Fixing numerous pits/porosity in gelcoat

[Thorne]

Here is a question to the crowd; how would you recommend I fix the pits/porosity in the gelcoat? Clean and spray with gelcoat, clean and paint, or something else? There are pics of the situation in the album. Thanks in advance!

[mdrake]

Hi I bought a 1981 in rough shape,I painted and it came out great.This is my first boat so, although it turned out good I'm not the guy you want to get advice from.I like how you rebuilt the bulk head on your.good luck

[thataway]

Painting is far easier than re-gel coating. In any case, you are in for a lot of fairing and sanding before you can apply any finish coat. (Of course there is always the option of bedliner spray over the entire boat: )

The best result is gong to be aggressive sanding, and it may be easier to sand off the gel coat to a smooth surface, rather than a light sanding and then trying to fill all of the pits. In either case, the best result will be the application of at least one epoxy coat--for a really good job it is gong to be epoxy, sand, epoxy sand, until surface is perfect--or near so. Do not use "Bondo" It will not hold up well with time. There are specific marine fillers--probably the best by 3 M, or making your own with epoxy and medium density fillers.

For the final coat you have several choices of paint types and of application method.

The best finish, and probably longest lasting (over 10 years) will be sprayed on two part linear polyurethane paints. You can also tip and roll on these two part paints. These are not for below the waterline, if the boat is left in the water for any length of time. Example of this would be Awlgrip or Awlcraft.

There are a number of single part polyurethanes--such as "Brightside". These are usually put on with tip and roll method.

I have seen some tip and roll which are nearly as good as a good spray job. But for the best--a team who is experienced with spraying two part LP is the best.

Then there is the method my dad used on his wooden boats: He felt that all boats would get a little ding now and then. A glossy finish looked great the first few weeks after application, but touching up dings, often was not perfect. He used a mat flat paint. When there was a ding (often caused by his young son's learning attempts) it was easy to just do some light sanding and brush on the mat finish...From 50 feet the mat looked just as good as the gloss. I suspect that you would still want to do some sanding to be sure that any surface contamination was removed, and do an epoxy coat. Then sanding as near to fair as possible, before the mat finish....In the olden days (1940's and 50's), these mat finishes had a slow sloughing of the surface, so always appeared reasonably fresh.

Good luck: ere is to you for the love and labor to restore this boat!

[Kushtaka]

I'm a big fan of preval sprayer for gelcoat spraying. Using a two-part system means you mix it all together and then put it in the sprayer, so these become disposable (even though they would be reusable with a latex paint), but if you prep everything you can get a lot done in one shot.

They have a great finish that can be polished smooth. As long as you match the color you will have a great repair.

https://www.amazon.com/Preval-267-Spray-Gun/dp/B0000AY19M/ref=sr_1_1?ie=UTF8&qid=1478024825&sr=8-1&keywords=preval+267+spray+gun

https://www.youtube.com/watch?v=CxoR7CPKXfI

[thataway]

How many Preval sprayers will it take the do the entire boat? Looking at the photos, it appears to me as much, if not all, of the boat needs to be sprayed. It is not just a few nicks or a square foot or two.

After sanding, he is going to need to put down at least 10 mil of gel coat. Never calculated the sq footage of a C Dory , but I suspect by the time you do the cabin it will be close to 200 sq feet. You are probably going to be looking at at least 3 gallons of gel oat and close to an equal amount of DuraTec for thinning. (If you want to use that--there are other agents).

The problem I have with the Preval (and I have used them a number of times--great for small touch ups; depending). is that you really have to thin the gel coat.

With a good gun, you can lay it down properly,. A good gun is much cheaper than number of Prevals,. Prevals tend to get cold, and then cause bubbling and orange peel--if you have some type of a hot box, or tub, to keep the gas cyl warm, it helps.

[Robert H. Wilkinson]

3M makes a plastic gun that uses disposable bags. The cap is also disposable. Only thing that you need to clean is the needle. It has a 1.8mm needle(not sure what size you need for gel coat). We pay about $90.00CAD for them where I work - buy the bags and caps as you need them.

[Thorne]

Thanks for all the suggestions. I'll post pics as I get farther into the project.