Painting problem

B

B0B

Member
:confused: I picked up an original 1929 hood in good condition and of course needed to paint it ...I took it apart ,sanded it to bare metal...I had some cans of Krylon white primer so I sprayed a piece of scrap sheet metal with the white primer and then my acrylic lacquer color coat which is Arabian Sand acrylic lacquer paint to be sure they are compatible ...It worked GREAT ! So Then I primed the hood tops with the Krylon white primer and let them sit for a week in the cold garage while I sanded the sides ... Then I primed the two sides of the hood with the white primer and the next day heated the garage and sprayed the Arabian Sand color coat on all of the hood ...The Side panels look GREAT no problem BUT the two top panels that set for a week have developed wrinkling the primer is wrinkling under the Arabian Sand color coat ...The top panels are not wrinkled all over just two or three small areas about an inch in diameter on each one ...

My question is

What to do now ? Can I sand these wrinkles out with 400 grit wet or dry sandpaper (Wet of course ) and re-paint these spots ? or will the primer just wrinkle up again in those areas ? Any suggestions are greatly appreciated ...Thanks Everyone ! Bob in michigan
 
If you are going to use spray can primer move to a higher quality product, the local auto parts store that also has a autobody section ---one that also mixes paint for cars should have some higher quality primers in spray cans, or go mail order
http://www.autobodytoolmart.com/search/search.aspx?keywords=sem+primer&s_kwcid=TC|6058|SEM%20primer||S|e|7185280745&gclid=CPTLpKH9t6cCFcTb4AodhEy9_Q

If you really want to keep going with what you have try light coats, don't try to do it all in 1 coat ---just remember that with paint the first layer is most important, and any problems in the first coat will eventually rise to the surface.
 
Without "being there" to see each step it's hard to pinpoint the exact problem.
My first thought is that you might have primered over some traces of poorly adhered old paint, or maybe a spot where the old paint is feathered very thin.
If you indeed took it to "bare metal" completely, perhaps it wasn't sufficiently clean and the primer bridged some contaminated areas like finger print grease. Did you metal etch? Did you use final wipe just before the topcoat then dry with a totally clean rag while the solvent was still wet? Did you push hard with the tackrag..transfering beeswax to the finish?
Bottomline is...the mild primer (home consumer freindly) wasn't strong enough to lift the problem area...but the topcoat did.
You see as auto paint dries the solvent go DOWN to the base metal first then slowly climbs back out, releasing into the air as it cures. These stronger solvents will react with anything they don't like.
A sealer coat "may" have prevented this problem, but not for sure.
I would keep the hood in a warm area for a couple weeks and the problem areas should "settle down" as the solvents dissipate and the paint shrinks & tightens up. When the paint is cured rock hard you might wetsand and polish any remaining marks depending on how thick the topcoat is. Keep in mind when polishing that if you break through the topcoat it's all over.
For now I would concentrate on keeping it warm and just wait.
 
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I think the key here is the temperature of the shop. You said the hood top was in the cold garage. Paint does not dry well in cold, and many paints do not spray well or adhere well in cold. I would start over, but then I would never use rattle cans to do a restoration, so I don;t have the definite answer.
 
Thanks everyone for your suggestions ... I agree I should have used a better primer I was thinking that because my test panel was ok that it would work ok with the cheap primer on the hood ...The Krylon people say that you should topcoat within a short period OR wait until the primer has gotten completly cured which would surely take a long time in the cold garage It would have been ok if I had topcoated within a few hours ...I painted the two side panels right away the next morning and they painted just fine ...

At this point I am going to let the hood set until the paint is completely cured for weeks anyway ...Then sand the imperfections and re-coat with very light coats as you have suggested...

THANKS AGAIN ! BOB :)
 
I had this problem a year or so ago... I painted a set of roof irons, after a few mins one wrinkled. Sanding it down, repainted and once again same thing. After much :mad:@!~$#^%& and a few @!$%#!%:confused:.. I called a friend who has more expertise. Here is how I got it correct..

1. Sand down to smooth (almost bare) metal...
2. Ensure piece is warm (not shop but piece itself)-- possibly store inside over night.
3. Wipe down with Naphtha (can buy at Lowe's for $15 a gallon)
4. Allow completely to dry, then wait another 10 mins.
5. Spray a very light coat of primer and wait to flash over (almost dry but not quite). This usually happens in about 10 mins.
6. Repeat spraying a little heavier and waiting between coats.
7. Once you have good primer coat-- wait a good 20-30 minutes and final coat.

After 3 times and several sanding back down to almost metal, this is the only process that worked for me... not sure if it was the Naphtha to removed all oil-- the primer coating in a stepped process--- or the waiting the correct time... BUT one worked. I do wipe down anything I'm going to paint now with Naphtha about 20 minutes before I start, just a good way to get everything (dusk, oil, micro-rust,etc) off surface.

Good Luck, D:cool:
 
Thanks big-D good suggestion I am going to get some naptha ! You reminded me of a story my father told me he was a millwright (maintenance man) at the Bendix plant in South bend Indiana doing some welding and a spark flew from the arc welding and went right down the vent pipe on a huge naptha tank WHOOSH the naptha fumes caught fire and flames shot out of the vent ! Another employee grabbed my fathers coat and threw it over the vent pipe and snuffed out the blaze his coat was ruined but the fire was out and they were still alive! they nic-named my dad Sparky and it stuck ...B0B
 
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