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Topic Review (Newest First)
10-10-2009 09:14 AM
MARTINSR
Quote:
Originally Posted by klingfilm
Hello guys,
Now that I have all my products. I need to plan how I am going to sand through my layers.
Just a remember of my future job : bare metal, bondo, 2k urethane primer filler, basecoat, clear coat.
Now, I want to repair my paint and my plan is to repaint the whole fender to have a uniform color all over the part. I tried to feather colors with a spray can earlier and the result was such a crap. After using spray cans, I wonder with that stuff exists to paint cars. An even more than that, I wonder why people keep buying it.
I am concerned become at some points, I'll put the same layer over different substrates. How can I make sure that the grit is always good enough under my new layer that go beyond the one under?
How would you sand?
People keep buying spray cans because they are using them for something else, something that works well. What you tried is nearly impossible. Kinda like a "Cresent wrench" will work just fine to adjust the chain on your bike but don't try to torque a head on your motor with it.

Apply epoxy primer over the bare metal before your filler work if you want the most protection. But just over bare metal is fine too as long as you TOTALLY seal it off with the primer.

Brian
10-10-2009 09:11 AM
MARTINSR
Quote:
Originally Posted by klingfilm
Hello guys,
I took a picture of the "beast" outside NAPA this afternoon after spending a little bit more money for my new project X.
I won't show my whole car, son you can imagine it like an orange Ferrari or something...
My girlfirend thinks that I'm crazy spending that much money on that type of car.
So, now I have bondo, 2k primer urethane (Dupont nason bla bla), basecoat and clear coat.
Ready to go!
What do you think about this rust problem?
You're going to have to remove the bumper and clean up the rust that is under it.

Brian
10-10-2009 09:08 AM
MARTINSR
Quote:
Originally Posted by Centerline
Sorry but you are dead wrong! Bondo sticks very well to etch primer providing its dry and roughed with something like 80 grit. Although it is yesterday's technology it still works very well. Epoxy is really the way to go but since the poster already had the etch I saw no reason to tell him to return it. Especially considering it was a very small job.

Also, the spell check button is there for a reason (it makes your posts more easily readable), please feel free to use it.
There is NO MANUFACTURER who has ever said to apply polyester filler over etch primer, EVER. And in fact, every manufacturer (but one) I know of warns not even to apply etch primer over filler! The one that does say it's ok has a special note that the filler be "fully cured" (meaning 12 hours).

NEVER apply filler over etch primer. You can apply it over epoxy (and SHOULD apply it over epoxy) but NEVER over an etch.

Polyester resins and the acids in etch don't get along well.

In fact, until GenII Featherfill Evercoat polyester primer came along every polyester primer (spray-able filler, EXACT same stuff as "bondo" basically) had a firm warning NOT TO spray it over etch primer!

Brian

EDIT: Sorry I just went back and read that Kenseth had said this info already.
10-10-2009 07:37 AM
klingfilm Hello guys,
Now that I have all my products. I need to plan how I am going to sand through my layers.
Just a remember of my future job : bare metal, bondo, 2k urethane primer filler, basecoat, clear coat.
Now, I want to repair my paint and my plan is to repaint the whole fender to have a uniform color all over the part. I tried to feather colors with a spray can earlier and the result was such a crap. After using spray cans, I wonder with that stuff exists to paint cars. An even more than that, I wonder why people keep buying it.
I am concerned at some points, I'll put the same layer over different substrates. How can I make sure that the grit is always good enough under my new layer that go beyond the one under?
How would you sand?
10-09-2009 05:19 PM
klingfilm Hello guys,
I took a picture of the "beast" outside NAPA this afternoon after spending a little bit more money for my new project X.
I won't show my whole car, son you can imagine it like an orange Ferrari or something...
My girlfirend thinks that I'm crazy spending that much money on that type of car.
So, now I have bondo, 2k primer urethane (Dupont nason bla bla), basecoat and clear coat.
Ready to go!
What do you think about this rust problem?
10-09-2009 12:37 PM
deadbodyman it'll cost 12.50 to send the gun to canada.keep in touch,dont forget pictures,they'll help if any problems come up...
10-09-2009 11:14 AM
klingfilm Good,
So now I'm going to the shop to get a 2k primer, but I am more tempted by a primer filler (I know there is primer-sealer too) to sand the proper finish before the base coat.
When I'll have it, I'll come back with some more questions about spray guns and nozzle size.
10-09-2009 07:16 AM
deadbodyman
Quote:
Originally Posted by kenseth17
Well looks like we have several disagreements in this thread.
I say epoxy will stick just fine to a scratch finer then 80, but I would sand baremetal with at least 80 grit, because being a harder surface, does not scratch as easy as something like paint or primers or paints do (and also do not have chemical adhesion like you do with paints and primers when done within a window of time)
And I also disagree that filler must have a 36-40 grit scratch to stick to. Maybe true in the old days when course grinding and applying over bare metal was recommended. I say today they are much improved from then, and filler will stick fine to 80 gritted metal, but am still a believer in going toward the course end of what I can get away with, for maximum tooth and piece of mind.
I have often applied more filler over filler that has been sanded down to 80 grit and the filler will adhere just fine. I'd also have no problem with applying filler over metal that was sanded with 80 and epoxy primed.
Today many of the quality oriented shops believe in applying fillers over epoxy, and fillers will stick just fine over the epoxy, or even epoxy thats been scuffed as fine as 180 grit.

