Thread: How to Work Fiberglass Right

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Originally Posted by NTFDAY

McDonnell Douglas used it to clean interior panels and just about everything else until, 69, I believe, when some idiot dropped a smoldering rag behind the aft galley in a DC 8 that was ready for delivery. That caused quite a fire that delayed delivery for 6 months or so. That crap will turn your skin white, nasty stuff.

older engine builder i know said all good carb guys died young from working in the stuff it a liver killer . eats the ozone .but smelled great and did a good job . my dad love to tell me storys when mom was not around . he went in the Army that or jail . he love to out run the cops with is 50 chevy 4 door with red ram in it . well ran out of gas sat on the hood till they found him . Army was a good deal for him.he need teeth and went to the doc as well . he was abit of a smart ass in a nice way. told the doc that when he was work in the parts washer cleaning parts . he would break out . doc told him i can cure you. all is i need abit of what makes you break out .doc told him i put some on this band aid stick it on you . before long you be fine next time dad shows up with a can of the stuff handed it to the doc sprayed on the band aid and it melted in this hands . doc said what the hell is this stuff

Fiberglass is great stuff! Whatever you can dream up is possible!!!

bodywork2 (3).jpg

Here is one of my projects from many years ago, which was intended to be marketed. Unfortunately, the bike market shifted unexpectedly before we got to market with it. The molds and some parts are for sale from my partner in the effort.

I've mocked up masters, built molds, hand laid car bodies, body parts, and done a ton of Corvette repairs and customizing, bike parts, and drag car work.

I would like to help, but my deep involvement slowed way down about 20 years ago. I am just not familiar with the chemical products available today. :-( If it is anything like paint products, they have changed radically... and not for the better.

Probably the best I can do would be to share some ideas for mocking things up. One thing I used to use was 1/4 inch hardware cloth. I used to buy it at Ace Hardware. It is like a stiff screen that could be cut and wired together, then wet cloth or mat laid over it. After you build up enough strength, the mesh can be pulled away from the inside, and the outer surface finished by skim coating with filler and block sanding. That technique, combined with finding some suitable shapes to add compound curves, could be used for almost anything.

Another thing I used regularly was a spray product that acted as a mold release. That kept the new glass from sticking to the old.

If I see something I can offer solid advise on, I'll jump in.

Originally Posted by HOTRODPAINT

Fiberglass is great stuff! Whatever you can dream up is possible!!!

Attachment 61602

Here is one of my projects from many years ago, which was intended to be marketed. Unfortunately, the bike market shifted unexpectedly before we got to market with it. The molds and some parts are for sale from my partner in the effort.

I've mocked up masters, built molds, hand laid car bodies, body parts, and done a ton of Corvette repairs and customizing, bike parts, and drag car work.

I would like to help, but my deep involvement slowed way down about 20 years ago. I am just not familiar with the chemical products available today. :-( If it is anything like paint products, they have changed radically... and not for the better.

Probably the best I can do would be to share some ideas for mocking things up. One thing I used to use was 1/4 inch hardware cloth. I used to buy it at Ace Hardware. It is like a stiff screen that could be cut and wired together, then wet cloth or mat laid over it. After you build up enough strength, the mesh can be pulled away from the inside, and the outer surface finished by skim coating with filler and block sanding. That technique, combined with finding some suitable shapes to add compound curves, could be used for almost anything.

Another thing I used regularly was a spray product that acted as a mold release. That kept the new glass from sticking to the old.

If I see something I can offer solid advise on, I'll jump in.

It is an awesome product,HRP..I enjoy my job,,even if it is a dirty job.. I use a mold release on a regular basis..I only wax my molds about every third pull of the product,,but spray two light coats on the mold each time I use them..

With race car body stuff plus go karts---


long time ago--used hardware cloth, plaster lathes, etc to build substructure then plaster of paris to which would file sand into shape desired, then make a heavy stiff mold over that, then make the lighter race car part(think dragster front body work)


Also have used lots of Styrofoam? for wing shapes---cut a couple pieces of plywood into wing profile and then use a wire with electricity for heat to guide over profile pieces to cut the foam to wing shape----then wrap the foam with waxed freezer paper and lay cloth (Kevlar,glass,carbon fiber)


Also for floor panel type stuff over transmissions, etc, I use the sponge egg crate type foam rubber packing material that comes in the Pro Charger kits to lay over trans and then freezer paper then glass cloth/mat/cloth

Originally Posted by rspears

....I'm posing a question to the guys out there who have been working glass through the years, and who know what's right and what's not without having to ask anyone for suggestions..... Any true Glass Master's out there who are willing to share? Looking for some good, step by step ideas on how to do the work and thinking it might save some of us some grief as time goes by.

