Soda Blasting Bottom

[Mark Wey]

The bottom paint that the previous owner has chosen has now come back to haunt me. Bottom Kote XXX is the brand that I must now remove. Not sure how many coats are applied, but way to many to sand off. I have heard of a process (like sandblasting) using soda bicarb in place of sand. Has any one heard of this or had experience with it?

By the way the replacement bottom treatment will be VC Tar followed by VC-17. This is a fresh water boat and I used this stuff on my C-30 with great results.

Mark

[Ted Pounds]

Mark,  

I've heard of soda blasting.  I believe it does a good job.  I had my bottom corn blasted.  They used esentailly ground up popcorn kernals.  It did a fine job getting the paint off and leaving the existing barrier coat behind.  Though I also put on two coats of VC-tar before the VC-17.  The cost was $1200 to have the yard do the blasting.  I think it was well worth the money not to have to deal with that mess.  One piece of advice:  make sure you close all your thru-hulls before any kind of blasting.  I had corn bits and bottom paint in my engine strainer and bathroom sink and fouling the flapper valve in the head. :)

Ted

[Norris Johnson]

I had a lot of experience with soda blasting in the chemical plant where I worked. It does a great job and removing bottom paint is a great application. You can use a different media for each job depending on the amount of paint to be removed. You can acutally take the first layer of paint off and leave the rest. Don't know why anyone would do that, but I'm just making a point. Too bad for me, but my yard doesn't have a soda blaster. Just curious, but what does a yard charge to remove all of the paint down to the gelcoat with a soda blaster?

[Mark Wey]

What a forum.
Type in a question, go to bed, wake up with three answers. Awesome! I don't know what it will cost as my yard does not offer this service. However I will look around for someone in the mobile business and get prices and info. Will post when I have the details. I assume that the reason we use Soda is so it is easier on the FG.Is there anything else I should watch out for? Is it possible to go to far?

Again thanks to all!

Mark

[Norris Johnson]

The advantages of Soda blasting:  

 - enviromentally friendly

 - A good operator can control the media so it takes off the correct amount of paint.

Like sandblasting, you can go down to the fiber glass and beyond.

[Mark Wey]

I have found a company experienced with sand-blasting. However they have no experience with soda-blasting. Is it much different from using sand? I also have an hourly rate quoted at $55 per hour plus I supply the soda. Is the soda just standard Bicarbonate of Soda or something else? Any ideas on how long it would take to do? Any thing else I should know?
Thanks,

Mark

[John Gardner, Seventh Hea]

I had a bad experience with my previous boat - a Catalina 27.  The operator sand blasted away the paint and just about everything else.  Instead of just painting I spent half the summer refinishing the bottom of the boat.  Make sure you have an experienced operator, and/or be there while he does it.

[Roc]

I think blasting the paint off is too invasive.  As John mentioned, more than just the paint can be blasted off.  What about Peel-away? Has anyone tried that.

-Roc-

[Mark Wey]

Roc

I saw the results of both processes. Both have pro's and con's. An experienced operator can adjust his equipment to take off as much or as little at a time as is required. Don't forget we are using Soda not sand. The peel away that I saw did not give acceptable results. It was a Catalina 42 only three years old. While to the smooth touch it felt like it had worked, but by looking at it you would have said it was only half done. This boat was only 3 years old. Mine is 13 and the PO plastered on the Bottom Kote XXX. I plan to be their when the boat is done and can control the agression used. Just an opinion. Any others are welcome.

Mark

[Ted Pounds]

I tried Peel-Away. It softend up the barrier coat which tended to come off with the paint.  Meanwhile in other spots it left paint behind.   That's why I went with corn blasting.  The cost was $1250 and it did a much better job.  Mark is right it's soda (or corn in my case) not sand which probably makes a big difference.  I'm sold on blasting.  Don't forget to close all your thru-hulls before blasting.

Ted

[Jim Rose]

I had the bottom corn blasted last spring.  She is a 2000 MKII.  The results was excellent, a company contracted by the marina performed the work.  It's expensive but worth it.  I stuffed rags in all the thru-hull fittings also taped cardboard around the strut to protect the cutlas bearing and metal prep work.  I solvent washed the bottom and washed again with soap and water.  Applied two coats of interlux micron extra.  She will be hauled for winter next week the bottom should be fine.  The bottom was never prepared properly when delivered and the paint wasn't adhering.  The sanding days are over, too much work.

[Mark Wey]

Gentlemen:

I hate to tell everyone this, but I also want to prevent it from happening to others. After careful consideration and fact-finding including this board. I decided to remove multiple coats of antifouling paint.  Namely “Bottom Coat XXX.”  To make a long story short it turned out beautiful.  Soda blasting is not the issue. I would do it again in a heartbeat. Now, for the rest of the story.

We started blasting on a very windy day, with rain showers threatening. Not a whole lot of options this time of year. My main concern was the neighboring boats. Not a big deal. Just a little difficult to keep the protective tarps in place. I had the boat hull covered (but not the deck). In addition, tarps on the ground to try to reclaim the spent paint/soda mix for proper disposal.  The wind continued to gust and would blow under the tarps and force the dust mixture out near the top between the toe rail and the tarp. It was then deposited on the deck. We were about one third finished when the fun starts or Murphy’s Law kicks in. Take your pick.

First, the motor on the sand blaster quit, and the operator retreats to his shop to try to find a new starter. Of course, it is an oddball and will need re-winding. This is not going to happen today. Ok tomorrow then. However, I cannot be there. Work just keeps cramping my sailing activities. Therefore, the operator goes ahead and finishes the job with out me. The wind was up again that day and then the rains came. I managed to go the next day and attempt to clean up as much of the mess as possible. I rented an industrial vacuum cleaner and removed as much off the ground as possible. While it is not ideal, it is as good as I can do. The marina owner had given me permission for this project and offered his clean up advice as I went along. Next, the rains started again and I had to stop for the day. I could not get back for a week and we have had a lot of rain in the interim. I came today equipped with a pressure washer wanting to remove as much as possible before I cover the boat for the winter.

I climbed the ladder and I was mortified! The paint/soda mixture had done a real number on the deck. Both on the non-skid, the gel coat and the teak.  I scrub (again in the rain) and try assorted cleaners that I had on board. Nothing works. What to do, I removed as much as possible with the pressure washer. I call it a day. Along with the paint mess, I notice a very distinct yellowing color in the corners. Anywhere the water would pool. I did coat the complete topsides with “Future Floor Finish (not wax) last spring as discussed on this board. Is this yet another chemical reaction that I will have to deal with?

I called the tech dept at Inerlux whom is the paint manufacturer. They offered their commercial strippers as their only suggestion. But did warn me that if the deck was painted and not just gel coat it would probably remove parts of the deck paint as well. Second choice was their thinner that would be used if the deck was painted. It is not as harsh on the original paint but of course no guarantees.

I then called Catalina Yachts and left a message with the tech dept. I await a wisdom filled return phone call.

Of course, I would like to enlist all of you as well.

Here are my questions.
1)   Is the gel coat painted or not?
2)   Is the non-skid painted on or not?
3)   Will this get worse through the winter, or can I wait and deal with it in the spring?
4)   As a last resort. Has anyone ever applied Awl Grip to their deck?
5)   Any suggestions are appreciated.

By the way, besides opening up the keel joint on the leading edge and some minor crazing on and around the rudder the bottom is in great shape.

Mark