To soda blast or not?

[Bearkeley]

Would love to get some advice for the group. We have adhesion issues according to the yard and they are recommending soda blast then epoxy primer and paint. I trust his recommendations but not sure if it makes sense to spend the money (a little over 4K for 30ft) now, or just sand and paint (1800) and have the bottom cleaned as needed. Oh, yard requires we buy paint from them if we decide to paint it ourselves, so we may just have them do all the work.

Our plan is to cruise this winter for 5 or 6 months, then either haul out for a couple of years on dry storage, or sell. Thoughts?

 

[Comodave]

If the current bottom paint is so thick that it is peeling off then you probably need to soda blast it off and start over. I hope they are referring to epoxy barrier coating and not a primer. If they are blasting, doing a proper barrier coat and then bottom painting then the price isn’t too fat out of line. A proper barrier coat would be a feature if you do sell the boat.

 

[Lou_tribal]

If the current bottom paint is so thick that it is peeling off then you probably need to soda blast it off and start over. I hope they are referring to epoxy barrier coating and not a primer. If they are blasting, doing a proper barrier coat and then bottom painting then the price isn’t too fat out of line. A proper barrier coat would be a feature if you do sell the boat.

Isn't a barrier coat depending on the resin that was used to build the boat? To my knowledge polyester/vinylester resins are permeable to water, epoxy is not so the later one does not require a barrier coat. Am I out of my mind?

L

 

[Bearkeley]

If the current bottom paint is so thick that it is peeling off then you probably need to soda blast it off and start over. I hope they are referring to epoxy barrier coating and not a primer. If they are blasting, doing a proper barrier coat and then bottom painting then the price isn’t too fat out of line. A proper barrier coat would be a feature if you do sell the boat.

They are planning to use Pettit Protect Epoxy Primer. https://pettitpaint.com/products/primers/below-the-waterline/pettit-protect/. It looks like it’s made for bottom jobs and repairs blisters but not sure if it’s the same as a barrier coat

 

[ksanders]

I have my fiberglass boat bottom painted every 2-3 years with ablative paint.

All they do is to sand the bottom which leaves a patchy look and re-paint a couple coats of bottom paint.

That way no build up over time.

Soda blasting works, but so does sandpaper on a disk sander.

To me soda blasting is reserved for thin lightweight material like floatplane floats.

 

[Comodave]

Isn't a barrier coat depending on the resin that was used to build the boat? To my knowledge polyester/vinylester resins are permeable to water, epoxy is not so the later one does not require a barrier coat. Am I out of my mind?

L

I don’t know of many, if any at all, that were laid up with epoxy resin. It would be very expensive to do.

 

[Comodave]

I have my fiberglass boat bottom painted every 2-3 years with ablative paint.

All they do is to sand the bottom which leaves a patchy look and re-paint a couple coats of bottom paint.

That way no build up over time.

Soda blasting works, but so does sandpaper on a disk sander.

To me soda blasting is reserved for thin lightweight material like floatplane floats.

We had a previous boat soda blasted because the PO just kept putting on bottom paint, non ablative paint, and it became very thick. So thick it was starting to peel off. Sanding would have been out of the question to remove the old bottom paint. Soda blasting made it very easy and was very cost effective for removing the old paint. I then used an epoxy barrier coat and ablative bottom paint.

 

[BruceK]

Would love to get some advice for the group. We have adhesion issues according to the yard and they are recommending soda blast then epoxy primer and paint. I trust his recommendations but not sure if it makes sense to spend the money (a little over 4K for 30ft) now, or just sand and paint (1800) and have the bottom cleaned as needed. Oh, yard requires we buy paint from them if we decide to paint it ourselves, so we may just have them do all the work.

Our plan is to cruise this winter for 5 or 6 months, then either haul out for a couple of years on dry storage, or sell. Thoughts?

4K soda blast and paint vs $1800 sand and paint sounds cheap. It`s a lot of work. Eventually build up needs to be stripped back,peeling/lost adhesion is a good indication, I`d do it.

 

[Portage_Bay]

A caution on buying paint from the yard.

Some yards will use left over coatings from previous jobs. I would insist on seeing new unopened containers being used on the job. That will require you or a trusted observer are witness at the time of coating.

