We have sanded most of the multiple layers of scabby hard bottom paint from the CD27 we are rebuilding. Horrible job! Probably 50% of white gelcoat is now showing and the other half is covered with a smooth light layer of paint. I assume that this is the the original bottom paint. The sanding process required the use of zirconium oxide discs to get the very hard old paint off and this did also remove a little bit of the gelcoat surface in places. We did not find any blisters. Not one!
We plan on using 2 coats Interlux Barrier Kote Epoxy above the waterline before applying the 2 part poly finish. We used this on the topside of CD25 we rebuilt 5 years ago and are pleased with the results.
My question is: should we use this, (or some other product, below the waterline before applying the bottom paint? If ALL the old paint must be removed before applying an additional coating, I might give up sailing and try to learn knitting.
Thanks
Jim
jtstull@earthlink.net
Question about epoxy barrier coat for John R.
Moderator: Jim Walsh
-
John R.
Re: Question about epoxy barrier coat for John R.
Hi Jim,
Nice to hear from you and the about the progress on the boat. That is a very nasty and long tiring job you've been dealing with. Many of us share in your observations. I hope you realize you had the option of using a stripper like Peel Away, sandblast, walnut blast, etc rather than sand but you did save yourself a lot of money doing it the laborious way.
Generally speaking the paint all should be removed to bare gel coat before application of any barrier coat. The degree of what that means is dependant on different barrier coat manufacturers but for the most part that is the objective. If it were my boat I would remove it all until at the most there is only trace areas of paint color remaining. You don't want to compromise the adhesion of the barrier coat to the gel coat. If you have sanded most of it off and some paint still remains (roughly 50% according to your comments) then you could fore go any further sanding and strip the rest with Peel Away or similar (follow the directions carefully). If you are damn sick of the filthy sanding then that is what I would do at this point unless you want to spend a few $$$ on some blasting. Even if you strip the rest you will still need to do a prep sand before applying the chosen barrier coat.
If you broke through the gel coat anywhere down to raw glass then you will need to seal those spots with West, Interlux 1000, vinylester resin, or similar product. Then do all the appropriate steps called for by the manufacturer of the barrier coat you elect to use.
I'm not sure why you are using the Interlux barrier coat above the waterline. It's not necessary but if the cost doesn't bother you and you feel it works better than a high build paint primer and you have already acheived quality results in the past then there is nothing wrong with using it. It is a product specifically formulated for below waterline use not above waterline.
You definitely want to apply a barrier coat before the bottom paint goes on. The Interlux 2000E is a below waterline barrier coat. It has lower solids than Interlux's 3000 barrier coat. I recommend you use the 3000 series barrier coat (high solids) or go with West System and 422 barrier coat additive. I like the West but it is a lot of work. The Interlux is also a good product. Preparation is everything! Follow the directions to the letter. You are lucky you have no blisters to contend with. Do the barrier coat job as best you can and you may be just as lucky to be without blisters well into the future.
If you choose to follow up on the knitting save me a seat!
Good luck Jim. Feel free to drop me an email if you run into problems.
We have sanded most of the multiple layers of scabby hard bottom paint from the CD27 we are rebuilding. Horrible job! Probably 50% of white gelcoat is now showing and the other half is covered with a smooth light layer of paint. I assume that this is the the original bottom paint. The sanding process required the use of zirconium oxide discs to get the very hard old paint off and this did also remove a little bit of the gelcoat surface in places. We did not find any blisters. Not one!
Nice to hear from you and the about the progress on the boat. That is a very nasty and long tiring job you've been dealing with. Many of us share in your observations. I hope you realize you had the option of using a stripper like Peel Away, sandblast, walnut blast, etc rather than sand but you did save yourself a lot of money doing it the laborious way.
Generally speaking the paint all should be removed to bare gel coat before application of any barrier coat. The degree of what that means is dependant on different barrier coat manufacturers but for the most part that is the objective. If it were my boat I would remove it all until at the most there is only trace areas of paint color remaining. You don't want to compromise the adhesion of the barrier coat to the gel coat. If you have sanded most of it off and some paint still remains (roughly 50% according to your comments) then you could fore go any further sanding and strip the rest with Peel Away or similar (follow the directions carefully). If you are damn sick of the filthy sanding then that is what I would do at this point unless you want to spend a few $$$ on some blasting. Even if you strip the rest you will still need to do a prep sand before applying the chosen barrier coat.
If you broke through the gel coat anywhere down to raw glass then you will need to seal those spots with West, Interlux 1000, vinylester resin, or similar product. Then do all the appropriate steps called for by the manufacturer of the barrier coat you elect to use.
I'm not sure why you are using the Interlux barrier coat above the waterline. It's not necessary but if the cost doesn't bother you and you feel it works better than a high build paint primer and you have already acheived quality results in the past then there is nothing wrong with using it. It is a product specifically formulated for below waterline use not above waterline.
