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I bought Dupont products to paint rusted car parts, but I feel like I'm wrong...

10K views 41 replies 8 participants last post by  MARTINSR 
#1 · (Edited)
I bought etch primer to fix my paint, but I feel like changing for epoxy primer...

Hi,
Here is my problem, I have a cavalier 05 orange sunburst II and some flakes of paint went off after an accident revealing rust just at the end of the fender beside the headlamp. I hit a little dear...It is sad, but it is not the point.
So, the insurance didn't fix it and I have to do something with it. I tried the spray cans, but what a disaster with the clearcoat!
One thing I know is that I'll have to sand block the rusted part and use something like BONDO (3M filler) to flatten the bare metal with the chipped paint.

So I started my journey at a NAPA shop. The guy sold me
Dupont Nason 497-00 urethane clearcoat
Dupont Nason 483-78 activator

Dupont ChromaBase base coat -Orange Sunburst II
Dupont Chroma System Basemaker 7175S Mid temp

Dupont Etch Primer 1k A-4115S

But my question is about the layers in between Etch primer and base coat.
Can I put bondo over etch primer and would they stick together?
And what should I put between Bondo and base coat ?

I don't feel like the sandwich

Bare metal
Etch primer
Bondo
Base coat
Clearcoat

is going to work well...
I need help.
 
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#2 ·
dupont products

hi, well you din't mention how big the damage is, sometimes is better get a new part than try to fix the one, however if you gonna put bondo you have to grind first the dent (make sure all the rust is gone) then apply the bondo, the etch primer use it only if there's big surface of bare metal if that's not the case use 2k primer right after the bondo dupont products are good the clear is not the best dupont has to offer but work just fine
 
#3 ·
Here is what I would do.

Grind all the rust off then shoot the etch primer over the bare metal. When its dry rough it up with some 80 grit and then apply the bondo. After you have the surface shape the way you want spray some high build 2K primer. Wet sand with 400 grit then 600 to get the surface nice and smooth. Now your ready for your base and clear coats.

Many people don't mind putting bondo over bare metal, that's pretty much old school but....... bondo sticks very well to roughed up etch primer and the primer will help seal the metal from any moisture that might get through the bondo before it is painted. Bondo is very porous and wet sanding and even high humidity will allow dampness to get through and begin rusting the bare metal again. Using the etch primer first eliminates that problem.
 
#4 · (Edited)
I'm quite impress! It's faster to get support here than at any Canadian Tire.
The damage done to my car is pretty small I think. It is not bigger than a thumb and the rust is still a the surface on the metal.
So, I won't have to grind it, I'll just use a sand block.
About the clear coat, I know it is not the best stuff but my cavalier will never do any expo show.
I only want to remove rust first, and then have uniform color with a proper finish. I just hate to see rust it's a real pain when you deal with hard winters.

So, If I get it right I should go back to the shop and buy a high build 2k primer. Also, the 3M bondo will stick to the etch primer.

P.S. Can you tell me the meaning of "1k" and "2k"? And what is high build?
 
#5 ·
how about no etch primer and epoxy primer instead?

Hi,
I've been reading about bondo and etch primer, and top coats. Bondo over etch primer could be a problem especially if you don't let it cure long enough to get rid of the acid.
But, with that product, I have to buy a 2k high build primer.
After hours of reading through Dupont technical manuals, I have another Idea and I need your opinion on it.

My idea is to return the etch primer and buy instead
Dupont DTM epoxy primer 25x0S.
This product can stick to the metal and protect it.
It sticks to bondo too.
And I can use my ChromaBase over it

So my new sandwich would be,
DTM epoxy primer over the sanded metal
Bondo over it to obtain a plain surface with the chips of paint missing
DTM epoxy primer again to offer a proper substrate to my basecoat
Basecoat
Clear coat

What do you think? Am I improving with my reading or am I getting worse? :p
 
#6 ·
You're on the right track. I'd still use a surfacer/hi build urethane 2K (2 component primer) to fill any pinholes and whatnot. Other than adding the high build primer, you're on the right track. Spray the entire panel with it and make it your coat between the bondo and epoxy before paint. You definitely want to start with the epoxy on bare metal.
DTM Epoxy
Filler/Bondo
2K hi build primer
DTM Epoxy
Color
Clear.
 
#8 ·
deadbodyman said:
Bondo will NOT stick to etching primer,it will stick to epoxy primer,but niether are nessary for such a car just grind, bondo, prime with 2k sand and paint
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.
 
#9 ·
First,
Sorry about the roughness of my words and spelling. But as a French canadian, I am about as good as a 13 years old average student, expecially when it's time to write.
Could you help me to understand the need for 2k primer? I thought it is mainly useful to sand the surface quicker than the epoxy primer to get a nice smooth finish prior to basecoat. But, the metallic area that I have to cover is small about the size of a match box. So I don't mind having to sand 30 min more over my epoxy primer just to get the same finish as I would get in 5 min with 2K primer.
I have sand papers with grid from 60 to 2000. I just feel like it's useless to buy a full can of 2k primer and epoxy primer on such a small area that needs bondo.
I plan to repaint the hole fender, but I'll just sand the clearcoat from it and paint over the original basecoat.
Can you show me your sandwich?
 
