# Primer question



## Suberman (Aug 16, 2010)

Hi guys,

All i know about primers is that it goes before the topcoat of paint. 

So, what exactly does a primer do? Prevents rust? Evens out the surface for paint?

Also i read that some primers are hygroscopic - only the epoxy ones are not. Does that mean regular metal even with regular primer will rust with time unless coated with epoxy primer?

Also, does galvanized steel simply mean metal with zinc coating? 

Thanks.


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## Andyb0127 (Jan 16, 2011)

2K is usually thought of as a "filler primer" that is sanded to help level the surface and take out slight imperfections. Epoxy primer is a "direct to metal" primer that can be a little gummy and not as good for block sanding. 2K has a hardener added but most epoxy primers have an "activator" that doesn't make the primer real hard. Some 2K primers can be applied to metal and some should have a direct-to-metal primer or other substrate under them.

Epoxy primer is a sealer, which is used for corrosion as it seals the metal and stop oxygen and moisture getting into the metal.

Etch primer is used as an adhesion promoter before applying high primer.

Galvanised is wherea car will normally be dipped into a tank of hot dip zinc.


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## Suberman (Aug 16, 2010)

Thanks for that Andy. :thumb:

So is there such a thing as a 2k epoxy primer?

And if so, i understand that 2k primers don't come in aerosol cans because of its thick nature. Would applying this by brush be ok for small touch-up in inconspicous places (and sanded down)?


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## Suberman (Aug 16, 2010)

Anyone?

And if working with an epoxy primer, could i apply it with a small brush instead of a primer that comes in an aerosol can because there are not too many epoxy primers in an aerosol available in my country. Is there any difference?

I could get some sample sized small tins of epoxy primer from my regular bodyshop.


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## Andyb0127 (Jan 16, 2011)

http://www.google.co.uk/url?sa=t&so...Z9an2ufIQuHNsJ2JA&sig2=7mpeLwRXKypUT-OYMoVOBA

Yes I don't see any reason why you can't brush it on in small areas as you suggested, but will need to check with the bodyshop that's supplying you with it if it will air dry, as some epoxy primers need to be baked in an oven or have an infa-red lamp on them to cure it.


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## Eskimo68 (Sep 25, 2011)

Applying primer by brush is ok because it needs sanding back regardless what type you use. Basics of primer is to allow the paint to properly stick, without primer paint tends to flake off quicker so there is differnt types for different surfaces and paints.

if the repair is deep 1mm use a high build primer (the thick gloopy stuff), for shallower repairs the thinner stuff is better for spot repairs. 

ps don;t sand primer with anything finer than p1000 otherwise its too smooth for paint to stick and let it harden for 24hrs regardless of instructions to avoid problems further down the line.


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## Suberman (Aug 16, 2010)

Thanks chaps. :thumb:


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## Suberman (Aug 16, 2010)

Another quick question. What type of primer do new cars generally come with? 2K? Epoxy? 

Are they totally different from the ones that bodyshops use? Or are they something that we can get in an aerosol?


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## Suberman (Aug 16, 2010)

What about issues with shelve life Andy?

I just got some 2k epoxy primer from my bodyshop, but apparently the stuff has been sitting on the shelve for some time. Would it become "less effective" if it's over its shelve life as i noticed that there is a shelve life for these things from the link you sent.

What about 1k 'spot primers' What are they then? 

Thanks for all the help fellas!


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## Andyb0127 (Jan 16, 2011)

Suberman said:


> What about issues with shelve life Andy?
> 
> I just got some 2k epoxy primer from my bodyshop, but apparently the stuff has been sitting on the shelve for some time. Would it become "less effective" if it's over its shelve life as i noticed that there is a shelve life for these things from the link you sent.
> 
> ...


if you let me know the make of the epoxy primer they gave you I'll find out for you about the shelf life for you. Has it been opened or still sealed up as this an make a diference as well.

Spot primers are usually just a 1k primer that come in aerosol form, to be honest I've never used, as I can spot prime with 2k primer as it gives a better build and finish, as aerosol primers tend to be rather thin, but obviously people use them and get good results with it. Probably because I'm use to spray guns and have more control over it. :thumb:


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## Suberman (Aug 16, 2010)

Andyb0127 said:


> if you let me know the make of the epoxy primer they gave you I'll find out for you about the shelf life for you. Has it been opened or still sealed up as this an make a diference as well.
> 
> Spot primers are usually just a 1k primer that come in aerosol form, to be honest I've never used, as I can spot prime with 2k primer as it gives a better build and finish, as aerosol primers tend to be rather thin, but obviously people use them and get good results with it. Probably because I'm use to spray guns and have more control over it. :thumb:


It's a Spies Hecker one. Not sure of the part number (i'll ask him maybe tomorrow). It's in a metal tin, so it's closed up, but is only quarter full, so definitely opened before in that sense. I'm quite sure it's quite old. I'm just concerned if these things still offer the proper levels of protection.

