Sanding body filler. Newbie question.

HAHAHAHA You might but it would take you about a year to get it done.

 

i prime over 80 sometimes if im in a hurry or lazy . i dont know why you would want to block the prime with 80 ? seems like you should have the mud close enough to hit it with 150 ...

 

usually you would. but not always... also have some of the primer stay on the car is a good way to avoid problems, and not have it shrink back to lumpy status. so another few coats , then 150 will make for a longer lasting, and flatter job...........remember, these tactics are for high end custom paint jobs, flat black, and production work you would never do this


skull

 

Im still in shock over the whole priming over 80 now i can see as stated before if your priming it with the spray on bono than sanding it down and then using a standard primer .. but i just cant see priming over 80 grit ....how many coats of primer do you put on it after you hit it with the 80? ... i just cant see you feathering the edge good enough wth 80 ...unless you prime sand and repeat that step like 6 times if thast the case wouldnt it be easier to sand the bondo down with finer grit paper like to a lets say 220 and only use 2 coats of primer if need be ? i mean thats just me, like i said if you guys do it that way thats crazy and i give you props ....but i will say that u-pol short hair galss is the $ht man. i was very skeptical about using it at first becasue of horrible results trying other garbage products like the metal filler and aluminum filler but that damn glass is solid i will never go back to bondo again unless its a small ding . and if i do i will use fly weight its the easiest sanding bondo i have used so far .

i wish i had a car that needed body work becasue i would ty it ..i am a firm believer of dont knock it till you try it ..so i will say no more about the 80 grit prime method !

and yea i agree 400 wet on the primer than 600 wet ..with a soft block

 

bullshit dude, you're talking about a product failure...

 

This all sounds like collision work which is not what these guys are talking about. They are talking about doing completes. I don't think anyone would say to use this (80 grit) method for collision repair.

 

on my gas pumps i use marhyde primer. its like bondo you can spray. sometimes you can't get in to some area's. and there will be 80 marks. three coats. and sand with 150.reprime. 400 wet . no problems .ive used this primer on cars .as well .its killer stuff.

here is a example of the shit i have to do. all the cast has to be smooth. you can grind on it .but you still have to mud it all. i bet i go thru 100 gal's of mud a year .
1934 eri 50 cash recorder ..worth around 15k

 

nice lookin work.........for that stuff, id just finish in 80, maybe clean up with some 150 and prime.........we do alot of odd shaped parts here as well

skull

 

We have taught for 30 plus years - shape with 36/40, lite finish with 80. With the advent of urethane primers used in most production shops the need to go one step more with a quick final finish of 180 has been used for a good 10 plus years. The urethane primers were not quick drying when first introduced so a finish of 180 prior to priming meant only one primer surfacer application (2-3 coats) versus the old lacquer days of prime/sand/reprime.

Even thogh newer urethanes dry much quicker it is pretty much body shop procedure to finish in 180 and prime once.

Sanding primer is usually done with a quick block of 180/240 on the repair area and then anywhere from 320 to 600 for the entire refinish area.

One thing to be careful of when sanding plastic filler. The 36/40 does the shaping (hand or power). The 80/180 should be quick, by hand only, as too much time with the 80/180 will start to give you waves.....and no one wants a friendly panel.

 

for example if i was doing a large caddy, compelte paint......the mudd and metal would be finished in 80.

i would spray 4 coats of primer . if the car was pretty straight, and the panels mostly reflected down, or were crowned, i might go to 150 now. if they are right in your face(like the qtrs on an elcamino) i might 80 them to get them real flat.

4 more coats of primer, block with 150, same, and go to 320.
most of our big jobs get 3 or 4 block sesisons. it just depends on the condition of what you started with, and where you wanna go.

now keep in mind that you gotta use the same, high quality primer the whole way through, you cant finsh off with something cheaper and expect not to have a problem. as other guys have mentioned , you have to use high quality materials , and pretty much adhere to the tech sheets for them.

the only failures i see are when a shortcut was taken, or a substitute material was used ,such as free samples from suppliers..

i can account for most of my high end jobs and they still are in like new shape if the customer hasnt damaged them.

i have a small portion of the jobs pictured in my albums, some with progression shots so you can get the idea.

by the way this is just to give you more info, not trying to call anyone stupid just because they dont do things the same way as i do. i can say i have alot of time invested though in what will work and what will fail, and i simply try to pass it on, and yes, i paint every day, not just here and there , but 6 days a week, for along time (too long) lol. i too, have had my share of paint problems, and try to avoid them at all costs

skull

 

for production work that is just what we do. i bake the primer so it wont shrink when you cook the clear.

and yes, you dont want to have to re-prime any production work, lol, as you are lucky to get the insur co to pay for even that one time

 

if you have these BASIC questions about sanding,, have a senior bodyperson check out your work as you go along and learn from him/her?....i spent the past 3 years helping and watching RAFFMAN restore a 57 chev resto rod, 58 chev restorod, mid year vette, and some late moddels too...sanding is the LEAST of your problems - best advice , take your time and ask before you mess up and don't OVER sand/digging the bondo back out,. block wherever you can...good luck!

 

This statement shows that we aren't on the same page. In a collision environment you would be absolutely correct. Time is money there. With what we do, its not speed its quality. Ya, I usually do block a car like 6 times. With the products I use, 80 scratches are nothing. I put on 3 coats per round of blocking and with one round the 80 scratches are gone.

