Noob Fiberglass Question...

[SaberFreak]

Just starting to do some fiberglassing, more for reinforcing items I made out of cardboard than to pull something from a mold.

My biggest problem so far is trying to make the fiber matt lay flat and even on the surface after applying the resin.

When ever I try to press it down either with a spatula or gloved fingers, the fibers would stick onto whatever I'm using and rise up, instead of staying down.

Now all the inside of my pieces look like a Wookie used them to rub off his molting fur. :unsure

How do the experts here tackle this problem? :confused

 

[swgeek]

With one of these

or these

 

[SaberFreak]

Thanks for the fast reply

Don't think I can get the rollers locally, maybe I'll have to make my own.

The brushes will need to be chucked after each use, no? Or can you soak them in thinner to remove the resin?

 

[swgeek]

You can soak them in acetone a few times but after a few hours use, you'll probably want to toss the brushes.
You want to use the brushes with a tamping motion and not a brushing motion.

 

[SaberFreak]

ok thanks! Time to go buy some cheap ass brushes :love

 

[themanwoaname]

those brushes in the picture look like "chip brushes", you can get a bag of them under 10 bucks and throw them out after use.

 

[exoray]

You can soak them in acetone a few times but after a few hours use, you'll probably want to toss the brushes.

Cheaper and easier to toss them...

If you have a local Harbor Freight they sell them by the box and they regularly have 1/2 price sales on them...

Brushes will be the best bet, the rollers only work well on long 'flat' surfaces, they are not very adaptable to bumps, corners and lots of curves, the chip brushes will be your friend... If you use the smaller brushes say 1" wide or smaller, it's adventurous to trim the bristles down a bit so they are shorter and stiffer...

Don't brush the fabric down, instead stipple aka push it down with a rapid up and down motion of the brush...

Watch this youtube video, skip to about 2:30 when he starts the layup...

YouTube - How To Fiberglass - Mold Layup

He does a little to much 'brushing' but it works since his mold is so 'flat' but pay more attention to his quick up and down push motions, that is what you really want for not flat surfaces...

 

[themanwoaname]

i second cutting the bristles down being advantageous. though ive cut them at an angle.

 

[SaberFreak]

If you have a local Harbor Freight they sell them by the box and they regularly have 1/2 price sales on them...

Nope. Not stateside, not even in a big city...

But we do have the local equivalent of your dollar store and they sell cheapo China made brushes for like $2 for 6 pcs...

Watch this youtube video, skip to about 2:30 when he starts the layup...

YouTube - How To Fiberglass - Mold Layup

Thanks! That's most helpful!

i second cutting the bristles down being advantageous. though ive cut them at an angle.

Can you explain more on the 'at an angle' part?

 

[Pilot]

Instead of cutting the bristles straight across, making them all the same length, you'd cut them at an angle like so:

They'll still be less flexible, and you get a little bit of versatility for getting deeper into corners and such.

 

[SaberFreak]

Ah, thanks!

 

[themanwoaname]

Instead of cutting the bristles straight across, making them all the same length, you'd cut them at an angle like so:

They'll still be less flexible, and you get a little bit of versatility for getting deeper into corners and such.

that exactly what im talking about! thank you!

 

[SaberFreak]

I have another fibreglass question:

How long does it take for a fibreglass helmet to become safe for wearing? It can't be good to put fibreglass right up to your nose shortly after its been made, right?

And how long should one wait after the fibreglass helmet is done before painting? Would painting it too soon inhibits the resin's ability to cure completely?

 

[Chiok]

Depending on your mix of catalyst to resin, the fibreglass could feel tacky for a couple of days if there wasn't enough hardener. But once it is dry, it won't be tacky, it'll just feel like plastic. At that point you can sand and paint. Because resin uses a catalyst, not air-drying like wood filler - if it's dry on the top, it's dry everywhere. If you mixed the resin well, that is.

 

[robn1]

I'd recommend using epoxy rather than polyester for a helmet. It doesn't stink nearly as much.

 

[hydin]

Just a side note, when you buy the cheap brushes to use with fiberglass, make sure it's HAIR brushes, and not plastic strands.

A friend learned the hard way that those cheap nylon strand plastic brushes tended to melt into goo when he was working on a project.

There isn't a big price difference, they are still dirt cheap, and save you time, effort, and a headache from slamming your head into the wall

Chris

EDIT - might also wanna try cotton batting. Less "stiff", and tends to absorb the resin pretty well.

 

[SUPERprops]

Use the rollers, there way better IMO. I found that you can buy a silicone ink roller for about $5 and re-use it a few times.

 

[michaudtime]

If I'm grassing a complex shape I spray some spray adhesive down and lay my fiberglass cloth and then hit it with the resin

 

[SofaKing01]

I've done some fiberglass work and I've had relative success with simple small foam rollers as I first begin spreading the resin. But you have to work fast! Once the you begin to feel the foam "catching" and the resin begins to harden/thicken immediately switch to the brushes. As stated above, be sure to tap the resin into the glass.

If you want perfect flat panels use a thick piece of glass as your base. I found using a roller to intially spread resin on the glass surface helps the fiberglass stick when you first lay it down - then switch to the brushes to tap the resin. Also, tapping helps get rid of most of the air bubbles.

When everything dries you simply pull the fiberglass from the glass and you have a perfectly smooth surface! Be sure to clean the glass when done. Another trick - while the resin is hardening and doesn't stick to your fingers (you have to watch it very closely) you can begin to cut your "flat" pieces using an X-Acto knife. It's a HUGE time saver! I made several custom interior pieces for my old Fiero and would cut templates out of paper/card stock. I layed the paper on the fiberglass, lightly sprayed black paint over the template edges then cut out the shapes using the knife and straight edge. I always left a little bit of overhang to work with once I began putting all the pieces together.

Here's a link to my center console build for my now departed 88 Fiero...
http://www.fiero.nl/forum/Forum3/HTML/000107.html

Hope all this helps!

 

[Toxx]

RPF-Member STEALTH mentioned to use Adhesive Sprays to stick the fibercloth on first and the apply the resin to it.

Another question: How do you get your fibercloth cut without getting frayed edges?

Cut it transversal/diagonal?