[Early B.]

[WARNING -- the professional paint guys here on AC should consider bailing on this thread now before it's too late...]

I want to "refinish" my servo subs. I painted them black using Duratex many years ago. The problem is -- Duratex loves to capture dust, and they're hard to clean. Plus, they excel at looking lackluster. I'm OK with the texture, but I'd like to add a clear coat (???) so they're easier to clean. But before you guys throw out some suggestions, here are the parameters:

1. I know nothing about paint, so keep it Home Depot-friendly.
2. I want a solution that doesn't require a lot of time or skill.
3. I have no interest in making them look perfect.
4. They have to be done "in sito." I ain't gonna break my back and try to move those subs. We'll endure the indoor paint odor, but it can't be too strong. I figure the odor will be no different than repainting the interior walls of a room while you're living in the house.

I realize what I'm asking borders on being ridiculous, and that's why I haven't done it. Nevertheless, I'm interested in exploring the possibilities. My 2-channel system is in the family room; everyone who visits my home sees the subs, so please help me make them look "sub-perb."   

This is a really old photo, but you can get a good idea of what they look like:

 

[WGH]

A water based satin polyurethane varnish applied with a foam brush might work. No smell, tough, dries in an hour, no cleanup.

Any brand will work, pick the cheapest.

Of course testing in a hidden area is always recommended. Since Duratex is water resistant a water based varnish may just bead up and roll off without sticking.

A couple of coats of Minwax paste wax buffed to a soft luster may work just as well.

[nlitworld]

Lol, EarlyB no judgements here. WGH has a good point with a water based polyurethane. Won't be perfect as perfect can be, but it'll suit your purpose well. Test in small area is always a good idea. Make sure you scuff down the surface with some gray scotchbrite pads (3M 37448) to get some good adhesion and wipe down with probably 99% isopropyl alcohol prior clearcoating. Should be good when youre all said and done.

[Early B.]

Aw, man -- this will be easier than I expected! The scotchbrite pads have been ordered, and I already have some water-based poly. Two questions:

1. After 10-15 years, the cabinets could use a coating of black stain prior to applying clear poly. Lots of scratches on the top plate, in particular. I'm assuming to apply a water-based black stain?? Any prep suggestions?

2. The remaining poly I have is old (no idea how old). Does this stuff go bad after a few years? Should I discard it and purchase a fresh pint? 

[NXSTUDIO-DRUMMER]

Early B,

A product I've used for years on Duratex PA cabinets, is Armor All.
Spray on wipe off. It puts back the color depth of the black finish. Basically, any finish you put on the cabinet eventually will develop dust again.
Another product I use is Pledge, it also works great!

I understand not wanting to do a lot of work, believe me. Think about the size of huge PA cabinets.
Like you, me or band members have no interest in refinishing PA cabinets. This is a great alternative as well.

Good Luck!

[fishboat]

A word to the wise.. if you apply any wax, armor all, or pledge to that surface, you can forget about coating it with any clear topcoat. There's nothing wrong with using these products to get things looking very black, but only if you're not going to apply a clear topcoat later.

I doubt a black stain will make scratches disappear, like, I assume, you want them to. Black paint might be better. I believe Danny has mentioned paint over Duratex works fine.

If it were me..

Wipe the subs down good with alcohol and a clean rag(s).

then..

I'd scuff them up with a scotch pad. (don't scuff them right away as this drives contaminants into the finish)

Find a scrap piece of wood and apply a couple coats of the paint I planned to use. Let it dry thoroughly..a few days to a week. If you rush putting a clear coat on a color coat then you may have issues.**  Then apply the topcoat I planned to use..a couple coats.. and see what happens.  If the paint & topcoat are not compatible, or you didn't let the color coat cure well enough,  you'll know.  Much better to find out on a scrap piece of wood than create a large mess on the subs.

If things on the scrap look good, then do the same to the subs.

Find out what kind of paint Danny used over Duratex. Stick to the same type of paint for the color coat and topcoat. If you use a waterbased polyurethane for the color, use a waterbased polyurethane clear coat.

You'll need more than a pint to cover the subs with either a color coat or top coat. The rough surface = lots of surface area.  You might make it with a pint..but I doubt it.. it's not good to run out partially the way through.  If nothing else..buy two pints of each and return the unopened pint if you don't need it.

I've never had great luck with foam brushes. It seems everytime I use them on a variety of finishes they get soft after a 15 minutes and are a pain to use.  If they lose their "backbone" they don't spread a finish well.  On the subs..you might consider a 4 inch roller for textured surfaces. It'll be much faster and you'll get a better looking surface. Have a shop light handy as you paint to get an angled reflection on the wet paint surface to make sure you're getting an even application.

(** You can put topcoats on top of color coats very quickly if the paints were designed for it.  Automotive paints are a pleasure to work with..fats dry..you can use vinyl striping tapes on them in 30-40 minutes. Recoat in 20 minutes.  The waterbased lacquers I'm using on the current Super V build are also production-type finishes..fast dry, fast recoat...  The downside of production paints are they're more pricey and it takes a little more knowledge/equipment/safety to use them.)

[Doublej]

For cleaning them you might try a lint roller. I don't know if it will work.

[Early B.]

I doubt a black stain will make scratches disappear, like, I assume, you want them to. Black paint might be better. I believe Danny has mentioned paint over Duratex works fine.

Oh, I just thought of something -- maybe I can use some leftover Duratex on the top plate and for touch-ups, in lieu of repainting them.

[goggle1824]

Would directed compressed air be effective at dusting them off?

