Need recommendation on Fiberglass/Fibreglass repair material

[pharriso]

I've not done fiberglass repairs before, but am looking to strengthen some interior parts (under dash trims) & maybe block off some holes & would like a recommendation on materials to use.

Should I buy a kit, or separate mat & resin?

What weight mat should I buy?

Bearing in mind that I'm here in the States, does anyone have a recommended supplier?

[pharriso]

Is this what I need - http://www.amazon.com/Bondo-422-Fiberglass-Resin-Repair/dp/B000BO7CVK?

[Craven]

Hi,
A crucial part of repairs to fibreglass is the bonding process between old & new, there is plenty of good info available on the net and well worth reading.
Separate resin & a fiberglass matt is the most economical, but for small hole repairs look for filler that contains fibre reinforcing. Isopon P40 being one, very easy to use and is ideal.
Ron.

[pharriso]

.... for small hole repairs look for filler that contains fibre reinforcing. Isopon P40 being one, very easy to use and is ideal.
Ron.

& Unfortunately not sold here... Anyone know of an equivalent product here in the States?

[Bud English]

Phil, I would say that much depends on how much repair you intend to do. For small non-structural areas the kit shown should work fine. (That deep discount might reflect old stock.) Separate materials will cost you more, but you can them select the weights of the mat and cloth instead of having to take what they give you in the kit. I second Ron's advice. Have a look on line for tips on the actual fiberglass repair or there are good books on the subject. I don't know if you have TAP plastics on the East Coast but I've sourced materials from them in the past with good results. Here's a link to their video on repairs. It's actually pretty good.
http://www.youtube.com/watch?v=SsoKAHU5xUw

Quite a few finish material suppliers sell fiberglass materials as well, but their selection probably won't be as good. Don't get talked into vinyl ester or epoxy resins. It's best to stick to polyester resin as that was what was used in the original construction and will make for a good bond. The fiber filled fillers that Ron mentioned are good for small fills. Bondo makes a long strand filler as do others. Have a look on line.

Pay attention to the warnings on the packaging as the materials can be toxic and are very flammable. Over catalyzed resin will get very hot and can self ignite. Clean your area of all rags used at the end of the day and get them out of the garage.

I'm no expert but that's been my experience. I've done repairs on quite a few things, done some custom bodywork on a couple of cars in the past, and even a little damage repair on a military helicopter in the 70's. I'm sure if I'm leading you astray, someone will step up and add to this. Other than the itching from sanding, fiberglass is really easy and fun to work with. It's a lot easier than banging out bent metal panels and coming up with professional results yourself. Good luck and have fun with it. I think you'll find it rewarding.

[gearbox]

Hi Phil;

The Amazon stuff is a polyester resin, as with most of the stuff you can buy at the local pepboys. From what I understand, you want to reinforce the under dash trim and perhaps the console, which is an ABS plastic. The Polyester may react with that material, possibly melting or distorting the plastic. Your best bet is to find a Marine store and find yourself Epoxy fiberglass resin made by West Marine. A quart should be ample along with a pint of hardener. The Epoxy will not react with the plastic and it is a much higher quality. As for the glass, woven (strands weaved side to side and up and down at 90 degrees) is the strongest for structural repairs, but needs to be covered in chopped strand (fibers going every which way in a mat) if the part is going to be painted. The weave has a tendency of showing up through the paint. If we are still talking about those small ABS parts, I would get what they call "Veil" or "Tissue" chopped strand fiberglass. This stuff is extremely thin and conforms to parts well. You can build up the layers to make it a thick as you want. As for the holes, I use duct tape to close up the holes on the front making it a jury rigged mold. Soon as the resin sets up, about 15 minutes, peel it off and it prevents excess resin to drip through and allows the fiberglass to form correctly. Give me a call if you need any help, Allan

[robertverhey]

Yes another vote for marine /yachting supply stores, (in my case https://www.whitworths.com.au/ )I'm finding they are reasonably priced and carry a good range, with stuff sold off the roll rather than (more expensive) pre packaged repair "kits". As an aside I also bought my window cable from them, again off the roll in their rigging section.

One tip I've found useful is the fact that aluminium foil won't adhere to curing fibreglass, so it's a good, cheap alternative for a release agent when moulding replacement parts

Robert

[nomad]

Saran wrap makes a good parting agent as does poly ethelene sheet. As mentioned the resin will eat into ABS and totally destroy styrene. So keep it away from expanded poly styrene foam cups. If you source some PVA [poly vinyl alcohol] you can get it to separate from just about anything. I've liked to use modeling clay for temporary molds. The oil in modeling clay is completely incompatible with polyester resin but if I cover it with PVA its not a problem.
Now if I could just find a decent fiberglass "tissue" in the US, life would be good!

Kurt

[pharriso]

Thanks for all the advice guys, certainly appreciated by a GRP neophyte.

So it looks like I need 2 sets of materials for 2 seperate tasks.

