Fiberglassing Advice

B

blockrocker

A Refined Basshead
Hello fellow junkies!
I have decided to go down the custom a-pillar road and am thinking about fiberglassing my mids and tweets into the pillars. I haven't done any work with fiberglass before, so I was hoping for some advice on avoiding the rookie mistakes or poor techniques that will leave me less than satisfied. I've been watching videos and trying to collect tips along the way. So I am looking for some shared experiences from those who have done this before.

I have bought an "extra" set of pillars, so I don't destroy my factory originals. My plan is to make baffle rings and hot glue them to the pillars and ensure they are aimed where I want them to be. Then stretching, gluing and stapling fabric over them and add an initial coat of fiberglass resin. Followed by the usual steps of fiberglass, then body filler/bondo to shape and smooth. Also some kind of "milkshake" on the inside.

I know to sand the pillars first to ensure adhesion, also cleaning and keeping them dust free during the process. I know about sanding/shaping during the body fillers green stage, rather then letting it cure all the way, and attempting to sand. I know about drilling holes around the fabric to allow the resin to plug and bond "mechanically" to the pillars.

Essentially I know what Mark @ CAF and Peter @ PS Sound has shown me, but I am sure there are many more tricks to be taught. So I am hoping that you folks can help me ensure I have taken all the necessary steps to produce a great finished product. What do I need to be extra careful with? How much/thick do I build the fiberglass? Are there some materials to avoid? How do I ensure they last a long time without cracking or breaking etc.? Also, paint or wrap?

Any advice from those who have walked the walk would be greatly appreciated! I fully plan to take lots of pics and do a build log with this project. Right now I am just trying to psych myself into it and come up with a solid game plan. Thanks!!
 
I've only done FG a couple of times, but my suggestion would be to practice on some sacrificial piece to get a feel for it. Also make sure to stir your resin until your arm falls off, then switch hands and mix some more. I can tell you it sucks when one part cures in no time flat, but another part stays gummy for weeks.
 
phroenips said:
Get a good quality resin. Hint: Home Depot and Lowes don't carry good quality brands.

I've used the stuff from them before, and compared to the stuff I used from US Composites, the latter is a delight to work with. http://www.uscomposites.com
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I've only done one fg project. Started with US Composites, ended with bondo because I didn't order enough. US Composites was MUCH easier to work with.
 
blockrocker said:
Thanks for the advice. I was planning on using bondo brand resin. I've heard good things.
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Don't. US Composites. I thought Bondo was fine. It worked for what I did. Then I used US Composites. No comparison. I can't believe I even used Bondo before. US Composites is actually cheaper too.

Rage Gold filler
 
I've also used US composites for my first project and it was fantastic to work with. I used chop strand mat for first layer or two and getting a shape, then I used one of their thicker woven mats for getting thickness/strength.

Sounds like you know about a lot of the tricks already. When I was learning how to fiberglass I was surprised how messy it was (or how messy I was). Buy tons of gloves and chip brushes since they aren't reusable after the resin cures. A plastic mixing cup can be re-used if you let the resin cure then pop it out of the bottom like a solid hockey puck. I was also surprised how important it is to get the activator/resin ratio correct for your climate and the amount of working time you desire. I started with the recommended ratio and adjusted a few times. Also, work outside, those fumes are crazy strong. Try not to go cheap on a facemask if you do any cutting/trimming of the glass after the resin dries. I bought a good one that also kills the chemical odor and it was brilliant.

I'm not sure how warm it is up in the great white north, but you might struggle getting the resin to cure like I did in the (mild) winter down here. I tried mixing extra activator with the resin hoping the chemical reaction would happen faster but that was really hard to control. I had better results with a pair of big heat lamps at a reasonable distance from the work, but not too close otherwise people warned the part would cure too fast and warp the shape (very true!).

The one thing that slays me with fiberglass is the prep work and what you do before the resin dries seems to dictate how much work you do after. If you plan well and forsee all the challenges of body filler and wrapping in vinyl and so on, then you can do the fiberglass work in a way that makes all the following steps really easy. I never figured out how to do that.

