying until it's dried.

[filthyPierre]

Sounds reasonable. Cheapest one I can find locally is about $80, so not too bad.

Wondering about the binding if I decide to go the spray route - should I mask or not? The problem I see with masking is that water or other liquid could accidentally get under the edge of the lacquer where it stops at the binding. Does binding normally get sprayed/clear coated?

Cheers

[Simon Barden]

Mine was from eBay, less than £30 here, so $50ish.

Binding is normally sprayed with clearcoat. Commercially, it's obviously easier to do this than take time to mask the binding or spraying and then scraping the clearcoat off the binding. It also means that you get a stepless edge to the finish. Binding doesn't need clear coating (unless it's a faux natural wood-edge binding so it does need protection) and some people here like to mask it off before clear coating. But you still need to let the clear coat cover just the very edge of the binding to ensure that all the wood is covered, so it really is easier to go with convention here and spray the lot.

[Andy40]

Yeah DT a no go with that stain, I think Simon's suggestion is the best

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[filthyPierre]

Righto, well I guess the next thing is to choose a type of clear - what is the best to use from a rattle can? Leaning towards acrylic, or poly maybe. Not sure about nitro, it's pretty toxic to spray isn't it?

[Simon Barden]

Polyurethane should give the hardest finish and will shrug off small knocks but is prone to chipping on the harder knocks. Nitro is the finish that will probably still look good in 20 years with a more natural wear look to it. I feel that acrylic gives the softest protective finish - it doesn't take much to put a mark on car paint these days. In reality, all of them will give a good shiny clear finish, just don't use too thick a coating (you'll rub most of it off anyway before polishing to a shine) and the body can still resonate.

All spray painting should be done using a vapour mask, regardless of the spray used. Yes, nitro has the worst solvents of the three, but they dissipate fairly quickly in a well ventilated area/outdoors. The nitro cans will be the most expensive by a large margin, so that may drive you to acrylic or poly. All of them should be applied in multiple thin coats. You need to use enough and get the can just close enough to the guitar for the spray to go on 'wet' rather than dry, but no more than that.

Acrylic is probably the worst in terms of drying if too thick a coat is used as the surface dries quickly and forms a barrier to the underlying wet layer, so it can take longer to dry properly than you think.

You should certainly wait at least two weeks after the final coat goes on before trying to polish the finish. The harder the lacquer is when you do it, the better the shine. You can't get a good shine if the paint is still soft.

[filthyPierre]

Thanks Simon, good advice. I will see what I can find locally. I will need advice on how many coats and sanding to get that nice finish - I've done plenty of spray painting, but it's mainly been for pinball machine restos, where as long as the paint is realitively smooth and dust free, it doesn't have to be sanded or polished. It's not hard to get a better-than-factory finish on a pinnie.

Cheers

[Andy40]

Hi FP, Phrozin has put his secret recipe when using rattle cans on his build diary

[filthyPierre]

Thanks Andy, I checked it out. Seems like something I can follow

The only problem I can see is that after putting on the dye, the grain has risen again, as it has done at every step of the way. Hard to see but if you run your hand over it, it feels a bit "hairy" for want of a better term. Wondering if I can build up enough clear to cover it, and then do the clear coat sadning step and have it all nice.

Was also thinking of doing a satin finish, as I still plan to use the dingotone I bought for the neck. So satin body finish will match. Is it even possible to sand/cut/polish a satin finish or am I delusional?

Cheers

[Simon Barden]

You can get satin finish sprays (I've got 3 tins of clear satin nitro I ordered by accident that you would be welcome to if you were a lot nearer) and no, you wouldn't cut those back and repolish. Obviously you would still have to sand back any runs and then spray another coat over that, but if you are careful, then you won't need to.

It's the main reason why the lowest-cost guitars, in say the Gibson range, have satin finishes. It takes a lot of time to sand back and then polish a gloss finish body, and time is definitely money when making guitars. Once you've got the wood and hardware, then all the rest of the cost is labour. Satin finish guitars often leave out any grain filling stage as well (more cost saving), so that ash and mahogany bodies feel a lot less smooth. But with the basswood on yours, you wouldn't grain fill anyway.

As the GR1-SF is all basswood ply, the top ply layer is thick enough to withstand some light sanding, so I'd use something like 400 grit paper and 'drag sand' the body to remove the loose fibres. Simply drag the sandpaper over the wood just using gravity to hold the paper down (or at most, lightly press with your hand). The paper should then catch the loose fibres and remove them without doing much else at all to the surface of the wood.