[nkb93]

Hi all,

I'm getting ready to construct a box for the SW-12a / PR-12a combo.

I had a few quick noobie questions:

When using a wall damping material, such as No Rez, do you have to account for the volume that the foam occupies when constructing the box? 

As far as sound quality is concerned, is there a limit on how close the SW and PR can be placed to each other in the cabinet?  For example, I might haveto design the box such that the PR and SW are only about 2" apart on the front face of the box in order to fit where it needs to go.

The box will be MDF.  I'd like to finish it in black, something with a gentle texture (a little more texture than regular paint). Any recommendations?    Also, does anyone use any primer or sealant on MDF so that it doesn't soak up so much paint?

Thanks in advance for your help,
Nate

[Blaine_M]

You don't have to be concerned about the volume with the No Rez. 

Also there are plenty of spray on finishes that have a texture to them...check your local hardware store..and yes, you will have to use several coats of primer with the MDF. 

[Danny Richie]

You can also mount them any where you'd like in the box so long as the PR is mounted vertically (not firing up or down).

A trick I learned from Al Wooley about painting the boxes is that you can take some Elmers wood glue and mix it half with water. Then brush it onto the edges to seal them. Then when you spray primer or paint on it won't just keep soaking it up.

You can primer it, then hit it with bed spray liner, then paint it some more. That will hide the seams really well. It's a cheap finish too.

[mpauly]

A trick I learned from Al Wooley about painting the boxes is that you can take some Elmers wood glue and mix it half with water. Then brush it onto the edges to seal them. Then when you spray primer or paint on it won't just keep soaking it up.

You can primer it, then hit it with bed spray liner, then paint it some more. That will hide the seams really well. It's a cheap finish too.

Ditto the elmers glue concoction, it works well.  You only need to use it on the edges as the faces are already treated and don't soak up the paint nearly as much.  As for a textured paint, take a look at Hammerite (I forget the manufacturer).  It leaves a finish that looks a little like hammered metal and it's pretty durable. 

Whatever you decide to use, try it out on a couple pieces of scrap MDF first. 

Michael


Edit:  take a look at this timely thread....he used hammerite paint on the main body of his RAW HT3 and I kind of like the look http://www.audiocircle.com/index.php?topic=33187.msg294925;topicseen#new

Also see http://www.audiocircle.com/index.php?topic=28047.0

[RAW]

Adda few more of Danny's driver and PR's this will work also



Here is a few cabinets from the past with the textured bed liner.

Below are a few sub cabinets we did as well.


The spray is the easy part all the prep is were the time is put into.The devil is in the details as I say.
few pointers.
-Sand and fill I can not say this enough
- Seal with the water and glue mix as noted from Danny.This will seal the cabinet and not take as much material to put a finish on the cabinet.
-Fill then sand did i say that
This will get rid of the seam and only this way if you are looking at the textured paint to fill the seam it will not happen.Well it will with 3-4 cans.
You can do this small of cabinet with less tahn a can of textured paint ,yes less than $6.00 worth of the textured paint.BUT.
-you must prim the cabinet with a black paint first.We use a water bases black latex we get from Wal-Mart nothing fancy.At this point if you see a seam fill and sand that seam.Then re prime with the black latex paint.
-Once you are happy with the seams and filling were you need them and the cabinet has a few coats of primer on it.Sand the cabinet with 120 lightly just to make it smooth.Do not remove the black paint down to bare MDF.
-Last clean off the cabinet blow off with air if you have it if not get a light damp cloth and wipe off the cabinet.

- NOW the fun part.
shake up the can of textured paint.1-2 minutes and have a cloth handy.(MUST BE DONE IN A WELL VENTED AREA OR OUT SIDE)
Cover all the floor around the cabinet as the textured spray will spray 4-6ft and some cans I have had spray 8ft of over spray very easy.
-Stand back and spray from 2ft way yes 2ft all you are doing is putting the texture on the black paint.
We start from the bottom and let it dry for a few minutes then flip the cabinet over and spray from the top down.

Hope this helps you a little.

And remember SAND AND FILL.

All the best

[TomS]

OK, Al, I got it, fill then sand and then fill and sand some more, and again, and again,.....

But since the topic's open, I do have a few more noob MDF woodworking questions:

- what do you use as a surface sanding filler, say if you wanted a smooth flat painted satin finish?

- for circular and table saws, what kind of blade do you recommend for both rip and fine trimming 3/4 MDF?

Thanks,

Tom

[Daygloworange]

- what do you use as a surface sanding filler, say if you wanted a smooth flat painted satin finish?

If you mean filling the surface of the faces, you need to build up layers of primer/paint. That's where the fill/sand, fill/sand advice comes in. You need to build up layers in order to fill the porosity of the MDF. The edges are obviously the most problematic. People use different things, the glue/water trick is also known as "gluesize". But you can use wood filler, bondo, I've even heard of people using drywall compound. ( not recommended though )
But as far as the surface, just multiple layers of paint, and lotsa elbow grease. There aren't any shortcuts.

- for circular and table saws, what kind of blade do you recommend for both rip and fine trimming 3/4 MDF?

I'd say just a regular triple chip is fine, which are what is now a very popular all purpose blade. As long as it's not a combination, or ripping blade you'll be fine. Look for a blade with at least 80 teeth, or at least over 60.

Another tip for you would be that when you assemble the box, make sure the sharp edges ( the edge that's on top as you are cutting the board ) are facing the adjacent panels sharp edge when you make your butt joints. This will save you some time in the prep for paint stages.

Also, I would consider the advice to go with a hammered or textured finish if you are new to this. If you are trying to get a commercial type finish the first time out you might get frustrated at the amount of prep involved. Also the textured or hammered finish will not show any flaws that you might have missed and the joint lines that can take a while to appear.

Good luck and have fun,

Cheers

[nkb93]

Thanks everyone for the great advice!  I think since it's my first time out, I'll try the glue/water and hammered finish.

My SW/PR-12a came today, they're great looking pieces indeed (especially considering the price).  Can't wait to get started on this project.

-Nate

[Blaine_M]

I wouldn't be affraid to try veneer.........this was my first attempt and they turned out very nice..