You definitely want to apply a barrier coat before the bottom paint goes on. The Interlux 2000E is a below waterline barrier coat. It has lower solids than Interlux's 3000 barrier coat. I recommend you use the 3000 series barrier coat (high solids) or go with West System and 422 barrier coat additive. I like the West but it is a lot of work. The Interlux is also a good product. Preparation is everything! Follow the directions to the letter. You are lucky you have no blisters to contend with. Do the barrier coat job as best you can and you may be just as lucky to be without blisters well into the future.
If you choose to follow up on the knitting save me a seat!
Good luck Jim. Feel free to drop me an email if you run into problems.
We have sanded most of the multiple layers of scabby hard bottom paint from the CD27 we are rebuilding. Horrible job! Probably 50% of white gelcoat is now showing and the other half is covered with a smooth light layer of paint. I assume that this is the the original bottom paint. The sanding process required the use of zirconium oxide discs to get the very hard old paint off and this did also remove a little bit of the gelcoat surface in places. We did not find any blisters. Not one!
Jim Stull wrote: We plan on using 2 coats Interlux Barrier Kote Epoxy above the waterline before applying the 2 part poly finish. We used this on the topside of CD25 we rebuilt 5 years ago and are pleased with the results.
My question is: should we use this, (or some other product, below the waterline before applying the bottom paint? If ALL the old paint must be removed before applying an additional coating, I might give up sailing and try to learn knitting.
Thanks
Jim
-
Jim Stull
-
Jerry Hammernik
Re: Question about epoxy barrier coat for John R.
Jim,
It may be too late, but if you have a lot of paint left you might try scraping it. I removed the old paint from my 28 by using a dull chisel. You push the chisel away from you and the paint just peels off. I think it works better the thicker the paint. I followed up with a sander to smooth and remove the final bit of paint. You might want to give it a try. The technique comes quickly. You want the chisel dull so you don't gouge the hull.
Jerry Hammernik
Lion's Paw CD28 #341
SSYC Milwaukee, Lake Michigan
dauntles@execpc.com
It may be too late, but if you have a lot of paint left you might try scraping it. I removed the old paint from my 28 by using a dull chisel. You push the chisel away from you and the paint just peels off. I think it works better the thicker the paint. I followed up with a sander to smooth and remove the final bit of paint. You might want to give it a try. The technique comes quickly. You want the chisel dull so you don't gouge the hull.
Jerry Hammernik
Lion's Paw CD28 #341
SSYC Milwaukee, Lake Michigan
Jim Stull wrote: We have sanded most of the multiple layers of scabby hard bottom paint from the CD27 we are rebuilding. Horrible job! Probably 50% of white gelcoat is now showing and the other half is covered with a smooth light layer of paint. I assume that this is the the original bottom paint. The sanding process required the use of zirconium oxide discs to get the very hard old paint off and this did also remove a little bit of the gelcoat surface in places. We did not find any blisters. Not one!
We plan on using 2 coats Interlux Barrier Kote Epoxy above the waterline before applying the 2 part poly finish. We used this on the topside of CD25 we rebuilt 5 years ago and are pleased with the results.
My question is: should we use this, (or some other product, below the waterline before applying the bottom paint? If ALL the old paint must be removed before applying an additional coating, I might give up sailing and try to learn knitting.
Thanks
Jim
dauntles@execpc.com
-
matt cawthorne
Re: Question about epoxy barrier coat for John R.
Jim,
You are on the right track adding the barrier coat at least several inches above the waterline. The waterline is a changeable thing. The year I bought my CD-36 I barrier coated to the original waterline. I then realized that the boat had much junk added to it and it sits an inch or so below that waterline. Two years later I got a few blisters above the original waterline. I then went back, stripped the boot stripe, and barrier coated above the waterline. Where I managed to get barrier coat over top of even the slightest bit of bottom paint it started to lift several years later. This spring I went back and took the paint off of the entire bottom, sanding through the barrier coat that was over paint in a few spots at the border and added some additional barrier coat. I could have saved myself much grief if I would have just moved that barrier coat up a few inches the first time. Actually, my barrier coat now goes up about 5 inches above the current waterline. I figure on going cruising someday and I wanted some margin.
Matt
mcawthor@bellatlantic.net
You are on the right track adding the barrier coat at least several inches above the waterline. The waterline is a changeable thing. The year I bought my CD-36 I barrier coated to the original waterline. I then realized that the boat had much junk added to it and it sits an inch or so below that waterline. Two years later I got a few blisters above the original waterline. I then went back, stripped the boot stripe, and barrier coated above the waterline. Where I managed to get barrier coat over top of even the slightest bit of bottom paint it started to lift several years later. This spring I went back and took the paint off of the entire bottom, sanding through the barrier coat that was over paint in a few spots at the border and added some additional barrier coat. I could have saved myself much grief if I would have just moved that barrier coat up a few inches the first time. Actually, my barrier coat now goes up about 5 inches above the current waterline. I figure on going cruising someday and I wanted some margin.
Matt
mcawthor@bellatlantic.net