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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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 Posted: Wed Jan 23, 2013 10:54 pm Post subject: |
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I still wanted to find a primer that would go over the Zinc Chromate, so I went to our local auto paint store with a sample and picked up their recommend two component (2K) epoxy primer, DP90LF, along with the activator and reducer:
I used the reducer to wipe a section of a Zinc Chromate plated fender, painted it, let it cure, and did the adhesion test:
I also did a test with no reducer wipe:
It looks like the adhesion was good in both cases, even over the Zinc Chromate.
The finish looks perfect, just the slightest matte:
Frankly I was scared of spraying, but I picked up a Harbor Freight HVLP detail gun, and the folks at the paint store walked me through the mixing, and I am very glad I took the plunge.
At this point I think I have a fantastic rust prevention system: The zinc chromate plated on the bare blasted metal, painted with the DP90LF 2K primer, then it will be topcoated with an 2K industrial coating.
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1975 LaGrande Super Beetle Build Log / Farm boy hinge pin puller / Farm Boy Chassis Rotisserie
"I'm not getting older, I'm getting bitter." |
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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| Posted: Thu Jan 10, 2013 11:00 pm Post subject: Adhesion of KBS RustSeal |
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I decided to test the adhesion of KBS RustSeal on:
* Bare metal, cleaned with a power wire brush
* Bare bead blasted metal
* Bead blasted metal, with zinc chromate.
We did each of these on both un-etched samples, and on samples prepared with KBS RustBlast.
Here is what the samples looked like when the paint was wet:
Here is what it looks like after a cross-hatch adhesion test:
My conclusions:
* Using a wire brush only, with or without etch does not get a good bond.
* Bead blasting without an etch does not get a good bond.
* We only saw good bonds on the bead blasted, etched samples.
The zinc plated, non etched sample had poor adhesion, but not worse than the wire brushed non-etched sample.
Etching the zinc sample is useless. The etch takes the etch off:
I might make one more test on the zinc plated sample, after scuffing it.
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1975 LaGrande Super Beetle Build Log / Farm boy hinge pin puller / Farm Boy Chassis Rotisserie
"I'm not getting older, I'm getting bitter." |
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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martyrg
Samba Member
Joined: February 29, 2004
Posts: 492
Location: South Lyon, MI. 48178
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dawerks
Samba Member
Joined: September 15, 2010
Posts: 2349
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| Posted: Fri Jan 04, 2013 12:45 am Post subject: |
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Live and learn brother! Thanks for sharing your experience. It's one thing to 'hear' of someone doing it, it's alot more important to hear first hand experience.
We all learn from our mistakes! Good to know I'm not the only one who screws up 
I obliterated a nice 55 Oval back in the day. I thought I was getting a bargain on sandblasting at only $100 (picked up/dropped off!!). Bug was sent straight to the crusher 
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543fold
Samba Member
Joined: November 30, 2007
Posts: 139
Location: Texas
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| Posted: Tue Jan 01, 2013 9:53 pm Post subject: Re: Cautionary Tale: sand blasting / bead blasting on body p |
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| baxsie wrote: |
| 543fold wrote: |
| baxsie wrote: |
| Can damage from a blaster be fixed? |
Sure it can!...I fixed some pretty heavy blasting damage along with hail and various other damage on a customers bug.  |
Wow, that body work looks fantastic! Do you want to come to Spokane for a week this summer and work on Kick Azz?
Your pictures obviously show that this kind of damage can be repaired (and quite well, I might add). My argument is that once the original stress that gives the part its original shape, springiness and "memory" is lost, and the part's metal now has different characteristics. The only way to test it would be to take a part that had been sandblasted heavily then expertly worked back into shape like 543fold did to those panels, and then (destructively) compare the re-worked part's memory and springiness against a factory panel. |
I would love to come to Spokane and help you out! But you know.....
True! Metal does have a memory and can be worked back to its original form. It just depends on how BADLY the metal is damaged.
