Scared to Sand

[moonie5961]

Hello boat gurus,

I have a problem. Yesterday I cleaned, dewaxed and otherwise prepped the topsides of my Contest 31 for sanding- but after doing a very small test section, I stopped. I have a new Porter Cable 7335 bought after reading this site, and I am afraid that I am going to take too much material off of my topsides. What should I sand to?

What grit is appropriate for removing old paint? I am reluctant to use too coarse of a grit, but won't subsequent sanding with gradually increasing grit yield a nice, smooth surface?

My situation is this: I am planning on rolling and tipping either Alexseal or Awl grip, the current paint is an unknown but I am guessing it's the cheapest Bright Sides can that the PO saw on the shelf at West. I know that I can't put a LPU over this paint so I am going to sand down to gelcoat. Here, I get a little nervous. Is there any danger of going too far at this stage? I have never worked on fiberglass so I really don't know what I'm looking at.

What if my gelcoat is crazed under the current paint that's on there?

I think that the underlying problem for me at this point is that I'm scared to start. I bought this boat with the plan that it's going to be a learning platform, and that while I will strive for my best, I wlll not beat myself up over the learning curve. I just need to bite the bullet!

As an aside, I would like to thank Tim and the forum at large for this site, and all of the project documentation, its very helpful!

austin

[Shoalcove]

Hi Austin,
There are certainly more experienced folks here than me but I did go through this last spring. I used 80 grit most of the time to remove the old paint. Keep the sander moving and move on once the paint is gone. The hull will need to be primed afterwards and a high build primer will adher nicely. I sanded my primer to 220 before painting. I used Perfection paint and was happy with the result but I won't tell you it was perfect when finished. From 10 feet it does look excellent but up close there are flaws. I'm OK with that, I saved enough over a Pro job to buy new sails!
Grinding old paint is mind numbing and hard on the shoulders. I tied a rope to my sander and looped it over the lifelines and attached a counterweight to the other end. That way the counterweight lifted the sander and I just had to guide it. Also rig up some sort of scaffolding. It makes life MUCH easier. I rigged up a vacuum to the sander and wore ear protectors and a respirator. The fine dust isn't the best stuff to be breathing.
Best of luck,
David

[Rachel]

Hi austin, and welcome!

I can certainly relate to your current thoughts. My mind also tends to think of the myriad of possibilities, at which time temporary paralysis + research ensues. On the one hand, it can really get in the way of a project, but, on the other hand, it keep you from doing things like grinding through your hull with 20 grit, or putting Awlgrip over Brightsides (as you already know).

I have a feeling you will get some really good, really specific advice here, but since I wanted to chime to say "Welcome," I'll add a couple of my thoughts:

1) First of all - and maybe you have already done this - I might step back and think about whether painting the topsides is the project to do now. Of course that depends on you, and the boat, and your plans for the boat. But if you are a beginning sailor (and for all I know you've been around The Horn, so I may be way off base), and if the current paint is acceptable, well, maybe it would be less intimidating not to have the perfect paint job this season. And as you're imagining in your mind, projects do have a way of becoming more involved than you first think.

On the other hand, maybe this is a clearly necessary or desirable project, and you're not going to launch right now either way; and/or you are certain you do want to paint right now.

2) You can't go wrong by starting with a "gentle" grit, sanding a small area, and then slowly going to rougher grits until it seems about right. Then you can proceed with the rest of the boat. Another way to get a clue is to read the primer can, and see what they say about sanding and prepping. Of course you will want to start with a rougher grit than what they say to end with, but it can at least give you something to go on. Keeping the sander moving will also be "safer." You could also potentially hand sand or hand scrape a small area just to get a feel for it, before bringing the big gun of the Porter Cable.

Too bad there really isn't the old "inconspicuous area" to test on. That said, if it is Brightsides-like, and the paint is not great, what's to stop you from sanding an area, say, under the counter (stern not galley ;), just to see what you have under there? If you find something that makes you say "Okay, not this year!" you could re-paint that area with Brightsides to hold you over.

If you'd care to show off your Contest, I know that you will have an appreciative audience here, and also it might help people to give you more precise answers to your paint questions.

Rachel

[Idon84]

Hello Austin, Welcome,

I'm doing the same project right now. Removed all of my Brightsides topside paint, nonskid, and bottom (the whole boat essentially) with 40g with a 7335 on a #4 setting. Now I'm filling and fairing before switching to 80g. Then after that 120 before primer. I think my biggest lesson learned in the whole project was the proper speed of the sander. Many think higher speeds work faster (5-6) but you tend to overheat the paper and it looses it's effectiveness quicker. I get much better results on a setting of 3-4 with less risk of causing extreme damage on the fiberglass from accidentally riding the sander on an edge.

[Tim]

Do you have to sand the bottom by chance? That would be a good place to learn the feel of your sander before attacking the topsides.

DA sanders are powerful tools and can cause damage it misused. It's all about experience, so start with less visible areas and feel your way along and learn how the tool works in your own hands. Unfortunately, there's no easy secret other than just learning your own way. Use lighter grits till you get the feel of things. Paint removal will be slower, but you'll run less risk of doing damage that will take even longer to repair.

[moonie5961]

Thank you for all of the replies. I have to say, I am shocked at the difference in tone between this forum and some others that I frequent. What a novel concept, that people help each other and offer encouragement rather than engage in endless pissing contests. I appreciate you guys very much.

[Mario G]

180 grit is great to start out with, if theres a heavy build of old paint then start with 80 grit, but it chews quick.

More importain try to keep the sander flat or you will make groves.

I've been restoring cars for years and know tilting a sander wrong makes fro rippled surface. Ant sanding you do you should have a block behind the paper, I even wrap sandpaper around paint sticks cut down to 4" to sand small areas. 180grit is the best for even-ing a surface.