A 'how to' for High Gloss Finishing

[Billyo]

Thanks for the replies everyone

Today I went to the hardware store and got a different primer - this one seems to be a thicker (they are both oil based - by the way) - its also twice as expensive @$10 per can and will barely cover 1 speaker to a couple of thin coats on top of the original cheaper stuff. This project has cost a motza so far! I've blown the estimated cost at least 2x with all of the little extra expenses and tools

I can definitely see how getting a compressor and gun can work out cheaper - unfortunately I dont really have the space or WAF for a hulking great barrel in my garage.

Will attempt for the 3rd time to get a pit-free primed surface tomorrow evening.

Alarmingly, some moisture got in when I was wet-n-drying the old primer and touched the MDF at a place where I went through the old stuff, and caused a swelling. I sanded it back, but its still quite visible, even under the new primer... I'm concerned that I've permanently blemished the MDF. Any tips for repairing this little patch? Will the MDF dry out and still be workable?

Digits - the idea of using a roller is intriguing - do I understand you right? You've not sprayed the primer, but rolled it on instead?

[digits]

primer and finish, some people paint cars this way with rustoleum...

http://www.club80-90.co.uk/pages/dow...ntfor%A350.pdf

[Renron]

Don't wet sand the primer! Primer is NOT sealer/topcoat, wetsand only after you have at least 3 coats of finish on top of the primer, be careful not to sand-thru the top coat. go slow, don't rush. post pictures of your progress and we'll stay interested and comment on your awesomeness.
Ron

[Billyo]

Originally Posted by Renron

Don't wet sand the primer!
Ron

So no need to get the primed surface perfect then? Given the orange peel from the color that will be going on, it did seem to be unnecessary to get a pit free primed surface.

I was aiming for it pit free but wasnt going to polish - glad (in fact, overjoyed) that its not needed in the first place.

Taking a week off with the family and going to Cairns - will continue on when I get back...

[Renron]

"Don't Wet sand the primer"
It Should be prepped properly, sanded smooth, but not WET sanded. No need to be a perfectionist about it, but no orange peel either.
Sorry,
Ron

[ptwining]

Just a quick note. I have painted a few cabinets in the past, to very unsatisfactory results. I have now followed Shinobiwans method and have a primer layer on MDF - from spray cans - (taken from 400 to 1000 grit by hand wet-sanding) that reflects.

That's not important in itself but I have to say that pure common-sense and elbow-grease yields fantastic results. I am not finished, nor have I even applied a color-coat but I have to say that Shinobiwan's method is magnificent. Perhaps I will fail on the piano-black but so far it looks great. We'll see...

I understood that he said that the foundation is everything, but maybe I took it too far. I couldn’t help it.

I sealed my MDF cabinets with alcohol based sanding sealer, then sprayed them with a million-dollars worth of Krylon spray black primer and then sanded them down by hand. It has taken two weeks but the result is amazing.

I started by using my sander but since spray cans put such a weak layer down each time I wound up re-spraying until I covered the burn-thru that each sanding session exposed. I do have a compressor and a gun but I was egotistical and thought I'd do just as well with cans - not. However, I am committed now and have carried thru with the method I started with.

I have learned that I want to hand wet sand the whole process (takes more time up front but results in less re-spray time because you take off less material each time) and I also enjoy it. I used a Makita, like Shin, but I have found that hand-sanding takes less paint off each time. Saves time in the end if you actually hand-sand it. Maybe because I have a testosterone-heavy sander. :-)

The next cab I paint will take *far* less time.

No wonder people charge so much money for this finish - it is all about labor and time dollars.

I will post pictures when and *if* (failure is still a very real option) I achieve a good final finish but I have to say that I have never before had a *primed* surface that has been glass-smooth and reflective.

Even if the primed surface is imperfect in many ways it still reflects the world and I have never before had that happen. It is a result of pure labor and common sense method.

I may yet fail and have a less than excellent result but I have learned so much in the process. If this method does fail, then I will step up the process and try with better tools - but - if I succeed it'll be a pretty cool lo-tech solution. Hi-labor, lo-tech, wicked finish.

I am foolishly hopefull.

Thank you Shinobiwan, many times. Live long and prosper.

Best Regards,
Tom

[GM]

1000 grit primer finish?! Hope the topcoat can bond properly to it.

GM

[ptwining]

Oh, oh, did I mess up?

I was hoping the better the foundation the better the top-coat.

I am new at this tho.

Primer too smooth is no good?

Best Tom

[GM]

Well, the top coat manufacturer should have some instructions WRT prep work and I previously noted I haven't shot a show car quality finish in decades now, but historically a topcoat requires 'X' amount of surface area to bond to and all the fine scratches of 400 grit [600 max depending on primer] adds a considerable amount. Also, at some point the primer's structural integrity breaks down to the point where the topcoat has to etch it to bond to it and why wet sanding it is not a good plan unless shooting epoxy or similar.

As I found out today WRT the various exterior primers/top coatings, etc., there's been a tremendous change in coatings for various reasons since I last got serious about house rehab ~34 yrs ago and not all IMO are overall for the better, but gov'ts. and the self righteous are determined to protect us from ourselves no matter the cost, so looking forward to seeing how yours turn out.

At this point, scoping out what, if any, top coatings are designed for such a smooth prep job and/or what precautions and/or intermediate sealer may be required to ensure a beautiful, durable finish using whatever top coating you prefer seems a good plan. Sure would be a shame to see all that time/effort be for naught if my ancient experience is still valid.

GM

[Renron]

Originally Posted by Renron

"Don't Wet sand the primer"
It Should be prepped properly, sanded smooth, but not WET sanded. No need to be a perfectionist about it, but no orange peel either.
Sorry,
Ron

Primer is NOT waterproof, RTFM. Automobile primer, which is meant to be applied to metal does not swell like MDF. Your pressing your luck if you wet sand primer over MDF.

1000 grit? Why? More is not always better.
Ron