Using a flap disk

two stroke mick · 18 February 2014, 15:35

AS I have stated in previous posts I am planning to flow coat the deck of the rib. It was suggested to use a flap disk to sand the deck rather than a orbital sander. Is there any knacks/ tips to using flap disks for this type of work.

TSM

Bigtalljv · 18 February 2014, 15:44

Be very careful. A flap disk on a grinder goes through metal very quickly, it goes through fiberglass like it's not there.

Tim&Linda · 18 February 2014, 15:53

they great but i also used those sanding discs with rubber backing plate on a small grinder

good luck

nugent · 18 February 2014, 15:58

Both workwell glass is stronger than you think

nugent · 18 February 2014, 16:01

God dam I pad

two stroke mick · 18 February 2014, 16:10

I got two flap disks with 40 grit paper. Are these the right type and are two enough for a 5m rib?

TSM

nugent · 18 February 2014, 16:14

Quote:

Originally Posted by two stroke mick

I got two flap disks with 40 grit paper. Are these the right type and are two enough for a 5m rib?

TSM

Should be fine. Dusty as hell tho

Wightdiver · 18 February 2014, 16:17

Quote:

Originally Posted by two stroke mick

AS I have stated in previous posts I am planning to flow coat the deck of the rib. It was suggested to use a flap disk to sand the deck rather than a orbital sander. Is there any knacks/ tips to using flap disks for this type of work.

TSM

Buy several grades and see which one works best for you.

jyasaki · 18 February 2014, 16:22

Are you trying to remove the existing gelcoat, or just key the surface for the new coat?

If the former, then you're probably OK (though 40 grit sounds a little coarse to me.)

If the latter, I'd think about going to a flap wheel on a drill rather than a grinder and flap disk. The loose leaves on a wheel are not as aggressive.

Then again, I don't have a glass hull, so it isn't something I have experience in, either.

jky

two stroke mick · 18 February 2014, 16:56

I want a key for some fibreglass and a key for flow coat

Bigtalljv · 18 February 2014, 17:27

i did the whole bottom of my boat with 40 grit on a 6" RO air sander. Gelcoat is tough, the 40 grit worked great. Anything less wouldn't cut the gelcoat. The second and third time I sanded the bottom I used finer grits on a regular 4" electric RO before epoxy and paint.

Jason

Peter_C · 18 February 2014, 20:58

I use a flap disk like the blue one posted above on metal all the time. There is no way I would take it to fiberglass and expect it to be flat when done. They just don't have enough surface area to keep the material flat.

I would on the other hand use my DA sander, and keep it moving to keep a flatter surface. The sanding surface area is 6".

Gramas · 18 February 2014, 21:52

Try keep grinder as level as you can!!! No sharp steep angles as edge will cut in and gouge. Used to build Ali boats and you can dress surfaces neatly if you use sweeping motion letting the grinder do the work ! Don't force it

two stroke mick · 19 February 2014, 09:54

Used the grinder and flap dick last night. It works very efficently. As stated keep it flat. In one spot I let it stand for a tad long and it did dig a localised hollow. Not hard to repair.

Pikey Dave · 19 February 2014, 11:05

Quote:

Originally Posted by two stroke mick

Used the grinder and flap dick last night. It works very efficently. As stated keep it flat. In one spot I let it stand for a tad long and it did dig a localised hollow.

Somebody stop me, please..............:P

Wightdiver · 19 February 2014, 11:35

Quote:

Originally Posted by Pikey Dave

Somebody stop me, please..............:P

Maybe it’s not a typo???

kerny · 19 February 2014, 12:12

Go on PD I dare yer

two stroke mick · 19 February 2014, 13:08

Very good. I will let the smart ones figure out if it was a type or if I was typing my actual experances

TSM