Sanders and Sandpaper - hull paint removal

[CLM65]

To break up the tasks inside the boat (stringer and transom work), I have started sanding the outside of the hull.  It has previously been primed and painted, so I need to remove all of that so that I can gelcoat it later.  I have a basic 5" DeWalt orbital sander and Bosch 40 grit paper.  It seems to be doing the job, but it is sloooow going and I'm using up quite a few discs.

Can anyone recommend a better, more powerful tool?  And what is the best sandpaper to use?  Note that I do not have a large air compressor, so going to an air sander would be an expensive change.  Therefore, I'm thinking electric.  But if a DA air sander is 10x better than an electric sander, I would like to know that too.

[jwill3131]

I know exactly what you are going through right now, I am using probably the same dewalt sander and 40 grit also. It is doing the job but it is taking a while. I have a buddy that offered to sand blast it off at his shop for $40 an hour so I am thinking of going that route so I can spend more time working on the rest of the boat instead of spending my weekends sanding. Good luck, I'm interested to see what else could be suggested.

[OldSkool67]

you can run the 7 inch grinder with some 60 grit, but it will leave you with a lot of fairing to be done later.  Its all a wash in the end.

[CLM65]

jwill - sandblasting is tempting, but I've been cautioned against that several times due to the risk of damaging the fiberglass beneath the paint.  It is fine for the inside of the hull, since that is probably going to get covered in new glass anyway, but outside...I'm not going to chance it.

Ryan - I must admit I've looked at my rotary a few times, but I haven't given in yet.  I know you were in the same situation with a painted boat, and managed to get through it with a couple of orbitals.  I recall you said your Makita did a better job than your DeWalt.  I've been looking at more powerful sanders than the one I'm currently using.  I think I may pull the trigger on a Bosch 1250DEVS.  Not cheap, but I have a lot of paint to sand, so it may be worth it.  Besides, a guy can never have too many tools, right?

[slippery73]

Have you thought about using a chemical stripper?  We purchases industrial stripper through our local paint supplier and it will pretty well take off anything.  I'll include a manufacturer link below of the producer, you can probably call them and see who you can purchase from locally.

Word of caution however.... this is industrial stripper. We wear full face respirators with enclosed eye protection, tyvek suits, chemical gloves, etc.  

http://bencosales.com/store/index.php


If you do want to go the sander route, look for a sander with a rotary option instead of just an orbital. I know festool makes one that has a switch from straight rotary to orbital, I believe porter cable has a rotary as well.  The rotary is just basically like a low speed grinder, it just spins. But, it takes off material quick.  

I'd say your best option is to try the stripper or seek a company out that can do it for you. It takes forever to sand a hull correctly where your not fairing or having a really distorted surface afterwards.

[bondobill]

If you use a chemical stripper make sure it's safe to use on fiberglass.
I made that mistake and used a aircraft stripper on the first Corvette I ever painted  
I ended up stripping and repainting the entire car one panel at a time
Every time the owner took the car out on a hot day bubbles would appear in the finish on the body panels. The stripper I used the first time had got into the fiberglass and when ever the glass got warm from the sun it would cause gas bubbles in the new paint.
They make chemical strippers that are for fiberglass. One I have used a lot used to be called Corvette Stripper .

[CLM65]

I have tried a chemical stripper from HD, and oven cleaner as others have recommended, on my bottom paint, but they were pretty much ineffective.  I'll call the company in slippery's link and see if I can get a sample.  I don't want to buy a bucket if it is not going to work.

Thanks for sharing your experience, Bill.  I don't have any experience with chemical strippers, so knowing the limitations and things to consider is very good info.

The sander I might buy is an orbital with rotation - like a DA, but they don't call it that for some reason.  Should be more agressive than an orbital, and not as dangerous as a true rotary.

[HIFLUTIN]

Ive had better luck with a  Pneumatic DA ,works better than electric for heavy duty sanding