JEM Watercraft

Just finished fiber glassing the inside of the merrimac. really was quite a challenge for me. The job appeared to come out ok but after the epoxy had cured I noticed lots of bubbles and bumps where I had evidently used too much epoxy and it had pooled under the cloth. I did sand many of these spots but realized that I was started to sand quite a bit of fiberglass off too. I am concerned about the structural integrity of the hull after I sand these bumps down and if I should sand it all down smooth and refiberglass the bottom, or if I can just sand and re-epoxy until I get a good finish.
Thanks,
Bob

pictures you could post?

A couple of questions........
1. Did you epoxy saturate the wood before glassing it.
2. Did you do the epoxy and glassing early in the day or as your working area would of been getting warmer and not cooling down.

As far as the glass and how much you sanded it , like Matt said , a picture would be helpful.

Chuck.

I did epoxy saturate the wood first, I also worked later in the day and it was quite warm. I am in the process of moving into a new place and dont have regular access to the internet so posting pics is kinda tough right now, I will get some on as soon as I can.

I got carried away with the sander in one spot and clearly sanded all the way through to the wood but the other places I sanded down through the fiberglass were on the bumps and were about the size of a quarter. Also I sanded through a few small air bubbles.

I realize its a lot easier to see some pics, I will try to get them off to you as soon as possible

I am thinking that it wouldnt hurt to error on the side of over build and just sand the bottom down and put some more cloth just on the bottom panels.

I would love to learn some tricks for fiber glassing the inside of the hull, I am really enjoying this build but that step really left me feeling like a beautiful boat just got a little rough looking, and I do worry a bit about sacrificing strength as I sand the bottom to a smooth (or at least smoother) finish.

thanks for taking the time to chat with me about this,
Bob

I had a similar problem a few years ago. Was my fault for using a tight weave glass. I'd always used a looser weave that would accommodate itself to being laid in either straight or on a bias. No sweat. I used a tight weave on the inside of a canoe, one piece for the front and a second for the rear. I laid the grain of the weave lined up with a gunnel instead of lining it up with the centerline of the boat. I think that made the problem even worse.

Got it all laid, epoxified, and smoothed out. Took a break for lunch, and when I went back out the darned stuff had bubbles - narrow and 1"-2" long - all over the inside. I was sick over this because it is my Granddaughter's boat. I've never had this difficulty with a loose weave glass.

And, I think a tight weave would lay easier if it was in strips of, say, 2'-3' wide instead of a large piece. It seemed to have a "memory", and wanted to go back to being straight instead of fitting the curves of the boat. I'll stick to a proven performer from now on.

Guest wrote:
I am thinking that it wouldnt hurt to error on the side of over build and just sand the bottom down and put some more cloth just on the bottom panels.

Don't give up the ship...... It is nothing more then wood and fiberglass and either of them can be saved.

If it is just the bottom and not the sides then you could lay another layer of glass over what you have , all it will do is to add a little more weight to the boat but will double the protection on the bottom of it.
The epoxy will seal the sanded spots and then the glass will cover it , at the worse there might be a dimple in the finish and that will not hurt anything and probably when it is done only you will know it is there.

A lot of the guys use this to remove excess epoxy and feather in edges.
A paint scraper is a handy tool to use for smoothing out the area where the extra layer of the glass meets the original layer , just be real careful when using it and keep it flat , the ends will dig ( gouge) in if you let them. The scraper is also a handy tool for removing epoxy if it clumped up on you , like a drop off the roller or epoxy container and you find it after everything has set up. .A good way to remove excess epoxy.
I like to sand , takes longer , a lot longer but the chance of damage is a lot less when feathering the edges together.

I probably create more work for myself because I like the tight weave and now do all of it in one sheet , this way I don't have to blend the different pieces together or smooth the edges.

Like Kayak Jack said ... It is a lot harder to work with but after a few boats you get the hang of it and can take shortcuts when you learn the tricks of working with it. The main one is do not let the supplier send it folded , it has to be on a roll to work with , easily.
I learned that lesson real quick on one boat but managed to make everything work for me. Took me several days to get the creases , almost , out of it before putting it on the boat. A lot of time and cussing did the rest , not sure if the perspiration on it helped or not but things came out as I expected.

Can't suggest a way for you to do that , you will find a way that suits you.
I lay my glass out and hand form it to the inside , let it sit overnight and then start on it in the morning. I start in the center of the boat and work to the ends , then back to the center and up the sides working up to each end. I use rollers for epoxy. I take a 9 inch one , cut it in half giving me two 4 1/2 inch ones.The reason for the roller is that I can get the epoxy on the glass and not use a lot of pressure which tends to make it move on you.

I was thinking you did this when the temperature was increasing in your work area and that causes the air in the wood to heat up and escape causing a lot of small bubbles in the epoxy, especially if it was not saturated ( to seal it 1st) which you did.

Chuck.