The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-22-2018, 06:36 PM   #1
Slowguy
Senior Member
 
Join Date: Aug 2017
Location: Chicago,il
Posts: 356
Prep right before painting frame after sand blasting

So I’m 95% done blasting the frame. Looking really good so far. I have to do my chores in stages so it will inevitably have some light surface rust when I get the time to get it coated. I’m using the pro 15 with chassis black on top of that. I knows it fine to put por15 right on top rust but I’d really rather wipe the light surface rust off right before I por15. Any recommendations? I used some “Krud Kutter” before and that phosphoric acid is like rust magic but I want to be sure that’s ok right before por15’ing. Figured spray down with krud kutter then hose it off with water but figured I’d ask in case someone has a better idea or otherwise thinks that’s not a good plan.
Attached Images
   
Slowguy is offline   Reply With Quote
Old 09-22-2018, 07:00 PM   #2
Artofdeath
Registered User
 
Artofdeath's Avatar
 
Join Date: Jul 2017
Location: Sandusky, Ohio USA
Posts: 104
Re: Prep right before painting frame after sand blasting

If you remove all the rust, the POR15 will not stick. So be careful how you use it. It will peel if it doesn't adhere to rust.
Artofdeath is offline   Reply With Quote
Old 09-22-2018, 07:02 PM   #3
Artofdeath
Registered User
 
Artofdeath's Avatar
 
Join Date: Jul 2017
Location: Sandusky, Ohio USA
Posts: 104
Re: Prep right before painting frame after sand blasting

http://67-72chevytrucks.com/vboard/s...d.php?t=589112

Check this thread out about POR15.
Artofdeath is offline   Reply With Quote
Old 09-22-2018, 07:05 PM   #4
notsolo
Registered User
 
notsolo's Avatar
 
Join Date: Apr 2008
Location: Md
Posts: 2,450
Re: Prep right before painting frame after sand blasting

Looking good, I used Phosphoric acid sprayed on with small spray bottle, wipe it also with cloth rag. Let dry to white film, wipe with wax and Grease remover, extra step may not be needed. Then paint...For me, epoxy primer and Hammerite.
notsolo is offline   Reply With Quote
Old 09-22-2018, 07:28 PM   #5
Husker
Registered User
 
Husker's Avatar
 
Join Date: Dec 1999
Location: Mid NE USA
Posts: 2,209
Re: Prep right before painting frame after sand blasting

Bare metal can be etched with POR metal prep before applying POR
Ron
__________________
Member #111
68 C-10 Daily Driver
70 4x4 Project
76 Jeep CJ-5

Help Support the Board:

http://67-72chevytrucks.com/vboard/payments.php


He who knows nothing is closer to the truth than he whose mind is filled with falsehoods and errors.
Thomas Jefferson
Husker is offline   Reply With Quote
Old 09-22-2018, 09:24 PM   #6
Slowguy
Senior Member
 
Join Date: Aug 2017
Location: Chicago,il
Posts: 356
Re: Prep right before painting frame after sand blasting

Thanks for the replies guys/gals. So it sounds like either let the surface rust form and hit it then with the basecoat of por15 -or- clean it with phosphoric right before and por15 prep coat -or- clean with phosphoric, wipe clean, then epoxy primer and hammerite. Decisions decisions?
Slowguy is offline   Reply With Quote
Old 09-22-2018, 09:44 PM   #7
darrellyates
Registered User
 
Join Date: Jul 2016
Location: Gallatin TN
Posts: 376
Re: Prep right before painting frame after sand blasting

According to the instructions on POR 15, the first step is to clean the metal. Yes, I'm aware you sandblasted, but cleaning the metal will remove all oils and stuff from handling.

Second, you apply metal prep, which etches the metal properly for the POR 15 to bond to. Both of these steps are really helpful to get the proper bond to the metal. Then either spray or brush the POR 15 on. It self levels, and I've used both processes with good results.

I've never used topcoat on a frame. After 10 years, the frame still looks glossy black, although in defense mine does not sit outside. Topcoat will only add another layer of protection.

Lastly, one coat of POR 15 is enough. There is really no value to a second coat, especially if you are going to use topcoat.

