Paint and refinishing

[PFitz]

7 hours ago, Frank DuVal said:

OK, I looked at SPI epoxy primer spec sheet, and I do not see where it is good for a build primer. Sounds just like the old DP epoxy from PPG.

 

Did you have failures with DPLF?

Started using the DP40 when it first came out. And continued right along using it when PPG switched it to DP40LF (lead free). Not one failure - including, I also use it as a primer for mufflers, tail pipes, and Franklin air cooled cylinders that run at 450-500 F surface temps.

 

I've had excellent results with PPG's tech line people and their color library folks. Plus their traveling tech session. Even picked up tips from their tech guys like how I can extend the temp rating of their urethanes to use on high heat engine parts and how to thin DP40 to work in weather conditions not covered in their literature.  I can't complaint about PPG's service and I've  been using them since back in the mid 1970's when they used the name Ditzler.  The first PPG Delstar paint job I ever did is still holding up fine. That was sprayed on in 1978.  

 

As for the ever increasing costs of automotive paints, you can thank government regs for that.  

 

Paul

[F&J]

1 hour ago, Janousek said:

Once dp40LF came along it was no longer sandable and would gum the paper.

 

I have been following your technical posts on primer paints, as I am merely a backyarder needing the ''straight scoop, with no lofty attitudes" , The above quote must be what I tried for the first time back around 1995-ish.  It was a PPG non-high build "epoxy primer" of a now forgotten part number.

 

Pre-internet, and I was told "you need epoxy" by locals.  I had the same results when I tried using it.  Info sheet said do not reduce.  It went on too thick, orange peel, not flowing at all, even on just the underfloor of a pickup truck cab that I did not have to rush.  I tried to sand it after a very long time, and it balled up badly like soft plastic. Horrible results for "me".   I NEVER used any epoxy again for 15 years, and then that type of PPG epoxy non-high build primer made me extremely ill, to the point of passing out, a half hour later.  I refused to go near it from then on, for health reasons, and not wanting to purchase/wear a space suit for such very small jobs.

 

 

I recently used a 2 part high build on just the nose of a vintage VW bug crash job.  I forget the name/type, it is a polyester?  Like thinned bondo?  It did not make me ill at all.  Sanded very well, excellent build thickness, flowed reasonably good.

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[PFitz]

PPG's DP epoxy primers were never meant to be sanded. If you read the PPG sheets of the DP series, both the original DP series and after the switch to LF, they refer to it as being a "subprimer" and a "sealer". It's just for increased adhesion of primer/surfacer, plastic fillers, top coats, and corrosion prevention.

 

As Frank DuVal said, it's intended to be used on cleaned, bare metal  before any fillers (both plastic and spot putty) are applied to increase their adhesion and protection of the bare metal. Just two wet coats. Then used again as a sealer over the fillers, after the fillers have been sanded, to prevent any moisture absorption problems with talc-filled fillers .  Then an approved sanding primer is used over it. The added benefit is the color change as you sand though to the subprimer shows you where you still have low spots needing additional filling, but you don't lose metal protection and risk rust when wet sanding.   It was never intended to be a sanding primer. It will clog paper quickly even when wet sanded.  For extreme shop temps you can thin the mixed DP series with up to 10% lacquer thinner to suit the temps - slow lacquer thinner for too hot a shop, and fast lacquer (AKA "wash thinners) for a cold shop down to 50 F. You won't find that on the DP data sheets, but that was as per a PPG tech on their 800 hot line, and it's worked very well for me for 25 years since the tech told me that.   

 

As for getting sick, some people are allergic to epoxies (me included), and should always wear an approved mask and nitrile gloves when working with any epoxy. .... including epoxy glues.  Plus, the severity of the allergic reaction can worsen with each repeated exposure.

 

Paul

Edited May 17, 2017 by PFitz (see edit history)

[Janousek]

The original DP40 would spray nice and be able to sand wet or dry pits in suspension parts and such without adding a 2k build primer to your suspension parts.  This is a nice way to do things as epoxy is more durable and less prone to chiping than 2k's.   One product not two.  We could no longer do this with DP40lf and it was important to us. We never had a failure but we dropped the lf after one car.  It was no longer a product we wanted.  The SPI epoxy is more versatile for me and better than I remember even the DP40 was.  Who knows, maybe the dp40lf would work for me now but I have a such a trust with SPI that I wouldn't use the lead free even if it was free.  

 

Some of the primers now are hybrids for fill and bare metal coverage.  They usually are urethane based.   I wouldn't use them personally but I know body shops do but thats a different ball game.  They need the most of speed and don't have time to spot prime bare metal with epoxies.   

 

Our local PPG dealer was the pits and now they are out of business.  I still have access to the Color library because I use their base.  

 

My recommendation for SPI is a solid choice for pros and hobbiest.  They put out a nice Tech manual, call the owner of the business for tech support 7 days a week,  2 full gallons of sprayable epoxy for $182.68 with free shipping, epoxy colors of grey,black,red oxide, white.   They also don't send out the letter once or twice a year with price increases like I get from local jobber.   I see RM won Pebble Beach with SPI products last year.  It's not mixed in a bath tub, and all the products I use are as good or better than the Dupont/PPG top shelf products.  Most of the time a lot better.   

 

I don't do generic body supplies nor do I buy tools that aren't american made.  I'm hard headed on what I use and I always try to use the best product for the job.  SPI has beyond met my expectations.

 

PPG bought our local bodyshop a paint booth when they signed a 3 or 5 year contract.  My Hershey buddy has a 30+ man shop and I could retire on his paint contract.  Regulations are one thing, but with SPI I'm not paying for someone else's contract, bass boat, nascar, sema booth, etc...   Stuff rolls down hill and small guys like me pay for this advertising.  

[Luv2Wrench]

I recommend SPI as well.   All focus there is on product and technique.   It is not often that you can call the guy that makes the products.  They have a system that will, if you follow it step by step, get a top quality finish with no screw-ups.