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https://www.instagram.com/w.a.r._wills.auto.restoration/
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543fold
Samba Member
Joined: November 30, 2007
Posts: 139
Location: Texas
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| Posted: Tue Jan 01, 2013 9:12 pm Post subject: Re: Hail damage |
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| Ian wrote: |
| type241 wrote: |
| I want to see some PROCESS pics on the hail damage. That is very impressive work. That would have been a ragtop graft for sure. |
I agree, the work looks amazing. |
Thank you!...yeah, I try to take as many pics as I can. But being a one man shop and restoring 6 cars at the moment....well.....
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https://www.instagram.com/w.a.r._wills.auto.restoration/
______________________
....even the rust has rust!
______________________
How "NICE" do you wanna spend?
W.A.R.
Will's Auto Restoration |
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volksaddict
Samba Member
Joined: August 19, 2003
Posts: 1754
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| Posted: Mon Dec 31, 2012 7:12 am Post subject: |
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Well the parts sure look cool with that plating on them. Just have them do the shell and the whole car will match, funky gold  |
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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| Posted: Sat Dec 29, 2012 1:00 pm Post subject: |
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| Mike Fisher wrote: |
| Master Series silver and/or black over the ZC would be fine for the suspension parts. |
Thanks for the suggestion.
I just took a look at the Master Series site. It appears to be in the same class of moisture-cure urethane rust products that also includes POR-15 and KBS RustSeal.
I'm sure each brand has its good points and failings.
Since I have the KBS system already, I'll give that a try first.
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1975 LaGrande Super Beetle Build Log / Farm boy hinge pin puller / Farm Boy Chassis Rotisserie
"I'm not getting older, I'm getting bitter." |
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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Mike Fisher
Samba Member
Joined: January 30, 2006
Posts: 18042
Location: Eugene, OR
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| Posted: Sat Dec 29, 2012 11:16 am Post subject: |
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Master Series silver and/or black over the ZC would be fine for the suspension parts.
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69 FI/AT square Daily Driver
66 sunroof,67,70,71,71,71AT,72,72AT,73 Parts
two 57 oval ragtops sold
'68 Karmann Ghia sold
Society is like stew. If you don't keep it stirred up you end up with a lot of scum on the top! - Russ_Wolfe/Edward Abbey |
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skills@eurocarsplus
Samba Peckerhead
Joined: January 01, 2007
Posts: 17828
Location: sticksville, ct.
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| Posted: Sat Dec 29, 2012 10:49 am Post subject: |
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i'm glad you don't see any malice, as there isn't any. i have made almost every mistake in the book, and where it comes to saving time and money, i like to share what i know.
i read thru your thread, and no matter what or how it turns out, you are spending time with your kid, and that is priceless
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| gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
| Jake Raby wrote: |
| Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
| Brian wrote: |
| Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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Der Speed Shack
Samba Member
Joined: April 10, 2010
Posts: 164
Location: Fullerton, Ca 92832
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| Posted: Fri Dec 28, 2012 9:42 pm Post subject: |
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| you might try sanding the ZC and then hitting it with a product called Bulldog Adhesion Promoter. it sticks to chrome, and other plating. it smells worse that a dogfart, but seems to work. you can buy a rattle can to test, if it works, buy a quart and spray i on |
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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| Posted: Fri Dec 28, 2012 9:08 pm Post subject: Re: Cautionary Tale: sand blasting / bead blasting on body p |
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| skills@eurocarsplus wrote: |
| . . . i am pissing on your cheerio's . . . |
Damn. I thought they tasted funky! I realize you do not have malice, and hope to learn from your experience. Thanks for your continued input.
| skills@eurocarsplus wrote: |
| . . . i did an experiment with . . . |
I have been working up an experiment of my own. Since I planned to use KBS RustSeal over the zinc plating on the suspension parts, and I already have material on hand, I will set up the following samples:
1) Bare metal (no plating) paint removed by wire brush (KBS acid wash "Rust Blast" used)
2) Bare metal (no plating) paint removed by bead blasting (KBS acid wash "Rust Blast" used)
3) Zinc Chromate as received from the plating shop (NO special wash)
4) Zinc Chromate cleaned (KBS acid wash "Rust Blast" used) My thinking is to use the paint to lay some strip of nylon cloth tape to the metal, then use a spring scale to see how hard the tape is to remove, pulling normal to the surface.
