Motorcycle Racing Forum

Racing Discussion => Racing Discussion => Topic started by: dwilson on June 02, 2003, 07:23:27 AM

Title: Working with Fiberglass
Post by: dwilson on June 02, 2003, 07:23:27 AM
I'm a real do it yourself kind of guy.  When I got into racing and bought my FZR it needed work so I started playing with fiberglass to do repairs.  Then I wanted to customize some parts and have done well with glass.  I'm doing pretty good with it and have made a few nice pieces by hand without molds but I'm starting to realize my limitations....

I usually use cloth, I've used mat but the cloth seems to like me better.  I usually spray a light coat of 3M 77 spray adhesive on the cloth, lay it on and get out any air with an acid brush.  Then I lay on the resin brusing it back and forth to get the coat as consistent as possible.  When ever working with 9o degree angles, I use 2 pieces and join them in the joint.  The main problem I get is the glass lifting off around curves or when wrapping it around the edge of a body panel.  I try to push it down with the brush, or adding a little extra resin, but it still lifts back off.  I'm also not sure about how much resin is too much.  I just slop a bunch on and wipe the extra off with the brush, then wipe the excess resin off the brush onto a piece of cardboard or something.  

Would it be easier to hold the piece in place with the gel resin and would the gel be easier to manage?  If anybody has worked with gel resin, I'd appreciate your input.

Whenever I make a piece with flat parts, I make them seperately on a piece of cardboard lying flat on the floor.  After it dries I cut the piece into the shape I need and build the curved areas or add more flat areas.  Anyone know of any better ideas?
Title: Re: Working with Fiberglass
Post by: tshort on June 02, 2003, 08:40:40 AM
I'm afraid I can't help you with your question, as I'm a real beginner in all this.  But I learned a lot just reading your post.  

And as I've got a seriously messed up set of bodywork after my getoff on Saturday, I'd love to know your recommendations re what brand/source you use for your glass materials.  Where do you buy it?  What do you get?  I need to repair some holes, scrapes, and cracks/breaks.  Thanks for any advice.
Title: Re: Working with Fiberglass
Post by: dwilson on June 02, 2003, 09:38:14 AM
***Don's guide to fiberglass repair***
You'll need
Resin (1 quart) (from Pepboys)
Extra tube of hardener
Fiberglass cloth
Acid brushes, any will do but these are cheap.  Home Depot calls them tin handled brushes.
Paper cups (NOT STYRAFOME)
Coarse sand paper
2 sided file, coarse on one side, less coarse on the other (optional).
3M 77 Spray adhesive
Scisors
Rubber gloves
A place to breath (aka outside)

Take your busted up panel off the bike, clean it and sand down around the crack/abrasion.  Sand the inside of the crack if you can.  You need to do this to give the resin something to stick to, otherwise it may peel.  If you have pieces broken off, tape them in place on the outside of the panel, if you can do the body work on the inside for reasons of appearance, it helps.  Put your gloves on (if you like your skin) and cut the cloth a couple inches bigger than your crack/abrasion, spray it with a light coat of 77 and put it in place.  With an acid brush tap it down and get it as tight on the surface as possible, especially in cracks/holes.  The key is to make sure their is nop air bubbles between the cloth & body.  Mix up a little resin, an ounce or two is usually more than enough, mix in a few drops more hardener than you need, don't go crazy with the hardener as it can make the resin to hard and even crack in the future.  Dab the resin onto the cloth and brush it off the edges.  It's pretty easy, just takes some practice.  If you have any more questions, feel free to ask.  
Title: Re: Working with Fiberglass
Post by: tshort on June 02, 2003, 10:11:29 AM
Awesome, Don.  Thanks!!  I'll be glassing...
Title: Re: Working with Fiberglass
Post by: tzracer on June 02, 2003, 10:24:26 AM
Remember to wear gloves and a respirator when working with fiberglass resin.

I never had any problem with glass mat or cloth sticking around bends once it was wet, might want to try different techniques. I push with the tip of the brush if it seems to be lifting. For larger pieces of cloth I will prebend it before adding resin. The pros use small rollers to get rid of air bubbles and get it to lay flat.
Title: Re: Working with Fiberglass
Post by: dwilson on June 02, 2003, 10:38:56 AM
The fumes off resin are bad.  I use it outside and keep the cup & project a few feet from my face.

I've heard of the rollers.  A body guy was telling me recently about a pizza cutter looking thing with some kind of a pointy pattern (cerated?) on it.  Said it makes little holes and pushes everything around.  My next step is to go buy some gel resin & see what that does.  I also considered asking Airtech whatthey use.  Their glass stuff is beautiful, but they use molds.
Title: Re: Working with Fiberglass
Post by: MZGirl on June 02, 2003, 01:07:57 PM
I was searching the web and found this article on Do-It-Yourself Composites:

http://speedtoys.com/~eric/misc/composites.html

Sounds interesting.  I'd like to try making my own bellypan for the MZ.  If I could make a mold that could be used over and over again, that would be great.

