You shouldn’t have to grind cut laps anyway. Maybe a tiny bit at a corner overlap. Can easily be done but hand with a file or sandpaper on a hard block.
I’m a hack. I watched a bunch of videos by long time builders using hard thin flex pads, so I started using that. Now that I’m getting used to them, I’m liking it. You can press hard and cut a lot or use very light pressure and cut a very small band if you want. My former go to for laps was a 90 degree drill with a small rotek wheel. Usually on the second lap where you have a hard glassed surface, and not on the first lap where you have foam. Keith’s method of a file or sandpaper and a block is better if you are sanding the first lap. Also check out Bud808’s methods of using a roller to push the lap down to the same level as the foam. I use a roller a lot too.
Soft pads and the slow RPMs, I find best for finish work. I have destroyed 2 soft pads working the rails wrong. You need to use them a certain way with pressure on one side of the pad or it will bite and tear. Too much RPMs will do the same. Check out videos by this guy he shows how to use the sander. https://www.youtube.com/watch?v=lrrM4iVPVX4
I never use a soft pad that large to grind laps so have never experienced that problem. Flex Plads are a light touch. Pressure free. The harder the pressure and the higher the RPMs the more likely there may be a failure. Having said that; It’s still worth an email or phone call to South Shore Manufacturing to see what they think. I use a $17 Harbor Freight die grinder and a 2 or 3 inch 3M Rolodc disk 50 or 80 grit. Simple, straight forward, once around the block, no problem. A lot of guys use a block and 80 grit. But the inexperienced using a Milwaukee or a high RPM right angle grinder on laps is a recipe for disaster. For one thing it’s overkill. Too big! Too heavy! And; laps require a hard backer. Sorry for your misfortune. Maybe South Shore will help you out. That’s about a $80 screw up. But, at least you didn’t get the board
Keith is right. A little touch up at the tail and nose should be all you need for cutlaps But sometimes we get a little sloppy and have to clean things up. You should try the roller method and press them down when they are fresh. Helps a lot. Lowel
Yes you were Jonesin’ to use that Milwaukee. Save it for hotcoats and grinding plugs. Also the tendency when first learning how to use a sander is to run it at too high an RPM or apply to much pressure/muscle to it.
I did email them and they wrote back asking about some specifics related to Milwaukee Model # etc. waiting to hear more. Although I wouldn’t expect them to replace the pads cause I didn’t know what I was doing. Live and learn.
Yeah I guess there was a reason I felt nervous going into it taking that big of a machine near a poor helpless lap line especially with shaped foam exposed. Skeeettchhyyyy.
Luckily the board is OK since the lamination came out pretty swell.
Shoot… when sanding epoxy fill coats, fins, etc I sometimes really lean on the pad. I kind of expect them to hold up within reason and they do! I would not accept any blame at this point in discussion with retailer.
Next time consider something tougher maybe? Some of the softest pads are designed for kind of ‘cupping’ around a rail and won’t hold up to much abuse. I don’t know the RPMs at #2 on a variable speed Milwaukee sander but the one pad says “2800” and you were probably well within that limit.