| skills@eurocarsplus wrote: |
| . . . the minute that pan was done, it should have been epoxied . . . |
I realize I have the cart before the horse here. I have just have resigned myself to going over the pan one more time with fine glass beads. It will not take too long. Then it will be right to the paint shop for 2K.
| skills@eurocarsplus wrote: |
| . . . shame on the plating company . . . |
I went in with eyes open. I am treating this whole mess as an experiment. If I learn something it will all be worth it. Somehow I had it in my head that Zinc Chromate would not give a paint adhesion problem, and I loved the idea of laying a real coat of metallic zinc on the part. As far as cost, they charge $60 per batch, and all those parts fit handily in two batches, so the expense is not so great.
My plan now it to experiment with finding a paint that will adhere to the Zinc Chromate. If I can find something I am home free. If not, I can re-blast the zinc chromate parts back to bare steel and use 2K.
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1975 LaGrande Super Beetle Build Log / Farm boy hinge pin puller / Farm Boy Chassis Rotisserie
"I'm not getting older, I'm getting bitter." |
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skills@eurocarsplus
Samba Peckerhead
Joined: January 01, 2007
Posts: 17828
Location: sticksville, ct.
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| Posted: Fri Dec 28, 2012 3:17 pm Post subject: Re: Cautionary Tale: sand blasting / bead blasting on body p |
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| baxsie wrote: |
| skills@eurocarsplus wrote: |
| Right after blasting would have been a great time to put the epoxy down. That (in my opinion) is the best adhesion known to man. |
For the chassis, this was and still is the plan. We are waiting on the seats to arrive, so we can fabricate and weld in those brackets, then the complete chassis will have a very light blast to remove the tiny bit of surface rust that has formed in the few months since the original blasting, then it will get wrapped up and taken to the paint shop for DP90 primer.
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you are walking backwards. the minute that pan was done, it should have been epoxied. when your stuff comes in, grind/weld the touch it up with epoxy.
now, you will re blast the parts you already blasted. and shame on the plating company for ripping you off. all of that plating needs to be sanded or blasted for paint to properly stick to it.
i may have a photo of some pan hardware i did an experiment with. after a light scuff and prime, i can take my fingernail and pull the paint right off. i will see if i have the parts and snap a pic
please, don't think i am pissing on your cheerio's just trying to save you from yourself 
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| gprudenciop wrote: |
my reason for switching to subaru is my german car was turning chinese so i said fuck it and went japanese....... |
| Jake Raby wrote: |
| Thanks for the correction. I used to be a nice guy, then I ruined it by exposing myself to the public. |
| Brian wrote: |
| Also the fact that people are agreeing with Skills, it's a turn of events for samba history |
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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baxsie
Samba Member
Joined: August 09, 2005
Posts: 606
Location: Eastern Washington State
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| Posted: Fri Dec 28, 2012 12:27 pm Post subject: Re: Cautionary Tale: sand blasting / bead blasting on body p |
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| 543fold wrote: |
| baxsie wrote: |
| Can damage from a blaster be fixed? |
Sure it can!...I fixed some pretty heavy blasting damage along with hail and various other damage on a customers bug. |
Wow, that body work looks fantastic! Do you want to come to Spokane for a week this summer and work on Kick Azz?
Your pictures obviously show that this kind of damage can be repaired (and quite well, I might add). My argument is that once the original stress that gives the part its original shape, springiness and "memory" is lost, and the part's metal now has different characteristics. The only way to test it would be to take a part that had been sandblasted heavily then expertly worked back into shape like 543fold did to those panels, and then (destructively) compare the re-worked part's memory and springiness against a factory panel.