Oh boy, another project!   ;)
Title: Re: Working with Fiberglass
Post by: MightyDuc Racing on June 02, 2003, 01:44:49 PM
Man...I just used my gloves and slapped the cloth and resin on at the same time and kept smearing it in with the gloves.  I guess after reading this thread I'll do it the proper way this time.  FWIW...it all held up really well at Moroso with only one spot cracking again where the bike landed.  Not too bad.  Thanks for all the good info! :)
Title: Re: Working with Fiberglass
Post by: tshort on June 02, 2003, 02:53:24 PM
Cool link (speedtoys).  Thanks.
Title: Re: Working with Fiberglass
Post by: MZGirl on June 02, 2003, 04:08:18 PM
Here's another good link that my husband just sent me:

http://www.fibreglast.com/

LOTS of videos and books listed on their site, as well as materials that can be purchased on-line.
Title: Re: Working with Fiberglass
Post by: Arnziffel on June 02, 2003, 06:31:48 PM
Don ,

you may want to try soaking the cloth first then applying around the corners or edges and maybe giving yourself a little extra material to lap over.

instead of using the cups I have used the same kidney shape plastic pan that I brought home from the hospital for a couple years, after in hardens just twist the pan and the old stuff comes right out.

If you need to make a pattern, like say an ear for the windscreen, cut it out of a manilla folder and tape it to the upper and you can glass over the top of it.

 the tool you are refering to is a dough docker and they come in many different styles and shapes.

hope this helps
Keith W

Title: Re: Working with Fiberglass
Post by: dwilson on June 02, 2003, 08:31:47 PM
Thanks for the tips Keith, the re-usable pan is a great idea.  I'll give it a try & the dough docker next crash  ;D

MZ Girl, I just made myself a pretty nice belly pan for my FZR last week.  If you're trying to make one I can send you pics of mine & post some instructions.
Title: Re: Working with Fiberglass
Post by: MZGirl on June 02, 2003, 08:40:42 PM
Don, that would be great!  I just picked up a book about fiberglass and composites at the bookstore on the way home, so I'm looking to learn all that I can.  If you want to send anything through e-mail, my address is seasly1 at cox dot net.  Thanks!   :)
Title: Re: Working with Fiberglass
Post by: dwilson on June 03, 2003, 06:56:51 AM
There are 2 ways to make your belly pan, the right way and the just-get-trrough-tech way.  I should also add that since it doesn't sound like you ever made anyhting from glass before, you should not expect to make a nice looking piece on your first try.  The materials are pretty cheap, so if you have the time make some kind of a practice piece first.  I don't think your bike has fairings so alot of this will be free-hand and you'll have to find mounting points as you can't bolt it onto the lower fairing.  

1. Make the bottom: Do you want the bottom to be flat, curved or V shaped?  I would go with flat or V, curves are a little tough.  Take a piece of cardboard and cut it to the size of the bottom of the bike.  Using a magic marker and a ruler, draw out the exact shape you want it.  If you going to do a V shape draw a line through the middle where you plan to fold it.  After it's the size and shape you want, leave a little extra just in case and cut out 2 sheets of cloth fiberglass and lay them on the cardboard.  You can hold the glass on the cardboard with a light coat of 3M 77 spray adhesive.  The important thing to remember is that the glass be tight together and on the cardboard.  If you get air bubbles in it, it will look terrible and won't be as strong.  Mix your resin and apply liberaly.  Brush off the excess and set it somewhere flat to dry.  After it's dry, trim it to the exact fit on your bike.  Now you get to make the sides & front.

2. Making the sides:  Your going to need *alot* of small pieces of cardboard & masking tape.  On the bike, tape the cardboard to exactly how you want the bellypan to look.  Remember that the glass will take the exact shape and texture of how you set the cardboard up.  After you have the cardboard setup, tape the bottom to it with some thin masking tape, fasten it front, back and middle is necessary.  Cut some large pieces of cloth to fit over the sides and over lap the bottom by an insh or two.  Spray the cloth with the spray glue and stick it on where you want it.  When attaching over lapping pieces on the side, try to keep the weave lined up and make sure the over lap areas (seams) are neat as you'll be sanding these later.  It's important that you do this in one layer, don't try to do this quick by adding a second layer of cloth now, if you do it will sag.  Pay attention to the point where the cloth attaches to the bottom, it will want to sag just above that spot.  I don't know how to prevent that but you could try using pins on the top to keep it from sagging.  Apply resin, allow to dry...
3. Make the front (and or back): This is jut like how you made the bottom but easier.  Make a mock piece out of cardboard, lay 2 layers of cloth on it and add resin.  After you cut it to fit the rest of the piece, support it on the inside with tape and cardboard if necessary.  Add a layer or two of cloth around the seam to join it on and over lap about an inch or so.  Add resin, allow to dry.  Now you have a rough belly pan.  
4. Finishing:  Clean up the seams with a file, the 2 sided Nicholson file works great.  If you know anyone who does horse shoeing, the files they use work great too.  If you find a thin or weak spot, or just a spot that looks like c.r.a.p, add a small patch on it and file it out when it's dry.  When it's lookin good, you can add a light coat of body puddy and sand it lightly to get it nice and smooth, I don't bother with that much though, the body puddy is heavy and not necessary on the track.
I've heard another common method is to make a mock (or mold) out of cicken fence and simply cover that with glass.  I haven't ried that yet but plan to try it soon.  
Title: Re: Working with Fiberglass
Post by: G1K@work on June 25, 2003, 01:14:00 PM
Here's another tip:
Extra resin does nothing but add weight to your part.

Wet out the cloth over a piece of glass (I use an old window).  After you have applied the resin, and the cloth is totally wet out (you can tell when it gets transparent rather than the white color), use a bondo spreader to take off all the extra resin.  You'll be amazed at how much extra is on there.

Lay up the next layer of cloth while the previous layer is green (not fully cured), then you will have a chemical bond between the layers.  If you wait until the previous layer has cured, you will only have a mechanical bond between layers, which will not be as strong.  It is easier to get air bubbles out of laying up green layers vs laying up over cured layers.


Ryan