125mm or 5" hook and loop recommendations?

[Ian_Edwards]

I have a fairly large sanding job coming up on gelcoat.
I can get 150 assorted paper disks from Amazon for £19, but the reviews are very mixed.
Mesh disk seem to be much more expensive.
I need a range for 80 grit up to 600 grit.
I bought some from B&Q , the mesh ones don't seem to last very long, and the paper ones clogged quite quickly but that was sanding Hammarite white gloss paint, which seems to be very hard.
Can anyone recommend some good quality hook and loop sanding disks, either mash or paper backed?

 

[Restoration man]

Forget all the other abrasives spend the extra and buy Mira abranet mesh sanding disks these guys invented the technology, I’m tight arse but i won’t waste my money on any other sandpaper hardly clogs and stays sharp

 

[Ian_Edwards]

Thanks for that, I've just ordered some Mira Abranet mesh sanding disks, 80, 240 and 600 grit, that should be good enough, then polish with Meguiars compounding polish. I might need a bit of 1200 wet and dry between the 600 and the polishing.

 

[savageseadog]

Buy an interpad as well, a foam pad that goes between the backing pad and standing disc. Not only does it reduce wear and tear on the backing pad it increases the speed and effectiveness of the Sanders.

 

[JimC]

Are we talking about random orbital sanders or rotary?

 

[Ian_Edwards]

I'm using a random orbital sander, not sure what others are using.

 

[lustyd]

on gelcoat don't use orbital you need to use paper and use it back and forth on a bit of ply or it'll take you weeks.

 

[Restoration man]

Thanks for that, I've just ordered some Mira Abranet mesh sanding disks, 80, 240 and 600 grit, that should be good enough, then polish with Meguiars compounding polish. I might need a bit of 1200 wet and dry between the 600 and the polishing.

Hope you don’t mind me asking , exactly what job are you doing on your boat??? , you mentioned starting with 80grit and then going though the finer ones to finally polish, I’m assuming your using a rotory polishing machine ( mop) for the final stage? , hope you have very thick gelcote as 80 grit and even 240g will will rip trough the gel very quickly, ive burnt through with just using the a rotory polishing machine ,trying to go from 80g to polished finish on large area is quite a task ,

 

[dankilb]

IMHO, Abronet is not the best choice for boatwork. It is a more advanced and expensive version of Mirka’s original mesh - Autonet, which is usually 2/3 to half the price.

So convinced of this was a (large/national) locally-based car paint/body supplier, they as good as refused to sell me Abronet in coarse grit (‘waste of money, mate’).

Abronet might be worth it for fine finishing, wet sanding, etc. Otherwise, go for Autonet (we used 3 boxes of 80 on our osmosis treatment).

 

[Ian_Edwards]

Thanks for all the input, some of which was too late, I've ordered Abronet, and it's on it's way, so too late to stop.
I'm hoping to sand off the non slip on a part of the deck, which is under the boom, that seldom, if ever, get walked on.
The non slip pattern looks like it was generated with a roller, it's is not a diamond pattern. It's quite shallow, perhaps no more than 2mm peak to trough.
The gelcoat is thick, looks like at least 2 coats applied with brush or roller.
Although it's the deck, it's a removable panel, which covers the halyards and reefing pennants between the mast and the cockpit.
It's about 2 m^2, and part of it is covered in sealant, I suspect CT1. I've scrapped off the bulk of the sealant but can't remove the sealant in the valleys of the non slip. I haven't been able to find a solvent which comes any where near softening it so it can be wiped off.
Sanding, just down the the troughs of the non slip should be quite easy to detect, the sealant is very obvious. 80 grit might be bit fierce, but that will become obvious.
There are also various holes in the deck which need repairing, and several areas where the gelcoat has obvious bubbles under it, where it hasn't bonded to the the foam core GRP under it. Some of these have already cracked open, that's how I know that the gelcoat is thick, if I go carefully, I shouldn't go though it.
I have gelcoat of the correct RAL number. I'll repair the bubbles and the holes as part of the job.
I think I have all the stuff I need, ready to load into the car, the boat is 165 miles away.

One thing I'm not sure of, is what kind of backing pad I need to buy, I've never used one before. There's a forest of option when I google "125mm backing pad for a Ryobi random orbit sander", which is what I'm going to use, because that's what I have.
I assume that I'm looking for some form of foam pad, with hook and loop on both sides, so it can sandwich between the Abronet and the sander.

Any suggestion on the best backing pad option to buy, I can order it for delivery to the yard?

 

[savageseadog]

There are quite a few, I couldn't really recommend one. We bought a few of the Toolstation ones which fell apart, they don't sell them any more, they were incredibly effective while they lasted. A tip though. I would suggest starting and stopping the sander while in contact with the job as the partial momentary contact when placed while running tends to destroy backing pads and/or throw the disc off.

 

[dankilb]

Any hook/loop backing pad should work.

On a presumably reasonably flat deck, I’d just go for ‘pad saver’ types. These are thin (3mm) and allow you to apply flat pressure from the existing pad.

For curves, e.g. hull/topsides, we used ‘soft interface pads’. These are thicker foam (maybe 10+mm).

Any old eBay ones seemed fine to me. They don’t last long as the Abronet seems to give them a harder time than grit discs. Still, you’ll want to protect the sander’s actual/original pad from that wear.