Fiberglass work the horror and wonder

[lout]

As someone who just started doing fiberglass projects I wanted to bring to my fellow boaters some observations.
Spend the money for good glass fiber, never get the cheap thin stuff that comes apart when cut. Covering everything including you with small fiberglass shards. You will finish faster and have a better outcome with thicker glass mat for most projects.
I am on the third day of cleaning fibers from the interior.
Cover yourself, head to toe You will be happier and healthier at the end of the day.
Now once you get the project complete and you get better at application you can sit back and admire your great work that will last decades.

Still itching,

 

[DDW]

You haven't really lived until you've sanded carbon fiber. Makes fiberglass feel like a walk in the park.....

 

[psneeld]

appropriate cloth, matt or roving for the job.....

thicker isnt always better.....also.... matt always the right material.

after 45 years of playing with composites.... I still learn way too much on every project....

 

[caltexflanc]

I learned early on that for me at least, glass work was a "life's too short and my time is too valuable and my skills too low, so hire somebody who knows what they are doing" item.

 

[SeaMoose]

Woven fiberglass, that looks like fabric, is easier to lay up, but harder to make fair. The pro’s will lay fabric - multiple thin layers are better than a few thick ones, because you get good wetting out - and then put down a layer of the stranded stuff. This gives you a surface that’s easier to fair.

So each type has its uses. For years I despised the big blob of fibers stuff, as it seemed to come apart when I hit it with resin, until I saw a you tube video where they mixed a batch of milled fibers & collodical silica with the stuff for a strong base layer in a build up.

Most of us amateurs overbuild everything, me included, so don’t swear it too much

 

[Fletcher500]

Past fiberglass projects involved small scale repairs on surfboards and carbon fiber outrigger canoes. Definitely one of those jobs its best to have someone else do it when it involves some scale.

 

[psneeld]

if one is lucky enough to be able to afford it....

 

[drinkenbuddie]

biaxial is what I use. I’ve done a lot of glass work and a bunch on my trawler. Fiberglass places are the way to go. I like to use epoxy because it sticks better. You buy it by the weight of the cloth. It stays together and lays down great and makes great edges. No strings at all. Just buy good scissors to cut it.

 

[drinkenbuddie]

If you going to use glass buy the 3m kind and they have that at Home Depot. Not the biaxial though. In Saint Petersburg you can get a great deal on the biaxial.

 

[Fletcher500]

if one is lucky enough to be able to afford it....

Rest assured Psneeld, I put in my time.

 

[drinkenbuddie]

If you buy it at a store you can see what your getting. I bought the first at amazon and wish I wouldn’t have. Buy the good stuff and way easy to lay up. No stress and clean and can go thick as you want. Heavy biaxial is the way to go. Way stronger for the amount too. No soft spots with that down.

 

[drinkenbuddie]

The pros down here lay biaxial. Heavy weight too.

 

[drinkenbuddie]

Good stores don’t stock cloth or woven roven. Old school.

 

[diver dave]

Good suppliers will have biax cut in 4,6,8” strips to make fillets easy.

 

[kapnd]

Good stores don’t stock cloth or woven roven. Old school.

“Good Stores”, do stock everything, amateurs need to do their homework in order to purchase the correct material.

 

[FF]

"Good stores don’t stock cloth or woven roven. Old school. "

I would be wary of any purchase at a shop that doesn't carry a full line of materials.

When you ask for un waxed or waxed resin and get a blank stare ,,,,its time to purchase elsewhere.

 

[psneeld]

Theres still pkenty of projects that dont need exotics.

Covering a strip canoe you can go crazy and make it bulletproof or plain old 6oz S cloth like many use.

Many places only carry so much stock, but the doesnt mean those are the only materials that are used.

 

[SeaMoose]

I buy from U.S. Composites in Florida, no complaints. 1/2 the price of the West System stuff. West is exceptionally nice resin but way too pricey for an old beat up Taiwanese Tub like mine.

I've always used Epoxy.

 

[Ski in NC]

Carolina boys use lots of biaxial at 1208 and 1708. And epoxy. 1208 more friendly at radiuses.

They know what "glue flu" is too.

Once you start grinding, just live with the prickly feeling. It will go away with your next molt.

The shift knob on my truck still has epoxy on it.

Glass work. Ugghh.

 

[jleonard]

Glass work. Ugghh.

