Sub finishing details...

[zzzz]

Hi everyone,

Some probably stupid questions regarding finishing up my sub. Have the wood cut and am wanting to start putting it together.

1. What kind of wood glue should I use. I picked up some bottles of "Elmers" wood glue. I'll use it with 3/4 in MDF and 2 in drywall screws every 5/6 inches.

2. I want a white lacquer finish. Would the following spray product produce a high quality finish to wow the wife?

http://img.epinions.com/images/opti/a1/7b/6666305020066190682.pre-resized200.jpg

3. Do I need to caulk the seams where the wood meets? Seems like the glue would do the trick. No big deal have caulk and can apply.

4. Is fill really necessary? I'd like to see how I get-on without using dampening material. Am I just being cheap and lazy or totally mad to consider going without?

Thanks all.

[jmb]

1. That glue should be fine. If you are going to use clamps in the glue up process, skip the screws. That will also make it a little easier to achieve the finish you want.

2. Should be fine. when you get enough coats on, rough up the finish and spray on 5-6 coats clear hi-gloss laquer.

3. Yes, you want to caulk all inside seams.

4. Fill is a very subjective issue. What type sub, sealed or ported?

Hope this helps and good luck.

[zzzz]

1. That glue should be fine. If you are going to use clamps in the glue up process, skip the screws. That will also make it a little easier to achieve the finish you want.

2. Should be fine. when you get enough coats on, rough up the finish and spray on 5-6 coats clear hi-gloss laquer.

3. Yes, you want to caulk all inside seams.

4. Fill is a very subjective issue. What type sub, sealed or ported?

Hope this helps and good luck.

Thanks JMB!

I'll go screwless then - make life easier!!!

Why would I rough up the lacquer finish - I presume you mean with some type of sandpaper?

How many coats of lacquer would I typically need? At $4 per can, I am hoping that I won't need too many cans. That could add up!

The sub is ported and it modeled very well with no fill (unibox diagrams here http://www.htguide.com/forum/showthr...t=26893&page=2 See post number 66).

[jmb]

I can't really give you the technical reason to rough up the white laquer, that is what the manufacturer recommends, and it hasn't hurt any of my projects to date.
Spray 2-3 coats of the white, just to get good coverage, then finish up with the clear.
You might also check with your local automotive parts store to see if they sell touch up paint. I bought a white pearl laquer from Pep boys that came out extremely nice.
Also with the sub being vented, you might want to just line the walls with an inch or two of polyfill, to help filter out any midrange.

[littlesaint]

Make sure the caulking is well cured before final assembly. Some caulking releases solvents as they cure which can weaken speaker surrounds.

[jmb]

One more bit of advice,

Brace that sucka. If nothing else some 1" dowel rods from side to side and top to bottom will help. And if you can, double up on the MDF for the baffle.

[engr_dave]

I want a white lacquer finish. Would the following spray product produce a high quality finish to wow the wife?

The spray can route can produce good results... but in my opinion, good surface prep (with a primer and some sanding) is a lot more important than a clear top coat. MDF and plywood both have very porous edges. If you spray finish directly on these, it will just soak up and look blotchy. A couple of coats of primer-surfacer with light sanding between coats before you spray the final finish will take care of this. You can get primer-surfacers in spray cans.

See http://www.htguide.com/forum/showpos...0&postcount=13 for the steps I used to do a black lacquer finish on a pair of subwoofer cabinets. Same process for white. No clear overcoat required (although it would have given a bit more "depth" and made final color-sanding less messy.

[zzzz]

One more bit of advice,

Brace that sucka. If nothing else some 1" dowel rods from side to side and top to bottom will help. And if you can, double up on the MDF for the baffle.

Yup - I'm planning on two sets of braces of 3/4 mdf. Should be rock solid. Baffle already doubled-up!

[zzzz]

Make sure the caulking is well cured before final assembly. Some caulking releases solvents as they cure which can weaken speaker surrounds.

I read this too. Shouldn't be a major problem with a vented sub, but I'll take no chances and give that baby a week or so to cure.

[zzzz]

The spray can route can produce good results... but in my opinion, good surface prep (with a primer and some sanding) is a lot more important than a clear top coat. MDF and plywood both have very porous edges. If you spray finish directly on these, it will just soak up and look blotchy. A couple of coats of primer-surfacer with light sanding between coats before you spray the final finish will take care of this. You can get primer-surfacers in spray cans.

See http://www.htguide.com/forum/showpos...0&postcount=13 for the steps I used to do a black lacquer finish on a pair of subwoofer cabinets. Same process for white. No clear overcoat required (although it would have given a bit more "depth" and made final color-sanding less messy.

Good call on the surface prep. I hadn't realized that I was doing the same thing as the piano black finish, just with a different color. Doh! Time to get the sander out!

[zzzz]

One other thing...

I was just going to use cheapo rubber feet from PE instead of using spikes. Does the use of spikes really help with subs?

Thanks once more!

[robfive]

One other thing...

I was just going to use cheapo rubber feet from PE instead of using spikes. Does the use of spikes really help with subs?

Thanks once more!

That depends on the surface the sub will be placed on. Spikes are god for carpet but the rubber feet are great for hard surfaces such as wood or tile.