Good Luck! I believe this to be an excellent product, superior to powder coat in many respects. I've enjoyed mine, and am likely going to paint the entire underside of the next project with this or KBS coatings Rust Stop!
darrellyates is offline   Reply With Quote
Old 09-23-2018, 05:29 PM   #8
plastercracker
Registered User
 
Join Date: Mar 2015
Location: Conneaut Township
Posts: 98
Re: Prep right before painting frame after sand blasting

my frame was clean but still needle scaled the whole thing. washed down with prep sol real good. the por 15 never peeled but the finish looks crappy. and rust was popping thru in places. went back to chassis saver and happy again. to many people around me that build hot rods for a living all so stopped using por 15. i will stick with chassis saver or maybe try KBS. there was a post here couple years ago from some company that made paint for commercial bridges that sounded pretty impressive. if anyone has that link.
plastercracker is offline   Reply With Quote
Old 09-23-2018, 05:51 PM   #9
notsolo
Registered User
 
notsolo's Avatar
 
Join Date: Apr 2008
Location: Md
Posts: 2,450
Re: Prep right before painting frame after sand blasting

Mastercoat silver is the bridge paint, Good stuff. Especially nice over sand blasted steel, top coat with just about anything....I had a bad experience with Por 15, years ago, probably my own fault. But did not want to chance a repeat.
notsolo is offline   Reply With Quote
Old 09-23-2018, 06:22 PM   #10
plastercracker
Registered User
 
Join Date: Mar 2015
Location: Conneaut Township
Posts: 98
Re: Prep right before painting frame after sand blasting

thanks for posting the mastercoat link. bookmarked,,, thanks,,,, will try that next time for sure.
plastercracker is offline   Reply With Quote
Old 09-25-2018, 09:12 AM   #11
mcampbell
Registered User
 
Join Date: Aug 2009
Location: Santa Clara, Utah
Posts: 48
Re: Prep right before painting frame after sand blasting

I use a lot of POR-15 as a base coat if I weld up a gate or railing that will be exposed to water like lawn sprinklers. It sticks to new bare metal if wiped first with lacquer thinner.
I put a color coat on almost every application because I've heard POR-15 fades quick with UV exposure. My top coat will not stick to fully cured POR-15 because the surface is too shiny. This means I have to paint POR-15 early and after 3-6 hours when it cures from runny to tacky then I can roll/brush/spray the color coat.
I have white rattle can top coated swamp cooler brackets in my yard that still look great after 15 years in Mr sun. The bonus is how smooth even the top coat flows out and even brush marks disappear with a POR-15 base.
mcampbell is offline   Reply With Quote
Old 09-25-2018, 09:36 AM   #12
special-K
Special Order

 
special-K's Avatar
 
Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,852
Re: Prep right before painting frame after sand blasting

Quote:
Originally Posted by notsolo View Post
Mastercoat silver is the bridge paint, Good stuff. Especially nice over sand blasted steel, top coat with just about anything....I had a bad experience with Por 15, years ago, probably my own fault. But did not want to chance a repeat.
Masterseries is an upgrade from POR-15. Company was started my the chemist that worked to develop POR-15 who left and started his own company to sell a better product when POR-15 cheapened their formula. You don't see hiway bridges or other large high dollar projects using POR-15 where the true test is. Bridges get salt and brine dumped on them all winter long, year after year. Classic cars are get done, then babied. Masterseries has a wide line of products to address various situations. I would never apply either straight over rust no matter what they might claim. Do the work and get the best job when it's easiest... a bare frame
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed"

GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project)
GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling)
Tim

"Don't call me a redneck. I'm a rough cut country gentleman"

R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~
special-K is offline   Reply With Quote
Old 10-15-2018, 07:02 PM   #13
Slowguy
Senior Member
 
Join Date: Aug 2017
Location: Chicago,il
Posts: 356
Re: Prep right before painting frame after sand blasting

Man, this turns out nice. Shame to even paint it with por
Attached Images
   
Slowguy is offline   Reply With Quote
Old 10-15-2018, 10:58 PM   #14
zicc1835
Senior Member
 
zicc1835's Avatar
 
Join Date: Mar 2011
Location: Hanover NJ
Posts: 4,104
Re: Prep right before painting frame after sand blasting

nice work
zicc1835 is offline   Reply With Quote
Old 10-16-2018, 01:02 PM   #15
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,783
Lightbulb Re: Prep right before painting frame after sand blasting

