Finishing advice needed...

[feetball]

So I am building a set of the mini-statements (Thanks Jim!) and am having trouble with my finish.

I'd like the finish to be piano black gloss.

I applied body filler to the cut edges and block sanded it smooth (so I thought). When I applied primer recently, It revealed the joints and a bunch of 60-grit sanding scratches in the non body-filled part of the mdf (couldn't even see or feel these scratches before. I checked.)

Can anyone recommend a product and process to get the edges hidden and scratches filled?

One option I was thinking of was to coat the side and top panels again with body filler and go about block sanding it again. I'd rather not do this ... I hate applying and sanding body filler. LoL.

Is there an easier way?


Has anyone had any success with applying a truck bed coating as a finish? I'm also considering this as a last resort.

Thanks in advance!!!

--Daniel

[Bill Schneider]

Bondo has its use, but there are better products for taking care of the small blemishes (sanding marks, scratches, etc.)

I have been using 3M Acryl Green spot putty for a couple of projects, and it's perfect for finish work.



It is much less viscous than body fillers, and fills the small stuff easily. After drying, it sands easily with a fine sandpaper.

But here's some bad news - if you have butt-joints, it will be very difficult to get rid of hair-thin joint lines in a paint job. I assume that MDF likes to expand a little differently "across grain" compared to "with grain" (anisotropic), causing lines to appear eventually.

I've made the seams completely invisible with putties and paints, only to have them reappear after a few days. I've tried very thick paint jobs in an effort to suppress the eventual reappearance of the joints, but that hasn't worked yet. I'm still searching for the magic bullet without having to resort to miter joints.

[Jim Holtz]

So I am building a set of the mini-statements (Thanks Jim!) and am having trouble with my finish.

I'd like the finish to be piano black gloss.

I applied body filler to the cut edges and block sanded it smooth (so I thought). When I applied primer recently, It revealed the joints and a bunch of 60-grit sanding scratches in the non body-filled part of the mdf (couldn't even see or feel these scratches before. I checked.)

Can anyone recommend a product and process to get the edges hidden and scratches filled?

One option I was thinking of was to coat the side and top panels again with body filler and go about block sanding it again. I'd rather not do this ... I hate applying and sanding body filler. LoL.

Is there an easier way?


Has anyone had any success with applying a truck bed coating as a finish? I'm also considering this as a last resort.

Thanks in advance!!!

--Daniel

Hi Daniel,

Gloss black finishes are very difficult to achieve professional quality results at home. As you're finding, surface preparation is critical to ending up with that glossy smooth piano black finish.

For light scratches and sanding marks, try lacquer putty or an epoxy equivalent from your local autobody supply store. You still have to sand it but it's easier than bondo. Once you've smoothed it start priming and sanding with progressively finer grit sandpaper until you hit 400-600 grit and the finish is glass smooth.

Now it's time to paint. If you're trying to "rattle can" it, plan on LOTS of coats with light sanding in between with 400-800 grit paper. I'm guessing it'll take at least 10 coats to get enough material build to do a final sanding at 1000, 1500 and 2000 grit before buffing the finish.

If you have access to professional spray equipment, it takes less coats of paint to get adequate film build but the work isn't significantly less. Another alternative is to haul them to a body shop and have them do the final prep work and paint them for you. Expensive but nice.

One other possibility I've thought of is to use the cheapest smooth finish veneer I could get, apply it and then stain it black. Then top it with your favorite clear finish. That would be way less work but wouldn't be quite as pretty.

Bottom line is, gloss black finishes are an incredible amount of work.

HTH

Jim

[chasw98]

Jim is right. It is really, really hard to get a great gloss black finish. I know, I tried. And it worked and they look great but it is a lot of work. Here is a thread on that other place that might get you started. Google gloss black piano finish and you will gets lots of how to. Just be prepared for a lot of work. Good luck.

