Stripping Fiberglass

I am in the process of stipping the fiberglass off a 1955 Paul Luke that had been covered in the last 5 years. I pulled it off the base of the keel where I found some damp wood.The rest of the fiberglass has good adhesion. The Planks are still in good shape although I will have to probably replace the shoe and around the rudder area. It has been suggested to me that I use a 10" foam pad with 36grit paper to take the rest down. Should I mark the water line and how before I continue, and are there other suggestions on how I should go about this.

 

There are no fun or easy ways to remove a 'glass sheathing. Buy lot of very rough paper and have at it. You may come across areas where it has delaminated and can be pulled off wholesale, like you did on the keel. Be on the look out for this, it will save a bunch of sanding. You may also try to pound the crap out of the planking, all over the areas affected, it may help dislodge areas already thinking about delaminating. Do this with a rubber mallet and try not to dent the planking with too hard a blow. When you get near the wood surface (you'll be able to see the wood through the dust and thin 'glass) stop before going completely through. Switch to a finer grit paper or you'll have to clean up a bunch of sanding marks on the planking.

Buy a Tyvek suit and dust mast, you'll be grateful you have them on.

 

Yes, mark the waterline. You can do this by measuring from the wl to the ground. Do this on port and starboard side. Take 4 point, so, bow, stern and 2 in between (as check for later).
Putting the wl back:

Place two bars horizontal and perpendicular to the centre line of the boat on the fore and aft end. Make them adjustible in hight.
Run a piece of string over them and adjust the hight till the string matches the points you measured before. You can do this by sliding the string over the bars till it touches the hull.
When the string matches you measured point you start sliding the string again and mark the waterline on more points.


Hope this makes sence to you, otherwise I'll try to find a picture to clarify.

 

Thanx, I know I'm in for a lot of sanding. I'm in no hurry and want to do it right. I posted pics. on the gallery (not realizing it is more for boat designs. oh well)

 

Makes a lot of sense. Thanks

 

try the scraper

If it is a thick lamination sanding is the easiest way. But if it is a relatively thin layer of cloth try an electric heat gun and a 2 to 4 inch putty knife. this process is better started in an area where the glass is cracked or otherwise breached. a razor knife is also handy. When you get an area started you may choose to cut the warmed cloth with the knife, so that you can keep going on a run. After a few straight runs are peeled you can work the diferent peeled strips towards on another. If you can peel off the glass it distorts the hull less. Because some areas grind off easier than others. and the wood around hard areas tends to get chewwed away by the sander. If you can peel it you will still need to sand the wood to let it air out and give a good bonding surface for the new epopxy clothe etc.

 

For the brave and talented ... or stupid if you don't get it to work for you. I have seen the not so professional Marseille, boat owners use a small angle grinder. It seemed to be faster than sanding. Was not close enough to see what the core looked like after the affair. smile

 

Removing the glass sheathing is a really good idea. I would, however, be carefull not to be too aggressive with your grinding. Gouging the hull with a grinder is a distinct possibility if you are not careful. I have also encountered situations where the person doing the sheathing had fastened through the sheathing at the halfway point, and then finished glassing over top of the fastenings. If there are areas that are soft due to water infiltration, then you can probably assume that there are more areas in a similar situation. Although this would make for an easier time removing the sheathing, it may require addressing the effects of the infiltration. As concerns your water line, the height will probably change due to the removal of the weight of the sheathing and with the hull drying out. You may find that there is still an indication of the old line once you have removed the sheathing. If you feel that you need to transfer the existing line onto the hull, then I would divide the boat into evenly spaced station lines and then measure from the same point of reference on both sides of the boat. Fair out your line, tape it off and paint away.

 

Drj is right on removing it in sections. You can do like i am doing on my old wooden boat. I am using the waterline as a dividing point. I had the yard that i am at sandblast from the waterline down. My boat was only glassed with polyester to the waterline. It was only finishclothe. I had the sandblaster to stop at that layer. i have went everytwo feet along the waterline put a pencil line vertically. I have measuered up 5 inches from the top and bottom of the boot stripe and marked the vertlines. Now I can take a 8 sander and clean the water line area. After i get the bottom glassed to the waterline. I can extend those vert lines down , mark offf the waterline and paint it. I only have time to get the clothe the bottom for this year, because i use my boat to take fishing charters and the season is starting. Next winter i will extend the glass to the deck.

 

Another note on removingthe clothe below the waterline. I have on one old fiberglass skiff used paint stripper. It had twenty years of bottom paint. I was stripping the paint so i could repair blisters. Through a marine distributer i was able to get hold of some super stripper designed for bottom paint. At first it was slow in coming. I left it on the bottom and took a long lunch. when we came back and started removing the stripper the gell coat was coming too. this stripper was strong enough to soften the gel coat. This didnt bother me. It actually opened some of the blisters and that was less grinding. I found the stripper would also soften the the clothe on areas that the owner had repaired. Depending on the application the super stripper might work

 

I have been plugging away with a variable speed Makita disk sander, set at a low speed, with a 3M foam disk pad and 36 grit adheasive pad. It's working pretty well and I stop when I see wood. Most of the fiberglass has good adheasion.