Agree. I have done lots of fiberglass work. I almost always use 1 1/2 ounze mat with polyester resin. I have used woven roving for strength a few times, but only in conjunction with mat. I was told by my local full service fiberglass supplier that it's best to first attach mat, then attach the roving to the mat for best adhesion.
What do I know? I just followed their lead and it has worked for me.

 

[Nomad Willy]

I worked at Uniflite in the 70’s. Worked on the line installing rudder ports, stuffing boxes and engine aluminum beds. Lots of fairly heavy grinding fo fit the engine frame. The itching was awful. Later I worked in engineering.

 

[diver dave]

I worked at Uniflite in the 70’s. Worked on the line installing rudder ports, stuffing boxes and engine aluminum beds. Lots of fairly heavy grinding fo fit the engine frame. The itching was awful. Later I worked in engineering.

Was it Uniflite that advertised fire resistant hull layups? Must be special resin.

 

[Nomad Willy]

DD,
Yes it was later that they had the blister problem. Never heard the word “blister” during that time. I was working in the printing trade by then down at the so end of Lake Union at Craftsman Press in Seattle. They printed the TVGuide then.

But I never had any reason to know about the retardent resin and had no interest as well. But in the shop I only worked on the 26’ Motor Whaleboat so I suppose it was fire retardent resin.

The Uniflite was a wonderful boat if you didn’t mind buying and burning lots of fuel. Most of the 42 footers had twin 6-71’s.

 

[FF]

"Was it Uniflite that advertised fire resistant hull layups? Must be special resin."

Military boats and charter boats above a 6 pack,( Subchapter T ), are required to use FR (fire retardant) resin,.

The CG requires an inspector on site as samples are pulled , then sends then off to their lab.

The concept is Oak burns at a rate of 100, most polly resin at about 500 , so the requirement is the FR must burn at 100 or less.

The same FR resin is used in factory ducts , where the burn rate is kept down to 15 or 20 with the use of chemicals .

The good news is FR resin is very little extra cost for the hull builder,

the bad news is FR is toxic as it is being burned.

Most FR will only be burned in the presence of a fire source .

After '73 when the first oil shock raised oil prices the materials in all resin became poorer in quality , blisters became common.

Sad that in raising resin prices from 20c a pound to 75c a pound the quality was not maintained.

 

[Mrwesson]

I like mat with a top layer of cloth so I don't have to do much grinding.

I don't cover myself head to toe. An ice cold shower will remove it from your pores.

I hate resin. No matter how thick the gloves or how careful I am it always ends up on me.

Also I always seem to be working when it's hot and in the sun(too much humidity early).

 

[DDW]

There are tricks to cut down on the grinding and finishing. Also the mess.

For the grinding, the best professional shops always cover the laminate with peel ply as the last step. This is wet out just like it was the last layer of fiberglass. When all is cured, it peels off the surface by hand. The advantage is since it is very fine grained cloth, it holds all the nubs and fishhooks down, smooths the edges, eliminates many of the fisheyes, etc. Well done, the result needs little or no finishing.

For mess, on small jobs, wet the cloth/mat/stitchply/whatever on a table, then move it to the job. Here's an example of the steps:

1) take a piece of 6 mil clear plastic, tape it over the repair. Use a sharpie to draw the outline of the piece of fiberglass you want, leaving a good border on the plastic.

2) set up a table and lay another 6 mil clear plastic piece on it, bigger than the repair.

3) cut a piece of fiberglass larger than the repair, put it on the plastic, mix some resin, pour it on the glass. Lay the first piece of plastic (with the outline) on top. Squeegee the resin around with a dry squeegee on top of the plastic. So far you haven't touched the resin. You can move resin to dry areas, or squeegee excess off to the side. If you don't have enough, lift the top plastic and pour some more resin on. Because you are rubbing on the plastic, not the glass, it won't tear apart and wrinkle up and get unruly.

4) When you have the glass wet out and squeegeed to a nice resin ratio (the minimum to still have it wet is usually preferred) take some metal scissors (no plastic handles) and cut out the shape you drew, right through both pieces of plastic and the wet glass. This is the first time you will need gloves, and maybe only one. Throw the scissors in the pan of acetone you have ready (no plastic handles....).

5) carry the piece to the repair location, flip it upside down and peel the bottom piece of plastic. Paint a thin coating of neat resin on the repair area, then slap the piece on the repair. Squeegee down if necessary or smooth by hand, then peel the top piece of plastic. If it is dripping with resin, you didn't get it dry enough in step 3-4. Repeat if more layers are necessary.

