Wet sanding enamel?

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Gwoloshyn
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Wet sanding enamel?

Post by Gwoloshyn » Thu Nov 22, 2012 9:42 am

I've painted my boat using SM-1000 and need to wet sand to get the orange peel out. I don't know too much about painting so looking for some advice and if this is alright to do. I tested it on a small spot with 400 grit and got a smooth dull finish which I plan to polish after it's done.

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Andy Garrett
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Re: Wet sanding enamel?

Post by Andy Garrett » Fri Nov 23, 2012 7:20 am

Here is the application sheet for that product:
http://supermarinepaint.com/applying_su ... lution.htm

It does not cover wet sanding but from my experience with single stage paints, you will want to give it plenty of time to cure (at least a week or so) before you do it. It has to be hard to get the best results.

A stiff foam backing for your wet/dry paper will create a nice level surface without taking it down too thin. Keep a close eye on it though. When you no longer see little shiny low spots, you are done.

If you use 400grit, don't press very hard! You can go right through pretty fast. 600 grit is more forgiving. 1000grit after that goes pretty fast and will yield stunning results if you do it evenly (depending on your selection of buffing/polishing tools/products).
Andy Garrett

Perhaps the slowest Zip build in Glen-L history...

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Roberta
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Re: Wet sanding enamel?

Post by Roberta » Fri Nov 23, 2012 7:42 am

What Andy said and go out to 2500 grit in 500 grit increments. Then use 3M Finese and varying foam pads. Finish with machine polish and wax. Wait at least two weeks after the last coat before starting any wet sanding for your finish.

Roberta :D
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Gwoloshyn
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Re: Wet sanding enamel?

Post by Gwoloshyn » Fri Nov 23, 2012 3:08 pm

Thanks. I actually started wet sanding today after waiting a week after painting and got good results starting with 600 grit paper knocking down the orange peel. Problem I have is there are many low shiny spots that need to be removed, but I don't want to go any further sanding risking bleeding through to the primer. I already did in a small spot (on the bottom). I'm using one of those stiff foam drywall sanding sponges as a backing for my sandpaper, it's working pretty well. We sprayed 3 coats so that should be enough. Maybe the paint just went on a bit thin in that area.

I'm going to be sanding with 1000 grit next than 1500. I'm using 3M Finesse-it II polish with a variable speed machine buffer to finish the job.

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Roberta
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Re: Wet sanding enamel?

Post by Roberta » Fri Nov 23, 2012 4:50 pm

The low spots are tricky. I'm in the process of applying Epifanes to my Zip. What I need to do to get that really flat shiny finish is to literally fair the varnish down as I lay down more coats. What I have been doing is putting on several coats, then longboard sanding the high spots and very lightly scotch brite sanding the rest by hand to get the glaze off for the next coats. Eventually I will smooth out the surface and it will be all one level or curve, as it were. This is a very painstaking and lengthy process, as you are finding out, and I will have at least 16 coats of varnish on before I get to the level of flatness for that really deep gloss. What your experiencing are those dipitydoos in the surface that stand out as you sand down the high spots. The only way to get them out is to keep on painting and sanding until the surface levels out and you gradually fill in the lows. You have to go slow and not remove too much product or you will sand through. When I longboard, I only remove a small amount of varnish to rid the small bumps. Then the scotch brite is done only enough to scuff for varnish adhesion. High gloss finishes need to be really flat or the gloss will reflect all those irregularities. Best of luck in the finishing.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Gwoloshyn
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Re: Wet sanding enamel?

Post by Gwoloshyn » Fri Nov 23, 2012 8:02 pm

I agree it's very time consuming but that's alright with me as long as my finish turns out nice in the end. This also gives me more time to plan my next steps and save some more money for materials.

I like your process but unfortunately I cannot paint any more because my spray booth has been torn down. Should I continue to sand down MOST of these craters and leave the rest be? I'm not looking for a showroom perfect finish here either. But I also don't want all these irregularities to really stand out once I buff out the paint. I'm under the impression that the dull sanded areas will be gloss, and will blend in with the glossy craters to some extent, maybe enough to satisfy me. Am I right?

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Roberta
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Re: Wet sanding enamel?

Post by Roberta » Sat Nov 24, 2012 5:34 am

I would think the sanded areas should buff out to the original gloss. It will take a lot of buffing. Be careful not to sand sand too much and go through.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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billy c
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Re: Wet sanding enamel?

Post by billy c » Sat Nov 24, 2012 6:26 am

three coats isn't much of a margin if you are sanding out the surface. there will be little paint protection left even where you don't cut thru.
IMO you should tip and roll a few more coats. much easier application for a beginner to control than trying to learn to spray on this large surface.
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