78 GS 750 Rebuild

[Sam 78 GS750]

Ok, well that's reassuring. I picked up some more 600 grit, and will continue to sand with that.

I'm actually grateful for the orange peel, because I think I can use that as a guide for how much I can afford to sand.

For the spots near the front where I was concerned about the texture, I'm not sure how to tell how much clear I really have to work with. Those were spots where I had issues the first time around with it being way too wet, and I think I sped up my passes in those areas and overcompensated. That made it so even my somewhat wet coat ended up still being dry in those areas.

[nvr2old]

That's just the texture you get when you spray it as dry as you have. I would sand it a bit more with 600. 800 isn't going to do much for you and really isn't enough tooth for the next coats to stick well. Only you know how much clear is on there, so don't push it to get it glass smooth if there's only one wet coat on there before you stopped. Yes, more clear to finish up with. At least three coats to have enough to sand and polish.

[Sam 78 GS750]

OK, so I could feel the layers so I hit it with primer and sanded again. Laying on the base for the 2nd time around, it wrinkled in one small area. It looked like what happened to Pete with his Kat in the silver. I did what he did...let it dry, sanded that spot back, resprayed, and kept it moving. So far, so good.

On to the clear. I didn't want to have to do this a third time, so I was pretty conservative on the coats. I did one dry coat, followed by one medium coat, and then a third medium wet coat. Then I let it be.

I'm thinking I need to do a couple more coats of clear to avoid sanding/buffing through into the color. There's some orange peel, and other spots that I think are from overspray, but I'm not sure. Since I layed it on super thin this time I want to make sure I have enough material to correct.

I scuffed it up with 800, since that's what the data sheet called for "if an additional application is desired after cure". Would I have any issues spraying a few more coats over the clear as it sits now, orange peel, overspray and all?

20181008_125209 by samL9, on Flickr

20181008_125224 by samL9, on Flickr

20181008_125233 by samL9, on Flickr


Not sure if this is overspray or not. I can only described it as "textured" or tiny orange peel...I don't know, it just looks dull and rough (it did even before I scuffed it with 800). I'm wondering if I clear over it again will it be fine, or will it look cloudy and I should sand it back more now
20181008_125303 by samL9, on Flickr

A bit closer...
20181008_125247 by samL9, on Flickr

[nvr2old]

Sorry for the delayed answer. Been on vacation this week. It's a shame you had to take your paint job so far back. Can you run your fingers over the sand throughs and feel the layers? If so, you'll have to go back to the high build primer to fill those areas again. If you can't feel the layers then I think I would spray a couple of VERY light coats of primer over the spots you've sanded through to. Especially where you hit bare metal. Keep them dry, too, If you spray them wet. it will lift, I guarantee. Let it set overnight, maybe take a bit of 600 to it to make sure it's smooth, re-base and re-clear. Again, when you re-start with your base coat, make sure you don't pour it on, because it will lift if you do because it's all so fresh still. Just enough base coat to cover and no more. Start the clear a bit dry to begin, and progressively get wetter towards your final coat, but as you've learned, not so wet that it runs, or you'll be starting over again.

Keep at it, nobody said this stuff is easy, even for someone whose done it for many years.

[Sam 78 GS750]

You can't really see it in the photos I posted before, because they weren't there yet. It looked great for a day before the solvent pop seemed to show up, but then the air bubbles gave the clear a really cloudy look.

You were right...they were really deep. When I would open up the ones I could see, there were still more trapped in the clear. Before I knew it, I had broken through to the base in spots so I figured I may as well sand all the clear off to get rid of all of the air bubbles. They went all the way down to the base.

Now I have all kinds of layers...clear still covering a lot of the tank, base in spots, various layers of primer, and I even broke through to metal in spots.

Not sure where to go from here. I'm between shooting a thin coat of primer to seal and then base and clear again...or just taking it all down, shooting one more round of high build just to make sure it's level after all that sanding, and then base and clear again.

