Help with bondo

CoinOp

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Hey was wondering if anyone had any tips for working with bondi, replacing broken pieces if cavs. Im having some difficulty getting it to stick to the wtood in some places. I also have trouble when i make a guidethe bondo will stick to the guide more than the wood and break pieces off of the bondo. I got one of the corners sorted out but where the control panel goes on one side has about an inch missing and is giving me fits.

On a side note, whats the best way to apply it? I mix it in a bowl then spread it with a putty knife. I have heard of a method with a ziplok bag and squirting it like cake icing, anyone have experience with this method vs any other?
 
On a side note, whats the best way to apply it? I mix it in a bowl then spread it with a putty knife. I have heard of a method with a ziplok bag and squirting it like cake icing, anyone have experience with this method vs any other?

Mix it on a clean piece of cardboard. That way, you can just throw it away and not have to spend hours cleaning the bowl. The store that you bought the bondo at should also have the application spreaders in three different sizes. They work well and you can clean them easily once the material sets up by bending them back and forth. The dried material will usually just pop off.

Put it on in layers. Don't try to apply it all at once. Also, remove whatever you use to back the material or align it fairly quickly.
 
Put vegetable oil on your guide and the bondo won't stick to it. Also, if you rough up where the bondo is going to go, that helps. It gives it something better to adhere to.
 
Some others (and myself) will put nails/screws into the wood to act as additional support for the bondo. Think of it like putting rebar inside concrete to add strength.
 
I've also heard of the screws/nails ect to give it something to grab onto, as well as scraping up the surface fairly well (which will also give it tons to grab onto in those smaller area's).

Tip: if you have some scrap lexan/plexi use that as your mixing board, when your finishing up try and get as much of it off as you can then use your sander to remove any residue/leftover next time.
 
Becareful not to over do it with the Bondo hardener, because not only do you have less time to apply it but it'll also not stick to wood as well, which I found out the hard way.
 
The nails into wood sounds like a good place to start since im basically rebuilding a chunk of the cab i would like it to be as strong as possible. Thanks for all the tips guys
 
It takes a surprisingly small amount of hardner to properly mix Bondo, and it should be a uniform pink-ish, flesh color when mixed properly, NOT terra cotta or orange. If you buy the Bondo brand spreaders, their plastic is tinted to match the proper ratio of hardner to Bondo so you know what to shoot for.

I like to use coated paper plates for a mixing surface and remember to apply the Bondo quickly after mixing for best adhesion. Even a few minutes is too much time and the product will begin to cure beyond the best adhesion point.

If it's not sticking, it's probably a case of too much hardner or too slow/too large an application area.
 
I never use a guide unless it is a fairly large repair.
I just build up a few layers sanding in between.
I just use a putty knife to apply,it is much easier to apply than with a spreader.
For clean up,I use Acetone and the bondo comes right off.
 
Bondo

Don't use too little hardner or your sand paper will gum up. Screws and nails are great there is also those wavy corner plugs that are used to join two pieces of wood, frames and what not. Also if you are good enough you can use fiberglass cloth in the bondo. You don't want it it exposed or it will be hard to get a paintable finish. You kind of embed the cloth but you have to be quick. Do it in layers as well so you will be sure to "bury" the cloth. I use this same process on rotted innner wheel wells in cars. I use , bondo with fibergalss cloth, then roofing tar with fiberglass cloth. It holds up suprisingly well.
 
Some videos I took while working on the Centipede cabinet that will be raffled off at the upcoming Northwest Pinball and Arcade Show.
I thought I'd share in case they help anyone. I don't talk while I'm doing the work, so it's just a visual guide. It starts with removing the art and ends with sanding the Bondo down. After that I went over it with 220 grit on an orbital sander, then 3 coats of Kilz primer applied 2 hours apart with a foam roller then sanded the primer smooth with 220 again.





 
I have always used a layer of wax paper between my "mold" and the cab. This way if the bondo sticks, it just sticks to the wax paper and not the mold. You can pull about 80% of the wax paper off and just sand the rest away.
 
Does bondo really dry up as solid as they say? I used epoxy to fill in cracks on my cabinet and it seems to end up much more solid than bondo. I'm worried about relying too much on bondo and having it degrade later on, taking the paint/finish with it.

A woodworker who modded my cabinet told me to completely cover the cabinet in bondo, then use automotive primer, is that good advice? I'd like a metallic green, so was considering using automotive spray paint with that method.
 
I use a thin sheet of plexi for a mixing board, when it hardens just flex it a couple of times and the old bondo pops right off. For a large repair the only way to do it right is new wood with the bondo to fill in any seams. You can use just bondo but you have to do a couple of layers and sand in between and some reinforcement is a good idea. If it is at the point where you have to use guides to shape the piece and try to fill with a big glob of bondo it is too far gone. New wood. It is not meant to make a new side of a cab or a structural point, just filling small damage.
 
Just made this

Whoa,
I just made this 5 mins ago so I can fix my edges, & I come opon this topic just now, Crazy!

Guys, I just drill and beveled the mounting holes & slammed a 90 on it.
I use a teflon base tape so it wont stick to the bracket.
I'll be using this tomorrow morning. I can make more, But not in 316 stainless here.
Maybe make some thinner plastic ones....? this is my prototype. it lips over the edge about a Qtr.
Corner.jpg
 
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Ok,
So I got home & I installed the bracket.

1st thing I did was apply the teflon tape so the bondo wont stick.

Attached you'll see what I am dealing with.

Then I added 3 more screws to the filling area to give the bondo strength. you know like rebar for concrete.
the next step was attaching the bracket. Which you'll see in the photos.

Ok, its 4am (PST), I am crashing out. I'll perform the plastic surgery tomorrow & take pictures & keep ya posted.


(Yes, this is a chunk Missing. I plan on filling it repairing it, when all said & done, I am gonna have to add those Cabinet corner Protectors. It'll be in the back no one will see.)

Bondo1.jpg


Bondo2.jpg


Bondo3.jpg
 
ok guys,
got the teflon tape on the bracket and mounted it to the cab.

I slammed on the Bondo and worked it in.
then I let it cure for 10 mins. After that I removed the bracket & let it cure over night.
Tomorrow i'll sand it down, & maybe apply another layer.

Dont ask me why there is T-molding grove on the back of this cab. I plan on filling it.

here are the Pic's
Bondo11.jpg


Bondo12.jpg


Bondo13.jpg

Now I got something to work with! not too bad....?

I hope this is helping a few of you guys out....?
 
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