Orbital sander or Sander Polisher??

[zooplax]

Hi all

Just looking for some advice on which tool to purchase.

I have a few hair line cracks and chips in the gel coat on the boat that I used a Dremel tool to open the area and then have used a Gel coat filler to fill it.

Didn't have a decent sander or polisher to finish the job off so need to buy one.

I was looking at Bosch Orbital Sander PEX 400 Ae (370w 125mm disc)
http://www.amazon.co.uk/Bosch-PEX-Ra.../dp/B005GIU3Y4
Listing even has a boat picture in the listing.. woop woop ;-)

But also looking at a Silverline Polisher / Sander 1200w 180mm.
DIY 1200W Sander Polisher 180mm

Two very different looking tools...

Except for the price does anyone recommend one more than the other in the long run?? and for using with boats? possibly other tasks i hadn't thought of?

The Orbital Sander with the smaller head does look like it will be handy on harder to reach areas. To begin with ill be doing the cockpit area so the small size for sanding i think would be useful (Boat is a 37ft with lowered GRP stern cockpit).

This winter I will be taking the boat out of the water and understand I will need something bigger than a 125mm head to polish and sand the hull and plan to buy another then or even a larger one to do the hull etc...

Can anyone advise are orbital sanders any good for sanding and polishing small areas with Gel coat?

for the moment I'm wanting to sort quite a few chips and hairline cracks around the boat in the Gel coat.

Appreciate any advice you can give. :-)

[cabo_sailor]

I don't think you need any of the power tools you reference. A selection of wet/dry sand paper in grits of say 320, 500, & 800 with a sanding block should work fine for small repairs. You perhaps would like a small tin of polishing compound for the final finish.

When using the wet sanding paper, I'd suggest a small pail with soapy water such as Dawn. It will keep the sandpaper from loading up so fast.

You will have better control and not make a small job bigger.

Rich

Ps: my first boat was a Morgan 32 that I wet sanded by hand with 1500 grit before polishing. Looked great, a lot of work but I didn't have to worry about the damage a power tool can do.

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[zooplax]

Thanks: cabo_sailor

I'm a big fan of power tools and the amount of ease they sometimes give, have tried the wet and dry sanding by hand already on this and it's just not working.. I'd also hate to eventually do the whole hull by hand.. Would rather be getting on with something else than doing it al by hand.

Anyone else got some insight into the mentioned two sander / polishers I mention?

Also it's a little more than hairline fractures one area had s many hair line fractures the area that needs sanded is 2ft by 2ft so sanding and polishing neatly is quite hard work..

[landonshaw]

I go with the hand polishing. I love power tools, have a bunch, but at times it is easier to control your pressure by hand than putting power to it.


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[Bulawayo]

We have both - though our Bosch is an older model. We use the Silverline purely for polishing. We have a number of power tools on board - mainly 18v DeWalt cordless.
Polishing a boat by hand is do-able but you grow old real fast doing so. Using the electric polisher means we do not put of doing this. Trying to do these jobs between tides by hand would really be hard for us - the power polisher, using our Honda generator makes the job pretty painless compared to the alternative. We also have a cordless polisher but the recharging time means using it for small jobs only.

[roland stockham]

Basic difference is speed. The faster sanders run the better they work but a polisher needs to have a good speed controller. 1, you can't turn a large polish mop to fast for safety reasons (they have max speed with instructions) 2, if you run it too fast you generate heat and can burn the surface or waxes. My suggestion is a polisher plus a 1/4 sheet sander (uses standard paper which is cheaper than buying the special discs). For large areas/repairs nothing beets a traditional long board.

[roverhi]

I like the versatlility of a sander/polisher. With a foam pad, you can use it to sand large areas with little fear of gouging after a little practice. Made up a planer pad with a piece of plywood glued to a foam pad. Took a large piece of rough sawn Koa and 'planed' it smooth with that set up. Also used it for rough grinding prep work before laminating to the FRP hull using 60 grit disk on a hard rubber pad. It's also a big time saver to use it for polishing the top sides at haul out.

The key to using a sander/polisher is keeping the RPM down because of heat buildup. Even at 2000rpm, 100 grit sand paper will remove a lot of material quickly.

