collision repair and auto painting

[oliver.r]

Oliver,

Etching primer is used in exposed metal. That I understand. However when doing spot painting on an area of a panel, doesnt etching primer harm the surrounding paint because of its acidic characteristics?

Sent from the heavens

sounds possible but from experiance i have not seen any negative effects from it being on paint

[FLG]

I prefer epoxy primer over self etching. Southern polyurethanes makes some awesome products... Their epoxy primer completely seals the metal and does not breathe like normal primer and you can apply filler right on top. Which is great because the metal is completely sealed.

Take a look at their stuff. The waterborne wax and grease remover is great as well... Esp for plastic/rubber bumpers.

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[oliver.r]

I prefer epoxy primer over self etching. Southern polyurethanes makes some awesome products... Their epoxy primer completely seals the metal and does not breathe like normal primer and you can apply filler right on top. Which is great because the metal is completely sealed.

Take a look at their stuff. The waterborne wax and grease remover is great as well... Esp for plastic/rubber bumpers.

Sent from my Galaxy Nexus using Tapatalk 2

we cant use was and grease remover in california. bay area air quality sucks.
we use this thing called " bug and tar remover" witch is pretty much the same damn thing just renamed. loopholes

we tend to use epoxy primer on large surfaces and etching primer on areas were small bits of metal show. no real reason thats just how i've alwyas doen it haha

[FLG]

Even waterborne stuff? Imo it works much better than solvent based removers for prep.

If you get a chance take a look at their site.

http://www.southernpolyurethanes.com/

Great products and relatively inexpensive. Also really nice to deal with, and very helpful
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[bmwstephen]

Regardless, isnt the metal still susceptible to condensation and moisture permeability? The chemical characteristics of etching primer is that it contains zinc which forms a lethal defense on corrossion

Sent from the heavens

[oliver.r]

Even waterborne stuff? Imo it works much better than solvent based removers for prep.

If you get a chance take a look at their site.

http://www.southernpolyurethanes.com/

Great products and relatively inexpensive. Also really nice to deal with, and very helpful
Sent from my Galaxy Nexus using Tapatalk 2

thats pretty neat, for prep we use duponts sontara line of cleaners that are all water based.
we havent used degreaser type of stuff for about 3 or 4 years because of the VOC regs in CA

[bmwstephen]

oliver,

as I understand, primer sealer shares similar chemistry/characteristics as the primer albeit much thinner and is used for color uniformity prior to painting. That said, can primer sealer be used to touch up small exposed metal areas like edges and body lines for corrosion protection?

[oliver.r]

you could. you could even use spray paint, anything that creates a barrier between oxygen and the bare surface

[bmwstephen]

interesting... then let me ask you this. in your experience working with classic cars (pre-80's), I'm sure you've seen cars with bubbling paint and rust underneath.

if the logic of preventing oxygen by creating a barrier applies, why is it we see that problem on much older cars? was paint technology more pore-ish back then?

[FLG]

As a guy with a pre 80s car (73 charger) I'd say older cars weren't sealed as well leaving some exposed metal. Other factors is how they were stored for the past 40 years. Also a lot of times they were fixed or repainted but usually very poorly leaving that metal susceptible to rusting.

If you look at a well maintained un restored classic car (survivor) you'll be surprised to see very little in terms of rust.

Also climate plays the biggest part. I've shipped quarter panels and rockers from a charger that spent most of its life in a Arizona scrap yard... Some exposed metal too... And parts were faded but absolutely zero rust. But look at any NE cars and between the rain and salt they just don't last if there not taken care of.

Newer cars have a lot of seam sealer and undercoating. Whereas older cars undercoating for example was an option.

Also id imagine single stage might not protect as good as a bc/cc

But I'd say the biggest factors is where and how it was stored, if it's been fixed over the years and if that repair was done correctly and what climate it spent its life in.

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[oliver.r]

i completel agree.

i'd say the biggest facotr is corrosion protection, not really what is visible on the panel from the outside but all the sutff inside, seam sealer corrosion protection sprays in side the panels etc..

[bmwstephen]

Oliver,

I was looking over your prep work on your m3 and noticed areas like the door handle and rear quart window area where the trim goes on not being sanded to metal. In the primered pics, it looks like you primered around the area too





I notice this area seems to be left alone or scuffed in a lot of e30 resprays. Did you just not get around to that or was there a specific reason those areas were not as seriously prepped.

[oliver.r]

Oliver,

I was looking over your prep work on your m3 and noticed areas like the door handle and rear quart window area where the trim goes on not being sanded to metal. In the primered pics, it looks like you primered around the area too





I notice this area seems to be left alone or scuffed in a lot of e30 resprays. Did you just not get around to that or was there a specific reason those areas were not as seriously prepped.

good eye, those pictures were taken after the car was sanded with the D/A, on the stripping and with the block on the primer, they were taken down to bare metal on the pic were it got stripped aand hand sanded when in primer but it happend after the pics

[bmwstephen]

so just to be clear, were those areas taken care of after or before blocking the car? I'd imagine that if that area was stripped and primered after the blocking, it would be unleveled with the rest of the panel

[oliver.r]

so just to be clear, were those areas taken care of after or before blocking the car? I'd imagine that if that area was stripped and primered after the blocking, it would be unleveled with the rest of the panel

they were stripped before blocking, beofre primer.

when i sand a car i sand the big surface areas first, go back and sand all the tight odd areas then go back and repair any inperfections