Hi there,

I applied bondo to the front plastic bezel of my case, and now its cracking up.

The bondo itself isn't cracking, but only the part where it's meeting the plastic. So that its not adhering properly.

It's only on a small section. And could I have added too much bondo? The bondo is about 3.5 cm high.

I REALLY don't want to do this again, unless it's the last possible choice, alot of time was spent on it.

Btw, can I have some of your msn's? I don't wanna make a thread for every small question I have. Of course you don;'t have to if you don't want to, I TOTALY understand.

In almost any case where you have large amounts of bondo, you will have cracking. There is stronger stuff you can get, I forgot what it is called, but it is like trying to sand steel, making it hard to work with.

I find if u do multiple layers the cracking isn't as bad.

Same here. Also, when you put the bondo on the bezel, did you rough up the plastic first? I find that it helps as well. As far as the IM's go, I don't have any but feel free to PM me anytime. Most of the time I am bored anyway

lol I've probably put at least 10 layers of bondo on it, that's why I really didn't want to do it again.

And by the stronger stuff, would epoxy work? Like the ones for steel or whatever.

Thanks for the offer for pm's.

Yeah, it might work better, but keep in mind that stuff like that wasn't made for molding or for looks. It was made to be pretty much glue and you may screw up your whole case. Definately test it on something else before you just dive in and slap it all over your case.

So.. Snowman do you remember the name of the "stronger stuff"?

C'mon guys... What would YOU do if this happened to you?

Quote: Originally Posted by Cyph3r So.. Snowman do you remember the name of the "stronger stuff"? C'mon guys... What would YOU do if this happened to you?

personally i would try to find some kind of adhesive to mix w/ the bondo, but thax just me.

Adhesive eh? So any glue + bondo?

Hmm.. I'll experiment around eh.

And now taking a look at it, I see that its cracking all the time because teh front bezel its on is kinda weak and bends too much.

I tried strengthening it with bamboo bbq sticks (lol srlsy) but its still too weak, and ideas how to strengthen it?

Something easy to do pls.

How about fiberglass or the black adhesive they use for windshields that runs $75 for a 12oz tube?


The windshield stuff is stronger than fibeglass, I've seen it in person. You have to use a wheel sander to smooth it.

Make sure the surface is clean.

I recommend using Evercoat brand "short hair" fiberglass filler instead. It has Kevlar strands in it, so it will flex under stress .....(Autozone carries it)

I'm using Evercoat here in this tutorial

How Evercoat "short hair" Fiberglass Filler compares to Bondo (Mud)

1. Evercoat Fiberglass filler applies smoother than Bondo (applies like spackle).
2. Evercoat Fiberglass filler cures faster than Bondo.
3. Evercoat Fiberglass filler is STRONGER than Bondo.
4. Evercoat Fiberglass filler won't crack under stress like Bondo.

Three things to take into consideration when using Evercoat "Short Hair" Fiberglass filler.

1. It hardens real fast!! (less than 5 mins) So only apply small applications at a time. Because mixing up a big glub of this filler may harden before you've even had a chance to apply it.

2. Because it's real strong, sanding it by hand takes a long time. I highly recommend a power sander. A Mouse sander works great!

3. It creates a lot of dust while sanding. Wear a Ventilator mask

Well put Bill !!!

Fiberglass filler is GREAT for case work, because most parts are in some way pretty flexable. I used a very similar product in one of my most recent updates for silver surfer.. I drilled a few anchor holes too, to promote a solid adhesion.

This stuff is a little more porris than bondo also, so if this is going to be a finished painted product then a thin layer of glaze would do good to fill any pin holes that might be present.

there's 2 main reasons your bondo isn't sticking, unfortunately either way you are going to have to reapply. first reason would be for regular bondo it HAS to have 36 or similar grit scratchs in the surface being applied you really have to mar up the surface so that stuff will stick. second it HAS to be 100% wax and grease free. it isn't as bad as a paint job but it's still a royal pain to have a greasy spot after applying bondo. something you are mostlikely going to see once you start scratching it to reapply is it's going to keep chipping back....if that happens man you are just going to have to take it all off and do it over again cause it means there's nowhere that it's sticking very well and it'll break off easy as ****.

