Fiberglassing Advice

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.

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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Originally Posted by phroenips

Get a good quality resin

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Thanks for the advice. I was planning on using bondo brand resin. I've heard good things.

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Originally Posted by phroenips

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.

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Originally Posted by blockrocker

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

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Originally Posted by Theslaking

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?

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Originally Posted by soundstreamer

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.

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Originally Posted by blockrocker

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!

Aquanet hair spray make a decent and cheap mold release, you can get it at Dollar General. For resin, it's best to get it from uscomposites.com. If you're dead set on getting it locally, try a boat repair, ATV repair, or auto body place to see if they sell any.

What is the attraction to using resin when epoxy is available?

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Originally Posted by Holmz

What is the attraction to using resin when epoxy is available?

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Could you elaborate on this a little bit? I honestly don't know much about resins or epoxies, but I'm willing to learn.

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Originally Posted by Holmz

What is the attraction to using resin when epoxy is available?

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Epoxy is good if you need maximum strength but it takes much longer to dry and if you're using thicker mat like knytex it's much harder to wet out with epoxy.

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Originally Posted by blockrocker

Could you elaborate on this a little bit? I honestly don't know much about resins or epoxies, but I'm willing to learn.

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Resins use a catylist and epoxies have a different chemical makeup.

Well there is West Systems 105 and similar epoxies.
most are not UV stable and need a top coat of some fashion like a 2-pack automotive.

Whether it is epoxy or resin, their strength is minimal compared to a cloth or fibre structure. They basically use the resin or epoxy matrix to just hold the cloth, and the cloth is what does all the work.

Painter's tape is what I suggested at the beginning. I have not used anything since Rage Gold. It's that good. It Should take less than a pint on fillers. But it's your first time. You'll screw things up. Shoot I've tinted tons of windows and just screwed one up this morning.

My fiberglass tip...... do it outside if you can, it will stink up your entire house otherwise. Fiberglassed some stuff a while back in the garage, even with the doors open and a fan blowing the house still stunk of it for ages. Also, when you think it is ready to put in the car, give it another week, otherwise your car will also stink like fiberglass.

So blockrocker, do you have enough advice yet?

:)

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Originally Posted by Justin Zazzi

So blockrocker, do you have enough advice yet?

:)

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Ha, I sure do. In fact, I have set up a couple of test pods to practice on, I'm just waiting for the weather to cooperate. Which may take a week or two, since they are calling for more snow this week and weekend. :rolleyes:

I really appreciate all the suggestions and hopefully I can do some of the fun stuff in the near future. Its tough to be patient.

I wanted to share the results of my first set of practice pods. These will replace my 3d printed pods and house some new speakers too. Naturally I made every single mistake one could make, but ultimately pulled it off and have some very usable pods. This was fantastic fun and I learned a ton. I'm already excited to move on to the pillars and do a proper install. Maybe one more practice set of pods first though. Lol.

Attachment 9847Attachment 9848
First, I chose a baffle shape that would fit my space and cut out the pieces.

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Next, I marked my pieces for a secure fit to the dash - riv nuts and a thin plate behind the dash to prevent pull through

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Glue up my frame

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Fleece and test fit for clearance (I was constantly test fitting everything including speakers together)

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Built up my layers and finished with a milkshake.

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Shaped the pods with two layers of body filler and sanded everything down to 400.
Yes, I know 400 is not necessary, but don't worry, I fucked up the paint job anyway. Lol.

Continued.......

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3 coats of paint and a final test fit.

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Voila! blockrockers first set of self built pods. I'm very pleased overall and learned a ton throughout the whole process. It was definitely a labor of love. I'm look forward to more.

Thing I wish I knew then and seems obvious now are plentiful. My milkshake was a near disaster, as I made it too runny and didn't add quite enough resin hardener. It eventually cured but but was like trying to keep tomato soup on a wall. I also forgot to cover my anchoring holes a poured a shit ton of goo all over my work top. Awesome stuff.

I used mdf for my frame and floor and never will again. Plywood or plastics all the way. My inserts are eating up the mdf and already showing wear.

Most of the shaping can be done with the body filler but it is very heavy. My little pods are absolute tanks and they are not terribly thick. Just food for thought. One note about shaping the frames, is to avoid sharp corners. Its tough the get the fleece to stretch properly without taking a weird shape or wanting to crease/sag. Again, keep a soft shape with the fleecing and sharpen it up with body filler.