I wouldn't sand my filler to 220 because I want it to have a better bite. I persoanlly think 220 or even 180 is too fine. I'd rather spend some time blocking the primer then risk losing the mechanical adhesion.

 

I used to work with this painter, that told me a bodyman that used to work with him, finished his body work off with a chainsaw. I think that he meant that it was a little rough.

 

Hey,

Um, what's a "bodyperson''?

Using high polyester resin/glass filler is a good idea, over my squirtgun welded rustout patch panel?

Using red hardener, using bleu hardner to mix my "Fender- In -A Can"....what if I mix 'um together?

I can/can't shoot primer over 80 grit and get it to fly?

I can't use " extra virgin " cardboard to mix mud of? So, I guess donut boxes are outa the question,too?

What kinda "Restoration Shop" is it that uses plastic filler?....trick question, I know, a Corvette shop, correct?

I'm so confoosed!

Swanky Devils C.C.
" Meanwhyle, back aboard The Tainted Pork"

 

SKULL now that you broke it down its makes way more sense i couldnt pictue what you were stating earlier .. yea i got it ..and its my mistake that is a good teqnique .and i see how if you lay on that many coats of primer its damn near impossible to not have a even surface

B.T.W. i did see your work and it is very good . your painting is impressive to say the least

 

I'm still enjoying this thread. I like to work my plastic with 40. Then finish it with 80 before priming. Now as I have stated earlier I have been working in a quick sand with 120 over the 80 before priming. 40 gives you your shape. 80 is to sand down the 40 scratches and final shaping. As for not caring if it comesback later because it is collision work,I find it to be B.S. Working for a DRP program, the insurers we work for make us warranty our work, (ALL THE WORK, from plastic to paint to corrosion to frame to mech work) FOR AS LONG AS THE CUSTOMER OWNS THE VEHICLE. So knocking it out and cashing in on a quick buck doesn't happen on most poeple's watch because when it comes back, the tech in question has to repair it for free and or lose his job depending on how bad it gets. So in closing, your local bodyman doing your collision work is rarely a hack who would lead you astray. Now back to your regularly scheduled program. By the way, I like to block my primer with 180 before reprime.

 

cool, no mistake, just different views

thanks

 

No one is say they don't care if it comes back in collision work but different techniques are used when doing a complete (restorations/custom work)as compared to collision repairs.

NO ONE in the collision industry is putting 6 coats of primer on hence more sanding is required to remove sand scatches which results in different techniques being used.

 

3 Coats of today's hi build urethane primer is like 6 coats of lacquer. It was common practice years past to use nitro-stan on your heavy primer to fill 80 grit scratches. Restoration work is not that far from collision work because if your client can see where your work has been done, they will not pay. If you are doing your work correctly, you won't have to prime and block 10 times.

 

We are not talking about lacquer primer. There is a huge difference in restoration work and collision work and that is time. Collision work needs to be done quickly restoration work doesn't therefore you can use different techniques to achieve the same goals.

 

True. But doing your restoration work in a timely fashion makes for happier clients and that goal is quality. So lets sum up for the newbie, 40 for rough sanding of plastic, 80 to knock down your 40 to get ready for prime, (80,120,) before priming, then 180 for blocking you primer afterwards before repriming.

 

You need top try the new Quantum fillers from Evercoat. Throw your 40 grit in the garbage where it belongs

 

Currently using evercoats rage. I would love to try out some of the quantum. Gotta get my jobber to send me some.

 

It sands in half the time of rage. Your 40 grit will have you reapplying filler as it will all be on the floor. No need to use anything coarser than 80.

 

that stuff sure does sand easy.

im not sure how strong it is compared to regular fillers though. it seems sorta like a cross between bondo and glazing putty to me.

ive had a couple glaze failures due to the production guys getting lazy and pourin the stuff on like bondo. not to say quantums gonna break up, id just keep an eye on it for a while.

i havent had it long enough to say , anyone have any problems with it?

skull

 

Then why hasn't any shown up on my front doorstep for a test run????

I heard it was the shizzle compared to Rage Gold, which is what I use and love. (For its ease of sanding, go figure) If this stuff is the real deal and holds up, I'm in.

And I'll still finish it in 80 and prime.

Whats the price on that stuff $300/gallon?

 

bump for more information

I am also new at this game......

 

Some interesting reading here. Thought I'd throw my question in here rather than start a new thread:
Current project is all new metal, and as much as I'd like my metalshaping skills (and patience) don't quite stretch to the "no filler" level.
Breaking it down, I used a 2K etch primer, with a 2K medium solids primer over that. Started applying filler and blocking (60, then 80grit)where needed. Once I was happy with that I shot more MS and misted a guide coat (2K topcoat) over that. Cut that back with 150 grit dry (lots of clogging from the guide coat). Attended to a few areas and glazed some pinholes. Shot MS & guidecoat again. I wanted to avoid the clogging and so flatted it wet this time - most of the way with 220, then went to 400.

My problem is there are a couple of spots where I have cut through either to bare metal (thought I'd lay some more etch primer over these before final prime) or to mud. The mud that has gotten wet is my concern - will it do to just let this dry out with fans on it for a couple days (it's in the high nineties, early hundreds here right now) to take care of any absorbed moisture. I really don't want to go digging it out again, but there are areas where while blocking I went all the way back to bare metal and just made sure they were well keyed (ie didn't etch prime again) before adding more mud.....
Any suggestions - both for now, as well as for what I should do next time?
Thanks
Barry

 

bump !!!!!!!!!!