Technical Difference in Primers

You can mix small amounts of epoxy. Just use a mixing cup. I would put 3 good coats on your bare spots so that way you have better moisture resistance.

 

P G - first of all like the rest have said "Thanks" for posting this - I'm in the process of starting my build and this couldn't have come at a better time for me - this is why I love the HAMB - the knowledge is shared and that goes a long way with me - Thanks again !

 

Thanks for the info! I was hoping what I was planning would work and not come back and bite me in the butt later on.

 

[QUOTE="BamaMav, post: 11185943, [/QUOTE]

BamaMav, pick up a touch up gun, the tip is a little small so it takes quite a few coats for a decent build but it will work for what you're planning.
http://www.tcpglobal.com/TCP-G5500_2.html?gclid=CPTv3Yfwn8gCFdcZgQodSYsOVA#.VgxrW58o7qA

Depending on your car color, you can tint the primer to a close match so it doesn't stand out as much.

 

Thanks for the reply. You know alot of technicallities about undercoats. Out of curiosity, do you work for a paint company?

 

I am a technical consultant for a couple different Paint companies where I spec specialty products for industrial, automotive, government industries.
I manufacture small batchs for my wife's automotive Paint Supply store. I don't grind pigments or anything at my low budget place of business though lol. But I can build most technology coatings there. Anything that is specific or has to be mil spec etc is done out of one of the lines I consult for.

 

The best paint advice I gotten in a long time. Thanks for caring enough to post. thanks Frank

 

Anytime!!

 

What??
First let me say I need the info in the first post and I appreciate you posting it.
Now about rust converters breaking down in 3 months---I applied POR15 to a rusty (no cake) 1935 Ford truck rear fender 23 years ago. Its been in the weather ever since. It got chalky but is still excellent, no rust has come back.

 

Thanks for the info. I learned a bunch!

 

Por15 is a moisture cure urethane.

 

Also this was scaled rust, no prep. And we were testing to see how long it would take for rust to start to reappear in weather, exposed 24/7. I have personally never seen any moisture cure last near that time exposed to the elements , on exterior surface.

 

Cool. Its actually refereshing to hear this, lol.
Iam a licenced autobody repairer and finally i found someonethat can understand what im talking about if i use technical terms lol.

 

great info,with all the different products seems easy to get confused at least for me

 

OK thanks for the good info, BUT, I'm with the PorknBeaner on this. I prefer the the ease of using lacquer top coats, and I prefer the look of a lacquer paint job plus the ease of repair. I have used the the urethane paints (top coat 2k) and I don't like them at all. I have a lot of experience with lacquers painting helmets and motorcycles then switched to the 2ks painting motorcycles but using these paints was a PITA for me and the caustic problems caused me to stop painting bikes altogether.
So forward to the present , I'm doing the metal work on my 56 F100 and will be using epoxy prime over bare metal. What high build primer should I use (if different than lacquer) over the epoxy to block with then top coat with lacquer.
I sent you a PM

 

BamaMav, pick up a touch up gun, the tip is a little small so it takes quite a few coats for a decent build but it will work for what you're planning.
http://www.tcpglobal.com/TCP-G5500_2.html?gclid=CPTv3Yfwn8gCFdcZgQodSYsOVA#.VgxrW58o7qA

Depending on your car color, you can tint the primer to a close match so it doesn't stand out as much.[/QUOTE]

I've got an older siphon feed touch up or "jamb gun" as some call them. I primed a entire car with it one time, you'd be surprised how far that little cup will go! I have a few areas around the glass rubbers, drip rails, and in the fender mount areas to work, as well as a couple of spots on the hood corners. Not really worried too much about it being a "speckled pup" for a while, it will be getting a color change anyway. It's currently gold, will eventually be blue.

 

You got it covered, I have a small binks siphon similar to the one shown, primed a lot of spots and have shot base clear fenders with it. Finally crapped out, I need to dig it out and put a kit in it. Perfect for touch up, I've pulled off some nice panel blends with that thing.

