Powdercoating vs Primer and Paint

[meadowbrook]

Hi, I am restoring my old Triumph but I think this topic applies here. I had the frame blasted and primed and then applied a product called POR15 Hard nose.

 

It claims to be tough but I did notice it does chip when I drop a tool on it (not intentionally )

 

Would powdercoating be any better? I really rather not do it, but the thought of building the car up on a less than durable chassis coating bugs me.

 

Maybe I am being OCD about this. I try to make myself feel better by imagining that with powdercoat, a chip would allow water to get in between the powdercoat and the metal whereas the paint would just chip and the rust would be at the exposed area only.

 

Any thoughts/ experiences?

[greg g]

Powder coating has no mechanical, or chemical bonding to what it is applied to.  this works fine if you assume there will never be a nick or a scratch in the surrface.  If you get a nick, chip, or scratch in the finish that goes through to metal, you have a problem.  Moisture will get in and bet between the coating and the object, pretty soon you will have large areas of Powder bubbling off the metal.  When the bubble comes off you have 0 protection of the metal.  I can take pictures of powder coated stuff that has failed.  I have a coupleof pieces of snow removal equipment that the PC has just about dissapeared from.  Here in the North east the probelm is accelerated because of the amount of salt used on the roads.  Snow blowers and lawn tractors that are put to work clearing the salty snow plow slurry at the end of the driveway don't stand a chance.  Paint and primer is repairable, Powder Coating is not.  YOur choice, but if you are going to subject the powder coated stuff to nicks, chips and scratches, it would not be my first choice.

[dale]

Id do the frame in urethane

[Eneto-55]

I worked in powder coating for a few years, and I agree with what Greg says above.  I would favor a good primer & top coat.  While I was wotking there, I powder coated a hitch I had made for my Chrysler T & C.  The paint bubbled & then came off in huge flakes, exposing major rust underneath.  It wasn't sand blasted before painting, & I know that would have helped, but powder doesn't flow easily into corners, so that's usually where you will see the first rust, unless it is chipped someplace.

[RodFru2u]

Bought a Gallon of Gloss Black Rustoleum, Had the two 12 year old nephews scrape, prime and paint the entire frame of our MG. That was 15 yeas ago, These Little British Cars leak ( mark their spots) so much oil, no chance for rust to form. I have see some bad results years after the awards are won. Cheers, Rod

[Don Jordan]

my 2¢ - I had my wheels PC - it's expensive and doesn't come in all colors.  But it looks good.

[Feudin_Wagon]

My brother does professional restorations on classic British bikes. He has had numerous Triumphs, Nortons, BSA's, etc, and even a Velocette Thruxton featured in calenders, museums and shows. He also built a '66 Triumph chopper for a customer that has been featured in Easyriders, and won numerous large show awards. We visited the National Motorcycle Museum in Anamosa a few years back, and it amused me that we would be walking along and he would say "built that one" every once in awhile. He does all the painting, striping, etc, himself as well.

 

Just saying that I think he knows his stuff. He uses powder coat only on every restoration or custom. That being said, there is a skill to putting on powder coat, and it took him a few years of trying different shops until he found one he is satisfied with. He's been using the latest shop for probably 8 or 9 years now. 

[dpollo]

Twenty years ago, I sprayed POR 15 onto a 51 Plymouth body's underside.  I had the body redi stripped so it was perfectly clean.

The body was supported on the rails of a single post  garage hoist.  After 20 years the POR 15 is still stuck to the hoist which is outside.  No surface prep at all !   It is still stuck to the car .  It remained on my hands for a long time too. Expensive but effective.

[meadowbrook]

Thanks for all the opinions. Since I already had the frame blasted, primed and coated, I will not undo it...I think. Sounds like pc is tougher but a chip may be more destructive. And like many topics, there is difference in opinions.

Here is anothe...what's the best oil? Just kidding...

[ROB-PA]

I used to race in the SCCA and was also a national Tech Inspector. After a fatal accident due to the problems noted (scratch yielding hidden corrosion) powder coating was banned on all critical parts; frames, suspension, etc. I doubt that the technology has progressed to the point that this has changed. I would never use powder coating on a frame.

[Eneto-55]

I think that the main convenience is for the manufacturer, not the end user.  There is no "drying time" - as soon as the parts are cool enough to handle, they can be taken off the line & packaged.  The appeal to the "consumer" is hyped up, because very few of the "little guys" can afford to do it in their own garage or shop.  Sure, it's hard paint, but my own opinion is that the disadvantages outweigh the advantages.  I was recently back in the shop where I used to work (doing powder coating), and I overheard one of the managers tell a customer (who was wanting an outdoor railing built) that "steel will always eventually rust", that she should strongly consider aluminum.  But powdercoating aluminum is tricky business, and it too will corrode when it is exposed, just not so obviously.

[jeffsunzeri]

The three generally available types of coatings you might use on your automotive project:

1. Urethane or acrylic paints with a variety of primers, including epoxy primers and conversion primers (POR, etc.)

2. Powder Coat, baked on thermoplastic or polymer over material prepared by media blasting.

3. Polyurethane paints over an epoxy primer, applied essentially as urethane or acrylic paints.

Type 1 coatings are generally the least abrasion and impact resistant, and lest corrosion resistant.

Type 2 coating are generally the most impact resistant and are significantly thicker in cross section than other coatings.

Type 3 coatings are very impact and abrasion resistant, chemical resistant, potentially very flexible and are chemically bonded to their substrate.

Each coating has it's plusses and minuses.

Type 1 coatings are those used as a top coating on cars and trucks. Base/Clear, single color, candies, etc. all fall in here.

If you are restoring, you will not be using powder coating unless the original manufacturer did. Powder coating does the most irreversible damage of the three types of coating (similar to polishing and plating) to an original part. In production-class judging, powder coating will lose points. In the real world, powder coating (actually the media blasting mostly) damages original material. Powder coating processes are great, but a good deal of judgment must be leveraged in its use especially for long-term viability. Powder coated items are easily discerned from other coatings by its thickness and texture.

A properly applied polyurethane coating system is extremely durable and aesthetically pleasing. It must be applied by a well trained technician using proper equipment as the components are extremely toxic.

Edited March 25, 2016 by jeffsunzeri