Gel Spraying Techniques

you know what they say those that fail to plan, plan to fail. I don't see you failing on your project Skibum, looks like you have had it well planned the whole way. Except wasn't this supposed to take a week. Just kidding, from all the pics and talking to Eric about my boat. I know it is a lot of work and time consuming. I hope to be brave enough to try one of these days.

If it were me, I would just do the following:

1. brush on thinned epoxy resin and apply heat to help if flow into any cracks.
2. Clean off blush and sand with 80 or heavier grit.
3. Apply Bondo as fairing compound. Sand ending in 120 grit.
4. Clean and apply gelcoat.

David, Thanks for the input. Like I said, I have never used the Bondo on fiberglass. I do use the epoxy with a fairing type filler / thickener that is as easy to sand as the Bondo.

SkiBum wrote: Next, I cranked up the heat in the garage to 85f. Then I applied a generous coating of vinyl ester resin. I chose this instead of epoxy for two reasons; first, the polyester gelcote and epoxy are not a good combination; second, I was hoping the vinyl ester resin would have more of a chemical bond seeping into the cracks.

The only chemical bonding that will or has occurred was the day the boat was made. After that, all repairs are a mechanical bond whether using polyester or epoxy resin. Epoxy resin is by far the better adhesive between the two and that is what you need. The gelcoat will stick to the bondo without issue. You will not notice any difference between the areas that have bondo and the areas that do not. As far as bondo absorbing moisture, I never thought or read or heard that this is a problem. However, if the boat is stored in the water for long periods of time, I suppose this could be a problem as moisture will eventually find its way through gelcoat if the boat is left in the water. This is the main reason for gelcoat blisters. But, bondo is simply thickened polyester resin...so to me it will behave just like gelcoat which is also mainly polyester resin.

So, in summary, the only place for polyester resin is the bondo and gelcoat; otherwise, stick (pun intended) wtih epoxy resin, especially when trying to seal the composite cracks.

I imagine that would assist in the adhesion of the polyester gelcote and perhaps seal in the bondo...sounds like a valid idea. Is it over-kill? I know that not much Bondo will remain once I sand. I really dont know. Never done this before.

well lets hope all that effort was for a great end result, Keep plugging away at it little over two weeks till spring Bill.

It is worth a try, perhaps by thinning the gelcote it would somehow flow more smoothly. I would prefer to have all of the grinding, filling, and sanding finished before I start spraying. So it will be some time before I am spraying again.

Jim, those shopping sprees can be expensive,but divorce even worse. Karen say's the same thing,she calls it girls day out. That Mom /Daughter thing. I am happy to do my time looking for daughter a car.
Speaking of Hi-Tek I an going polished too..boat dr

Skibum I know how you feel about the Mrs. when it comes to the checkbook. Should have seen the look on her face when I told her I was odering $2300 manifolds for the boat. Then she just smiled and said I am going shopping, be back late. I just smiled and laughed what else can you do.

I am the only one working on the boat. SkiBum Jr, SkiBum Juniorette, and Mrs. SkiBum don't want any part of the project. Well, Mrs. SkiBum has been very generous with the check book.

I actually bought one of those gelcote spray guns from US Composites. No need to thin the gelcote. Easy cleanup, just wipe the plate and swab the nozzle. Haven't yet figured out the best PSI and other adjustments.

       
   Skibum,how many people are working on that boat of yours? You're making great progress.Keep plugging.   

                      Farmer                 

Boat doc, Eric is doing a great numbe ron her. I wont hardly be sure it's my boat when he's done with it. Well I will know it's mine but just saying. The pics just make me want to go down and check it out right now before he's even done with it. But I couldn't do that to him.

skibum that is exactly why I didn't try to do the repairs on my bfn myself. My work schedule is all over the place. One week it forty hours the next it's 120 hours. My wife hates it.. Then to throw a boat project in the mix, and have to have it done in time to use. No way.. Your wife must be an amzing woman..

David,

The primary color will be white. I have two and a half gallons on hand. The stripe will be blue. I have one gallon of nuetral and the 5oz jar of colorant. The US Composites guy said to pour the entire gallon into another container, then mix in the colorant, stir thoroughly, then put it back in the origional container. I know just the white gelcote work I did inside the boat on the gunnel consumed half a gallon of white gelcote. How much do you think it will take to do the boat?

I would mix the colorant in all at one time because then you will not have to worry about all the color matching. It can sit forever like that because you haven't catalized it yet. Is the 5oz recomended for the whole gal.?

Wow Bill, You are sure making progress!! But now the fairing will slow things down some what.