Por15 is a good product. The problem in my experience is that there is no simple prep for topcoating. I too have topcoated it when the Por15 is tacky or still has drag to it but not to a 100% success rate. If you miss that window then you have to hand scuff the Por15 to get the topcoat to adhere. If you provide tooth for the Por15 to grab on to it will stick. Either solid rust (not lose or flaky rust) or acid etched clean steel. Then getting the proper tooth in the Por15 for the topcoat is the key to getting a nice topcoat that lasts.
As far as hot rod builders not using it I would bet it is from an economic standpoint and not from a product failure issue. Using Por15 correctly is a labor intensive project that quite frankly isn't in the budget of many projects. Especially cars that only see the road on dry sunny days. Not to mention the fact that today's standards of street car builds are more than the show cars of 15 years ago. Economics mean that as a builder I will get a new frame from a aftermarket vendor and paint it with a good single stage paint. That will allow me to have a sharp looking product at a good price and it will also allow for easy touch ups that will follow as the owner uses the vehicle. Powder coating and products like Por15 cost me more money to apply and in many circumstances I can't charge more for that extra time. In addition they make invisible touch ups a pain even though I can charge for those.
Now all that being said I have used Por15 extensively on my Burban and my Javelin to good success. It works well on projects that are not being completely disassembled and restored, especially year round driven vehicles.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is offline   Reply With Quote
Old 10-16-2018, 09:03 PM   #16
Slowguy
Senior Member
 
Join Date: Aug 2017
Location: Chicago,il
Posts: 356
Re: Prep right before painting frame after sand blasting

Now that I’ve actually done my homework (obsessive searches and reading opinions and instructions) and worked with this stuff I can say if it’s applied correctly, it’s virtually indestructible. I sand blasted and according to por15 instructions, that alone is enough to go ahead and coat. Instead, after blasting, I went ahead and used their prep stuff including the etching. I applied three coats in the method of letting it tack and test with the finger drag. This stuff is like rock. And I think it actually somehow permeates the metal. Like the metal absorbs it somwhat. On top of this I’m using the por15 “tie” coat which is now called “high build primer” and can be applied even after the por15 has cured. On top of that primer, I can apply any (most) type of coating I wish and I think I’ll use a two part chassis coat from Eastwood.

Had I known all that would be necessary to do this correctly, I would have opted for another method. Talk about time consuming! It’s too late now, however, and since I’m this far into it I have to complete the process. After seeing the results I find it difficult to imagine anything that would be stronger or better. Research, research then more research. Sandblast, Prep, prep and paint. Bonding tie coat, then top coat. Stuff will be an inch think by the time I’m through!
Slowguy is offline   Reply With Quote
Old 10-16-2018, 09:55 PM   #17
projectking
Registered User
 
projectking's Avatar
 
Join Date: Oct 2006
Location: Orland Park Il
Posts: 2,041
Re: Prep right before painting frame after sand blasting

3 coats of SPI epoxy and the ability to get sockets onto painted fasteners gets my vote but it does look nice with the por on it
__________________
68 GMC C3500 Longhorn DRW
67 Chevy C10 LWB
90 Mustang Gt
90 Mustang Notchback
projectking is offline   Reply With Quote
Old 10-16-2018, 10:12 PM   #18
Jason Banks
Senior Member
 
Jason Banks's Avatar
 
Join Date: Dec 1999
Location: TX
Posts: 1,494
Re: Prep right before painting frame after sand blasting

Quote:
Originally Posted by projectking View Post
3 coats of SPI epoxy and the ability to get sockets onto painted fasteners gets my vote but it does look nice with the por on it
I do the same. SPI Epoxy. I usually only do 2 coats because it builds up pretty thick.
Jason Banks is offline   Reply With Quote
Old 10-16-2018, 11:02 PM   #19
Red71gmc
Registered User
 
Join Date: Jan 2017
Location: Brookston, In
Posts: 482
Re: Prep right before painting frame after sand blasting

I'm confused and have done this for years. Etching gives you a bite onto any metal as said.
Sandblasting is the mother of all etching. I believe it's the rough surface after sandblasting that gives this.
I would like to hear from those that have done both. I have and sandblasting is a mechanical way or creating a etch. If I'm all wet then I would like to know why? I will always look at different points of view.
Red71gmc is offline   Reply With Quote
Old 10-17-2018, 01:12 PM   #20
HO455
Post Whore
 
HO455's Avatar
 
Join Date: Feb 2016
Location: Portland Oregon
Posts: 10,783
Re: Prep right before painting frame after sand blasting

Your not all wet. If your doing the sandblasting and know your grits then all is well. The problem can come from the wrong grit or worn out grit causing the metal surface to resemble a bead blasted surface instead of a sharp toothy surface. So if you are unsure of the surface quality then the acid prep ensures good paint adhesion. There also commercial tests for metal surfaces to ensure that the metal has the correct properties for the paint to adhere.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help.
RIP Bob Parks.
1967 Burban the WMB,1991 S(stink)-10 Blazer,1969 GTO, 1970 Javelin, 1952 F2 Ford 4X4, 29 Model A, 72 Firebird. 85 Alfa Romeo
If it breaks I didn't want it in the first place
The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377
HO455 is offline   Reply With Quote
Old 10-17-2018, 05:46 PM   #21
oldchevynut
Registered User
 