[WGH]

Oh, I just thought of something -- maybe I can use some leftover Duratex on the top plate and for touch-ups, in lieu of repainting them.

   excellent idea

[WGH]

Would directed compressed air be effective at dusting them off?

Not really. An official tack rag works best, they are sold everywhere.

A light spray of compressed air after using a tack rag is OK if the piece has been sitting for a little while but the compressed air is also stirring up dust that will settle on a wet finish.

[Early B.]

On a related note, I have a third double trouble lying on its side in the middle of the other two subs. I ordered a set of 1/2" walnut panels for the sides to match the speakers. I'll poly them up once they arrive. Anyway, the question is -- how should I affix the panels to the sides? I don't want screws to be obvious, and I'm not sure if wood glue alone is strong enough to support the weight of the panels. Any ideas?     

[WGH]

Are the walnut panels solid wood? Solid wood cannot be attached to MDF. Well, it can but expect a disaster because solid wood moves with humidity changes and MDF doesn't.

The width will change but more importantly the the face and back side will have a different moisture content. During high humidity the face will expand, the back side will still have a low moisture content  resulted in a bow. The opposite will happen with low humidity and the face will cup. Varnish does not seal out moisture, it only slows down the process. A boat building epoxy like West brand applied to both sides of solid wood is 100% waterproof but expensive, messy and hard to apply.

Edge banded walnut plywood will work perfectly.

[Early B.]

Are the walnut panels solid wood? Solid wood cannot be attached to MDF. Well, it can but expect a disaster because solid wood moves with humidity changes and MDF doesn't.

Thanks for the warning. Is there some sort of material that can be sandwiched between MDF and solid wood to mitigate this issue?   

[WGH]

No. How big is the panel?

The tried and true method to deal with solid wood panels is the frame-and-panel design, like in kitchen cabinet doors. The cabinet door panels in my kitchen are 7/16" solid wood but the panels fit into a frame that allows the wood to move. Each panel is one plank wide, there are no glue lines and every panel is from one single tree that was flitch cut. I designed and made my kitchen.

[Early B.]

No. How big is the panel?

The panels are 26"x14".

[WGH]

Yup, to big to glue on MDF. You will have to use them on another project.

[goggle1824]

On a related note, I have a third double trouble lying on its side in the middle of the other two subs. I ordered a set of 1/2" walnut panels for the sides to match the speakers. I'll poly them up once they arrive. Anyway, the question is -- how should I affix the panels to the sides? I don't want screws to be obvious, and I'm not sure if wood glue alone is strong enough to support the weight of the panels. Any ideas?   

Do you have a picture you could share of the current set-up?

This is probably a ridiculous idea but “an idea” none-the-less, I’m thinking of some way to “suspend or mount” the panels vs affix them to the mdf which would allow the panels to move a bit as needed vs flat out not being able to use them at all.

Things like a couple spots on the panel using a thin layer of blu tack in the corners and maybe two in the center area or even some 3m velcro dots (they are available in different velcro strengths Reg/Heavy Duty/Industrial etc.) to attach but float the panels to the mdf may be an effective option.

Probably not really a solution but just something I thought as I was reading the posts. 😅 😇

[fishboat]

Thanks for the warning. Is there some sort of material that can be sandwiched between MDF and solid wood to mitigate this issue?

What WGH is saying is true, but there may be a way to use the panels you ordered. 

If the panels are 26x14, (a photo would help) I'm assuming the grain of the wood is the 26 inch dimension.  There will be very little humidity caused expansion in the grain length...so little that you can pretty much ignore it. The grain width, 14 inches, is where some expansion will occur.  In 14 inches there will be very little expansion. As an example, I built my kitchen table.  It's 42 inches wide and 1.125 inch thick solid (curly) cherry.  I built breadboard ends on the table to accommodate the top width expansion.  Throughout the seasons(winter, forced air heating, very dry) the top expands and contracts about 3/16ths inch on each side.   So that's 3/8ths total expansion over 42 inches.

Now, if that 42 inch wide table top was glued cross-grained to the breadboard end on one side, and thereby inhibiting or stopping expansion on that side, but the other side of the top was allowed to move with the seasons, then that one side would have about 3/8ths movement over the seasons.  The top will expand and contract like normal, but only in one direction.

Ok..now for your 14 inch wide panel..we're looking at about 1/16th inch total potential expansion, or about 1/2 of an inch on each side.   If it were me, I'd apply a couple coats of finish to all six sides of the panel.  This keeps moisture entering and leaving all sides at about an equal rate.  Then I'd mount the panels on the mdf sub-box sides with a half dozen or so dime-sized dabs on RTV silicone(or pure silicone caulking..basically the same thing).  Apply the dabs to the wood panel (a couple inches from the edges so it doesn't squeeze out past the edges) and lay it RTV side up on the floor. Tilt the sub onto the panel and line it up the way you want it. Let it dry for a day. Then do the same on the opposite side. 

The RTV-silicone will hold the panel to the mdf box and, with RTV remaining flexible, will allow the wood panel to expand as needed. The wood will expand/contract, you won't stop it, but it won't crack.  I'd expect, if the panle was made correctly, you won't have any bowing issues..post a photo  of the ends and we can take a look.

[Early B.]

post a photo  of the ends and we can take a look.

The panels are being made now. I'll post pics once I receive them.

For the pro woodworkers, please refer to the first sentence of this thread and change "paint guys" to "woodworkers"... OK, having said that, I'm gonna do it anyway. The solid walnut panels will be purely decorative. The worst-case scenario is that the wood panels crack, and I need to remove them. No big deal.