Ian, skills@eurocarsplus:
Please understand: I am not trying to come off like an expert . . . I have no formal knowledge or training and very little experience in this area. I am trying to share my embarrassing mistake so others may proceed with caution. I do have some technical training in another field (electronics), and I personally have a very great need to understand what is going on. Perhaps my biggest failing is not being able to take things at face value and just practice a technique, I need to understand (or at least think I understand) what is going on underneath the technique. This often leads to me learning by hard experience what I do not understand and therefore will not take as granted.
| skills@eurocarsplus wrote: |
| Right after blasting would have been a great time to put the epoxy down. That (in my opinion) is the best adhesion known to man. |
For the chassis, this was and still is the plan. We are waiting on the seats to arrive, so we can fabricate and weld in those brackets, then the complete chassis will have a very light blast to remove the tiny bit of surface rust that has formed in the few months since the original blasting, then it will get wrapped up and taken to the paint shop for DP90 primer.
| skills@eurocarsplus wrote: |
| . . . epic failure like no one has ever seen . . . |
No disagreement here. Ruining all those parts with the bead blaster has been a serious slap in my ego face. I think blasting the body panels is an epic fail already.
My new plan, starting with the beautiful doors from the 1973 parts car is to use very minimal bead blasting only at the tiny rusty spot in the weatherstrip track at the bottom of the door. The the rest of the paint prep will be done using sanding or scuffing. Lesson learned.
I will need to deal with the miscellaneous suspension parts that are already zinc chromate plated. As skills points out, there may be some challenges getting paint to adhere to them. These threads back him up:
http://www.finishing.com/2400-2599/2444.shtml
http://www.finishing.com/150/46.shtml
On the other hand, these pages indicates that yellow zinc chromate is a good base for paint:
http://www.infinitechfinishing.com/Articles/Article7.htm
http://www.allegiscorp.com/docs/materialFinishGuide.pdf
I guess you can find backup for any argument on the intarwebs.
My plan was to paint the zinc chromate plated pieces with the KBS RustSeal system (de-greaser, etcher, then paint). I guess I will use that approach on a disposable part then destructively test the finish adhesion.
I know that a lot of replacement automotive parts are shipped in yellow-zinc chromate, if you needed to paint one of those, how would you approach it?
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1975 LaGrande Super Beetle Build Log / Farm boy hinge pin puller / Farm Boy Chassis Rotisserie
"I'm not getting older, I'm getting bitter." |
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Ian
Samba Moderator
Joined: August 28, 2002
Posts: 4958
Location: 713
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| Posted: Fri Dec 28, 2012 12:05 pm Post subject: Re: Hail damage |
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| type241 wrote: |
| I want to see some PROCESS pics on the hail damage. That is very impressive work. That would have been a ragtop graft for sure. |
I agree, the work looks amazing.
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IN LOVING MEMORY OF ROB CRESS 1968-2012 & KEN CRIMMINS 1957-2024 |
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type241
Samba Member
Joined: June 02, 2006
Posts: 1010
Location: MOSES LAKE, WA
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| Posted: Fri Dec 28, 2012 10:04 am Post subject: Hail damage |
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| I want to see some PROCESS pics on the hail damage. That is very impressive work. That would have been a ragtop graft for sure. |
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Ian
Samba Moderator
Joined: August 28, 2002
Posts: 4958
Location: 713
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| Posted: Fri Dec 28, 2012 9:16 am Post subject: |
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| skills@eurocarsplus wrote: |
Right after blasting would have been a great time to put the epoxy down. That (in my opinion) is the best adhesion known to man.
Have you ever painted over cad? You can peel the paint off by the sheet. I honestly think you will have a epic failure like no one has ever seen.
You might get lucky, but there is no way I would ever in a million years do it that way |
I'm with skills on this one, you should have done some homework first. Sorry dude, epic fail.
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Love and good roads!
IN LOVING MEMORY OF ROB CRESS 1968-2012 & KEN CRIMMINS 1957-2024 |
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