6) put peel ply over the whole thing and squeegee down, wetting a little more if necessary to get completely wet. Leave a couple of inches of dry peel ply hanging off it every direction.

7) Have a beer and let it go off. Peel the peel ply. Fish your scissors and squeegees out of the pan of acetone.

Many variations of this for various situations, for example you can wet out many layers (I've done 8 - 10 at a time), tapering to the outside, all at once on the first go. Do the first, peel up the top plastic and lay another on, etc.

 

[Simi 60]

Have a roll of stitched 440gsm double bias and 30 litres of epoxy onboard at all times on this and my previous 2 boats.
Stitched double bias is the easiest of glass to use, the 45/45 lay allows it to go around complex shapes and radius with ease.

I always get a thin screed of filler on when the resin has kicked.
Much rather sand filler than grind glass.

 

[diver dave]

There are tricks to cut down on the grinding and finishing. Also the mess.

For the grinding, the best professional shops always cover the laminate with peel ply as the last step. This is wet out just like it was the last layer of fiberglass. When all is cured, it peels off the surface by hand. The advantage is since it is very fine grained cloth, it holds all the nubs and fishhooks down, smooths the edges, eliminates many of the fisheyes, etc. Well done, the result needs little or no finishing.

For mess, on small jobs, wet the cloth/mat/stitchply/whatever on a table, then move it to the job. Here's an example of the steps:

1) take a piece of 6 mil clear plastic, tape it over the repair. Use a sharpie to draw the outline of the piece of fiberglass you want, leaving a good border on the plastic.

2) set up a table and lay another 6 mil clear plastic piece on it, bigger than the repair.

3) cut a piece of fiberglass larger than the repair, put it on the plastic, mix some resin, pour it on the glass. Lay the first piece of plastic (with the outline) on top. Squeegee the resin around with a dry squeegee on top of the plastic. So far you haven't touched the resin. You can move resin to dry areas, or squeegee excess off to the side. If you don't have enough, lift the top plastic and pour some more resin on. Because you are rubbing on the plastic, not the glass, it won't tear apart and wrinkle up and get unruly.

4) When you have the glass wet out and squeegeed to a nice resin ratio (the minimum to still have it wet is usually preferred) take some metal scissors (no plastic handles) and cut out the shape you drew, right through both pieces of plastic and the wet glass. This is the first time you will need gloves, and maybe only one. Throw the scissors in the pan of acetone you have ready (no plastic handles....).

5) carry the piece to the repair location, flip it upside down and peel the bottom piece of plastic. Paint a thin coating of neat resin on the repair area, then slap the piece on the repair. Squeegee down if necessary or smooth by hand, then peel the top piece of plastic. If it is dripping with resin, you didn't get it dry enough in step 3-4. Repeat if more layers are necessary.

6) put peel ply over the whole thing and squeegee down, wetting a little more if necessary to get completely wet. Leave a couple of inches of dry peel ply hanging off it every direction.

7) Have a beer and let it go off. Peel the peel ply. Fish your scissors and squeegees out of the pan of acetone.

Many variations of this for various situations, for example you can wet out many layers (I've done 8 - 10 at a time), tapering to the outside, all at once on the first go. Do the first, peel up the top plastic and lay another on, etc.

Thats a great piece. Thanks. Especially relevant to using chopped mat, maybe a bit less so when using stitched biax, that tends to stay together better when pushed around.

 

[DDW]

Stitched 45/45 biax is great stuff for general use. There are versions with a light mat stitched to one side, this is said to improve interlayer bonding, though it also reduces the ability of the Double Bias material to conform to compound curves.

I rarely use mat for anything, mat will get very unruly as the binders in it break down from the wet out. That is also what makes it conform to any shape. The stitched cloths tend to stay together better than the other types, but I still use the 6 mil poly sheet method on smaller pieces. To patch a small hole, a piece about the size of a half dollar works well, and in small sizes like that even DB stitched cloth can come apart or distort enough to be unrecognizable.

 

[ABL]

Best tip I ever got for cutting any fiberglass matt is a roller cutter! Works like a pizza cutter! Best investment when doing glass work. Can be picked up at any fabric store!! Lay the glass on a piece of scrap plywood and roll.....works great for making those strips for fillets.