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Discussion Starter · #1 ·
I primed my car with evercoat slicksand and didn't have enough primer to do the whole car. I started sanding and realized that i needed another coat on everything that had been done previously as well. My question is does it need to be sanded to reapply the primer? If it does, does it have to be completely smooth as there are lots of ripples and bumps on the surface which comes with using a polyester primer i guess. Thanks for the help!
 

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Brian Martin,Freelance adviser
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Sorry to tell you but it sure as heck needs to be sanded. The recoat window on that polyester primer is pretty short. When it kicks it is hard as a rock and MUST have a mechanical bond the chemical bond isn't going to work with it.

Just block it down with 120 and apply a good application (thick enough to block).

By the way, if you don't REALLY need some filling that is the wrong product to use.

Brian
 

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Discussion Starter · #3 ·
I was mainly using it as insurance to make sure all my body work was straight as an arrow. I know the roof wasn't for sure and a few other areas that i just couldn't straighten out with filler. I was going to use a 2k primer but only have a 1.4 tip or a 2.0 tip and i didn't figure either would work and still would have a few areas that need a little blocking, too much for a 2k i think?
 

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Slick sand might seem a little cheaper but trust me it isnt...its basicly thinner feather fill it also absorbs water like laquer primer and will crack on you,its not very flexable.I'd sand it almost down to nothing so it's only in the low spots(dry sand with 80 or 180 block)..SPI has some pretty good primers at a good deal that I use...Thier 2k is a high build as far as I'm concernd,they have a high build also but I've never had a need for it and never used it.the regular primer is more than good enough...I've use many types of primers at my shop and this is what i've found is best for me,it sands great too....Blocking SUCKS dont it? :sweat: :sweat:
 

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If you wet sand it ,water gets underneath and starts metal rusting causing it to loose adhesion, causing cracks and where it flexes(especially bumper covers) ,I used it a lot in the 70's pretty much everybody stopped using it ...slick sand I tried but its basicly the same thing,it dries rock hard and dont flex...MEK hardner (fiberglass hardner) in a little plastic tube...Right? if you still got a lot of it dry sand and use a sealer...but it sands hard and theres much better primers out there,even Nason 2k is much better for cars..We all thought it was good back then...and compared to laquer primer it was...
 

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Robbins Racing
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I was wondering the same thing about it cracking.... I have some bumpers about to get sealed/painted. Where was the weakness of it? Time, flexibility on bumpers, heat? I would like to know so I can do a torture test and see how well the bond holds. So far, I've treated some pieces like trash out in the elements and still maintained it's plasticity. But, I never went more than one coat without fully sanding with 320g.... Maybe layering it on wet coats with only 80g at the base material? I seek you're reasoning for it's demise so I can replicate it and finally find a good reason to trash it. Something about it hasn't sat right with me since I put it on, I just haven't discovered what it is....
 

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Problem Child,Hard Case
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It's REAL SIMPLE.
You BLOCK for the START and it gets EASIER as you go.
You have a LUMPY,UNEVEN surface to START with, You end up with one.
You don't fill waves and lows,You just make them BIGGER unless you KNOCK them down FIRST.
I've never cracked poly either,don't mean it can't happen but I figure it's either a serious hammer job or too much reduction and shrinkage.
I'll "agree" with DB here,
SAND DOWN what you HAVE as FLAT as you can and either poly and/or 2K it.
SPI rules. :thumbup:
 

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Problem Child,Hard Case
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I would NEVER use poly on PLASTIC, It's EPOXY and 2K. NO flex junk as epoxy and todays 2K's are good.
POLY is for glass,SMC,and METAL.BUT,OVER EPOXY,not bare metal or uck,acid etch.
Fact is, I use EPOXY,spi, before ANYTHING.
BEST initial product you can find.
2nd fact is,I use EPOXY almost exclusivly anymore. Todays spi epoxy is just in another world. Then it's Turbo 2K "if" I use a "primer".
 

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rcrobbins said:
I was wondering the same thing about it cracking.... I have some bumpers about to get sealed/painted. Where was the weakness of it? Time, flexibility on bumpers, heat? I would like to know so I can do a torture test and see how well the bond holds. So far, I've treated some pieces like trash out in the elements and still maintained it's plasticity. But, I never went more than one coat without fully sanding with 320g.... Maybe layering it on wet coats with only 80g at the base material? I seek you're reasoning for it's demise so I can replicate it and finally find a good reason to trash it. Something about it hasn't sat right with me since I put it on, I just haven't discovered what it is....
Ive found that a good way to tell about the 2k's i use is to leave some in the container after you mix your primer or clear to harden ,the more it pulls away from the edge and cracks when there is an inch or so left over tells how good it is or bad .If i remember right the slick sand and feather fill shrank very little but had no flexability at all,but the biggest draw back is it absorbed water like laquer does...We also shot it all at once then sanded but I think you'll find that if you sand it and THEN leave it out in the rain it'll start rusting pretty quickly..its very pourus mostly talck
 

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Does no-one here use plastic body filler ("bondo")? or does everyone here use lead, and primer?

"bondo" is a much thicker version of Polyester primer, Slick Sand, Finish Sand, FeatherFill, etc. It seems to hold up quite well. I've used Slick Sand in the past, with no problems, and will use it again.

To the OP, Block it down, and re-prime, with slick sand, if you want to.
Or you can use a urethane primer (2k), or even laquer. But in answer to your question, Yes it needs to be sanded. I would use either 80 or 100 grit.
Then follow with about 3 coats of what ever high build primer that you want.
Just remember to seal with epoxy prior to paint.
 

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I do ,I do :welcome: I also love SPI epoxy primer as a sealer. heres my system for a nice job ...Strip,Ospho etch,Spi epoxy,bondo ,polyester putty,(EZ sand) more epoxy ,sand, epoxy reduced 20%as a sealer, paint...SPI sands very well,no need for 2k primers any more...
 

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deadbodyman said:
I do ,I do :welcome: I also love SPI epoxy primer as a sealer. heres my system for a nice job ...Strip,Ospho etch,Spi epoxy,bondo ,polyester putty,(EZ sand) more epoxy ,sand, epoxy reduced 20%as a sealer, paint...SPI sands very well,no need for 2k primers any more...
What is this? SPI specifically says dont use epoxy over etch.
 

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I know....and when I asked Barry, why?,I've been doing it for years and it works fantastic...He said more people screw it up than use it properly,then they put the blame on the epoxy primer...It works pretty well without ospho and I also dont recomend doing it this way but I've been using it under all types of epoxy for over 25yrs ,very successfully and know how to use the stuff,if not done properly you'll have adheasion problems I've tried it both ways just to make sure (with and without)...my way is better,much better....but only the people that use it correctly believe me and I'm tired of people that would rather argue than try it....We are getting way of topic but the thread is nearing an end, so I'm just responding to your question,PM for any more. I'll be happy to answer questions about Ospho there...I'm a bodyman that swears by and uses both products not a salesman for SPI or Ospho, just tellin it like it is:thumbup:
 
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