Orbital Sander vs Belt Sander

Does it make a huge difference if you use an orbital sander or a belt sander? Also the boat I got I bought specifically to try and repair. The person who had it before me sanded all the way down to the green fiberglass in some places. So I will need to add gelcoat to the top again correct?

Thanks

acs026 said:

Does it make a huge difference if you use an orbital sander or a belt sander? Also the boat I got I bought specifically to try and repair. The person who had it before me sanded all the way down to the green fiberglass in some places. So I will need to add gelcoat to the top again correct?

Thanks

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I prefer a orbital sander however I never used a belt sander on my boat before. If you decide to go with an orbital make sure you start the sander while its laying on the boat and not in there air. I say this becuase if your not careful and do start it in the air and bring it down to fast on the boat you will see circles imprinted later.

A belt sander is much more aggressive than an orbital one--and not in a good way! Use the orbital unless you really want to see what your boat's fiberglass looks like underneath. BTW, there is a third option that I've preferred on many jobs, which is to wet sand by hand. I've done a whole catamaran by hand while restoring it, and I like the control it gives to avoid biting too much into the gelcoat. What, exactly, are you trying to accomplish on your boat?

As for using the orbital, I've heard (and practiced) the opposite of Jeepin, i.e., that you shouldn't start or stop the sander while contacting the gelcoat so as to avoid scuffs. (Just be careful not to set the sander onto the work surface at an angle.) Whichever, you can take out any scuffs by wet sanding with a fine grit paper (1000 or 1500). Just don't bear down too much.

Kevin

Good advice. If you are trying to take out some minor scratches, do it by hand.If you have some bumps or trying to smooth out some bad gelcoat, use a random orbital sander. If you start the sander "in the air," put it to work before it gets up to super high revs, or it will scratch the surface, as mentioned previously. You can start it on the work surface, but with a light touch. Dont forget to wipe down between sandings, as a single "grit" from a previous (coarse) sanding will give you a lovely circular design scratched into the gelcoat.

If the PO has sanded all the way to the glass, I would repair (generous re gelcoat) that area first then resand it with the surrounding area when you do your over-all sanding.

That's just my two cents. Good luck.

acs026 said:

"...The person who had it before me sanded all the way down to the green fiberglass in some places. So I will need to add gelcoat to the top again correct...?"

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A gelcoat repair adds very little in the way of strength: It's a time-consuming step you can skip if you're a recreational sailor.

You could just sand it smooth. Minor surface imperfections can be covered with paint.

If you want to check for "trueness" of the surface you can paint it with a test coat of gloss-black paint or just spray water on it to check for "hills" or "valleys".

If you bought the boat to practice on and/or to make it into a "beauty", it's possible your gelcoat patch may be a slight mis-match in color—then you'll want to paint it anyway.