Another way to handle it if you can't witness is buy the paint yourself and pay the yard their markup.

 

[FF]

"So thick it was starting to peel off. Sanding would have been out of the question to remove the old bottom paint."

Actually with some effort if the bottom does not have steps or channels sanding is quite easy fast and effective.

A large grinder fitted with a 2 inch thick sanding disc pad and by using sanding disc adhesive and a square snapped from a floor sanding source should do the job in an hour .Leave the ears on , it helps not creating a depression.

The material from the floor sanding folks looks like a hunk of cardboard with silicone carbide chunks stuck on.
#16 is fastest but requires some practice as the unit must Barely touch the surface being sanded.
A home hardware store that rents floor sanders will have the sanding material and sell you 2 or 3 ft , a long time supply.

Start with finer grit like 40 grit if you have never used a grinder to practice.


WEAR A MASK!!!!!!

 

[GoneDiving]

I just had my new to me bottom blasted. It removed any and all loose and defective paint and created a clean, solid, blank canvas so that anything added in the future will be on a good base. It also gave reassurance as the condition (both good and bad) of the hull became very visible

While everything was out it was also easy to spot blast any other questionable areas on the hull. Note my vessel is steel.

 

[Gdavid]

If you are looking at getting the boat back into service quickly, the value of soda blasting is greatly diminished. After spending the money to soda blast, it is best practice to allow the boat to lay up for a few months to ensure any moisture has escaped prior to applying an epoxy barrier. Given your situation, I would have the yard scrape and sand flaking paint and just have one layer applied to get you back underway.

When your are done for the season, I would think long and hard about whether your are going to keep or sell the boat. If you are keeping it, soda blasting just prior to long term storage is really smart if you are selling, I would put it on the market prior to hauling it and hope to offload it prior to paying for storage. End of season is usually a bad time to sell but this market is so crazy that you may be able to find the right owner ready to step in prior to paying for storage. Additionally, shoppers can see the boat in working order prior to decommissioning everything for storage.

 

[psneeld]

I have to disagree that after soda blasting that you have to let a boat dry out.


Unless the blasting also too the gel coat and possibly the mat underlayment off, drying out is a crap shoot that can take many, many months and still not be dry.


Blasting is just a paint removal tool usually (not sure soda blasting can even remove a fairly solid gelcoat).


If...and that is a big if.... the hull is in good shape but never had a barrier coat...and you blast the paint off down to bare gel coat...again if sure the hull is dry...then a barrier coat is then a pretty good idea at that point. It's cheap insurance against later problem. But a barrier coat over a wet hull is like painting over rotten wood...a disaster in the making.


Very few boaters and very few professionals/yards really have a good handle on hull saturation,blisters, de-lamination, hydrolysis, etc...etc... there can be a lot going on there...take very little advice from forums and do real homework if there is a blister, wet hull issue.


But for a simple paint removal by soda blasting...heck it's just money and makes for a new start n your choice of bottom paint systems and future.

 

[Gdavid]

I have to disagree that after soda blasting that you have to let a boat dry out.


Unless the blasting also too the gel coat and possibly the mat underlayment off, drying out is a crap shoot that can take many, many months and still not be dry.


Blasting is just a paint removal tool usually (not sure soda blasting can even remove a fairly solid gelcoat).


If...and that is a big if.... the hull is in good shape but never had a barrier coat...and you blast the paint off down to bare gel coat...again if sure the hull is dry...then a barrier coat is then a pretty good idea at that point. It's cheap insurance against later problem. But a barrier coat over a wet hull is like painting over rotten wood...a disaster in the making.


Very few boaters and very few professionals/yards really have a good handle on hull saturation,blisters, de-lamination, hydrolysis, etc...etc... there can be a lot going on there...take very little advice from forums and do real homework if there is a blister, wet hull issue.


But for a simple paint removal by soda blasting...heck it's just money and makes for a new start n your choice of bottom paint systems and future.

I have no idea of the condition of the hull and whether removing the gelcoat would be warranted but from the estimate of $4k for a 30' boat, I was assume it to be pretty extensive.

It sounds like alot of labor for just paint removal of 30' boat (no matter which method) whether it is just alot of bottom paint or the gelcoat as well.