Certainly try making *something* before you work on your pillars. I found fiberglass to be unforgiving for mistakes and learning opportunities.
 
You could also look for Solarez UV curing fiberglass, which doesn’t use temperature to cure but uses UV rays from the sun. You’ll need to work with it some without the sun (indoors) and then move it out into the sun for curing.
 
Thank you folks for the continued advice. This is really helpful stuff. I will certainly stay away from Bondo and find some us composites instead, excellent advice!

I appreciate the detailed response Justin. I'm certainly going to make a practice project first, to try to get a feel for what I'm getting myself into. It seems that I am going to have to pick a good weekend to give this a try, as the temperature is all over the map at the moment (9 degrees C today and sunny, -11 degrees tomorrow with several cm of snow). Preparation, anticipation and following the resin instructions closely seem to be the best things I can do for myself and I already have a great mask with cartridge filters and rubber gloves. Plus I plan to do this in the garage with the door up, on a nice day.

Rage Gold filler is also good to know!

A few follow up questions, if you guys don't mind. How thick should I build the walls? How strong is needed? Does the milkshake add any strength? Or is it just to seal and deaden?

The plan is to install gb10 & gb25 speakers into the pillars.
 
thickness depends on the application. For a pillars, 5-6 layers should be close. Needs to "feel" solid. (you will have a better understanding after first couple of layers)
 
You've gotten a lot of good advice here. I just want to echo those who have mentioned that you try *something* before going to the real job first. Even if that means just setting up a little area to mess around in and try to get the hang of what happens to the mat as you brush over it, or pre-soak the area before you lay mat down. Just play around with the materials and get familiar with them.
 
Well this is good timing. I have some midrange speakers and tweeters that I may try grafting into the A pillars (maybe). Where do you guys procure your vinyl, paint, and other supplies?
 
Is painters tape an appropriate masking material for resin? Could I lay some tape on a surface, make a small resin/fiberglass sheet, and be able to separate it from the tape after it dries? Or is there another product I should use?
 
Blue 3m tape works. There is better/smoother release but that's fine. You can also use Johnson's wax as a mold release. It's good because it's available at every hardware store. Really actual mold release is best and cheap.
 
I'm getting ready to start on my a-pillar project soon as well and was wondering what is another filler to use other than Rage Gold. No one around here carries it in stock so I have always used bondo filler. Is there something better that would be available at like an Advance Auto or Home Depot?
 
Call an automotive paint supply store. Amazon prime will have it there in 2 days if not. It's not cheap but to me it's worth it. It stores for more than a year too.
 
I will add that cheapo brown packaging tape (the 2” thick stuff on parcels) works exceptionally well as a masking tape, sticks to everything pretty well and is better than masking tape for releasing
 
Theslaking said:
Call an automotive paint supply store. Amazon prime will have it there in 2 days if not. It's not cheap but to me it's worth it. It stores for more than a year too.
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I was trying to get something a little cheaper than the Rage but still better than Bondo and would prefer somewhere locally in case I do run out. Do you know approximately how much filler it would take to do 2 a-pillars I have only done sail panels in the past?
 
soundstreamer said:
I was trying to get something a little cheaper than the Rage but still better than Bondo and would prefer somewhere locally in case I do run out. Do you know approximately how much filler it would take to do 2 a-pillars I have only done sail panels in the past?
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I was going to say you could get true 3M filler from Napa but I don’t think it would be cheaper than Rage Gold.
 
blockrocker said:
Is painters tape an appropriate masking material for resin? Could I lay some tape on a surface, make a small resin/fiberglass sheet, and be able to separate it from the tape after it dries? Or is there another product I should use?
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I once saw aluminum foil was recommended and it did release pretty well for me, except for any spot where the foil wrinkled a little bit and the resin seeped into the folds and trapped the foil. So pretty much everywhere. I wouldn't use foil again on my next project!
 
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