Sanding the hull
 

I will be sanding, priming, and painting the hull this winter. I'm trying to figure out how deep to sand. Is the below picture in the spots I sanded about right? Also does that look like fighting lady yellow under there? That's the color I'm actually going to paint it with interlux perfection.

http://i1326.photobucket.com/albums/...ps3ad68674.jpg

http://i1326.photobucket.com/albums/...psed7b3c3e.jpg

I would sand it all the way down to the gelcoat, which looks like what you have done in some spots. The polyurethane perfection dose not work over other types of paint. you can apply over polyurethane or epoxy primer but that's about it. Best if you take it to the gelcoat then apply a high build primer to sand on so you can fair out the surface then use the inturlux epoxy primekote to prime pre paint then use 3 coats of perfection. It is a self leveling paint so it will flow out flat and look good as long as you don't over do it and get runs. If you get a few runs just wet sand them out with 320 then add the second coat and then the third. I used it on my last hull I painted and it worked real well and turned out great for me a inexperienced painter. I sprayed mine but you can get a good finish rolling and tip method with interlux perfection too. The brush strokes will flow right flat and it will look like you sprayed it.

That doesn't look like fighting lady yellow. It just looks like the off white gel coat on a lot of seacrafts. It looks like the gel coat on mine.

Thanks guys. That was my plan frizz. Does interlux make a good high build primer before I do the regular interlux primer followed by the perfection.

There was no FLY factory gelcoat back in the day. The interlux epoxy primer builds high. You need to thin it wicked. I think it's suitable under Perfection paints.

Yes, They make a standard base primer and a high build primer as well.

You can also prime with the 2000e (It builds fast as well) for under the water line and it sands ez if done in the first few days of applying.

High build:
Interlux Interprotect 3000 High Build Primer Gallon Kit PN# 3000/3001-01

Interprotect HS is also a high solids that builds thickness faster than the 2000e and is good under the water line too.

All are 2 part epoxy products, Use the epoxy primekote for final prep prior to paint.

All are very thick and need reducing with 2316n

Water tight is a smooth fairing compound that is good under the water line too for light fairing and for filling blisters and cracks as well.

Just remember you can only use 2 part primers (epoxy or urethane) under perfection as it is a polyurethane.

Assuming I use the primekote, how many coats should I apply and how much would u guess I need to paint a 20 SF from the waterline up? Also, how much perfection for 3 coats on top of the primer? Thanks

If you fix all the imperfections and don't have to do to much sanding on the primekote you could get by with one coat but I would do two so that if you wet sand it block it down prior to paint you will not cut threw it.

On my 20"hull it only took 2 quart kits to do the out side (water line up - hull sides) but that was spraying it too. Rolling will waist less but it will go on thicker causing you to use up more possibly. I still had some left for touch ups afterwards. When I did three coats of primer it took a Gallon due to the primer going on thicker than the final paint. The primekote is much thinner than the 2000e base primer so 2 coats could be done with 2 quart kits as well. If you do any fairing or repairs and spray high build or 2000e I would get the gallon kit due to you will need to fair threw several layers to get it prefect. If your hull is clean and problem free you can skip that step and do just the final primer and paint but all imperfections will show threw if there are any.

By imperfections do u mean scrapes, gouges or something else? Thank you

Exactly, The scrapes and gouges will need filler. The rest and any light scratches can be filled with the high build primer. Also I found out on my 20' hull there were stiffeners glassed to the inside of the hull sides that showed threw in the gel-coat. Molds can get bad print threw from the roven fiberglass as well. There was a section that was kinda wavey from bad mold prep on my boat too. I had a lot of slight high spots that needed fixing so it would not show in the final paint. It took me 3-4 thick layers of high build and sanding with a blocking DA sander in between each layer to get all the imperfections and flaws out. Then I did 3 layers of primekote so it was thick enough to get a good wet sanding in it with out going threw the coat into the high build. In this pic you can see the high spots in blue where I sanded them down. I kept adding primer till I could sand with out high spots showing threw. Also alternate colors grey and white to show you where the different primers are. I used white primekote so It covers over it well and grey high build. When I sanded the white PrimeKote and the grey started showing threw I knew I still has some light high spots. A few coats I could wet sand with 320 grit and it stayed white.

High Build grey:
http://i1291.photobucket.com/albums/...ps474fddf4.jpg

The first pass sanding:
http://i1291.photobucket.com/albums/...psb871c70b.jpg

The second pass sanding:
http://i1291.photobucket.com/albums/...ps69ab8146.jpg

This is a good sander Hutchin straight line sander with DA rotary action:
http://i1291.photobucket.com/albums/...ps622da72a.jpg

Excellent!
 

Thanks. I'm just getting ready to sand, prime, etc. the 19' Moesly Bowrider. That is all great advice. I have a good air 5" DA w/o vacuum and a good electric 5" DA with vacuum. Would you suggest investing in the Hutchins straight line sander at $300+ with all this work in front of me? Since I'm doing this indoors, dust is a real concern.

