Chunk out of Gelcoat

[Mack]

So, it is winter time and I am trying to work on my CP-16 and get some things done.   I have a few questions to ask.

I have a pretty good chip in the gelcoat on the top of the boat that I need to take care of.   How do I fix it?   And is it something I can do in the winter (average daily temps between 35-45 degrees with lows in the 20's at the worst so far)?




Thanks,

Mack

[cas206]

In my opinion you shouldn't do Gelcoat (polyester resin) or an epoxy repair at those temperatures.  The chemical reaction will be too slow and take too long.  The extended cure time has an adverse affect on final hardness of the material.  However, if you have a heat source that can keep the repair area warm for several hours, then it can be done.

If you have a broadband internet connection, you can search for gelcoat repair on youtube.  There are a couple videos that step through the process.  I can't tell from the video how deep that chip is.  It might require some filler first before laying on a coat of gelcoat.  There is one video "Fiberglass Repair" by "Andy Miller" that goes through the process of filling a stress crack and then coating with gelcoat.

Finally, don't attempt to fill with epoxy thinking that you can coat with gelcoat later.  Epoxy can be applied to polyester, but polyester (gelcoat) doesn't stick to epoxy.

[Mack]

Do you think that a halogen lamp would be enough to keep it warm?   

[cas206]

Can't answer that.  I haven't used it.  It depends on the heat output of the lamp compared to ambient temps and wind conditions.  I would suggest trying it first.  70 degrees Fahrenheit is optimal.  The linked PDF suggests that below 60 degrees (15 C) is not recommended.  It also suggests an hour (or two) is sufficient for cure time at 70.  Hairdryer?

http://www.fibreglasssales.com/wp-content/uploads/2013/03/Polyester-Resin-Guidelines-also-Casting-Resin-PDF-0.1MB.pdf

[skip1930]

Make a tarp 'tent' around the repair area and slip a small electric heater under it. Insert a small dial thermometer through the tarp and wait for 65 degrees F.
Do the repair. Keep checking for runs or drips.

Pick up a ready mix tube of West System 6-10 thickened epoxy working time about 40 minutes. Or a large container of 2 part Marine-Tex in white color and either squirt it on [6-10] or squirt it into a small roller pan and roll the goop on with a 3 inch paint roller.
"Roll out thin and always win". Tac it a bit and maybe a second layer.
Stay below 'grade level' You'll have to match color and paint. If it's not the right color compound rub it back down to the epoxy and try again. That can be done all next season till your happy or give up. I have two dime sized tiny little spots like this and that's what I did years ago.

I did my whole dingy winter project on the outside of my hull with 6-10 and a roller after sanding the hull with 80 grit. Tented-heated-cured for 7 days.

skip.

[MacGyver]

Because of the time it takes to do a gelcoat repair, I would wait.

In the coming spring you will have a good day to do that in. And actually at the shop at the marina I dont typically do much Gelcoat during winter months, I try to push those jobs off so that I dont have to heat the shop to about 70 (due to temp swings, It must be higher) heating the hull for a few days and then doing the job.

You really dont want Gelcoat issues.......... It is something that will effectively piss you off quickly, trust me. And it is a mess when things dont go right.....

Mac

[Mack]

Ok!   Thanks for the good advice.  I will wait on the gelcoat repair then.  I have to paint the boat anyway, so I might as well rope that into one long project when it warms up.

thanks!