man did I screw that up

jimfergie

New member
Messages
13
Warmoth alder strat body, I routed my own dual humbuckers and control area. I sprayed Deft sanding sealer and automotive primer and sanded in perfect. I wanted to spray it with Automotive base/ two part urethane clear coat in black to match my existing American Strat. I bought the Omni paint, bought a HVLP gun, tested it on a couple panels before getting it all ready, with a little spray tent in the garage. The base went on OK, every time I put it up on the wire, I guess a little material on the hanging wire would flake little specs, no problem though. Then I touched the wet base with the wire, again no real problem. The sprayer had a couple globs of jelly paint in it, but it kept spraying OK. I then started with the clear, first couple coats were OK, then by the third, I saw the couple big runs under neath at the low spots. Then I touched it again with my sleeve. I let it dry a couple hours then managed to put finger marks on it.  So it's all screwed up. I'll try and sand all the flaws and runs down and spray another clear coat. If it looks like crap, I'll either have to sand it all off or just buy another body. I did it as a learning experience. I learned it's a real pain in the butt to spray two part automotive paints, it's done because it's fast in a shop. The next one will be pigmented lacquer with clears coats from cans. Lacquer is so much easier to spray light, good coats and polish out.
 

jimfergie

New member
Messages
13
an update, I tried to sand down the clear to see if I could, the drips sanded out OK, but I couldn't get a consistent finish to polish out. I decided to sand it and try again, base and clear coat again. I was just about finished sanding it all out with 220 and I noticed a tiny flap near the neck pocket. When I scratched it with my finger nail, the clear and base coat could be peeled off the primer! I could fairly easily roll the edges with my finger and roll of a bit of paint  an area of a couple square inches. So it's a totally lost finish attempt. I filled out another order form for another body. I did take my  orbital sander and sanded down to the sanding sealer fairly easily. All the rounded corners and inside curves will take some time but I might try to sand it all down. I don't want to change the shape obviously so as soon as I see wood I can stop.
 

Alfang

Senior member
Messages
2,596
It seems obvious that the first coats of paint didn't adhere to the primer.

I'm not the finishing guru here by a long shot, But I have shot 4 guitars with auto paint laquer in rattle cans with great success,  I think until you
have done a few it's a good idea to stay away from any two part stuff.  Keep it simple.

I think sanding back clear with 220 is a bit coarse, I wouldn't go less than 400 for an initial leveling sandback , and that's a wetsand.

If you get another body to retry, keep the first one, when you figure it all out, you can "save" that one no problem,

Good luck
 

jimfergie

New member
Messages
13
another update, today I finished sanding down the back and front since they're flat. Obviously I could tell when to stop as the primer exposed itself right before the wood and sanding sealer. I don't want to screw up the original shape and edges. I bought some Klean Strip heavy duty stripper as it said polyurethane on the can. That stuff works great, within 5 minutes the paint wrinkles up and comes off. It's kinda messy, but with most of it stripped off I'll come back tomorrow with another application and Scotch pads followed by a wash off with lacquer thinner. I'm removing all the paint from inside the cavities too. I'll sand with a block and Scotch foam pad, 320 or something and start with the sanding sealer, black color coats of lacquer and all the clear coats like I SHOULD OF DONE IN THE FIRST PLACE.
I don't know why the base didn't stick in that spot. The primer was SEM high build primer recommended by the paint store. The base coat was Omni MBC Acrylic with their MR186 reducer at a 1:1 ratio. I wiped it with Naptha and a light tack rag before spraying it.
I had tested the paints both with a Preval and this HVLP gun and I could wet sand and polish it to a "factory" type glass finish. I screwed up when I actually got to the spraying.
again I think that if you knew what you're doing, had a room or spray booth available then the auto paint is very good and fast. It's what a lot of electric guitar makers use but a for a hack like me, lacquer, especially in cans is the way to go
 

vanhagar

Senior member
Messages
227
I've been painting cars for years and the naptha may have been the problem, Use a prewash for auto paint, you should be able to get this at the same place you got the paint. What I would do is respray a fresh coat of primer, do not use naptha before it and very lightly sand the primer with no heavier than a 600 or 800 grit before applying the paint. Then use a clean rag to wipe it down, then use the tack cloth just before spraying the base coat. don't try to cover completely on the first coat, spray all the harder areas first then lightly coat the rest of the body. Use the back of your nuckle after about ten minutes to make sure no paint comes off, sticky is ok, but if the paint strings off wait longer, same goes for the clear coat except you should try to cover with the first coat of clear. Good luck! I painted a warmoth jazzmaster recently in black with dupont base and clear coated with nitro and it turned out great!

