PDA

View Full Version : DIY Keel Repair


Finnsdad
06-02-2011, 10:23 PM
A while back I started a thread about my keel being worn from going to the sandbar to many times. http://www.mastercraft.com/teamtalk/showthread.php?t=31346

It is gotten worse since then! I decided it needs to be fixed, boat repair shops wated 500-800 to fix it. The glass wasn't worn through, just the gel worn off smooth. I don't have that kind of money this year, so I had to find a way to do it myself. I went with the West Marine white gel coat: http://www.westmarine.com/1/1/5690-waxed-non-laminating-finish-gel-coat-coat-quart-white.html

These are the before pics:

Finnsdad
06-02-2011, 10:32 PM
I started by roughing up the area with 400 grit, then clean with acetone. I'm going to use a foam brush to apply the gel. I considered a preval, but read mixed reviews on spraying gel through them. Plus, with the area being on the bottom it would be hard to keep the preval at less than a 45 degree angle.

Once the gel is applied to the worn area, I'll wetsand/buff the area which will take care of the other small scratches.

1st application: Went on ok, got tacky after 10 min. Directions say it should be hardened within 30-45 min, but it didn't. Waited 2 hours, not cured. Waited overnight, not cured. I think one of two things happened, either the temp was too cool (about 62F), or I didn't mix in enough hardener in my partial can batch. The next morning I aimed a space heater at the area for a while and most of it cured.

Still needed another coat, so I scuffed it up with 400 and wiped down with acetone. It was obvious what areas weren't cured because the acetone wiped the gel away.

2nd coat: Increased the hardener ratio a little based on the recommendation of someone who has done gel work before, this should compensate for the cooler temps. I made an enclosure from blankets and put a hologen work light in it to keep the temp closer to 80, which is the optimum temp for gel to cure.

Finnsdad
06-03-2011, 11:21 AM
2nd coat is done, worked much better this time. I wet sanded with 600 to smooth it out, and I think I'm done till fall. No use in making it perfect and then going to the sandbar this weekend. We have the boat to use it, and not beaching is not an option. We'll see how this holds up. If it wears through quickly again, I think I'll get a keel guard.

Jorski
06-03-2011, 11:35 AM
Finnsdad...

Your curing problem may not be due to the amount of catalyst used in your mix...though that will durely help.

Gel coat was desidned to be used in a mold. The molds are coated with a special release wax whoch not only allows the boat to be pulled from the mold, but also has additives that help with the gel coat cure.

When doing repairs outside of a mold, you should spray PVA or something like it on the gelcoat to help it cure...you can use a product like this:

http://www.apsltd.com/images/CATEGORY/medium/7719.jpg


Recommended for use with Evercoat Gel Kote, the Mold Release is great for putting over the catalyzed Gel Kote to fully cure and eliminate the tacky feel. Use by spraying a light mist. It can also be used on it's own as a mold release agent.

Good luck!



EDIT: looks like you made out fine...your last post went up while I was writing mine. Good work!

JeromeM
06-03-2011, 12:12 PM
Finnsdad...

Your curing problem may not be due to the amount of catalyst used in your mix...though that will durely help.

Gel coat was desidned to be used in a mold. The molds are coated with a special release wax whoch not only allows the boat to be pulled from the mold, but also has additives that help with the gel coat cure.

When doing repairs outside of a mold, you should spray PVA or something like it on the gelcoat to help it cure...you can use a product like this:

http://www.apsltd.com/images/CATEGORY/medium/7719.jpg


Recommended for use with Evercoat Gel Kote, the Mold Release is great for putting over the catalyzed Gel Kote to fully cure and eliminate the tacky feel. Use by spraying a light mist. It can also be used on it's own as a mold release agent.

Good luck!



EDIT: looks like you made out fine...your last post went up while I was writing mine. Good work!

Very interesting, thanks for the info. I did a small repair on my last boat and for the life of me couldn't get it to cure and this may be why. Cool.

Finnsdad
06-03-2011, 12:34 PM
There are two types of gel used in repair, laminating (non-waxed) and non-laminating (waxed). The differerence is that a laminating is meant to stay tacky for easy application multiple layers, then on the final layer you mist the PVA over the top, which acts as an air barrier and allows the gel to cure. A non-laminating like I used has a wax coating built in, and when the gel sets the wax barrier forms on the outside to seal it from air. If you need to apply an additional layer, you need to scuff/sand the area to remove that coating and make it ready for the new layer to adhere to.

If your going to use a laminating gel coat, you can also cover the area with saran wrap or wax paper to seal it from air. This will allow the chemical reaction to be completed and the gel can cure.

hz900
06-03-2011, 01:48 PM
Install a keel guard. Problem solved. I beach mine as well and IMO this is a must if you are going to beach it regularly.

psychobilly
06-08-2011, 04:45 PM
Install a keel guard. Problem solved. I beach mine as well and IMO this is a must if you are going to beach it regularly.

yep..... Best money spent....