Ultimately, this is a fun and very doable project for any DIYer, but it gave me a ton of respect for people who do this professionally. It is labor intensive and has some trial and error to it - even when well prepared.

Finally, be prepared for each step. Rubber gloves, disposable cups, stir sticks, brushes etc. Have too many instead of not enough. Keep in mind that it is a step by step process. It can be done in layers and doesn't need to be perfect on the first coat or the second or third. Keep working it and it will get there.

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Originally Posted by blockrocker

Thing I wish I knew then and seems obvious now are plentiful. My milkshake was a near disaster, as I made it too runny and didn't add quite enough resin hardener. It eventually cured but but was like trying to keep tomato soup on a wall. I also forgot to cover my anchoring holes a poured a shit ton of goo all over my work top. Awesome stuff.

I used mdf for my frame and floor and never will again. Plywood or plastics all the way. My inserts are eating up the mdf and already showing wear.

Most of the shaping can be done with the body filler but it is very heavy. My little pods are absolute tanks and they are not terribly thick. Just food for thought. One note about shaping the frames, is to avoid sharp corners. Its tough the get the fleece to stretch properly without taking a weird shape or wanting to crease/sag. Again, keep a soft shape with the fleecing and sharpen it up with body filler.

Ultimately, this is a fun and very doable project for any DIYer, but it gave me a ton of respect for people who do this professionally. It is labor intensive and has some trial and error to it - even when well prepared.

Finally, be prepared for each step. Rubber gloves, disposable cups, stir sticks, brushes etc. Have too many instead of not enough. Keep in mind that it is a step by step process. It can be done in layers and doesn't need to be perfect on the first coat or the second or third. Keep working it and it will get there.

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you live and learn buddy! I’ll do you a video next time I’m doing some (could be a while mind due to lockdown and not going anywhere near the workshop... it’s my mates business so I don’t need to be there no matter how much I’d love to be spending time doing my boot build or sub box... dash sub sounds good so far, redesigned already with a view to altering it some :)

once you’ve made a few sets the milk shake gets to be better, if I use 250ml of resin I then use roughly 1/3 in filler (think a ball about the size of a golf ball) and if it’s not going off fast enough add a little heat for 30 seconds, it’s faster in summer so a little heat helps it go, then keep the pod moving and roll it round as it goes (I poured it everywhere doing my dash and found a hole the glue hadn’t quite bridged lol... we use body shop style plastic sheeting on the bench or floor depending how big the item is)

as for saggy bits, you can use chopsticks or dowel to bridge areas and stop it sagging into areas with big spans, I am also a fan of using wire mesh rather than fleece, you can ca glue it into place and carefully apply filler so it goes on even, wraps just onto the mesh and use a pallet the knife to smooth it on the inside if required

i have also ca glued cardboard into shapes approx 1/4” under the level I need and then fibrefilled over the lot, it’s sometimes easier than mesh if it’s a bigger flat area, it’s surprisingly robust when ca glued on four sides and defo glued better than metal mesh

Maybe use an epoxy next and compare the two?

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Originally Posted by blockrocker

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Ultimately, this is a fun and very doable project for any DIYer, but it gave me a ton of respect for people who do this professionally. It is labor intensive and has some trial and error to it - even when well prepared.

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This.

Stepping back into this hobby, I'm doing a lot of new things thanks to the people here. I'm fabbing up my first set of sail panel tweeter pods. It's not going well and I haven't even used fiberglass yet. I also have mad respect and appreciate the beautiful projects more than before.

I also want to thank you for this thread as well as all of those who contributed. I will be using fiberglass for my sub build and appreciate the information.

I'm in the same boat Smitty. Getting back into the hobby after years away, as well. Without the sharing of knowledge on this forum and some great youtube videos, I would never be able to advance my installation. It would be the same jumble-fuck installs I did as a teenager. I've always been willing to learn something new and am not afraid to try, but without instruction and a little positive reinforcement, I'm dead in the water. That is the one place the car audio community has improved as a whole, since I was young - teaching and helping others. I was fortunate to have a couple guys show me the ropes as a teen, but thats been about it, until I found this place.

I have reignited my passion for car audio and the fabrication part is what I want to do the most. Now, for the first time in a long time, I feel like I am actually getting better at this hobby.

Keep putting forth the effort and I know your sail panels will come out great. Also know that my pods have lots of flaws, but I was careful to capture there good side. :p

I'll just say this... for being your first attempt at fiber-glassing, you did an outstanding job!