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Noob painting and sanding que's
http://www-.luthiersforum.com/forum/viewtopic.php?f=10122&t=52242		 Page 1 of 1
Author:  flemsmith [ Sat Aug 03, 2019 10:58 am ]
Post subject:  Noob painting and sanding que's
Never built a guitar, thought I'd start with trying to do a Strat style electric. Never even played an electric, but why not?
So, I did a cherry burst, finished with four cans of clear lacquer (although they aren't all totally empty, I quit when I started to get sputtering). Let it sit for a month and then started sanding. Using the Stew Mac aerosols.
https://photos.smugmug.com/Guitars/i-3m ... 4020-M.jpg

I was a bit dismayed to see I had sanded thru the color, so I stopped and thought I'd ask for some advice. I started with 220, very lightly, then 320, then 400. The next pix should show that I'm not getting thru the clear completely (ie, the shiny spots tell me I should be sanding a bit more aggressively...?!). I suppose I was not getting uniform coverage in each clear application, which isn't a big surprise.
https://photos.smugmug.com/Guitars/i-nv ... 4109-M.jpg
So, my question now is what should I do next? Spot spray the edge I've sanded thru with red, then clear just there, or do I need to do more clear all over, or sand it down all over so I can get rid of the low spots and see if I go thru the color some more before I try to fix any of those spots that show up? I've never learned how to finish anything perfectly, and I don't mind working on this til I get it as close to right as I can. Thanks for any advice. Roy Hmm, I mostly lurk rather than post, looks like I've forgotten how to embed pix.
Author:  Glen H [ Sat Aug 03, 2019 4:35 pm ]
Post subject:  Re: Noob painting and sanding que's
I’m not sure I understand your question about spot treating but typically I level sand starting with 800 grit. Some folks use coarser. You may also not have had enough finish built up.
Author:  flemsmith [ Sat Aug 03, 2019 5:59 pm ]
Post subject:  Re: Noob painting and sanding que's
Thanks for that input....I think a good bit of what I don't know relates to how much sanding pressure to use with what grit. 800 is a lot finer than I would have thought, but that's what I'll try. That's aside from how to deal with the spot where I sanded thru the red. I suppose my only real choice is to spot spray it with the red and try getting some clear over it and see how it looks as I sand again. By spot spraying what I really mean is to use some sort of mask so that I can spray a very localized area to cover the bare wood and hopefully not much else. I'm in the fairly typical spot of not knowing, but at least I know that I don't know. Roy
Author:  Glen H [ Sat Aug 03, 2019 9:35 pm ]
Post subject:  Re: Noob painting and sanding que's
If I sanded through red to bare wood, and didn’t want to go through stripping down and starting over, I would airbrush the spot with red then spray over all the red with a darker red, assuming that the spot did not hide well. Good luck.
Author:  Freeman [ Sun Aug 04, 2019 8:05 pm ]
Post subject:  Re: Noob painting and sanding que's
Try spraying a little of your red into the cap and lightly brushing it on the sand thru. It will probably take several coats. You may want to keep a small container of lacquer thinner on hand and brush a bit of that to help the transition. Once you have some color there I would do several mist coats of red to try to blend it into the old paint. You may not be able to hide it completely but I bet it will look OK. Then mist several coats of clear trying for a little bit larger area, sand lightly every 3 or so coats.

One thing you might consider is that nozzles in most rattle cans are really hard to control. I bought a few of the special nozzles that StewMac sells and they make rattle cans almost controllable. I would also mask around your sand thru maybe an inch or so back from the actual wood- you will get a ridge at the masking tape but that will sand out. I would use 400 or 600 wet for removing that ridge - again, be careful that you don't go thru again. One thing that I'm seeing in your second picture is a bit of a pebbly surface - thats pretty common with spray cans and about all you can do is keep sanding with 600 until its gone. Watch the sludge that forms as you wet sand - it should be white but if any pink appears you have gone thru to the red - stop and shoot some more clear over that area. After you get that all leveled you might want to shoot a couple more coats of clear - try to lay down good wet coats with no runs. Then let it cure again for a couple of weeks and do the final sanding and polish. I usually start with 800 wet and go up thru the grits - 1000, 1200 and 1500, then I buff with auto polishing compound (no wax or silicon).

I really think you will be just fine - I like the finish a lot. Looking forward to seeing it when its done.
Author:  flemsmith [ Sun Aug 04, 2019 10:04 pm ]
Post subject:  Re: Noob painting and sanding que's
Thanks, Freeman, that sounds like the kind of advice I was hoping for. Never thought of spraying the red into a container to paint from with a brush...Roy
Author:  flemsmith [ Tue Aug 06, 2019 10:48 am ]
Post subject:  Re: Noob painting and sanding que's
Did the brush coats over the sand thru, then resprayed the edges with red. Afraid it wasn't a light mist, but at least there are no runs. Do weird things happen when I spray red over a few coats of clear? Then more clear before I start sanding again? I really have a lot to learn, ordered the stew Mac finishing book. roy
Author:  flemsmith [ Wed Sep 04, 2019 5:19 pm ]
Post subject:  Re: Noob painting and sanding que's
Ok, just to sorta do a wrap on the painting and sanding...I am pretty darn happy with the way it looks now. The lacquer really does a nice job of blending in with previous coats. Since this is my first real attempt at trying for gloss, and I'd already sanded thru the clear once, I was nervous to sand aggressively. I started the levelling at 400 grit, worked up to 1500 without sanding thru the clear, the did some hand polishing with a medium auto compound, and finally a fine polish compound, using one of the foam pads on my drill. I was a bit afraid of going to the buffer at all. Partly because I didn't have any new pads and had always used it for polishing aluminum motorcycle parts. Partly because I'm afraid I'll burn thru the clear and I'd rather finish it. Anyway, it feels perfectly smooth, looks great at 3-5 ft or more. A close inspection with sunlight does show some issue, not sure how to describe exactly, but it kinda looks like some areas have clear spray which wasn't totally levelled; tiny bits of orange peel?...For now I'm gonna call it done. I think it's good enough and I could really screw it up if I go after it again. Thanks for inputs. For now I'm gonna go to the electric forum and ask assy questions. Pix as it is now...Roy
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