In either case I would not spend the $4k now.

The situation may be that the remaining bottom paint is so poorly adhered that the only way the yard is willing to take on the job is to remove it all, this is understandable as boat yards don't want to put out shoddy work. If this is the actual situation, you have no option but my bottom line advice would be avoiding it if you can ifbyou are just looking for 6 more monthes of cruising

 

[psneeld]

I was mostly disagreeing with after blasting laying up for a couple of months to dry out.


Unless the gel coat is removed and sometimes even more layers, 2 months won't hardly do anything even in a hot, dry climate according to most of the reliable studies I have studied.

My real point is beyond simple blister repair and bottom paint...mos boaters are not educated well on the subject and even most yards don't have all the facts.

 

[Fr8dog61]

The yard that painted the bottom on my new to me MS Pilot 30 slurry blasts. Very aggressive but I watched and it did not remove the gel coat, although it roughed it up a bit. The media used was black beauty and having sandblasted cars with it I was concerned. It did a good job and with the right operator, I think it is fine. The point of this is that I have had cars soda blasted and I don’t see how you could remove gel coat with it. I had a 1965 Volkswagon Beetle soda blasted and you could see the stamping marks in the steel. It is definitely less aggressive than sanding with a DA. My opinion would be soda blast it (or slurry blast) and start over.

 

[Bearkeley]

Lots of great feedback. Thank you! The yard is simply removing the paint via the blast and doesn’t think there’s an issue with the gel oat…as far as he can see. The soda blast work will be around $2k-2500. Paint and primer and labor will be the other $1800-2k.

I’m think I’ve attached a picture of the bottom after haul out and power wash. She has been on the hard since April and won’t be in until October so hopefully she’ll be really dry. Could we be opening up a can of worms if they blasted it and found blisters? Seems like the Pettit Epoxy he wants to use can fix and prevent, but wonder what’s under the years of paint!?

Would a blasted bottom add more speed? 1/2 knot on a trawler as you all know is a big deal!

 

[Comodave]

Lots of great feedback. Thank you! The yard is simply removing the paint via the blast and doesn’t think there’s an issue with the gel oat…as far as he can see. The soda blast work will be around $2k-2500. Paint and primer and labor will be the other $1800-2k.

I’m think I’ve attached a picture of the bottom after haul out and power wash. She has been on the hard since April and won’t be in until October so hopefully she’ll be really dry. Could we be opening up a can of worms if they blasted it and found blisters? Seems like the Pettit Epoxy he wants to use can fix and prevent, but wonder what’s under the years of paint!?

Would a blasted bottom add more speed? 1/2 knot on a trawler as you all know is a big deal!

I am not familiar with the Petit Epoxy. If it is just a primer than it won’t help as a barrier coat. I use Interlux Interprotect as a barrier coat. Don’t you want to know if there are blisters? I would want to know, at least how bad they are anyway. I doubt you would get a significant speed increase in a trawler. Maybe in a high speed boat you would see an increase.

 

[m10brink]

I can't comment on the longevity of the soda blast/paint yet, but we did the same thing for our 40' this summer. We had a similar situation: years of paint applied that really needed to come off and give us a fresh start.

FWIW, the price for the sandblasting you mentioned seem quite in line with our final bill. The soda blasting portion was about 2,500 at the end of the day. (Bigger boat than yours, but probably a bit cheaper out here in the Midwest.) Good luck whichever direction you decide to go!

 

[Comodave]

About 8 years ago we had our then boat, four boats ago, soda blasted and it cost $35 per foot. But we live in a very small city and the prices are quite reasonable.

 

[BruceK]

Lots of great feedback. Thank you! The yard is simply removing the paint via the blast and doesn’t think there’s an issue with the gel oat…as far as he can see. The soda blast work will be around $2k-2500. Paint and primer and labor will be the other $1800-2k.

I’m think I’ve attached a picture of the bottom after haul out and power wash. She has been on the hard since April and won’t be in until October so hopefully she’ll be really dry. Could we be opening up a can of worms if they blasted it and found blisters? Seems like the Pettit Epoxy he wants to use can fix and prevent, but wonder what’s under the years of paint!?