And at what point are you going to fill the holes in the transom?

sand all the way down to gelcoat. prime. block sand. prime, block sand. prime... block sand...... repeat if necessary.... pay some one to spray.

Is a narrow block sander narrow enough to get the curved parts up near the bow. I know my 5" Orbital sander is too wide to get the bow area evenly.

Hutchins is one of the best. They are costly but you get what you pay for. There are many line sanders out there but most are just basic piston driven that only have a forward and backwards motion. Online you can get some low as $50 that are fairly good sanders but a line sander that is only directional one way (forward and back) will generate lots of scratches. I would use them for "ruff in" only! Usually they work best with 36 grit to 80 grit and will take down maternal fast and level it out well. Only problem is that they leave lots of scratches to fill or you can stop early and then finish down lower with a da and avoid filling them but you can take to much off to do this. Even with 320 grit you will get directional scratching with one. The one I have pictured in my earlier post is a Model 3800 which is a DA (Dual Action sander) It has the same size board 2 3/4"x16" as the straight line model 2000 but it has a action similar to the 5" or 6" da sanders most people use. It dose not leave the scratches behind like the piston driven model dose. You can use 180 -220 grit and get a good finish with it and still take down material fast. I get about the same finish (scratch wise) with a 320 hand block as I will with the 3800 hutchins with 220 grit in less than half the time. The narrow 2" wide block will get into tight curves while the 17" long board keeps everything flat and flowing together while working down a good section at one time. You can get similar results with hand blocks with lighter grit but you will work your self to death. They make a smaller version that is a 2 3/4" x 11" for tighter spots and they make a 2 3/4"x8" for even tighter spots. There is a 4 1/2" x 16" version and 4 1/2" x 9" for lager areas. They even have one that is a 8" x 18" for big flat areas like transoms and floors model 3805. The standard unit works well if just buying one but I would get 2 if possible- straight line model 2000 (hustler) for fast course grit and a Model 3800 for the fine light grit finishing. I have a $70 craftsman piston driven model that works fine but the 2000 hutchins is much faster and smother than the craftsman just like it. You can order any part to rebuild the hutchins sanders straight from them where the cheep ones you cant. A one time deal a cheep one will do just fine but you will have a hard time finding a DA action line sander for cheep. The straight piston course type is a dime a dozen.

For indoors all their models can have an optional vacuum attachment built into them,

What point do you fill holes in the transom? I fill any holes with fiberglass matt or 1708 if it is a bigger hole. Small tiny holes a syringe with thickened resin works well. I will do all the glass work First prior to priming and ruff it down with a 6" da or the course line sander then do any filling with fillers. Once I have everything close I will start priming, And at that point I will swith over to the 3800 da action line sander and work it with the fine grit. I use interlux watertite to do final filling if needed over the primer. It is a thin glaze putty that flows out well and can be used up to 1/4" thick they say but I try to keep it under a 1/16" if possible No more than a 1/8". At that point I will knock down the filler with a 6"round da for speed but use the line sander to blend large areas. The round 6" da works well for those small areas of spots of filler and random repair spots but if you try to do the whole boat with one it can cause the finish to have waves in it. The round sanders do well if held flat and worked right but you can get a flatter finish over a larger area with a long board or a block type sander.

One other product they just came out with, (I don't own stock in hutchin but do love their products) is the profinish line of round da sanders. They have a 3/32" stroke (model 500) for fine finish up to a 3/16 stroke sander (model 600) for fast sanding. This a cheaper line they came out with that is around $100 each on ebay new for da sanders vs the $350 for their 3500 original da's. I got one last year and love it. It is low profile and will not tilt over on you like the bigger more expensive 3500 model and they are composite not aluminum and are much more lighter. I know you can find da's from $20 to $500 and there are so many out there but I feel like their new proline series is the best bang for the buck you will find for a good quality sander at a fair price.

There are other brands like dynabrade that are just as good but I am a hutchins fan if you didn't know already, You get what you pay for and a few good sanders of the right type for the job goes a long way when redoing a boat....

I got 2 of mine used off ebay and one new for less than half price new and both were like new only used once and looked brand new when received. Shop around and you can find one for a good price. Jamestown dist. is fair on new ones too.

The standard piston driven single action:
Attachment 8920

The 3800 dual action:
Attachment 8924

The 3805: (this one is the larger 8"x 18")
Attachment 8923

This is the proline sanders that are reasonable priced:
Attachment 8922

The 2 3/4" wide line sanders will get just about any where. I did the bow of mine and just worked it up and down horizontally and it got in 95% of the areas. Dura block makes a nice hand set that has 5 bocks in their kit different sizes that will get just about anywhere and in any contour.

A lot of the work can be done with air tools but there is no replacing a good hand block set when doing a final wet sand.