Paul.
 

jimfergie

New member
Messages
13
thanks for the advice Paul, the Naptha might have been the problem. I also have a truck tail gate I'd like to spray so I'm picking up info for that project too. I finished with all the paint removal, again a bit messy but it's all off and lightly sanded so I'm at least relieved with that. My biggest problem, Paul was with the spraying itself I think. I know how I'm supposed to have done it but the base coat seemed to have spattered on almost like the textured paint from a spray can. I know the base coat is a flat finish and one person described is the appearance of 400 grit sandpaper. The dealer said you shouldn't have to thin it past the 1:1 ratio. So it's obviously my adjustments of the spray gun, too little or too much air vs fluid. The clear I guess has a lot of solids in it, I actually experimented with a bit of Xylene as a reducer that worked fine, It hardened fine. Still not a very good spray job, too thick and heavy, especially the runs. Once hardened it all can be sanded/ polished out but not like you'd get from an auto paint shop for sure.
I have some Deft satin brushing lacquer that I wanted to experiment with thinning a pinch and adding some universal black pigment for a base coat before spraying the top clear coats of lacquer. I've read that the brushing lacquer can be sprayed it just has retarders for brushing. The next one I'd just buy ReRanch or StewMac, but I'm stubborn now.
 

vanhagar

Senior member
Messages
227
Yeah it sounds like a pressure problem, I have two guns, one for metallics and large spray jobs, it's a Binx and costs about $500 ! the other is a small touch up gun I got for $40 and works great for projects like this. Even the small gun requires at least 45 Lbs of pressure to spray properly, but I was never one for mixing instructions :) I will mix my clear coat to the letter, but not the paint. Just try mixing a little reducer at a time while stirring, then lift the stir stick out of the paint about an inch or so, If it stays stringing it's too heavy, if it starts dripping the second you pull out the stick it's too thin. The paint should just begin to string and then start dripping. The base coat that I use requires only a basemaker and no reducer, unless the brand you are using is calling this a reducer. I also have the deft brushing clear and it does work great with a spray gun and it requires at least 50 Lbs of pressure if you don't thin it, I like it better straight out of the can, It has a great leveling property to it way better than the deft clear in the spray cans! Test spraying on something, the fan of the spray should be at least 4-6" wide. Do not use any oil based cleaners or solvents when working with auto paint, It won't stick and will usually cause fish eyes! When you are ready to spray again put a couple coats of primer on, then sand very lightly with 600 grit dry, wipe clean with a clean rag, and I mean clean, not something you have been wiping your hands on! Then use your tack cloth very lightly and your ready to spray :) I'll post a pic of the black jazzmaster with the dupont black base and deft clear on Monday. If you spray with enough pressure and thin enough coats you should not get any runs in the paint or the clear, remember the first coat of paint should never completely cover the primer. Hope I didn't confuse you too much !

Paul.
 

jimfergie

New member
Messages
13
no that's the kind of info we need! thanks. I bought a can of Ace brand black satin lacquer paint today just to test it. I sprayed it easily over a coat of Deft sanding sealer with no problem. Let it dry a couple hours and sprayed a coat of deft satin lacquer just to see what it would do. It's fine, actually perfect with no hassle. I'm sure I can follow the three sprays a day routine with the Deft lacquer, either sprayed from my gun or the rattle cans and polish it out. I will keep working with the auto clear for the other projects. Another item, I'm still interested in the lacquer toner idea for the neck. I bought a can of the ReRanch neck amber but it's too yellow. I discovered the brand Mohawk lacquer toners, I believe we have a dealer near us that carry it. They seem to have many different colors instead of just the ReRanch yellow. When I get this finished I'll send a photo.
 

jimfergie

New member
Messages
13
two other things Paul, I bought the HVLP gun from Harborfreight and the instructions were poor. I didn't realize that the inlet pressure was supposed to be 30-50 psi and that the gun regulated the pressure down to the 10 psi or whatever! I tested it with 10 psi inlet and obviously did nothing, I started turning up the pressure to see what was wrong and it started spraying!
second thing, can you spray satin for all the build up coats and then gloss for the final coat? If satin is the final caot it can be polished out too, correct?

thanks
 

-CB-

Senior member
Messages
5,427
correct and correct - as long as the satin and gloss are from the same company product line

that is... dont mix say... dupont with ideal, or deft and reranch. 
 

jimfergie

New member
Messages
13
all righty then, thank you very much, I will continue on and hopefully finish this thing before Christmas!

Jim
 

jimfergie

New member
Messages
13
I was able to successfully strip all the paint, primer and sealer off, re sand, new Deft Sanding Sealer, new Ace Brand Black Lacquer and several coats of deft Satin before it started raining and get colder. After all that I'm very happy with the finish so far, absolutely no flaws, wood grain or dust nibs. I've started assembling it and will try and work on the wiring and preliminary setup. When it's warm and dry again I'll spray more finish coats on both the neck (amber tint) and body, glossy and polished. The neck it misaligned just a pinch, I'll try sanding the pocket in the future, it might not be anything, the high E string is a bit closer to it's edge than the low E but you'd only bend it in anyway.
 

-CB-

Senior member
Messages
5,427
Wooten zooten banigootin sha-zaMMie!  Nice!

Thats thar' is one cracker crunchin' armadillo wrestlin' smack eye spitoon nice finish ya got thar' pard'ner.

Or as Alvarez Kelly said... "Just as cute as the dimple on the end of your... <gets face slapped>, ma'am!"
 
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