I'm using it to cover up a small scratch that has a bit of surface rust, but i want the best protection possible. So i'm just wondering if it's better to use an "old" 2k epoxy primer or use a new 1k spot primer that i have.  sorry to sound paranoid, but i'm hoping to learn as i go along.

Heres the scratch. http://www.mig-welding.co.uk/forum/showthread.php?t=31426(I know it's small, but hey! this is a place for OCDers right?):lol:


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## Andyb0127 (Jan 16, 2011)

We've use the spies hecker one at work for warranty on Mercedes.
If its the same one, it doesn't air dry has to be baked in an oven. What we had to do was shot blast the corroded area, Orbital sand all the edges back, then clean with solvent wipe, apply two coats of epoxy primer the bake in an oven.

After that any pits that were left in the corrosion (you had to apply epoxy over these first) you would use body filler and flat down, the worst part was you were not aloud to break through the epoxy or you would have to re-prime it with epoxy again, once you were happy with it. You would then have to apply a high build primer over, once that was done you would prep it ready for spraying.

It was such a long process, especially having to prime it twice and flat it all down twice, if the primer they gave you is a light biege colour then it's probably the same as what we had.

Best solution is to mix some up and brush it on an old piece of metal to see if it will cure and dry, shelf life shouldn't be a problem with spies as long as its been kept sealed up.

With a 1k spot primer it probably won't offer the same protection as the epoxy will.

No problems mate ask what ever you need to know. :thumb:


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## Suberman (Aug 16, 2010)

I'll find out the number maybe tomorrow. From there, i should be able to google the TDS of that product. 

Did you see the scratch from the link i posted? I'm imaging it should be quite a straight forward fix? This will be my very first attempt at something like that.


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## Andyb0127 (Jan 16, 2011)

Suberman said:


> I'll find out the number maybe tomorrow. From there, i should be able to google the TDS of that product.
> 
> Did you see the scratch from the link i posted? I'm imaging it should be quite a straight forward fix? This will be my very first attempt at something like that.


yes mate saw the scratch, it will be fairly easy to fix it especially the way your going to do it.
Can't see you having any problems what so ever.


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## Suberman (Aug 16, 2010)

Some update and questions Andy.

I went back to the bodyshop guy to check out what was given to me. It'a apparently the Spies Hecker 4090. It's formulated for Trucks actually.  Concern? http://sdstds.shcolor.info/ShowDocu...ONE GREY/82e913dc-5fdb-4cf8-a7ae-dbeda3f01d20

I tested it out on some metal parts and i have been mixing it with the wrong ratio (as per the chap's instructions!) which is probably partly the reason why it's not drying well.

Anyway, he reckons it's probably over it's shelf life and not the wrong mixing ratio , and gave me a small tin of Spies Hecker Priomat 1k wash primer.

This:
http://sdstds.shcolor.info/ShowDocu...MER 4085/56daf692-c4ba-4fd9-b2ac-a7362afcd225

Now, i've read that wash primers are only for use on bare metal surfaces and any surrounding paint can/will be lifted by the acid. But this particular product does seem to suitable for spot repairs as well (which is what i need?)

Would the wash primer work for my situation?

Many thanks as usual. :thumb:


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## Andyb0127 (Jan 16, 2011)

With 4090 if I remember it won't fully cure with out heat ie baking in an oven.

Priomat is just an 1k etch primer, and your correct it can lift the surrounding paint. So in all honesty i wouldnt use it.

I'm not back at work until next week, but if it would help you I can send you a sample of the Glasurit one we use, it would be a couple of touch up pots, one with primer, one with hardner in. And it will air dry that should be Enough or what you need.

Let me know if that helps mate as like I say I'm back at work wednesday next so I'll sort it then for you.:thumb:


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## Suberman (Aug 16, 2010)

Andyb0127 said:


> With 4090 if I remember it won't fully cure with out heat ie baking in an oven.
> 
> Priomat is just an 1k etch primer, and your correct it can lift the surrounding paint. So in all honesty i wouldnt use it.
> 
> ...


Although etch primers could lift surrounding paint, could this one (4085 wash primer) be "formulated" for spot repairs as it says on the TDS?

The scratch is actually on an area with very little paint to be honest. It's on on the chassis sill where it's just the factory primer and a bit of paint overspray from the robots.










I asked the bodyshop guy twice, and he did say that they use this for scratches down to the bare metal.

Looking at other types of etch primers, U-POL etc, they do seem to be suited for spot repairs as well? 

That's very helpful of you Andy. :thumb: But another potential issue is that the topcoat i'll be using is also from the bodyshop guy and is from Spies Hecker, not sure if it'll accept other brand primers? What part number is this Glasurit one?

I'm leaving for Australia on Sunday until Friday. Meanwhile, do you think i by sanding it down and applying the touch up paint on it would be better than leaving it rusty as it is?

At some point, i think i'm getting a little too paranoid in this as i see touch up kits like those sold by www.paints4u.com just being packaged with "regular" gray primer.


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