View Full Version : Pinholes after primer
07-06-2006, 08:48 AM
Using the technique advice I got on working my quarterpanel, it went very well. I worked the rough edges down with an air board, then blocked it with 80-grit and then with 180-grit. I had to fill a few little pinholes and I thought I got them all, but when I applied the Z-Chrom Rust Defender, there is a big pinhole about the size of the end of a pencil lead. I guess in my excitement for everything going so well, I jumped the gun and shot the primer before I made a thorough inspection. Since the Z-Chrome is sprayable filler, can I use some Metal Glaze to fille the pinhole? Also, the Z-Chrome literature says that it serves as a sealer. Can I use this as the last material before a topcoat? If so, what grit paper should I finish it to before spraying the topcoat? I assume that if I'm able to use the glazing putty on top of the Z-Chrome AND use it as a sealer, I'll need to shoot another couple of coats to cover the glazing putty. Correct?
07-06-2006, 09:38 AM
I've never used Z-Chrome Rust Defender and have no idea what its chemcial attributes are so I can't help you with that part. But a question that comes to my mind is why would you use a rust inhibitor on bondo ? The professionals standby for covering baremetal is epoxy primer followed by high build 2K primer. You can use a two part polyester spot putty to fill that pin hole pretty much at any step short of applying your topcoat paint.
07-06-2006, 10:04 AM
As someone who doesn't do this alot, the Z-Chrome was recommended because of its forgiving nature regarding filling, sandability, ease of spraying, etc. plus the fact that it seals in preparation for the topcoat. It's expensive, and maybe there is a cheaper alternative. How much is a good epoxy primer per gallon, plus sealer that must go over that? I might want to change my process.
07-06-2006, 05:49 PM
Epoxy is its own sealer so you don't have to buy another sealer. How much of a car or what size car do you plan on spraying ? A gallon of epoxy primer goes a long way.
07-06-2006, 10:50 PM
at 80.00 per gallon icanadian t is very cheap.
DP 40 old style probably cost me 200.00-400.00 I can't remember but can look it up think that was a gallon of activator and a gallon of product or maybe 4 litres of each.
You should read the P sheets on the clausen and you should find someone who uses it and has for a while. If it holds up to all the claims then it is magic, you can chuck all products spray three coats of that bl0ck it to 320 or whatever you need then put on your base right on top at least that is the claim.
It claims to be the only OEM product that is warranty covered with the zinc additive.
I have not used it in a while and would be suspiscious of all the claims yet there are supposed to be shops who just use that nothing else and go right to base and clear. I would want to talk to them first.
One thing I think I remember that I did not do was sand it just before I top coated it and I think that is important, in other words don't sand one day then the next day do your top coat,. do your final sand an hour or so before it is coated.
As far as a polyester primer it worked the same I think as slick sand or feather fill more or less but it is the same powdery talc that comes off it when you sand it.
I have seen it used for blocking and straightening on some of the very top show cars at Cobal Hall so for sure it has proven itself at the filler level or it would not be used on those very high dollar cars.
07-07-2006, 11:20 PM
at 80.00 per gallon icanadian t is very cheap
Using a currency converter, $80CDN is about $72US. I'm paying about $120US.
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