By the way here is what the back of the can of evercoat lightweight filler I just picked up this past weekend says.
Preparation. clean surface. Remove all dirt, oil, grease and wax. Use 40-80 grit disc to remove paint. Note coarse grinding, along with improper mixing and application increases pinholes. Surface must be completely dry before application.

I believe in application over epoxy though, as you have the corrosion protection underneath your filler, and fillers stick well to properly prepared or epoxy in its window.

When in doubt, its best to follow manufacturers directions for use of there product, not what someone you don't know tells you on a forum.
Ken your absolutly right, First of all they use epoxy at the factory and they dont sand the panels...second I used SPI epoxy for a sealer over 600 grit It was reduced 20% and makes a better sealer than the sealers do...Third ,When using bondo,after grinding you should feather the paint back with 80 da because the bondo will swell when it gets in the heavy grinding marks..(mostly after its painted).it sticks very well to 80...all the way up to 180,I done some cars(used cars)by sanding with 180 then hitting the little dents with bondo,No grinding at all,so I know this works...after 180 I use a polyester putty(thin bondo)(ez sand from evercoat)and work that to 320 then prime...On resto's I always epoxy after stripping then bondo,Reading the directions should always be done first...BEFORE,all else fails...All we can do is put our experiance's out there and let them make up thier own mind...
10-09-2009 06:59 AM
deadbodyman
Quote:
Originally Posted by klingfilm
Yeah,
This is an interesting offer. But, I am in Canada remember? Can you send it here?
My stepfather has a mastercraft siphon spray gun and I am not sure if it would do the job. I am scared about the clear coat. I don't I can "fix" by sanding it if the finish is not good.
I tried to sand a clear coating from a spray can, and the result was devastating. The clear turns cloudy and whiter.
Yes ,of coarse I can send it to canada,I'll find out what the shipping is...but it was 10.oo to NY so it cant be that much more, I used this gun for everything it'll do a great job for you its just not as efficent as a gravity gun thats all....concentrate on your body work and dont worry about the paint for right now...you'll overload your brain with info and talk yourself right out of it...
10-08-2009 03:24 PM
kenseth17 Well looks like we have several disagreements in this thread.
I say epoxy will stick just fine to a scratch finer then 80, but I would sand baremetal with at least 80 grit, because being a harder surface, does not scratch as easy as something like paint or primers or paints do (and also do not have chemical adhesion like you do with paints and primers when done within a window of time)
And I also disagree that filler must have a 36-40 grit scratch to stick to. Maybe true in the old days when course grinding and applying over bare metal was recommended. I say today they are much improved from then, and filler will stick fine to 80 gritted metal, but am still a believer in going toward the course end of what I can get away with, for maximum tooth and piece of mind.
I have often applied more filler over filler that has been sanded down to 80 grit and the filler will adhere just fine. I'd also have no problem with applying filler over metal that was sanded with 80 and epoxy primed.
Today many of the quality oriented shops believe in applying fillers over epoxy, and fillers will stick just fine over the epoxy, or even epoxy thats been scuffed as fine as 180 grit.

By the way here is what the back of the can of evercoat lightweight filler I just picked up this past weekend says.
Preparation. clean surface. Remove all dirt, oil, grease and wax. Use 40-80 grit disc to remove paint. Note coarse grinding, along with improper mixing and application increases pinholes. Surface must be completely dry before application.

I believe in application over epoxy though, as you have the corrosion protection underneath your filler, and fillers stick well to properly prepared or epoxy in its window.

When in doubt, its best to follow manufacturers directions for use of there product, not what someone you don't know tells you on a forum.
10-08-2009 03:22 PM
klingfilm Yeah,
This is an interesting offer. But, I am in Canada remember? Can you send it here?
My stepfather has a mastercraft siphon spray gun and I am not sure if it would do the job. I am scared about the clear coat. I don't I can "fix" a clear coat by sanding it if the finish is not good.
I tried to sand a clear coating from a spray can, and the result was devastating. The clear turns cloudy and whiter.
10-08-2009 02:00 PM
deadbodyman I have a gun you can use...its an old style sphon gun but a nice one "devilbis" sprays very nice,I was thinking of loaning it out to all you newbies, I dont use it...costs around 10.00 bucks shipping,if your interested let me know...
10-08-2009 01:28 PM
cyclopsblown34 The epoxy won't stick to those fine of scratches finer than 80 grit. As for sanding the epoxy prior to paint, you can sand the epoxy as fine as you wish but I don't get any finer than 600 grit before applying paint.
10-08-2009 01:21 PM
88_mopar Just to make sure you understand, body filler needs a 36-40 grit scratch to hold on to. So sand rust off with 36 grit, apply filler, sand that with 80 grit to form it, then 220-320 to remove the 80 grit scratches. After its sanded with 220-320, spray your epoxy primer. Once its dry, block sand it out with 400-600 grit. Now your ready for base and clear.
10-08-2009 11:09 AM
klingfilm Wow,
Now ready to go!
I'll just switch etch for 2k primer at the NAPA shop.
Thanks a lot for the information and tips, it is very interesting and useful.

We'll meet on another thread soon I think. I need a paint gun now!
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