Polishing Before and After

ZZ13 said:
Why no circular sanding strokes? Is that so you won't inadvertently create a low spot?
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Never sand in circles, and always follow the direction of the body lines as your final sanding. If you get a piece of dirt or scratches that come back afterwards, they will be minimized by the eye in the direction of the lines.
 
RollerCoastr said:
We need to talk you out of compounding with the 7424. It'll be 3 weeks before all the blood you'll shake out of your hands returns, and the results won't be nearly as good as using a simple vibration-free rotary.
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Lol...

Curious on everyone's thoughts on rotary vs. orbital. I've read that rotary's should not be used by amateurs because the unintended consequences (risk of melting your gelcoat if you don't know what you're doing for one). On the other hand I've read here and elsewhere that random orbital buffers give a more consistent shine without the swirl marks.

Aside from vibration induced neuropathy from an orbital -- why rotary over orbital?
 
Here's some of my work on a couple customer's boats.... Crappy cell phone pics, but I think you can see what I'm trying to convey about my methods.

Before - Had zero shine. Completely chalky. Tree sap and mildew everywhere.

IMG_20130401_181820_077.jpg



After - 800 grit, compound, polish, wax. Literally like a mirror. No refraction of the light. Glass.

IMG_20130405_184211_485.jpg




Another customer's boat....

After -

IMG_20130418_181358_148.jpg




Another boat -

IMG_20130423_190048_821.jpg




Doug
 
I have both a Makita orbital and a Porter Cable 7424 - The Porter will NOT take the sanding marks out. The Makita has the grunt to do it with a wool pad.If you keep the Makita moving and let it do the work you will not do any damage to the gel. You really have to want to damage the gel to damage it.
 
The risk of damage depends a LOT on the material. I've burned my boat in 3 different places using a rotary machine, a wool pad and Finesse-It II. All it takes is hovering too long in one spot. The worst burn actually produced a puff of smoke! Fortunately, it was the top of the arch, but the burn mark faded and disappeared in just a matter of months anyway. (all of them did)

I still use Finesse-It II on a regular basis, but I mist the surface with water as I work. The water greatly reduces the chance of a burn and extends the product at the same time.

Buff Magic poses very little threat of burning. I assume that's because being oil-based, it contains lubrication properties.

Turbo Cut is water-based, so I will tread carefully with that in regards to burning potential.
 
RollerCoastr said:
The risk of damage depends a LOT on the material. I've burned my boat in 3 different places using a rotary machine, a wool pad and Finesse-It II. All it takes is hovering too long in one spot. The worst burn actually produced a puff of smoke! Fortunately, it was the top of the arch, but the burn mark faded and disappeared in just a matter of months anyway. (all of them did)

I still use Finesse-It II on a regular basis, but I mist the surface with water as I work. The water greatly reduces the chance of a burn and extends the product at the same time.

Buff Magic poses very little threat of burning. I assume that's because being oil-based, it contains lubrication properties.

Turbo Cut is water-based, so I will tread carefully with that in regards to burning potential.
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I use a wool pad for polishing with Finesse-It II every spring. Also use a rotary machine. If you set the RPMs to 1500, the pad does not get hot enough to burn gel coat. Just don't lean on it too much, keep moving and let the pad do the work. Hope to be doing this in 2-3 weeks. I also use a clean wool pad to apply the wax, again at 1500 RPMs. Works like a champ.
 
Tjjf44, the amount of sanding depends entirely on the thickness of the oxidation layer. So on the top of the boat where it gets the most sun and damage you have to sand a lot, on the sides of the hull where it gets less sun you sand much less. It just takes practice and experience to determine how much to sand. You get to where you can feel that what you are sanding is harder than what you started with. When the gel coat is very chalky it is soft and sand easily. It makes a lot of white sludge as you sand. When all that oxidation layer is gone, the finish is harder, when you rub the paper or your hand on it it feels smooth and slick, and as you sand the white sludge turns clearer signifying that you have sanded away all the oxide layer, which is what you are trying to achieve. If you don't sand it all away, it won't polish up well and you'll just have to sand it again. Spider poop stains are the best indicator for sanding. The spider poo will stain all the way through the oxidation layer, but not into the good non oxidized gel coat. So keep sanding until the spider poo stains are gone and you have eliminated then oxidation layer. On my 400 DA it took two guys 4 days to sand, polish and wax from the railing down to the waterline. The boat was out of the water for two days while we did from the rub rail down to the waterline. We also used 25-30 half sheets of 1000 grit paper!

Hope this help!

Someone else also asked the difference between the effectiveness of a rotory buffer over an orbital buffer. I've used both and would say that the rotory if 100 times more effective that the orbital. On a boat I would say the orbital is a total waste of time for anything except putting on wax or polishing isinglass.

Good luck,

Pete
 
Pete, did you consider Presta Supercut as a one step solution rather than the two steps of sanding then compounding? I have read where some users consider it the wonder drug of gelcoat restoration.
 
douglee25 said:
Here's some of my work on a couple customer's boats.... Crappy cell phone pics, but I think you can see what I'm trying to convey about my methods.

Before - Had zero shine. Completely chalky. Tree sap and mildew everywhere.

IMG_20130401_181820_077.jpg



After - 800 grit, compound, polish, wax. Literally like a mirror. No refraction of the light. Glass.

IMG_20130405_184211_485.jpg




Another customer's boat....

After -

IMG_20130418_181358_148.jpg




Another boat -

IMG_20130423_190048_821.jpg




Doug
Click to expand...

Is that your blue BMW m3? I had a 99 Coupe the same color and same wheels. Loved it!
 
I don't have true before pictures of my boat, but it wasn't good, and it now looks showroom new. I've used the Presta side-by-side with Buff Magic on the same section of boat, and it was a complete joke. I've used gallons and gallons of 3m products, and the only product they had that even remotely stacked up was Perfect-It III Extra Cut (not Perfect-It 3000), and they stopped making it. I've buffed countless boats as I used to do it professionally, and I've used everything that's out there, and I'm still constantly on the hunt for the next great thing. Presta is it.

I have no stake or financial interest in Presta of any kind. This is my unabashed opinion, backed up by years of experience.
 
My assumption is you only use the Presta as a one time restoration application. That it is too abrasive to use it annually. Is that correct?
 
ZZ13 said:
My assumption is you only use the Presta as a one time restoration application. That it is too abrasive to use it annually. Is that correct?
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It can be used annually if you just use less of it. If I would normally use a 2' long ribbon of it to do a 3x3 section (or something like that), You could just use a 1' long ribbon.
 
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