trouble using bondo

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cuda guy

cuda guy

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Hi all,
Sorry if this post is in the wrong area I did not know where else to put it.
Ok here I go.
I have welded in all the repairs, I have done the rough body work it looks pretty good but not perfect. So when I try to put a final coat of bondo on it looks like crap, I sand it down and try it again and the same results.
My question is how do I get it perfect? What should I do or what I'm I doing wrong?
Is there any body men in the Toronto who could maybe do the finish body work and maybe even paint in there spare time.

Confused in Canada

Rick
 
I have always used duraglass as the first coat over welds than finished with regular bondo and its worked fine. I was told a long time ago to do this and haven't had any problems.
 
im kinda confused myself but what i would do is put that coat of bondo on, sand it and then prime it... that will tell you where you really are...
 
Maybe try and send a PM to 66 Dartman, he's in the TO area.
I believe he is doing pettybluedart's '66. Keep it in the FABO family.

I would also like to get a bit more info on the Bondo subject, as I'll be tackling some body work myself.

All the best!
Giles
 
you have to train your hand to tell you if its straight or not, there are small imperfections you just cannot see but you can feel. I like to use a fiberglass filler over weld areas (like everglass), then a nice polyester filler like Upol. trying to fix small spots at one time can be aggravating (to get straight), sometimes its much easier to cover the whole panel with filler and sand down, this seems like it would take longer but it really doesnt. this will also cover low and high spots you didn't see before.
 
Thanks Dartman

I will give you a PM

Maybe I can buy u a beer and pick your brain

Rick
 
I'm taking an auto body class and this is how we do it.
Spread your filler over the weld area. Sand with the flattest longest sanding block u have and 36 grit paper. Fill in low spots with a bondo / filler skim coat and repeat block sanding with 36 and long block.Then mix up new batch of filler with Plastic honey to thin out filler or use body glaze (Honey and filler mix gives u more work time than glaze)and skim coat to fill in 36 grit scratches. Sand with 80 grit and a hard block. Prime with Surfacer/high build primer,guide coat and block sand with 220 grit paper wet and hard block,re prime,guide coat and sand with 400 grit wet. Make sure that your mixing board and spreader are clean and have a burr free edge on them before doing final skim coat.
 
Agree. Just finished buddy's 69 Charger body. weld in new metal, used evercoat/rage, then it was the pits to smooth it(and, no, it was not too high, as I used a 2' stick to check from good ends). It was crap sandpaper. Use 3m. Cuts good, no clogging. (We used 17" long air and hand files. And round tubing for some round contours; charger at the rear sail panel has too much rounded areas). Don't sand straight, go in a 45 degree x pattern from contour to contour. Then spread rage icing (it is so much easier to sand, and it fills in pits and scratches. Use straight edges on the lines, tape the lines to run filler to; then pull tape, run filler to what you just did.
We started with 36, then kept going up, finishing with 180. Then shot Sherwin Williams FP410 on it (2 part primer/heavy filler). then totally screwed it up. We sanded that with 180 NO! we sanded off the filler, but low spots really showed up. Lesson learned; Primering my 70 Duster at the same time; shot primer, used 400 grit on blocks(get the self adhesive stuff). Light pressure, just knock of the high spots- real low, more icing, kinda low, can't feel, but can see it, more paint filler.
And you don't have enough light, unless you pull the car out into the sunlight. And use undercoat or anything, to seal the weld on back of panel.
Also, we learned that without at least 1/8" gap, even stitch/ moving all over with a wet rag welding- A weld contracts while cooling, not enough gap, it expands outward (no good). 1/8" gap, it pulls inward (good).
The quality material costs more, but it is the only way you can get the repair right.
 
Lots of good stuff here and I'll just add a bit since I've been at this so long, it's the internet and I'm entitled :iconbigg:

We used to use a product called Allmetal back in the day for that first coat of filler over the weld. It's not to build but to get the material over the weld. It was (is?) a filler product with aluminum powder in it that inhibits rust. A bit much for most applications but for the fusspot out there it's the way to go. Grind it down well past flush so the next layer of bondo completely covers it. Mix the filler well to eliminate as many air bubbles as you can. Cover as much of the repair as you can-hopefully all of it. Sand in a cross-hatch pattern to get it straight; not up-and-down or along the length. If you need to apply more filler to get it, be sure to reapply over the whole area or you will take filler out of the spots you think are done when you sand the parts that aren't. Finish with at least 80 grit before you prime. I use 180 just to save myself the trouble of wetsanding deep scratches out.

One more tip comes to mind. If you're right handed, check your work with your left hand. It's more sensitive. Vise-versa for lefties.

HTH

Ken (hacking up bondo dust as I type)

And another-the best metal prep for filler (if you can get away with it) is blasting the metal. Grinding scratches the metal and works well enough but blasting puts hundreds of pits in the metal that really grip the filler.
 
