Paint Problems on plastic housing

challenger150 says "the paint has markings of foam which was used to protect this casing and the paint itself." And asks; How can I package the product better?

First thing I thought was; Is all the coating atop the ABS plastic not fully cured or finished drying."

Do we fail a 100 wipe MEK? Sure that will happen. How do we check for cure on ABS coated substrates having 4 layers of paint, 2 layers of lacquering, with sanding, and polishing between layers?

Does not sound like an adhesion problem. So the above may not have much to do with marks in the coating during shipping. I don't think the ABS plastic has much to do with the problem either.

Oh Snap! Why not do 4 layers of paint, 2 layers of lacquering, with sanding, and polishing and waxing between layers on a steel, flexable plastics, wood, paper and glass substrates and play with hardness tests, scratch and pull tests, bending, and peel off a couple of square inches and chew it. Really. If it's chewy it's not cured. If it's brittle it's cured. Maybe. Understand what this coating is. You won't die. Lastly go to Radio Shack and purchase a $5 Cat No 63-851 30X Illumnated Microscope and 8x magnifer and look at the coating. What can be seen at the exposed edges?

Materials used are PPG paint, 3M polishing/waxing care products and PPG lacquers. Call tech support.

Can all these layers be force dried? That would eliminate the soft and hard to protect coating during shipping IMHO.

I have to think about that waxing business.

I cured the silk screen imprints for H.O. and N gauge Model Rail Road Rolling stock for a fellow. Made an table top electric forced air conveyorized oven. Just thinking out loud.

Can another coating be used? Say a no temperature UV light cured coating like on bowling pins? I used this set-up for high end furniture on Italian $15k to $22k dining room tables. This works well if the 'pigments' are not real 'heavy or deep in color'. Think tints. I see deep red colors on this product. I don't know. Bowling pins have red stripes.

I need to study up on PPG products and what is in them and how to harden these up. I'm thinking formulas used on automobile finishes. They have hardners.

Looking at the attachements [not the big pics under the post] is this furniture? Big heavy pieces?

Begs the question. The part goes out, comes back, and it is 'sanded off and resprayed?'

skip.

Last edited by skip (01/13/2010 - 05:46 PM)

challenger150. Had not expected to hear from you this soon. I assumed that you were an American working within one of our 50 states. I shall redouble my efforts to write in proper English. I shall not be so 'flip' by using phrases like 'IMHO'.

Challenger150 says, "I don't know what means: 100 wipe MEK, IMHO, 'H.O', 'N', gauge, chewy, brittle... I'm really sorry but when I was studying English, my main points were business terminology, not technical."

Those abbreviations are--> MEK is methyl ethyl ketone. MEK softens and dissolves almost anything. More so if some of the solvents in the paint have not been driven out during the forced cure in an oven or over time at ambient temperatures through evaporation when the paint/coating is drying.

Uncured coating are soft and I was thinking that your packaging was imprinting itself into your uncured, and soft paint. This I think is the problem. Not the packaging. Let me continue...

A un-cured coating when wiped with a cotton swab dipped in MEK will deposit the color of the coating onto the cotton swab. If the swab picks-up the color of the coating this is one way to determine if a coating is cured, cured means to have the solvents in the coating have been driven out of the paint and the binder's used in the paint have chemically cross linked. MEK will not pick up color from a cured coating with just 100 double wipes of a cotton tipped swab. And cured coatings will not be imprinted by packaging materials.

IMHO is In My Honest Opinion.

H.O. is the size gauge of toy model railroads. N is even a smaller size gauge of toy model railroads. [See pictures]

Chewy is like bubble gum. Very flexable. Not quite a fully cured coating. Easily imprinted with packaging materials.

Brittle is like glass and shatters into many pieces. This would be a fully cured coating, I'm thinking. Now!! A fully cured coating CAN have elasticises in the coating formula that allow 'flexing' on ABS products.

I still think that you will not have a packaging problem with a fully cured and hard coating.

1~Devise a test to assure full cure. A bend test, an impact test, a scratch and tape and then pull test. See what coating/paint sticks to the sticky part of the tape. Reverse bend, does the coating/paint come off the ABS?

2~Test the coating and the packaging. [You are doing just that right now with with different packaging materials and stacking with 100 kilo weight] Take two ABS small test pieces and paint them normally. Put one in an oven at the maximum Degree C. temperature that ABS can handle. Over bake it, say 180 minutes? And the other let dry for a few days. Look for differences. Package both normally and press with 100 kilo on both for two days. WHICH ONE SHOWS PACKAGING MARKS?

3~Test to see if the packaging leaves marks or imprints on non-painted ABS plastic after wrapping, and compressing un-painted substrates of ABS together with 100 kilo. No marks mean the coating is not cured or finished drying. And marks would mean what? That the bare ABS is too soft to not be marked by the packaging. Then and only then would the problem truley be the packaging.

What else could it be? There is no other answer that I can think of. Anybody else care to join in on solving this problem?

Let me know if you are making any good progress.

Akzo Nobel BV makes a 'Soft Touch Paint' that is sprayed onto hard plastic automotive dashboard facades that is soft to the human touch and self healing. One can imprint their finger nail into the cured paint and within a few days the finger nail imprint can no longer be seen.

I built a paintline for Windsor Plastics Products and they used Akzo Soft Touch on Ford F-Series Pick-up Trucks, Thunderbirds, Mustangs, as an example.

skip.

Two Pictures:

1~ First one is of 'N" guage railroad.

2~Second is of 'H.O.' guage railroad

Last edited by skip (01/18/2010 - 08:10 PM)

Dear Skip,

I really don't know what to say than WOW!!! If I were a girl, I would marry you :-) I was around several foil manufacturers for past week. I've seen more
than 1000 variations of different foil protectors and so on.

Regarding what you wrote, I completely agree with you. When the housing dries, its still soft and a package leaves the markings. Maybe that's why those guys from PPG told us its necessary to wait for 1 month to get the paint dry. Your questions and ideas are extremly logical and helpful. I mean, they explain many things in logical way. Regarding your question No.3, nothing happens with ABS when its not painted. Those casings you saw on photo were designed to hold a weight of 200 Kg and whenever we transport them, we stack them one on another (since we don't have such big mould injection machine, so we rent one) and each casing comes normal before sanding.

Regarding the paint, I was also thinking that there is maybe MEK (we call it Nitro, a transparent liquid which practically dissolves everything). Since I have more than 700 such devices now which are painted, we are looking for a solution to ship them as they are and to find the reason why is this happening. What is interesting is that after polishing, when devices come after 30 day transport, those markings don't happen.

I will defenetly make those tests you told me this week and report to you so you know what is happening. I really hope this could be the solution so I don't need to break my head any more :-)

By the way, the railway which you made is beautiful. How long did it took you to make it?