SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Questions: Bottom paint prep work for trailer boat

10K views 22 replies 11 participants last post by  Renceb 
#1 ·
Ok..now 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 - 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.

Mike
 
See less See more
#2 ·
This months Practical sailor has a good review of bottom paints and how well which paint worked. Where are you located ?
 
#5 ·
Mike,
You'll find my description of how I did my 21' Cal in this thread:http://www.sailnet.com/forums/gear-maintenance/32011-bottom-painting-trailerable-sailboat.html

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. (!)
 
#6 ·
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.
http://farm4.static.flickr.com/3049/2327269217_b79faf29dc_b.jpg
http://farm3.static.flickr.com/2251/2327278341_e9421bb087_b.jpg
http://farm4.static.flickr.com/3090/2328094532_1a7a19824d_b.jpg
http://farm3.static.flickr.com/2122/2328093064_27be182634_b.jpg
http://farm4.static.flickr.com/3035/2327274303_190404a89f_b.jpg
http://farm4.static.flickr.com/3087/2327272867_605782cbf3_b.jpg
http://farm3.static.flickr.com/2074/2327270423_b9c9b38b35_b.jpg

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.
http://farm3.static.flickr.com/2308/2328083746_d332fdd1c5_b.jpg

Any suggestions, comments, or criticisms?

Thanks...

Mike

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

http://farm2.static.flickr.com/1031/1317485300_d2469e6aff_o.jpg
 
#8 ·
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.
 
#9 ·
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.
 
#10 · (Edited)
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.
 
#13 · (Edited)
I've finished all of the sanding except for a small area under the bow roller. But that will be easy to take off and do. Now just waiting for my paint to come in. I used concrete blocks with two 2x8s on top along with a towel for cushioning. I thought I would have to do the bow also, but as I lifted the stern, the boat came up enough off the bunks for me to sand underneath the entire length of the bunk area. I guess this was because the bow was resting on the bow roller. I placed jack stands under the front part of the trailer to take some of the pressure off the trailer jack. I used sandpaper attached to a piece of wood to sand under the bunks as I was not comfortable sticking my whole hand between the bunk and the boat. For the small area under the keel I used a piece of sandpaper attached to a long stick so I would not have to get under the trailer while it was being supported as it was. I don't mind getting under it while the boat rests on the trailer but I was not about to while it was on those concrete blocks. I am linking some more pictures from my flickr site. Any suggestions or constructive criticisms? Please send them my way.....

Mike

Note: I was not finished sanding when I took these pics so the hull still looks shiny where the bunks were. But they are nice and matte looking now...

http://farm4.static.flickr.com/3267/2329034591_4a1e3406dc_b.jpg
http://farm3.static.flickr.com/2350/2329856792_74ddd461f1_b.jpg
http://farm4.static.flickr.com/3044/2329031907_bb1738ca50_b.jpg
http://farm3.static.flickr.com/2027/2329030363_25b0b18bdf_b.jpg
http://farm3.static.flickr.com/2352/2329852208_6c8ba623e8_b.jpg
http://farm3.static.flickr.com/2370/2329850828_ec0ba24929_b.jpg
http://farm3.static.flickr.com/2183/2329025945_7b7f1eb5ac_b.jpg
http://farm4.static.flickr.com/3266/2329021839_a143b1d54f_b.jpg
http://farm4.static.flickr.com/3271/2329846148_ed3859b6a2_b.jpg
http://farm4.static.flickr.com/3224/2329024377_bf08a46f70_b.jpg
 
#14 ·
this one still has enough shine to reflect the towel. It's your call because sometimes pictures don't cut it:
http://farm3.static.flickr.com/2370/2329850828_ec0ba24929_b.jpg

My earlier comment was based on what I now see be reflected bunker boards (the black looked like previous paint).

Seriously, it's all fine. Paint it, launch it, pull it in 6-8 weeks and take a look. If you can take a snorkel here and there and scrub the bottom.
 
#16 ·
Yeah I guess I should clarify. I was not finished when I took those pictures. That was right after I lifted the boat off the bunks...I assure you that it looks like a matte finish where you see shine. But thanks for noticing. That's why I post the pictures to see if any of you more experience sailors could give me some advice......
 
#15 ·
That hull looks awfully shiny for something prepped for new paint... One way to tell if the hull is really clean is to spray it with water... if the water beads up or sheets anywhere, then you've got some more cleaning to do.
 
#18 ·
I sure hate to see anyone trust their or their boats safety to concrete blocks.
They can crack and split and you could end up with a lot bigger problem than you started with.Timbers of some kind(railroad ties?) would be a lot safer.
 
#20 ·
The concrete blocks are not the blocking to be using. Especially since they are stacked the wrong way! The holes in the blocks should be vertical and not horizontal! The strenght of the concrete block in in the direction of the holes. Please, be very careful since there are only three parallel webs supporting the weight.
Yeah I went against my better judgment when I bought the blocks but I am anxious to get my boat in the water and I could not think of anything else that would be strong enough to do the job. This winter I am going to invest in some boat jacks. Thanks for the advice on turning them the other way. I got my paint in today and I will stack them differently when I paint the bottom this Sunday.....

Mike
 
#19 ·
The concrete blocks are not the blocking to be using. Especially since they are stacked the wrong way! The holes in the blocks should be vertical and not horizontal! The strenght of the concrete block in in the direction of the holes. Please, be very careful since there are only three parallel webs supporting the weight.
 
#22 ·
http://farm3.static.flickr.com/2069/2339361598_74282fce0e_b.jpg
http://farm3.static.flickr.com/2284/2339363912_91949003e4_b.jpg
http://farm3.static.flickr.com/2187/2339368454_3a770837f5_b.jpg
http://farm3.static.flickr.com/2414/2339366150_2348ab7bd2_b.jpg

Well finished my bottom paint job today. I know it's not as pretty as some of you more experienced painters but I did it and I saved about 650 dollars. It took almost 2 quarts of VC17. Now its time to put it in the water for the season. The next project will be sandblasting and repainting my trailer after the boat is off of it this summer.

Things I learned after my first bottom paint job.
1. Use a power sander next time instead of a sanding block.
2. Use 80 grit sandpaper instead of 150 grit.
3. Find somebody that rents boat jack stands.
4. For the hard to reach areas that a roller will not go use a foam sponge to "pat" the area.
5. Copper powder is very very messy.

Mike
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top