#11 ·
Hum...This is a really helpful comment from you cyclopsblown. But frustrating at the same time.
Let me resume, If I use epoxy primer as a layer under my base coat, I must not sand it with a grid finer than 80 grid because my base coat will not really stick to it.

So, I have to put 2k high build primer over it anyway to be able to gain a smooth finish for my base coat.

Whatever I do, I must buy a 2k primer to put in between the bondo and the base coat.

This might be my last question. Which Dupont 2k primer would be compatible to stick to bondo and ChromaBase base coat?
 
#12 ·
The sanding scratches the epoxy covers can be no finer than 80 grit. As for 2K primer, ask the supplier for some Nason 2K primer. They offer a 4:1 mix I think and it is a high build polyester or Urethane, I can't remember which. They should be able to supply you a one quart kit and the same quantity on paint and clear. That is unless they already mixed the color as a larger quantity.

As for sanding the epoxy, I usually let it dry a couple days if I'm going to sand it and then only gently so it doesn't gum the paper. i usually don't sand the epoxy, I try to get the 2K primer on it while it is still "open", that way the 2K primer sticks by chemical reaction.
 
#16 ·
Finally!
Here is my special sandwich recipe to fix paint.

Bare metal
Bondo
2K Urethane primer-filler
Basecoat
Clearcoat

Sounds good? :mwink:
If it's a yes, I'll jump into my car to get all that stuff!
I am so excited to try fixing my car painting for the first time.
 
#17 ·
Looks good to me. Make certain your sanding of the filler is within the tolerance of the 2K surfacer/primer. Don't get much finer than 600 grit before the color/base coat goes on. it needs some tooth to bite to.

When you mix the filler make certain it is consistent color and not two colors. mix just enough for the task at hand. You shouldn't need more than a quart of any of the materials you're looking at. You do need lacquer thinner/gun wash for cleaning the paint gun between materials through it. A set of gun cleaning brushes doesn't hurt either.
 
#18 ·
Centerline said:
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.
All I got to say is it didnt stick for me and if you sand the etch primer it with 80 it'll come right off so way use it in the first place? ...the proper way to use etching primer is like a sealer transparent (thin enough to see through when wet)I know this very well you may think its sticking but when your all done and blow it off, if the air catches an edge it'll start coming off I know this as fact I've done it with dupont etching primer I did have to pull most of the thicker parts off with a putty knife but the spots where it was thin blew off ...It was 8hrs of work on a Trans Am shaker hood and I'll never forget that lesson .primers will stick,bondo WONT...Return the etching primer and get some epoxy.....SPI has the best and the best deal...bondo sticks well to it...This is what I do for a living...but like i said you really dont need it any of it for a small spot job just some 2k will be fine BUT an aftermarket fender runs 50.00 and a hood 100.00 for that car so I wouldnt waste my time doing a repair its way cheaper to replace and just repaint,an even cheaper option is to get the right color sheetmetal from a salvage yard and just bolt them on and be done with it.I sertainly hop dat were clear enough .LOL
 
#19 ·
klingfilm said:
Finally!
Here is my special sandwich recipe to fix paint.

Bare metal
Bondo
2K Urethane primer-filler
Basecoat
Clearcoat

Sounds good? :mwink:
If it's a yes, I'll jump into my car to get all that stuff!
I am so excited to try fixing my car painting for the first time.
The one thing I havnt conciderd is ..If you want to learn ,this is a great way to do it.some pictures of the damage will help.painting from edge to edge might not be a good way to paint... blending is preferd and not that much harder get back with us before you sand the primer the sandpaper grits are important
 
#20 ·
Ah...,
You are just making me feel more uncertain all the time :drunk:But you won't get rid of me like that!
I really plan to try to paint it whether it's cheaper to buy new parts or not. The question is more about the fun and the thrill to try it for the first time. This car is my big toy. I don't care about its value. This is my first car and I try to fix everything on it. If I do worse I'll send it to the garage.
Now, I'm not gonna keep the etch primer for sure, I bought that because it's in a can and I have only 1 gun. So, wouldn't have to clean it 3 times. I didn't know what I was buying and the guy at the shop gave me this primer. When I saw primer, I felt confident because primer is what you use before painting when you have to paint a room. Well, I realize it is not so simple with car painting.

