SailNet Community

SailNet Community (
-   Gear & Maintenance (
-   -   Questions: Bottom paint prep work for trailer boat (

venturousviking 03-10-2008 04:46 PM

Questions: Bottom paint prep work for trailer boat since you all have convinced me to paint the bottom on my boat I am looking for some opinions and constructive criticism on my methods. I have a Capri 18 that's never had bottom paint. Its a 1989 model. I am using VC17 paint. I have 2 quarts of Interlux 202 solvent to wash the hull. I am going to sand the hull with 150 grit sandpaper since Lowes doesnt seem to have 180 grit. Does it matter if you wet sand or dry sand the boat? To get the area under the bunks on the trailer I bought these jack stands. Torin Double Lock Jack Stands ó 3-Ton Capacity, Model# T43002A | Jack Stands | Northern Tool + Equipment
I am going to use concrete blocks under them to add about 18 inches or so to the stands. I am going to lift the stern and bow one at a time by using the trailer jack and placing the stands under the stern and bow. Should I use a 2x4x10 doubled on top of the jack stands to support the boat or maybe a 1" round iron pipe? The reason I ask about the pipe is because of the curvature of the tops on the jack stands. It seems like it would be more secure than the wood. I checked Interlux's website on the amount of paint and it suggested 2.5 quarts for my boat so I will get 3 quarts for good measure. How does everything sound so far? I will be posting pictures of my progress to help out other people that may have the same dilemma.


Freesail99 03-10-2008 04:59 PM

This months Practical sailor has a good review of bottom paints and how well which paint worked. Where are you located ?

sailingfool 03-10-2008 05:11 PM

54 Attachment(s)
Use 80 grit paper, dry is fine, see the interlux instructions. You need 80 for the paint to bite to the hull.

venturousviking 03-10-2008 05:21 PM


Originally Posted by sailingfool (Post 280506)
Use 80 grit paper, dry is fine, see the interlux instructions. You need 80 for the paint to bite to the hull.

Actually I just checked the site again and it says 320 for bare fiberglass. I wonder where I got 180 grit from? Oh well...


sailaway21 03-10-2008 06:21 PM

You'll find my description of how I did my 21' Cal in this thread:

If you're looking for those finer grades of sandpaper you need to look for wet-dry paper. Lowes should have it. It's black. As SailingFool says though, for the bottom paint you're going to want a course grit to etch the hull and give the paint something to adhere to. Use the Interlux 202 before sanding.

Get two quarts of the VC-17 in one color and another in the color you want for the finish coat. That will make your application more uniform and will also allow you to see wear more easily. I didn't do that but wish I had-another lesson learned. (g)

I don't think you're going to find those automobile jack stands of much aid. What might work quite well though is a bottle jack for the lifting and then a couple of 4x4's at bow and stern supported by those concrete blocks. You'll jack each end sequentially until you can get the trailer out from under. Within reason, the higher you get the boat the easier it will be to work on. Read the thread I've posted here and if you have any questions feel free to send me a private message. You CAN do this cheap. (!)

venturousviking 03-11-2008 09:17 PM

Ok I cleaned the hull with Interlux 202 solvent and now have started the sanding. I am using 150 grit sandpaper and everything seems to be going well. I should be able to finish with the sanding tomorrow. Here are some pics of the progress.

How long should I sand? Until there are no more shiny spots?

This is the distance from the bottom of the hull to the ground at the stern. I am going to use concrete blocks and a 4x4 on top. Then I am going to use the trailer jack to get the stern of the bunks then do the same thing at the bow.

Any suggestions, comments, or criticisms?



A shot of my boat in the water last year..

sailingfool 03-11-2008 11:49 PM

54 Attachment(s)

Originally Posted by venturousviking (Post 280510)
Actually I just checked the site again and it says 320 for bare fiberglass. I wonder where I got 180 grit from? Oh well...


I know 80 grit was correct, so i took a look and confirmed it in the Micron CSC instructions, but then noticed that the instructions for VC17 actually does say 320 go figure. I haven't used VC 17 in fifteen I live and learn.

sailingdog 03-12-2008 01:00 AM

An easy way to get the boat off the trailer is to use the trailer as a "see-saw". First lower the trailer tongue as much as possible and block the stern, then raise the tongue as much as possible to raise the bow up and then block the bow. Should work fairly well for a boat as small as yours.

You want the whole area to be painted to be uniformly dull. If there are any shiny spots, you've missed something. The hull has to be sanded for the paint to adhere well to it.

Wash the hull really well before sanding, as you don't want any oils, grease, waxes or other contaminants on the hull when you sand it. Sanding it without thoroughly cleaning the hull will embed those contaminants in the fiberglass and may interfere with the paint sticking.

Sailormon6 03-12-2008 08:58 AM

Catalina started barrier coating their boats at the factory in about 1989, so your boat probably has a barrier coat on it to protect it from blisters. If you sand off too much, you'll lose that protection. I'd sand it the bare minimum necessary to scuff the bottom so that the paint will adhere.

chucklesR 03-12-2008 09:11 AM

Bare minimum - using a finer grit - the 320 as recommended.

It's too late now, but less is best. You really don't need a big toothly ripple for the paint to get a mechanical bond. On the other hand, ignore all advice here and believe and follow the directions of the manufacture.

PS. some of that doesn't look like bare fiberglass to me.

All times are GMT -4. The time now is 07:23 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
(c) LLC 2000-2012

For the best viewing experience please update your browser to Google Chrome