Get your primer tinted beige it'll "disappear" right into the gold.

 

The owner of Southern Polyurethanes discusses this on his company website. He says he gets calls regularly where a paint job has failed anywhere from a month to a year later where the painter has used etch primer or he has used one of the acid based metal prep solutions and then put epoxy primer over it without fully neutralizing the acid.

He says the acid prevents the epoxy from ever setting fully anywhere it is in contact with acid. He also says this problem is so prevalent that he tells people if they insist on using etch primer or acid metal prep solutions then he prefers that they buy their other materials from someone else other than SPI so that when the paint job fails they won't have any reason to think its the fault of his products.

 

I have a display of old spray Guns and I have one just like that.

 

Here's a common problem for sure.
Some epoxy will work with an acid and some won't.

An unintended, alternative and positive use for this problem -
Lets say you want temporary protection, acid prep your stuff and shoot it with epoxy. The epoxy seals out everything and offers protection. You remove the epoxy film with a blow gun. Could come in handy

 

This is why tds sheets are so important. Just because something worked on your buddies front bumper doesn't mean it's going to for you. When a product is made we test over multiple products, put in extreme weather chambers, do chemical test, abrasion test, adhesion test, then after hundreds of hours and only positive results do we then write a technical data sheet with a approved method to use the product over certain substrates.

 

Thanks for the info. Glad your here.

 

YUP! Thanks Guru!

 

Are high build primers usually epoxy or urethane? I'm working on a project and not sure to self etch, high build, and then what. What would your recommendation be? The car is partially stripped but will only be scuffed in other areas (only one layer of paint on it now).

 

Great "primer" on primer!
Now, folks need to know that different manufacturers have different formulations, and uses, restrictions, and mix instructions for their products. I've had guys try to mix up one brand of epoxy, like another brand, and have it fail. All because they failed to read instructions, and they just do it like they did the "other" brand.
Some epoxies are used for adhesion coats, perhaps sealer, but not as a high build. I prefer using HOK epoxy, as it has all these qualities. It even sands easily, unlike some epoxies. I still keep some etch primer for small jobs needing no filling qualities, or for thin film build, but use HOK's almost exclusively.
The point is: know your product, read the tech sheets, ask people who are proficient in painting for their preferences, and ask why. Paint, and primer even, is expensive, you don't want to make stupid mistakes, get expert advice before buying, and using them.
Beaner, I've done a few lacquer over epoxy jobs, and I will say they come out much better, and it's easier, less work, because of lack of shrinkage, than using lacquer primer ( and the dreaded "Nitrostan"!) Even did a custom 53 Merc in black nitro lacquer, and it still looked great after 10-2 years, when he returned to throw some scallops over the original job.
Fortunateson, you can get high build primers in urethane, epoxy AND polyester (FeatherFill). Slightly different applications, but 'almost' interchangeable. Some just do better jobs in certain circumstances, than others. (i.e. FeatherFill works great over fiberglass

 

OK, but what does a novice painter do when he has already primed with self-etch (over sand-blasted metal)? What do you recommend from here?
Great stuff, thanks for sharing your brain trust.

 

Guru,
Question. I have read about chemical bond vs mechanical bond. I am going to have my T Coupe blasted and shot with Epoxy. It sounds like I can use filler over the epoxy on pitted areas. Is there a time frame to get this done? Would it be best to hit it again with epoxy right before painting? I get sidetracked a lot and this may be over the course of 2 or 3 years.

 

Uhhhhh, makes sense now. Thanks for the reply

 

It would be nice to have a side by side comparison of polyester filler primers.
Qualities as far as price, texture ,sandability, DTM for bare spots, adhesion, cured hardness, build mills.

I've been using "u-pol reface" and want to try something different.

 

Any answer here from a paint expert