What do you think?

20180927_083244 by samL9, on Flickr

[nvr2old]

Solvent pop usually occurs when the clear, as you mentioned, is sprayed really thick and it gets a "crust" on the top before it has a chance to dry deeper down. The solvents don't have a chance to breathe and air out, get trapped..and "pop" More often then not, they're really deep and to get them completely out, you risk sanding into the base coat color, and then basically have to start over if you do. Sand them to the point you're comfortable with, and just re-clear over them. Start a bit dry and then build up to a few wetter coats to finish. They should fill up. It's also a good idea to keep air moving around your parts after your final clear coats with an oscillating fan..not on high to raise dirt in the air, but just enough to keep the air moving. It'll help dry from the inside out that way instead of getting a crust on top. It's all a learning experience and you're doing fine.

[Sam 78 GS750]

So the good news is that I was able to sand all the runs back. The bad news is there were air bubbles trapped in the runs and it looks pretty bad. After sanding back the orange peel with 1000 grit, I can see that they're in a couple other areas also. Google tells me it's "solvent pop" which seems to be reason #2 why it's a bad idea to lay it on in super thick coats.

I'm thinking I need to sand until they go away, which I hope doesn't mean sanding all the clear off.

[Sam 78 GS750]

Note to self: It's much quicker and easier to scuff sand and spray more coats of clear if needed than it is to sand runs out of clear...

[nvr2old]

Use 600 and a block to cut those runs out. Anything less and it just won't work. You don't have to worry about getting it so wet that it runs. It's easier to sand out a bit of orange peel then a run.

Look how straight your body work is, though. That's where all the block sanding pays off. Nicely done.

[Sam 78 GS750]

So a bit of orange peel, a bit of overspray, and a few nasty runs, but all in all not too bad.

20180916_190100 by samL9, on Flickr

You can see the runs on top in this one.
20180916_190206 by samL9, on Flickr

20180916_190154 by samL9, on Flickr

Runs on the side
20180916_190122 by samL9, on Flickr

...and on the top.
20180916_190139 by samL9, on Flickr

...and of course, I had to throw it on the bike. Starting to look like an actual motorcycle.
20180916_191501 by samL9, on Flickr

[pete]

Glad to hear it Sam and looking forward to the pic's! I know the too wet problem, that's such an easy thing to do and I usually end up doing that myself.

When I did my 450 I didn't have my reasonably well sealed up shed, which meant I had dust and crud floating around and landing in the paint which wasn't great, but like you say most of it will sand out. The only painful part for me was the bits that landed in the white stripes *before* I cleared it without realising they were there... I can still see them...

[Sam 78 GS750]

I'll post some pics tomorrow in the daylight. Maybe disaster is a bit of an exaggeration. I definitely have some sanding ahead of me, but it really did come out awesome.

[Sam 78 GS750]

Progress!

Color went on nicely. A little hair or something got stuck in one spot. I sanded it out, resprayed, and kept it moving.

Then came the disaster of the clear coat. I got 2 guns...one for primer and color, and another for clear. I had the color one dialed in nicely. The clear one, not so much. I was trying to spray wet coats, but not as wet as it came out.

To say I got a few runs would be an understatement. I have paint dripping on my garage floor right now. There's also some pretty big dust particles that landed in the clear.

Other than that it looks awesome though.

[Sam 78 GS750]

I was able to take care of the trouble spot. I think I've got it as good as I'm going to get it. There are some small imperfections, but this is the point where I usually ruin good enough trying to get to perfect so I'm going to stop. I sprayed one more thinner coat over the whole tank like you suggested, and I've got about 10 more minutes to wait until I can spray color. Wish me luck!

[nvr2old]

If you've already broken through to bare metal spots around the area you're talking about, yes, stop sanding. You've probably gone as far as you can and as you mentioned will start negatively affecting other areas. Just re-prime and block sand that low area again. You'll be fine.