just a side note bondo is effectively a....rock it's basically talke or however you spell it. rocks don't flex or bend that's why you don't bondo anything on say a quad it just doesn't work. the fiberglass filler thoughs guys are talking about is lovelingly named "gorilla" or "tiger" hair in the autobody world- its pretty much just bondo and with fiberglass strands in it, it does have a bit more bend to it because it's not completely a rock.

the best way i'd say to do some kind of fiberglass filler work would be i say buy some fiberglass mat or cloth or however else it comes and dice it up put it in a cup with some resin and some hardnerand mix it up really well(side note do NOT make too large of a batch of fiberglass resin with hardner IT WILL start on fire if mixed in a large enough batch with enough hardner this is a chemical fire and water WILL NOT put it out very well. most cases it just melts the cup and or smokes a bit but still just a warning not to make a 5 gallon tub of this stuff)

tis all from the bondo man,
drew

Quote: Originally Posted by kickboarder90 there's 2 main reasons......... just a side note ...... the best way......... tis all from the bondo man, drew

Welcome to PC Apex, Drew.
I've never had any resin catch fire.
I grew up in a body shop, I 100% agree with all three points made.

Also something to note, is the proper mix ratio..to much hardener, and it will be brittle....to little and the stuff never hardens up.

Finding the sweet spot is something only experience can teach you, but if it's mixed right, it should set up in about 15 minutes and fully harden in 30 or so...if it hardens in 5 minutes, you got to much hardener, if it stays tacky even after sitting all night...you got too little.

I also used to use "Flex filler" for rubber/plastic bumpers that will not crack, but the bitch of it is working it to get a smooth feathered edge...maybe they have improved it a bit since I worked with it back in the early 90's, it would tend to peal and lift when it got to thin at the edges when sanding, forcing you to re-apply it again...and again...and again lol

Wow.. some ppl have serious experience here, compared to some 14 year old kid (me).

Well I seriously respect all of you right now, but one more question eh?

Drilling through bondo should be fine eh? Cause I cut through a relatively thin layer with a dremel and it didn't crack. I going to try one more thing before I admit defeat. Anyways it IS my first mod and I'm supposed to experiment right?

Well hope you guys get to that quickly.

my first time using bondo on my front bezel i had no cracking, i drilled through it with a 4 inch whole saw and it worked perfectly. What is the temp like where your doing the bondo work? I found that if it was over ohh 78F degrees there was no chance the bondo would mix up well enough. Good luck man and YES your suppose to experiment sadly that usually means spending more money than one wants to.

lol i took auto body in high school SO MUCH BONDO. i did, and redid so many cars, tanks,and random projects it wasn't even funny. pretty much anything that i could have done wrong i did many many times and luckily my teacher was an ass and told me to take it off and do it again till i got it right. i've never had any resin start on fire either, that's like the most extreme example. i have gotten a batch to smoke though....damn vettes and their cracked fiberglass.

anyway as for drilling bondo it can be done, just do it slow, make sure the bit is sharp, and don't put alot of pressure on it.

bondo's overall characteristics change with temperature,quality, and how new it is. a new tub of high grade bondo on a hot day is almost impossible to work with it's running messy and thin, it's also going to cure rather fast(it's a wonder in about 70-80 degree weather though). on cold days it's not going to cure as fast because there isn't as much heat. heat=cure and cure=heat, next time you want bondo to dry faster take a hair dryer or heat gun to it...does the trick pretty well if it's cold or you didn't put in enough hardner. pretty much bondo work is all trial and error and no one can really explain how it's supposed to work out for you, you have to find that out on your own after many applications and removals.

yay,
drew

p.s. thanks for the welcome!

Hey bud, Its like this... all you need to do to stop bondo from cracking at the seams is a little scotch tape at the seam and bondo just a touch to the other side. Its the fact that the 2 pieces are not connected that make it crack. When people put up drywall, they tape the edges and where it meets to prevent cracking.

luv ya modder fockerz

oh yea, as the other guy said, adding a addhesive anything might help, try contact cement heh

you are adding too much hardener to the bondo, i had that problem. its about 1/2 an inch of hardener to a golf ball size of bondo, i could be a little off with my calculations though, someone correct me if i am