It seems that 2k primer is a bigger need, but what type should I buy? I want to stick with Dupont to ensure the compatibility of chemistry.
I'll go take a picture of my car outside to show you the damage. :thumbup:
 
#22 ·
dp 90 is not etch primer, it is ppg's epoxy, before it went lead free. Can't remember the colors, 90=black? but ppg used dp and the number after it was different for different colors. Was a very good epoxy. Not its dplf, and I haven't used it since the old dp days, but in past threads it has been discussed how the quality has declined since it was reformulated and went lead free.
I'd personally would use epoxy, and return the etch, and let the bang em out collision shops use the etch. I have to agree with deadbodyman here. To many risks (now or in the future) and potential compatability problems with the acid components for the quality of the product IMO. It also is a 1k product that stays soluable and can be softened by solvents in materials applied over it. The Etch primers I have used were not meant to be applied heavy like dbm meantioned, and they would easily enough run all over the place if applied heavily, and another primer must be used over them before paint (again watch compatability). I haven't used etch often, but when I did, probably used variprime the most.

Many manufacturers have strict warnings in there product data sheets about not using bodyfiller over etch or etch over body filler, as the acid etch and polyester fillers don't get along, and the filler could never cure properly. You better make sure it has cured plenty enough time so that the acid component won't cause a problem with you filler or other products.

The safest way with least risks of problems and incompatabilitys, that will give a strong foundation for a long lasting durable paint job, IMO is physically removing all rust, sand any baremetal with 80 if not media blasted for something for the epoxy to hang onto, and start with an epoxy foundation over baremetal and under filler areas, apply filler over epoxy and seal up bodywork areas with epoxy.

I have no problems with a high build urethane primer (and I've used them often enough) over the epoxy if needed, but urethane primers do shrink somewhat, and are somewhat porous, and will not give the best corrosion protection applied over metal, so epoxy is prefered first under the urethane. But if you have a straight vehicle, and spend a little extra time finishing off your bodywork and getting it straight, epoxy may be all you need for a primer.

Most epoxys don't have the amount of build of a urethane or sand as easy. But I used only epoxy on a dent repair this weekend. I used southern polyurethanes epoxy, and it has a bit more build then other epoxys I've used, and could be dry blocked the next day. Choose the best color for coverage of your base color, finish off your bodywork well, and epoxy may be all you need.
 
#23 · (Edited)
kenseth17 said:
dp 90 is not etch primer, it is ppg's epoxy, before it went lead free.
Good information to know. For some reason I always thought of it as a self etching primer and not epoxy.
 
#24 ·
klingfilm said:
Ah...,
You are just making me feel more uncertain all the time :drunk:But you won't get rid of me like that!
I really plan to try to paint it whether it's cheaper to buy new parts or not. The question is more about the fun and the thrill to try it for the first time. This car is my big toy. I don't care about its value. This is my first car and I try to fix everything on it. If I do worse I'll send it to the garage.
Now, I'm not gonna keep the etch primer for sure, I bought that because it's in a can and I have only 1 gun. So, wouldn't have to clean it 3 times. I didn't know what I was buying and the guy at the shop gave me this primer. When I saw primer, I felt confident because primer is what you use before painting when you have to paint a room. Well, I realize it is not so simple with car painting.

It seems that 2k primer is a bigger need, but what type should I buy? I want to stick with Dupont to ensure the compatibility of chemistry.
I'll go take a picture of my car outside to show you the damage. :thumbup:
Now your talking,Nason (dupont's cheaper line)has a 2k thats fairly good sands easy and is fairly inexpensive...a quart should do ya.....dont forget the hardner.... If that deer damaged the center of the hood at all you might not be able to fix it.
 
#25 ·
Centerline said:
Good information to know. For some reason I always thought of it as a self etching primer and not epoxy.
DP was good it could be applied over bare metal aluminum and galvinized from what I remember but it was an epoxy....Variprime was what I was tring to think of, it washed right of with laquer thinner and wax & grease remover if I remember correctly(its been over twenty years since I used it)..after stripping it was used to help the old laquer primers stick to metal...Yup ,I remember when the 2k's came out. :( :(
 
#26 ·
Ok,
Let me resume again everything. Whatever I do, I'll have to make a compromise if I don't want to buy the whole range of Dupont products.

Plan A sandwich with epoxy primer
-Bare metal
-Epoxy-primer -->Sticks well on metal and protects against corrosion, I am in Qu頡nd corrosion is a problem here.
-Bondo
-Epoxy-primer --> Which needs a 80 grid finish to let the base coat sticks to it
-Base coat
-Clear coat
Pros: Good protection against rush, no need to buy 2k primer
Cons: Finish may be rough between epoxy and base coat and the final result may reflect this. Sanding could be long because the epoxy is hard.

Plan B sandwich with 2k primer
-Bare metal
-Bondo -->no real barrier for rust
-2k primer filler ---> easy to sand for a smooth finish
-Base coat
-Clear coat
Pros:No need to buy an epoxy primer, easier to sand to get a smooth finish
Cons: No real protection for rush in between.

Plan C sandwich "gourmet"
Stop looking at your wallet and go buy epoxy and 2k primer :sweat:

Which menu would you suggest?
 
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