star crazing

Unfortunately when looking to repair a bottom which is showing signs of crazing regardless as to what type, it will take a significant amount of work to get the bottom sealed back up and looking good. 

Below is an example of the typical process which would be required in order to complete the job:

1. Sand the bottom with 60-80 grit paper to open the gelcoat up

2. Remove of all sanding residue via a solvent such as Fiberglass Solvent Wash 202

3. Apply of 1-4 coats of a clear epoxy resin such as Epiglass to seal the gelcoat

4. Wash the epoxy to remove the amine blush

5. Sand the epoxy with 80 grit paper

6. Remove all sanding residue via a solvent such as Fiberglass Solvent Wash 202

7. Fair the surface with Interfill 830

8. Sand the Interfill 830 smooth with 80-100 grit paper

9. Remove all sanding residue via a solvent such as Fiberglass Solvent Wash 202

10. Apply 5 coats of InterProtect 2000E

11. Sand the last coat of InterProtect 2000E with 80 grit paper when applying racing finishes such as Baltoplate/VC Offshore or sand with 180 grit when applying VC17m/VC17m Extra

12. Remove all sanding residue via a solvent such as Fiberglass Solvent Wash 202

13. Apply 4 coats of either Baltoplate/VC Offshore or apply 2-3 coats of VC17m/VC17m Extra

14. If using Baltoplate/VC Offshore remove all imperfections by wet sanding starting with 400 grit paper then progressively work your way up through higher grades of paper. If planning on burnishing you can do so with fine bronze wool after the wet sanding has been completed (VC17m/VC17m Extra should not be wet sanded/burnished)

 

Not sure how the above mentioned would match up to the quote from the yard, but as you can see the bottom will require a significant amount of work.

 

Hope this helps.

Mirage,

Most of the work can be completed by the crew, you just need to make sure that eveyone is on the right page and you follow the system to each individual step. Sure it absolutely is a large amount of work, but if you are looking to seal off the crazing and preventing it from showing through once again, those would be the steps required. If you chose to do nothing on the bottom, the crazing will remain present (possibly worsen overtime) and will also continue to show through each of the coat's which are applied overtop.

 

- Sanding will allow adhesion between layers

- Solvent wiping's will help to remove contamination which in turn helps to enhance adhesion

- The clear epoxy resin will seal off the crazing

- The use of Interfill will help to ensure that the surface is as smooth and uniform as possible

- InterProtect 2000E will seal off the Interfill and prevent the absorption of moisture

- Application of the antifouling paint and wet sanding/burnishing will help to prevent the accumulation of marine growth, but also to ensure that you achieve a smooth and slick bottom

 

I can understand that you would prefer to not spend alot of money on a boat which is 28 years old and especilly since similar boats are going for $60,000, but in order to complete the job properly, those steps will be required. Therefore I would recommend that think about the scenario for a bit and try to determine what would be more important, repairing the bottom completely or creating a quick fix for the bottom which will allow the crazing to remain present and possibly worsen as time passes along. The decision is ultimately up to you, just be sure of your advantages/disadvantages for each and make a decision based off of that and one which best suits you.

As long as the surface has been given a good and thorough sanding with a 180-220 grit paper and you have removed all sanding residue with Special Thinner 216, I would anticipate on 1 coat of VC17m holding to the bottom for that season. However the likely complication which you will encounter would be the lack in biocide across the surface as you will only have 1 coat of paint on the surface which will contain half the biocide in which you would ideally need for that whole season. Since you have a diver clean the bottom in the middle of the season, I would instruct him to remove any growth but be very careful when doing so, this way you can utilize as much of the biocide out of that coating as possible before it were gone. I would also recommend that you use the boat as much as possible to help limit the chances of any growth from forming on the bottom, which in turn would limit the amount of work that will be required by the diver and will help to keep that bottom clean.

 

Hope this helps some more and good luck!

The biggest challenge with using something along the lines of Mineral Spirits or Paint Thinner for wipedown's would be that we have no ability to guarantee one way or the other that neither will effectively clean the surface nor will they leave the surface completely clean without any residue remaining on that surface which could possibly result in some detachment. Therefore with those few unknown and potentially risky variables, I would recommend that you stay away from the use of both the Mineral Spirits/Paint Thinner and still use the Special Thinner 216 for guaranteed success.

 

 

 

 

jay, will this process work for similar problem, but using vc performance and water-tite filler instead? Also you said to put filler on first and I thought that it went between coats of 2000e or paint?

 

Jack