Just so you know, in the end I bought a spray gun Jim had for sale and that had made life much easier. Thanks Jim! :T

[PoorboyMike]

I haven't used truck bed liner but I've used Duratex and really like it. You can go from mild to wild on the texture depending on how you apply it. You can also get a leather look using it. It's tough stuff and you don't need to prime the mdf before applying. Here is a couple pics of it applied with a smooth roller.





A gloss black laminate is another option that is much easier than trying to paint piano black.

[Jim Holtz]

Jim is right. It is really, really hard to get a great gloss black finish. I know, I tried. And it worked and they look great but it is a lot of work. Here is a thread on that other place that might get you started. Google gloss black piano finish and you will gets lots of how to. Just be prepared for a lot of work. Good luck.

Just so you know, in the end I bought a spray gun Jim had for sale and that had made life much easier. Thanks Jim! :T

You are welcome. I'm glad that it worked out for you. :T

Jim

[feetball]

Wow guys ... as I've noticed from lurking here you all always come through with the advice!!!

Thanks!

Bill, the spot putty sounds exactly like the stuff I need!!! Will check out the local body supply shop.
Regarding the butt joints, has anyone tried putting a crazy amount of body filler on top and then getting everything level?

Jim, I do have professional paint equipment and a "temporary" paint booth in my garage. This is all a first for me so maybe I shouldn't be trying the most difficult finish huh? ;-)

I wonder if a super thin vaneer could be applied to the top and sides of the cabinets to hide the butt joints and then painted and cleared? Would the edges of the vaneer look bad?

PoorboyMike that duratex sounds promising. Where can I get it?

Regarding the gloss black laminate, I already hit the front vertical edges of the baffle with a 1/2" round over bit. Would that be too thick to bend over a 1/2" radius corner?


Thanks again for all the advice gentlemen!!!

[feetball]

I assume this is the duratex stuff? http://www.acrytech.com/store.asp?pid=14119&catid=19771

[Vilbig]

Bondo has its use, but there are better products for taking care of the small blemishes (sanding marks, scratches, etc.)

I have been using 3M Acryl Green spot putty for a couple of projects, and it's perfect for finish work.



It is much less viscous than body fillers, and fills the small stuff easily. After drying, it sands easily with a fine sandpaper.

But here's some bad news - if you have butt-joints, it will be very difficult to get rid of hair-thin joint lines in a paint job. I assume that MDF likes to expand a little differently "across grain" compared to "with grain" (anisotropic), causing lines to appear eventually.

I've made the seams completely invisible with putties and paints, only to have them reappear after a few days. I've tried very thick paint jobs in an effort to suppress the eventual reappearance of the joints, but that hasn't worked yet. I'm still searching for the magic bullet without having to resort to miter joints.

Another vote for the green putty. This is something I rattle canned today - one coat only so far of Rustoleum Appliance Epoxy. Sorry for the camera phone pics.

[PoorboyMike]

I assume this is the duratex stuff? http://www.acrytech.com/store.asp?pid=14119&catid=19771

Yeah, that's the stuff.

Forgot about the roundover. Not sure if there are any laminates available that will bend around a radius like that. It would be nice if there was!

[Jim Holtz]

Jim, I do have professional paint equipment and a "temporary" paint booth in my garage. This is all a first for me so maybe I shouldn't be trying the most difficult finish huh? ;-)

I wonder if a super thin vaneer could be applied to the top and sides of the cabinets to hide the butt joints and then painted and cleared? Would the edges of the vaneer look bad?

I've started building my cabinets so I can put a piece of 1/8" thick MDF on the top (and bottom on a monitor) and back which hides all but the edge of the 3/4" front baffle. You do have to plan ahead to hide all of the joints that one typically has. With the thin MDF you end up with only a 1/8" edge to seal. It's MUCH easier. :T

I shoot waterbase Crystalac with an automotive gun and it works great. If you've not had much experience with a spraygun, practice 1st. You'll be glad you did. BTW, I highly recommend gloss black Crystalac. No fumes, lays down very nice, sands easy and buffs out great. It's great stuff. Check McFeelys.

HTH

Jim