Ok folks, here is part 1 of a multi-part tutorial on fiberglassing.
* Please note this is not something for everyone, and I take no responsibility for what you do with this information.
In this first tutorial, I am going to show you how to make basic shapes when starting from scratch. I will NOT go thru how to mix your resin and MEKP(hardener) or how to apply the resin and mat. I will also not go thru mixing body filler, etc. These are things you will have to learn with practice. I suggest testing a few small projects before jumping into a big project. Save yourself the headache and start small.
If you have specific questions, feel free to post them and either I or one of the other rsident fiberglassers will be glad to answer to the best of our ability.
So here we go.....I decided for the sake of this tutorial to use a small piece that pretty much everyone should have access to for reference. So I decided on the front defrost vent as a good spot for a small speaker. Please excuse some of the blurry pics as my camera doesnt like dusty areas
First I get the fire blazing to keep the garage warm
for supplies, some resin/MEKP from US Composites. I will forewarn you that using bondo brand resin, it WILL shrink/warp a bit as it cures, especially if you use wrong ratios of resin to hardener. Bondo brand is alot thicker, harder to apply, and just all around not worth it. I highly suggest using quality materials if you want a quality outcome.
30 yards of fiberglass mat from USC. me loves glasing
a picture of my trusty roloc grinder
heres the piece im starting with.
and heres the speciman.....a new set of Polk 4" coaxials
a quick mock-up of roughly how it will sit
trace out your mounting base for the speaker, and I drill holes to make jigsaw work a little easier.
center cut out
ring all cut out *note, it looks rough as i used the jigsaw, since my router is out of order. I later cleaned all the edges up with a roloc grinder and some hand sanding.
cut out the plastic in the vent to make way for the speaker.
here i took the DA to the edge to flatten the "lip" where it will be attached to the vent
this shows how the flattened "lip" mates to the flat vent surface
cut my piece of fabric to wrap the structure in after it is ready. for this project i used an piece of an old t-shirt.
here i cut wooden dowels to hold the ring in place while i wrapped and glassed. for these i use hot glue to secure since it dries quick and is easliy removable after the fact if needed.
quick mock-up with the speaker and trim ring in place
wrapped the structure in my material. i used super glue around the edges, and obviously staples around the wooden ring. normally I use CA glue, but was out and all i had handy was the super glue. make sure you pull as tight as possible to keep a solid backing when you lay your glass. if you leave it loose, it will end up sagging.
*note - in my experience, using hot glue where you're laying down glass doesnt work well. it tends to lift after a little sanding, so i wouldnt suggest using hot glue in areas like around the edges.
then i wetted out the fabric with resin, and began adding fiberglass mat. i do not reccommend using the cloth unless doing large flat areas. its alot tougher to work with in rounded or concave areas.
heres after 2 layers of glass. on the first run i usually try and get the larger areas pretty good, and dont worry too much about the little tight spots like in front of the wood ring until after the first run. for me it just makes the process go quicker and less chance of air bubbles.
then once it was dry, i did a quick sand down to take off any small hairs that may have lifted, as well as clean up the edges to make sure my next few layers tacked up tight.
heres a quick test fit just to get an idea of what it will look like. Note it isnt clipped in, hence the reason its sitting up a bit, but you get tje idea.
then i moved onto my 2nd round of glassing. i laid down another 3-4 layers making it 5-6 layers thick. may be overkill for something like this, but i dont like flimsy parts
they key is to get minimal to no air bubbles in your glass work. air bubbles/pockets = weakness in structure.
after those layers had dried, I took the scissors and cut arouns the edges to take away the excess matting hanging off that you can see in the previous pics.
then i did another hand sand down to clean up the edges and open the speaker pod/ i always use 36 grit for rough sand downs like this.
normally at this point you would go ahead and body fill the piece to take out high/low spots, but since i managed to lay the glass so smooth all the way around, i was able to skip the filler and go right to the icing. icing is basically like filler, but its softer, and alot easier to sand. you usally hit this with 150 - 220 grit, then move upto a 320, or as high as you want to go to your preferred smoothness.
you can see the thick lines in the icing.....i picked up a different brand icing than i usually use, and boy do i regret it. this stuff hardened up immediately with the same mixture i usually use. needless to say i had a little extra sanding to do because of it.
so then i sanded it down to my preferred smoothness. normally i would go firther into making it perfect in all lines, but for the sake of this tutorial, that was not necessary. here is the piece sanded down.
one more test fit
looks good, so its time for primer. again, i normally use true auto body high build 2k primer, but for the sake of the tutorial i used rattle can primer. maybe ill cover spray gun primer in a later tutorial.
and thats it. next step would be to wrap in fabric or paint, and install. Hope this helps some of you. Again if you have specific questions, feel free to ask.
Keep an eye out for future tutorials working with different techniques and types of projects.
Hope you enjoyed