Beginner paint question

[impala454]

I've seen a few threads on painting and getting high gloss piano black finishes, etc etc, but I just have a pretty basic MDF paint question. I have a simple 2-way design I built as my first DIY speaker project, and am ready to finish it. For the moment lets just say I don't have an air compressor or fancy spray gun. I also know it's a little weird but I'd like to paint it white and get kinda a candy shell looking finish. The main questions I have are:

1. Prep- What type of filler is good to fill any small gaps/cracks in MDF? I've heard people say plain old DAP is good, others say reg wood filler, etc.

2. What's the best way to seal it up so the edges & seams don't show? I've heard some have used bondo, some mention a "sanding sealer" (although I seem to be unable to see anything called "sanding sealer" at the store).

3. Do I need some kind of primer?

4. When I apply the finish, am I correct in thinking it should go, "sand, primer, sand, paint, sand, paint, sand, paint? or do I finish with a sanding and then some kind of sealer/lacquer/clearcoat?

5. This will be a "rattlecan" paint job, so if you guys can recommend brands widely available, say at home depot/lowe's that'd be great

I searched and saw other threads, but this speaker isn't going to any beauty contest, it was more of just a first project to get going on this stuff. I'm pretty simple minded as far as following directions, so something like "go here, buy this, and do this with it" is easy for me . Treat me like a dummy. Assume I have never in my life painted anything made of MDF.

[Astroguy]

I'm not very experienced, in fact I'm ALMOST finished with my first subwoofer project. I can give you a little input on what I've experienced:

1. I used a wood filler to fill in the small holes (like countersunk holes from screws). Just massage it in with your finger, allow to dry, then sand even.

2. I'm having hard time with concealing the seams. I'd say when you're gluing the joints together, make sure there's enough glue in there so it splooges out of the joints, then you can sand the glue down to be even with the mdf. If you still have joints after it's glued together, I found that applying some wood glue in the crack with the tip of a toothpick and then sanding it flat worked out OK.

3. Yes, you need a primer, or also called a wood sealer. MDF soaks up products like a sponge, so you need something to seal it up to the paint will stay on the surface and not absorb into the mdf. Many recommend shellac, you can get it at home depot.
http://www.zinsser.com/product_detail.asp?ProductID=31. Apply it on with a foam brush, you'll notice the first coat really soaks in there. The second coat not so much, and the third hardly at all. I used 3 coats and it worked out good, you can use a few more for peace of mind. Sand it smooth with 400 grit sandpaper when you're done sealing. Allow 24 hours between coats so each dries sufficiently.

4 & 5. Honestly, if this is your first job AND you're using a rattlecan, I'd stay away from the piano black finish...which is arguably the toughest finish to get right. I would step it down and attempt a satin black finish...I'm having a helluva time with this and can't imagine if I had attempted the piano black. Getting an even sheen with the spray cans is quite tough, and under certain lighting it will look blotchy and unprofessional. Piano black will show every single imperfection. Here's a walkthrough in case you're wondering what it entails:

https://www.diyaudio.com/forums/showthread.php?threadid=83141&highlight=piano+black

What I'm *attempting* to do is 3 coats of satin black spray paint (lightly sanded with 400 grit in between), take your pick with the paint, stick with a reputable brand and you'll be OK , then finishing with 3 spray coats of Minwax satin polyurethane. I asked the same question on another forum and a few others gave me some input on the application. I'll let you know how it turns out in a few days. Here's the link:

http://www.avsforum.com/avs-vb/showthread.php?t=953242

An alternative, more foolproof finish that still looks good is spray on bed liner finish that you'd use for your truck. I know what you're thinking, but it's application is very forgiving and it will give your box a more professional, though industrial type of look. Here's another link of this finish:

http://www.avsforum.com/avs-vb/showthread.php?t=952907

If my satin finish doesn't work out, I'll be sanding it back off and going with the truck bed liner. Funny how I first was aiming for piano black, then stepped it down to satin, and may finally step it down to truck bed liner. Having the right tools to do the paint job is, apparently, quite essential

Hope this helps.

EDIT, oops just saw you're aiming for a candy shell white, that would probably be more forgiving than the piano black I'm sure as far as concealing blemishes. Maybe a semi-gloss white spray basecoat with a gloss polyurethane on top would look good?

[impala454]

Awesome thanks for the tips that's a huge help. Yeah I just meant "I've seen the threads about piano black finishes or 'advanced' finishes but just want to do a simple one."

[PMazz]

Biggest mistake I see when butt joints in MDF are used is the use of too much glue and not letting the glued joint properly dry before sanding. What happens is the raw MDF edge absorbs glue and swells in thickness. If sanded too soon, what seems like a flat joint will soon show the overlapped edge as the adjacent edge shrinks and stabilizes. That's one reason to do a mitered joint but they are a pain to do with the usual tools.

I use auto spot putty for small imperfections. Non water based products speed up production when filling/sanding.

[jj2stack]

For sealing MDF, Minwax's Sanding Sealer is pretty good stuff to work with. It can be found at wal-mart for about $10.00 a quart. I recommend about 3 coats with a sanding inbetween coats with 320 grit sandpaper. It also has a fast dry of about 2 hrs. For painting with spray cans, Krylons paints are pretty good. As advertised no runs, no sags, no errors! I do not recommend any water base acrylics of any kind.
For sealing ends, diluted titebondII is a good sealer. Use sponge brush/no streaks!

[impala454]

Awesome thanks for all the replies!

[impala454]

Here's how it turned out. This was my first DIY speaker project so I didn't expect an award winning finish. I think next time around I'll using even more of the sanding sealer, but it still did a pretty good job of hiding the seams. I may be weird but I gotta say I dig the white speaker . This was a slightly modified version of the TriTrix by Curt Campbell. Definitely a great, cheap, first project.

[NateTTU]

I'm looking at painting my speakers with a flat black paint and then follow up with a spray on poly coat. My question, has anyone used a HVLP paint sprayer like the ones you can rent from HD or Lowes?

[Jim Holtz]

I'm looking at painting my speakers with a flat black paint and then follow up with a spray on poly coat. My question, has anyone used a HVLP paint sprayer like the ones you can rent from HD or Lowes?

Hi Nate,

I haven't rented from them but I did buy a Wagner HVLP spray outfit from Lowes early on for about $100 and got pretty good results with it. I then moved on to an automotive gun which I currently use. The Wagner worked pretty well though.

Jim