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How should I sand/clean between boards before bottom paint

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caseyharris
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How should I sand/clean between boards before bottom paint

Post by caseyharris » Wed Jun 06, 2012 4:15 pm

Hello, I'm Casey the veteran again and I have questions and issues. I have been sanding the bottom of my 67 double lap constellation. How can I clean the seams between the wood...ie how can I get out the old caulk from between the cracks of the boat and do I even need to. Sanding the wood is easy but where and how much I need to clean the cracks,..... I don't have a clue. It had a professionally bottom job in 09 and lots of the cracks are still sealed. when do I know if I need to dig all the cracks and when not to. some gaps are huge and some don't need anything at all. I can send pics. my email is [email protected]
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Last edited by caseyharris on Thu Jun 07, 2012 1:48 pm, edited 1 time in total.

Peter M Jardine
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Post by Peter M Jardine » Wed Jun 06, 2012 8:39 pm

What you really want to look for is how hard the compound between the planks is... if it is crumbly and falling out, then yes, it needs to be cleaned out.
If it is still pliable to the touch, but the planks have gapped a bit, not a big deal, the plank will expand in the water, and seal up the gap.

Without seeing the seams, it is kind of hard to say... post us a picture.

A seam reamer is usually a hook shaped pick.. it can be made out of the tip of an old file, hammered to a hook, then sharpened somewhat on a bench grinder or another file. Here is the real issue: Chris Craft constellations do not use seam cotton, just calking. The size of the seam, and how the edges of the planks relate to one another is a pretty tight fit. If you use a seam reamer, you could quite easily damage plank edges. If you haven't done it before, use a mechanics pic, or a small slot screwdriver. Just get rid of the loose crumbly caulking or compound and put new in. Easy does it, especially if the bottom was recaulked in 2009. 8)

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debiby
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Post by debiby » Wed Jun 06, 2012 9:06 pm

I thought that there was not supposed to be anything between the planks, cotton or caulk. From what I have read in other posts you should use something like slick seam and let it swell untill the gaps close up. Am I wrong?
Dan Biby
38' Challenger "DreamOn"

Peter M Jardine
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Post by Peter M Jardine » Wed Jun 06, 2012 9:24 pm

I won't comment on the smaller boats, but it appears that pre-NAFI boats stuck to the ply/canvas/dolfinite smear before the outer planking went on. In the construction of my 36 foot 64 Challenger, there is no canvas or dolfintite, and it appears there was always some caulking between seams. On the larger boats some of the reasons for caulking later in the boat's life is the fact that after a significant number of years, the planking does not expand as much as it used to... making the use of caulking more obvious.

CC also used candle wicking with dolfinite at the chines, but I can't comment on whether any or all of these techniques were used into the sixties.. it is apparent that some of them were not.

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debiby
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Post by debiby » Wed Jun 06, 2012 9:56 pm

I am getting ready to paint the bottom on my challenger and she has been out for about 4 years. I found caulking cotton in the seams and was told not to replace it. The seams are all around 1/8 or less other than one or two that are a bit larger, I was going to just paint it now then a good soaking then when I get ready to splash I plan on using slik seam on the bottom seams. If I should caulk I would like to know with what so I can do it now.
Dan Biby
38' Challenger "DreamOn"

Peter M Jardine
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Post by Peter M Jardine » Thu Jun 07, 2012 4:22 pm

I have found a little caulking cotton up in the bow area on my Challenger express, but I don't believe it is original either. I use Sika or boat life, and I am careful about how much I put in the seam. Still, there are a couple of planks nearer the garboard that are wider, and they just don't expand quite as much anymore.

Wood Commander
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Post by Wood Commander » Thu Jun 07, 2012 9:36 pm

Top Side (Hull Side) seams on painted cruiser hulls do use seam compound. Bottoms on all models did not and should not have any caulking or paying. But over the years "stuff" does happen!
Bret

1953 35' Commander "Adonis III"

1970 23' lancer project

solopar
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Re: How should I sand/clean between boards before bottom pai

Post by solopar » Wed Apr 24, 2013 7:57 am

I have the same questions and thought that I would just add onto this post.