.....well it seemed like a good idea.

There's a decent amount of info at fibreglast. They mention that the preferred thickness for gel coat is .010 to .020 inch. If the gelcoat is no thicker than that and has some pinholes, sanding the area down to the base fiberglass is easy, but you may find more pinholes in the base fiberglass. Polyester glazing putty is sufficient to fill pinholes for a car body, but not a boat hull.

There are some videos too. There's some info on various fillers that are used to repair boats. One mentions using a lightweight filler, to a thickness of up to 1/4 inch. They have other reinforced fillers for deeper fills.

Gel Coat Troubleshooting Guide | Learning Center

Fillers for Resins and Composites in Stock | Fibre Glast

Books & Videos for Fiberglass & Composite Material DIY | Fibre Glast

I'm fighting a unique problem with my body. The gel coat thickness is OK in most places, except on many external corners of the body, that were internal corners in the mold. The gel coat apparently ran into the low areas and pooled to a thickness of up to 1/4 inch in the internal corners. The gel coat is full of bubbles and must be removed to avoid future paint problems. I've even found areas where the thick gel coat is not bonded to the base fiberglass.

I've removed the gel coat, and feathered out the repair area with a 36 grit disc or 60 grit sandpaper. Since the body is not lacking is layup thickness, I use fiberglass reinforced filler to make the repair.

I have only found a few spots where the layup thickness of the body is lacking. Most are around the rolled-under edges of the fenders or the fender mounting flanges. If I find a thin area, I've sanded the back side and built up the thickness with matt and resin.

FWIW, if I find a slight wave or mismatch at a mold line that needs a shallow fill, I just scuff the area with 60 grit and use any good polyester filler. I see no need to remove the gel coat because filler always has to feather out onto the gel coat. The bond between the gel coat and base fiberglass should be every bit as good as you'd get between the filler and the base fiberglass, so I see no purpose in removing a large area of gel coat, where a thin layer of bondo is applied.

I'm scuffing my entire body with 80 grit and applying several coats of Evercoat G2 featherfill, a high build polyester primer, after all of the bondo work is done. More sanding follows that. In the end, I want the whole body to have a decent layer of polyester primer.

Evercoat

Dave,,the reason why the gelcoat is not stuck to the glass layup,,is usually because it(the lay up) hasn't been rolled into the corners,,or any one area properly.. If the gelcoat has been sprayed into the mold,,it is quite often the case,that it's hard to get the spraygun into the area to get the gelcoat into the mold..I usually follow up with a brush,to even it out in those cases..can't do much about it sometimes.. As I said elsewhere,,if the glass isn't rolled into the mold properly,,this is what happens..

Originally Posted by lamin8r

Dave,,the reason why the gelcoat is not stuck to the glass layup,,is usually because it(the lay up) hasn't been rolled into the corners,,or any one area properly.. If the gelcoat has been sprayed into the mold,,it is quite often the case,that it's hard to get the spraygun into the area to get the gelcoat into the mold..I usually follow up with a brush,to even it out in those cases..can't do much about it sometimes.. As I said elsewhere,,if the glass isn't rolled into the mold properly,,this is what happens..

I've seen that in a couple of places, where my fenders have a rolled-under edge. Even found some dry fiberglass in a spot on one rear fender - it never saw any resin. What irritated me is that the gel coat was falling off in that area and the seller didn't both to fix it before sending me the body. That fender also had a small crack where the layup was real thin. Probably cracked it when it was removed from the mold. I ground all the way through that crack from the outside and feathered it out with a 36 grit disc on both sides before applying mat and resin.

My build log has some pictures of the first fiberglass console that I received, that had gel coat that was probably 3/8" thick. That console was not useable and was replaced for free. All of the other repairs were on my time.