Would a blasted bottom add more speed? 1/2 knot on a trawler as you all know is a big deal!

A smooth bottom is definitely faster.
If you had blisters they should not be concealed by the antifoul paint, they should be apparent. Blisters are best viewed just after haulout while the hull is wet or drying off The yard would surely be quoting for blister repair if they are present.
I think the advice to allow months of drying out conflates stripping for a/f build up with blister treatment, and is wrong.

 

[FF]

Since you are contemplating selling the boat there is a good plan B.

Scrape the bottom to get rid of the loose old paint and then paint over all with soft inexpensive bottom paint
. This will stop fouling for the months you contemplate using the boat and still allow the old paint to depart.

The next owner can contemplate just how smooth he is willing to expense the bottom.

Smooth does make a difference on racing sailboats where 10 seconds a mile counts.

If the bottom is fairly smooth the speed will not increase as major resistance is caused by wave making, the fuel consumption will be higher (but you cant measure it) because of the increased surface area.

A clean prop does count tho for speed and fuel burn.

Scrape it , paint it cheap, and go have fun!!!

 

[Mako]

Our plan is to cruise this winter for 5 or 6 months, then either haul out for a couple of years on dry storage, or sell.

Scrape the bottom to get rid of the loose old paint and then paint over all with soft inexpensive bottom paint. This will stop fouling for the months you contemplate using the boat and still allow the old paint to depart. Scrape it , paint it cheap, and go have fun!!!

Although this has been an interesting thread on sofa blasting, @FF’s comments above are the only ones I’ve read that are logical.

You’re selling the boat. Why in the world would you waste/dump thousands of dollars into it? Knock the loose stuff off, paint with cheap anti fouling and go on with life. And if you’re planning on storing for several years, we’ll… don’t! Sell the boat.

 

[mike66]

I have been in the FF camp for 10 years now......every year I have areas of bottom paint fall/scrape off. I use ablative paint, former owners apparently didn't. At some point all the old stuff will eventually fall off. I don't sweat it, but perhaps the fish in Newport, RI are a little offended by the less than perfect paint.

 

[Alaskan Sea-Duction]

Following

 

[Bearkeley]

Although this has been an interesting thread on sofa blasting, @FF’s comments above are the only ones I’ve read that are logical.

You’re selling the boat. Why in the world would you waste/dump thousands of dollars into it? Knock the loose stuff off, paint with cheap anti fouling and go on with life. And if you’re planning on storing for several years, we’ll… don’t! Sell the boat.

That’s what my husband is leaning towards. Unfortunately, the yard requires us to buy paint from them so scrape and paint would be $1800 vs 4K to blast and paint. Maybe plan C is put her in as is, then haul out elsewhere a couple of months later when we get to the keys and do it ourselves?

 

[Mako]

Or just use it and have it scrubbed monthly (or more frequently), then put it up for sale. New buyers will never balk when you tell them it's time for a bottom painting job - won't affect your resale.

 

[mike66]

Gee that seems high. 60/ft to scrape and paint? My 40ft uses 2 gallons. Labor at my yard in RI is 20/ft to scrape and paint. For a one season ablative I can't see them charging you over 150/gal.

 

[Seanair]

Having the bottom soda blasted and then a barrier coat applied is a positive thing to do, no question about it for a variety of reasons. Wether the cost of the procedure is worth it given a possible sale in the near future is something to consider.

The quote you have been given seems reasonable, provided its comprehensive and includes aspects such as removal of the swim platform, all blisters/dings filled and faired, ect.

 

[Deckape]

Before you get to the keys, find and call a yard and get a price , not many do it yourself there. Most yards you have to buy paint from them. Think you will save money somewhere else . I had Playboy Marine-in Dania haul, block, and paint my bottom for years. Anything below waterline, as to be bought from them, prices were ok. When I sold my 45’ Jefferson the bottom had years of paint. Rough , patches , blister repairs and looked like **** after pressure cleaning. Lookers didn’t like how the bottom looked and low balled the offer. Finally bit the bullet and had the bottom blasted, barrier coated, and new paint. Looked smooth and fresh. Next looker liked it and boat sold for asking price. So you can just paint and go, or do it correctly now , or if you sell get a lower price as it will be a knock on the sell.