Join Date: Dec 2013
Location: northwestern PA
Posts: 54
Re: Prep right before painting frame after sand blasting

I have never used POR-15, but I have used Masterseries coatings extensively due to it's better reputation as stated above, and to the best of my knowledge they are similar products with similar prep requirements. The blasting does leave a surface with plenty of profile or "tooth" for the coating to adhere to. However, if the sandblasting has been done with sand, there is a lot of free silica from the sand embedded in the metal, creating adhesion problems for the coating. The cure is to treat with metal prep to remove the silica. For that reason I have switched to crushed glass for blasting, as it supposedly does not leave any silica embedded in the metal, eliminating the metal prep step. So far, so good. Only time will tell. Randy
oldchevynut is offline   Reply With Quote
Old 10-17-2018, 06:11 PM   #22
Snake72
Registered User
 
Snake72's Avatar
 
Join Date: Jan 2017
Location: Iowa
Posts: 239
Re: Prep right before painting frame after sand blasting

I blasted my frame with Black Blast from Menards, no silica dust to inhale or get embedded into frame and works very well. Left the frame with a lot of sharp "tooth" and grit to adhere to. Blew off the frame with filtered compressed air and coated with POR. I did not acid etch. POR went on great and I cant even scatch it. So far no adhesion or peeling with assembly of the truck. Did not top coat either but wish I would have while tacky just for extra insurance. Time will tell...
Snake72 is offline   Reply With Quote
Old 10-17-2018, 10:27 PM   #23
Slowguy
Senior Member
 
Join Date: Aug 2017
Location: Chicago,il
Posts: 356
Re: Prep right before painting frame after sand blasting

I can tell from test spots that most stuff does not adhere to por15. So I decided to order and try the high build primer. They claim it will bond great to fully cured por and allow a top coat of just about anything. Still have to decide on the actual final top coat. I used por15’s top coat satin black on a few other parts and I do not like it. It is difficult, at least for me, to get a consistent finish. It’s either satin or completely flat. That’s why I figured use the tie coat and finish off with something easier to spray. Anyone have a top coat suggestion that’s easy to spray? I’d like a strong, satin black finish.
Slowguy is offline   Reply With Quote
Old 10-17-2018, 10:32 PM   #24
Slowguy
Senior Member
 
Join Date: Aug 2017
Location: Chicago,il
Posts: 356
Re: Prep right before painting frame after sand blasting

Quote:
Originally Posted by Snake72 View Post
I blasted my frame with Black Blast from Menards, no silica dust to inhale or get embedded into frame and works very well. Left the frame with a lot of sharp "tooth" and grit to adhere to. Blew off the frame with filtered compressed air and coated with POR. I did not acid etch. POR went on great and I cant even scatch it. So far no adhesion or peeling with assembly of the truck. Did not top coat either but wish I would have while tacky just for extra insurance. Time will tell...
I was thinking about the black blast (coal slag) from menards also but the amount I used would have been very expensive. I didn’t get much dust (if at all) since I used a wet blast method. I’ve used the slag in my cabinet before and it worked well. The silica actually put a perfect finish for coating and I wonder if much could have embedded in the metal since it was done with very high pressure water as well?

As you can see from the pic above, it cleaned the cross member somwell it looks almost white like it was painted. That is actually the 50 year old steel perfectly cleaned and acid etched.
Slowguy is offline   Reply With Quote
Old 10-18-2018, 08:48 AM   #25
zicc1835
Senior Member
 
zicc1835's Avatar
 
Join Date: Mar 2011
Location: Hanover NJ
Posts: 4,104
Re: Prep right before painting frame after sand blasting

Quote:
Originally Posted by Slowguy View Post
I can tell from test spots that most stuff does not adhere to por15. So I decided to order and try the high build primer. They claim it will bond great to fully cured por and allow a top coat of just about anything. Still have to decide on the actual final top coat. I used por15’s top coat satin black on a few other parts and I do not like it. It is difficult, at least for me, to get a consistent finish. It’s either satin or completely flat. That’s why I figured use the tie coat and finish off with something easier to spray. Anyone have a top coat suggestion that’s easy to spray? I’d like a strong, satin black finish.
Eastwood chassis satin black was my top coat choice after, blasting /epoxy primer/ slick sand to get the deep pitting out from the rust another coat of epoxy and then eastwoods satin black lots of slick sand left on floor lots of work got the results i wanted..more in my Kim and Doc build thread..........have fun
Attached Images
     
zicc1835 is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:21 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com