So if you are familiar with auto repair or are new to it, without a doubt you have at least heard the word "Bondo" thrown around, for those of you who have purchased Bondo and are looking at it with a confused face because there are little to no instructions, here are some tips on how to use it, how it works, so on.

Bondo is a company offering different auto body repair materials, from fiberglass resin, auto body filler, auto body filler "gold", spot glazing puddy, and fiberglass jelly.

THE FIRST STEP IN USING ALL OF THESE WILL BE THE SAME, CLEAN THE AREA ABOUT TO BE REPAIRED AND RUB OVER WITH A HIGH GRIT SANDPAPER FOR ADHESION PURPOSES.

FIBERGLASS RESIN
Best to be used on fiberglass or plastics, such as bumpers, side skirts, so forth and so on, use your imagination. for this you will need to get the resin, a resin mat, and a putty knife. This stuff is a HUGE pain in the *** to work with, its not suggested by me.

First off take a good look at what you are planning on using this for, cut a piece of the mat to size of area being used on, make sure its larger than 2 inches square, or well it wont really work too well, also it will seem as if its becoming unthreaded, dont fret too bad, its not a matter of life and death, it happens.

To use this place mat and hardener together on clean surface, preferabely one such as a paint roller plastic thing. mix hardener and resin together, ratio of 5 resin, and 1 hardener, then dip the mat into it. now that your mat is drenched within the fiberglass apply to the area of car to be used on, then use putty knife to smooth the mat down so that you dont have weird areas to work with that are as my friends and i refer to as "cottage cheese ***" because there are multiple dimples which trust me, are no fun to sand.

Once the mat has dried sand over to smooth, i suggest 140 grit sandpaper, takes off a decent amount, but still retains its shape without scratching like 60/40 grit would.

If you happen to sand down too far and reach the the fiberglass mat, its just going to become a more tedious task unfortunately, apply more fiberglass without the mat to the area in which is exposed, then redo all the fun steps of sanding.

AUTO BODY FILLER/GOLD
In my opinion this is the easiest form to work with, take your time with this, best for use on bare metal, can also be applied to fiberglass. In my personal opinion there is no visible difference between the two types. For this process all you need is a set of putty knives, a base to mix the materials, try and use something with as little pores as possible (stay away from wood, cardboard, hell no to paper). This comes with a coordinating thing of red cream hardener, don use it all at once that would be idiotic.

The downfall of this is that it will shrink, it claims it wont, ive seen many times great performance, but sometimes, well **** just doesnt work out, and it does have a tendency to do so. Also this is very easy to work with dont get me wrong, but be prepared to spend a good amount of time sanding, this is not going to be the easy slap on and your done procedure you saw on pimp my ride.

My suggestion for applying this is to do it in 1/16 or 2/8 inch increments to prevent shrinking one layer on the other, over and over, sand in between and clean thoroughly to prevent air pockets from forming, which is another reason why i suggest not adding it all on at once, air bubbles are damn near inevitable. Another suggestion that would be very helpful to you is get some gloves, and my gloves, im sorry i dont mean Mechanix gloves, theyre too worth wile to be covered in this junk, dont use latex gloves they tear easily, get yourself some grandma's out gardening gloves, theyre the best option youve got because you will get this junk on your hands, it will stick, and it will tear off your skin, its not fun. (mainly if your a smoker like me and you have a smoke without using gloves with bondo, it gets on your lip, and you have to tell everyone that it is not herpes, and explain, thats a real story, that really happened, fml)

Mixing the two are not a difficult task, take a ratio of 3 parts filler 1 part hardener, add as needed i like to make it from being red/gray mix to a semi red mixture, you dont want to apply this stuff without mixing well, it will be gloopy, will become distorted once sanded. I suggest using a 100 grit sandpaper.

SPOT GLAZING PUTTY
This stuff is a blessing and a curse in the same, it can go on practically anything, but best suggestion is just to fix ends/air pockets you missed within using regular body filler. All you need with this is the toothpaste looking tube of putty, and a putty knife.

Use this a small area at a time, piece by piece, when applied all at once and over a large area it tends to crack/not hold well almost immediately, when in small pieces that intertwine it holds much better.

This stuff is a curse because its so fragile, you will need to apply at 1/16th thickness layers, if you go any higher as soon as you start sanding you basically are down to 1/16 all over again if not less almost immediately, its a damn shame. When applying this just take your putty knife and squeeze it onto there, then apply.

Sandpaper preference for this is roughly the 300's, it needs to be something that will not scratch the surface, nor will it tear the putty to shreds, just enough to smooth it out.

Here are some tips that could help you out a little.
- Bondo is available at Advanced Auto Parts, Pep boys, so forth, so on. It is ALSO available at Walmart, which is where i suggest you get yours because its much, much less expensive.
- Bondo comes in increments of 1 gallon and 1 pint, i suggest a gallon as always, because more is better, less and your just screwed afterword.
- When getting a gallon, theres a white cap first off take that off, make sure you have hardener in it (some douches take it out)
- I do not condone nor do i suggest stealing, but while the cap is off because its a rather good area to be covered, it wouldn't be too bad of a call to grab some putty knives or more hardener in order to make your job easier, if your cashier notices, say oops, if not, congrats.

 

You sir are a douche-waffle. Don't steal and don't knock fiberglass. Bondo has it's uses, but fiberglass is a much stronger material that won't crack or pop off so easy.

Bondo is for filling in small dents, final smoothing of panels, etc. Places where it won't be thick.

Fiberglass is for big dents you can't pull out, repairing rust after taking it down to solid material, custom stuff, etc.

 

maddd props for this thread... i was actually looking for some info on fiberglass work since i used REGULAR BONDO on my roof molding smooth out body job after about 5 months it started to crack.. now i at least know i have to work on it little by little... tomorrow i actually start to take off the old bondo, clean it off and apply the fiberglass. sometimes its easier and better to go the expensive route the first time instead of doing the job twice because my side moldings that i smoothed out are still not cracking and its been about 14 months which it was really expensive for me to do the roof so i got the cheap non fiberglass bondo and now i got to redo the job and use fiberglass bondo this time so the work is done perfect!!!

 

Nice, i actually did the exact same thing ha, my side panels are currently filled in as well as my roof moldings, what i did was got some fiberglass resin AND regular bondo, because the side moldings had holes in them and i was too lazy to weld them shut or anything i applied little pieces of fiberglass cloth, then applied the standard bondo to that, for the roof i also used a fiberglass mat and used the rest in body filler bondo. make sure you take off that weather stripping stuff on the roof before you put on the bondo, the rubber tends to shrink/push pull, under sudden weather changes (global warming FTW) its not significant enough to the point where you can almost ever notice it unless you pay close attention, but it will cause little pieces of air to slip by the bondo causing pressure cracks.

 

ahhh look at that... we both got a little lazy doing that job. i got the side done good but the roof i got lazy and i didnt take off the weather strip so i guess thats a reason why its cracking the weather has been bad the last few days so i havent had any chance to work on the car...