I have a 1957 19' Capri that I just finished sanding the bottom on. The bottom is original, but I can see where somebody has epoxied the bungs on the bottom. There is also a little caulk of some sort in a few places. Overall the bottom looks good and my partner and I decided not to put a 5200 bottom on. The boat hasn't been in the water for at least 5 years, but I did test the wood by running water into the bilge. The hull leaked like crazy at first, but it did tighten up pretty well (for a 50 year old boat).

I'm a bit worried though. After becoming intimate with the bottom through the sanding process :), a lot of the canvas that was in the seams came out. The seems have a lot of loose crap in them and all the seems are about 1/8" to 3/32". From my understanding, the boat was originally planked, lined with lead soaked canvas and then planked again. That's it. I think that the wood will swell pretty well, but I gotta believe I'll still have a fair amount of water in the bilge at any given time. I was thinking of putting dolphinite in the seems b/c it stays flexible and can always be scrapped out.

So now to the advice, should I...

- Leave as is, paint it (btw using the original copper based paint that costs $100/quart - that might give you and idea of my poor judgement :). See what happens with regards to swelling.
- Scrape seems so they are completely clean with a seem reamer, and fill seems with dolphinite, then paint.
- Scrape seems and fill with something else?

What do you think? I can add some pictures if needed.

Thanks in advance.

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Doug P
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Re: How should I sand/clean between boards before bottom pai

Post by Doug P » Wed Apr 24, 2013 11:24 am

If your bottom seams are < 1/8", they should be ok.
If you need to clean them....use a tile grout cleaner.
Pettit 1959 copper bronze is $50 a quart.
Many references to your situation in earlier boat buzz.

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debiby
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Re: How should I sand/clean between boards before bottom pai

Post by debiby » Wed Apr 24, 2013 11:43 am

Mine swelled up just fine and my gaps were like yours. I am still seeping water someplace and will have to figure it out once the water warms up but not so bad it is a big deal. I put some slick seam in the bigger gaps and wish I would have done them all just so it wouldn't leak so bad before it swelled. The only trouble with that stuff is you have to clean it off after it gushes out of the seams. Good luck.
Dan Biby
38' Challenger "DreamOn"

solopar
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Re: How should I sand/clean between boards before bottom pai

Post by solopar » Thu Apr 25, 2013 6:38 am

Ok, the consensus is that I should bet the seams clean and then bottom paint and then drop her in the water. I guess that I'll make sure that the bilge pumps are working:) I guess that I am just a little paranoid, it makes me nervous when you can see tiny holes in the bottom of a boat, but the swelling of the wood should make those disappear. I remember when I was about 12 my dad and I scraped, sanded and caulked a 29' Belcraft. My older brothers used to help, but they were away at college so it was up to dad and I to get the job done. Luckily the boat was big enough to need a sling, b/c she took on so much water she sat in the sling for 3 days. My brothers still make fun of me for that:( Thanks!

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debiby
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Re: How should I sand/clean between boards before bottom pai

Post by debiby » Thu Apr 25, 2013 8:13 am

Mine is a 38 footer and she leaked like there were no walls when we first put her in, talk about scary and stressful. If you leave it sit on the trailer for a day or two that would help.
Dan Biby
38' Challenger "DreamOn"

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Doug P
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Re: How should I sand/clean between boards before bottom pai

Post by Doug P » Thu Apr 25, 2013 11:30 am

Solopar. I do not suggest you put the boat in the water dry.
There are ways to presoak the boat before putting it in the water.
Many will put 3-4" of water in bilge.
You can also tie a soaker hose around the gunwale and allow the hose to drench the exterior of the hull.

solopar
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Re: How should I sand/clean between boards before bottom pai

Post by solopar » Sun May 26, 2013 12:29 pm

We are getting ready to put her in the water in the next couple of weeks. I think that we decided that we will soak her as much as possible from the inside of the hull with a garden hose. Then we will let her set a for sometime on the trailer and finally we are working on a back up bilge pump (already have 2 ready to go). I'll report our progress as we go in the next few weeks.

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