1. For small holes (old wire holes etc) Isopon p40 was recommended, this stuff is available here in the States & looks similar http://www.amazon.com/272-Bondo-Glass-Fiberglass-Reinforced-Filler/dp/B000VKZ3JM

2. For re-enforcing trim panels, I should use Glassfiber tissue & Epoxy resin from a boat builders. Looks like tissue is not generally available in the US, but this guy is selling on ebay http://www.ebay.com/itm/10m-x-1m-Fibreglass-Suface-Tissue-30gsm-used-with-fibreglass-moulds-resin-/251248851248?pt=UK_Crafts_Other_Crafts_EH&hash=item3a7f993930. If I buy 10m (30 feet) on eBay is anyone else in the States interested?

Next issue... One of the common faults of our favorite cars is that the double screw fasteners tear out of the rear tray flange like this (not my car):

Would the best way to repair this be with tissue & resin, or the glass strand re-enforced bondo?

[brettengelaz]

Fiberglass repair isn't too hard, but can be really messy! I'd suggest cutting some trash bags or plastic painter's drop sheets to cover the carpet and seat areas. As backing to fill firewall holes I've used cut-up plastic 1 gal milk cartons for bigger holes duct tape for small ones. Most decent auto finish suppliers should have "kitty hair" resin filler, it's polyester resin with chopped fibers. For smaller (< 1in) that should work fine. It uses a cream hardener much like body filler and is easy to work with.. For larger holes, two or more layers of glass mat/roving is really needed (and easier!), cut one or more pieces to fill the hole, and a another cover about 50% larger.. In any case, preparation is vital, sand the cockpit side of the firewall down to the resin, using coarse (60-80grit) paper, then wipe with acetone, allow to dry, then apply the new resin.. After the patch sets, you may want to wipe some thin filler on the engine side and sand to cover up the repair..

Oh, there are TWO types of polyester resin, Finishing resin, and Laminating resin.. Finishing resin is what you will likely find at a local auto parts store, it contains some PVA and will set up with a tack free surface.. If you are doing only one layup (and likely you are!) this is all you need.. If you are doing multiple layups (layers at different times) then laminating resin is best, it will remain tacky and will bond to the next application of resin and glass nicely.. Then finish with the Finishing resin.. AND there is yet another type of resin, thixotropic, that can be used on vertical and sometime overhead applications, it has an agent that keeps it from flowing or dripping.. useful for larger repairs on vertical surfaces like the firewall

"Stickystuff Sales" is a Phoenix area resin/glass supplier, and has a decent selection on-line, including various weights of mat/cloth, and some tutorial videos too.. You should be able to "google" a supplier near you as well, also check with a marina or boat dealer, they usually do repairs and have a local source for resin and glass.

No relation other than a happy customer: http://www.stickystuffsales.com/


Cheers,
Brett

[Gordon Sauer]

I have found it very useful to also consider some of the superglue types along with some filler or cloth used either in the boating or model plane hobbies. I like the very thin fiber glass cloth that you can get in the model airplane hobby shops and find it to be quite strong without the buildup that gets in the way of using any of the mats. It also hardens very smooth if used with polyester resin and consequently finishes with paint well. On other areas where strength is not that much of a factor there are super glue specifically designed to use with plastics, such as found at Ace Hardware that comes under the label Plastic Surgery--this Can be used with the aforementioned cloth or even some of the Powdered fillers sold at marine outlets that is designed to make a paste out of epoxy resin to allow it as a filler Or for larger areas it could be used with the epoxy resins rather than the plastic surgery. Gordon Sauer

[nomad]

Phil, in the photo you show of the broken out hole, I would grind down the adjacent fiberglass to a knife edge and probably at least a couple of inches around it. Then have it laying on its side so that gravity is in your favor. Back the area with something that will part from the glass as was mentioned in the other post's. Then laminate it back to original or a little thicker if there is room. After curing clean up with a grinder then I would try to modify the metal bracket so that it would spread the load. At least that is how I would attack it taking in mind that I am only working from a photo.
Spring for a cheap kit and do a little practicing. Keep in mind that curing polyester give's off pretty strong fumes that are flamable. I don't plan on doing any fiberglass work till I can do it with plenty of ventilation and warmer weather. If you are only doing a small area there should be no problem though. Keep in mind though that polyester resin cures very poorly at temps below 50F and awfully quickly at temp's above 90F.
BTW, you can do some shaping and trimming of the laminate with a utility knife if you catch the curing laminate at the hard rubber stage. I would trim the edge of the example above when it reached that stage.

Kurt.

[nomad]

Took another look and realized that is not a removable part of the car which would make it a little trickier but still doable. Need to put down a lot of polyethelene sheet to protect everything!

Kurt.

[gjz30075]

Kurt, the hole Phil shows is the tray where the top sticks sit when retracted. It's all removable.

Greg Z

[nomad]

Thought it sounded like it was removable from the description....that make's easier!

Kurt.