Thanks everyone
This information is unbelievably use full and beneficial for everyone who reads this post.
My only question is what is body honey?

Rick
 
you can get the filler honey at most paint supply stores....normally comes in a can.

you add it to your body filler and it thins it out and makes it more the consistency of "honey" .....fills in imperfections easier as it "flows" out.....and makes the filelr easier to sand when you use it in your final stages of body filler work.

for large flat surfaces you will want to try to use a long block to sand with or use a paint stick with sand paper wraped around it (stick sand) the more you do this, the flater it will get.

do not use this approach on areas with contour or you will end up with flat spots.

you want to make sure you prep your metal for body filler well as was mentioned above....you can either blast the metal or you can take a grinder to the metal and give it a slight roughing up .....this will give the body filler something to stick to so it does not fall off of the body in the future.

as was mentioned for your welds.....for example if you replaced a tail panel.....you can either do what the factory did and fill the seems with lead....or you can use a duraglass filler to fil lthem....which is basically a resin compund with pre mixed in fiberglass fibers for strength.

then you would grind that down as much as you can and you would want to go over the top of that with your body filler (bondo or whatever brand).

you need to take into account the temperature of the area you are doing filler work in though!!!! lets say you are working in 90 degree weather in florida.....you are going to want to use less hardener because heat/and or humidity will make your filler tack up and harden alot faster than it should.

lets say you are working in 40 or 30 degree weather in the north....you might want to add slightly more hardener to speed up the reaction process that the cold is trying to slow down.

normally I find that one good sized bondo paddle full of filler ( about a cup full) works great in about 60-70f weather with about a 2" long line of hardener squirted on top.

as always, make sure it is mixed well before applying.

you want to apply the filler to the areas you plan to work on.

let it sit for a few minuites.

then tapp the body filler with your finger to check if it is hardened up enough yet (should be sticky and almost rubbery feeling) at this point is when I pull out my cheese grater (saves a ton of elbow grease and sand time and sand paper)....you use the grater to knock down the body filler CLOSE to where it should be. then you can let it harden more for a few minuites after you are done....At which point you can THEN start to work on sanding the body filler.

(quick tip.....after applying your body filler....use your paddle to scrape off any remaning filler on your mixing plate and then squish you paddle into the blob of filler you scooped up. why do this? for one.....when the filler drys you simply pull on your paddle and it pops right out of the dried filler (which means no clean up needed on your filler paddle) reason 2 is.....you can poke your finger in the blob of body filler you scooped up to check and see how hard it is and it will give you a good idea to know if the filler on your car is ready to be worked).

after you have gone through the steps to knock down the filler on your car you may have to do 1 or 2 or 3 extra coats in spots.

mix up another batch and hit any critically low spots again and go through the grating process and sanding process again.

then you can mix up a honey coat or skim coat.....(smoother lighter easier to sand) and go over with a final coat and then sand it all off.

then if you are confident things are really close you can prime the car .

then you can either visibly see imperfections if any or feel them...you may have to do some minor filling with some more glaze or something to get it just right.

those are the basics...of course it all depends on how bad the body is,if you have expeirience in the area,the temperature of the area,the products you are using,when you feel comfortable that its straight enough to prime,if you use guide coats in between your work,if you run into and fudge ups lol....and there are alot of things to factor in......but atleast there are a few ideas for you to look over. good luck!
 
1st you have to make sure your patch work is butt welded the better your metal work is the less bondo you need. There is epoxies on the market that you can apply you filler on top of this way you get a premium chemical bond and have no rust issues down the road,you ever grind old bondo out to find rust under it ? that's caused by the chemical reaction from curing.If you use a premium filler like evercoat,gold or xtreme,there's little to no pin holes. I don't use body butter for my final coat i use polyester putty ( 2 stage putty)
Like i said i'm just east of ya Pm me if you need any more help.
 
Some really excellent information here, I've just had slew of questions answered that I've always wondered about. Some guys make it look so easy (referring to amateurs - not the professionals) - that I wonder why I'm not doing bodywork myself sometimes. That has got to just about the most expensive part of getting an old Mopar going and quite often the most neglected. Thanks for the info...........
Daryl
 
Not a body guy, but my car is getting done by a guy that worked in a shop for a 10 years or so. He has used several different products on my car. From what he told me what he uses will depend on what he is doing. I know he is using a product called Rage on my car. But he has mentioned several other ones. He did mention that where he had to make a patch panel on the 1/4 after welding he did mention a product called Duraglass, if I remember right. I know the one thing that is required is patience, which leaves me out of doing body work......
 

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Where would you buy sandpaper long enough for the "longest board possible"? I have the same tool pictures on the trunklid of Ink's ride, and I can buy paper for it in different grits, but anything longer than that.......?

George
 
3M (among others) make their file board paper available in self adhesive rolls. Not sure how long they are-50' maybe? We have 80, 180 and (oddly) 220 grit in our shop.

Ken
 
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