Orbital sanders work fine on larger flat surface but are hard to control for detail on general sanding. The small diameter of the disks can also result in gouging even with 220 grit paper. Prefer using a 1/4 sheet vibrating sander like the Porter Cable Speed Block or cheaper models from Bosch, Milwaukee, etc. for finish work.

[TheThunderbird]

1) cordless Milwaukee handy grinder, w triangular head, and additional tools. With 2 batteries, it take less time to recharge than to deplete it in usage....

2) AC sander (metabo) 150mm diam:-)


... i cant live any more without them :-)
....

3) professional sander, for removing gel coat only
In italy (EU) you must operate it in fenced specific areas.. upon owner's permission.... with pro apparels, vacuum aspiration etc

[Uncle Bob]

Originally Posted by zooplax

Hi all

Just looking for some advice on which tool to purchase.

I have a few hair line cracks and chips in the gel coat on the boat that I used a Dremel tool to open the area and then have used a Gel coat filler to fill it.

Didn't have a decent sander or polisher to finish the job off so need to buy one.

I was looking at Bosch Orbital Sander PEX 400 Ae (370w 125mm disc)
http://www.amazon.co.uk/Bosch-PEX-Ra.../dp/B005GIU3Y4
Listing even has a boat picture in the listing.. woop woop ;-)

But also looking at a Silverline Polisher / Sander 1200w 180mm.
DIY 1200W Sander Polisher 180mm

Two very different looking tools...

Except for the price does anyone recommend one more than the other in the long run?? and for using with boats? possibly other tasks i hadn't thought of?

The Orbital Sander with the smaller head does look like it will be handy on harder to reach areas. To begin with ill be doing the cockpit area so the small size for sanding i think would be useful (Boat is a 37ft with lowered GRP stern cockpit).

This winter I will be taking the boat out of the water and understand I will need something bigger than a 125mm head to polish and sand the hull and plan to buy another then or even a larger one to do the hull etc...

Can anyone advise are orbital sanders any good for sanding and polishing small areas with Gel coat?

for the moment I'm wanting to sort quite a few chips and hairline cracks around the boat in the Gel coat.

Appreciate any advice you can give. :-)

Hi I can't emphasise enough, don't machine sand gel coat repairs, you will still have to wet sand and polish only it will take even longer!
The sander polisher is a peerfect tool to give that brilliant shine to prepared gel coat, and easy to use too.

[wbradreed]

I haven't started on the topsides yet. Thanks for the tip on the dremel. I took 3 layers of various bottom paints off the hull of my Alberg. I had the same question as you and bought an orbital and a sander/polisher. The sander polisher was harder to control. If it gets away from you, you can gouge the surface. The diminutive orbital, in comparison, was taking off material just as fast and was much easier to control. I burned up my cheap orbital in no time and bought a quality name brand which I have been unable to destroy. There was a tool for punching holes in the sandpaper so that the fan could draw dust from the paper into the collection bag. I found this increased the cutting power and made the paper last longer too.

Just one guy's opinion,
Brad

[zooplax]

Thanks for the advice everyone, its helped steer me to a decision.

So It looks like I'm moving away from Bosch for the moment for this tool anyway.

And have decided to go for the following: Sealey DAS149 -

Supposedly its an orbital sander but on websites says

1. It also polishes (takes polishing pads anyway)

1. Has 8mm Orbit,

1. Uses only 600w of power (my inverter I believe only gives out 1000w) hence why i don't believe i could use a 1400w Silverline model

1. Main factor was that it has a variable speed option from 1500 - 6800 RPM (which is about 2500 less RPM than all of the other Orbital sanders I've looked at, the bosch was 4000 - 22000)

Link to the item: Sealey

So.. looks like ill buy a smaller mouse sander for the hairline cracks and then use this for the larger areas.

If anyone thinks the above is the wrong way, other than wet polishing and by hand, which I've tried and will try again, happy to hear from you.

[sophiedaisey]

Recommend that you read an article on restoring gel coat in SailBoatOwners.com by Maine Sail. I followed his advice on 26 yo gel coat and it was a miracle. I bought the sander he recommended and also the materials. Like has been said previously wet sanding with fine grit makes a world of difference. Found that wet sanding by hand went very quickly.


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