[slosjo]

Hello all

This is my first speaker build, so I'm looking for any advice you may have to offer; especially related to finishing.
Right now, I have both speaker boxes built and the front baffles are completed.  I'm working on finishing them next, but not sure what products to use yet. 
The boxes and bases are made of MDF; I would like them to be finished gloss white.
The baffles are made of baltic birch and I would like to keep them natural.
Any suggestions on finishing would be greatly appreciated.  I have done some sample pieces with various products, but nothing that I'm really happy with yet. 

I tried 2 different types of gloss white paint and it has become evident that the only way i'm going to get it perfect is to spray it in a dust free environment.   That will be difficult for me, but it may come down to that.  Even brushing with products that are supposedly "free of brushstrokes" like Glidden Gel Door and Trim Paint yielded only marginal results.  Glossy and smooth, yes.  Perfect, no.
 
I tried Minwax polycrylic on a scrap piece of Birch.  It was OK, but I'm looking for something that will smooth out more.  Also, not sure if I should use some kind of grain filler first.

I was able to get everything cut from (1) 4x8 sheet of MDF, and (1) 5x5 sheet of baltic birch.
The baffles are (2) 3/4" pieces laminated together with tightbond II.

Here are some photos of my progress:

[Danny Richie]

Front baffle looks wide.

Be sure to put a large radius on the back side of the woofer holes.

Finishing can be tricky. You can always hit the box with bed liner spray then veneer the front baffle only. If you round the outside front edges then you can roll a paper backer veneer all the way across the front and around the edges.

[slosjo]

I used a 1/2" radius on the upper and 3/8" on the lower woofer holes. 
I purchased the birch with the intention of keeping it natural.  I need advice on getting a smooth finish with a water based product, as typically oil will yellow over time. 
Brush, spray or wipe?
Sand between coats?
Use sanding sealer before?

Thanks

[Danny Richie]

I used a 1/2" radius on the upper and 3/8" on the lower woofer holes. 
I purchased the birch with the intention of keeping it natural.  I need advice on getting a smooth finish with a water based product, as typically oil will yellow over time. 
Brush, spray or wipe?
Sand between coats?
Use sanding sealer before?

Thanks

That will work.

I have used brush on polyurethane several times with good results. Apply with foam brush, let dry, then wet sand it down. And you can lay it down over most oils if it is an oil based polyurethane

[Danny Richie]

So how wide is that front baffle?

[chipperman]

I can suggest some things regarding refinishing. If you want to keep the front baffle "natural" you have to undertand what happens with wood. It will all darken with time regardless of the type of wood.  This happens because of oxidation and light (mostly ultraviolet, but not all). So the trick is to keep out both if possible.

We have all seen varnished windows or siding that had peeling. This is not usually due to a failure of the finish as is commonly thought, but the degredation of the lignin in the wood that causes it to delaminate at the finish/wood interface. That is caused by the ultraviolet rays penetrating the finish.

Your indoor situation can be solved in a variety of ways. First off, you cannot get the correct finish at a big box store or at a normal paint store. And, other than the voc's so called "water based" paint is also toxic, just usually not as nice a finish.

If you can stand just a little yellowing, Park's urethane floor finsh (oil based only) works wonders. Home Depot used to carry it, but not in California.

Of course, you can use automotive paint like Wilson and others do, but that requires a compatible primer. The automotive clear coat works wonders and requires a hardener and a spray gun. I no knowledge if it can be sprayed on raw wood. It is, of course, uv resistant and hard as nails.

Sanding sealers are used to fill pores and even out the grain for more even staining. If you want the raw look, it is not required.

Now, for your situation, if you do not have a sprayer (HVLP being best) you need to look into a high quality waterbase that will do the job. And this is where the specialty houses come in. I have not used any of the products since the middle 90's, but even back then we used sprayable clear coats that dried harder in 30 minutes than cured oil based finishes  ever did (one part types). The technology has to be better today. Because they cured so fast then, we had no option but to spray.

Here is a good place to start: www.thefinishingstore.com   They are connected somehow with Apollo sprayers, and we always used what our Apollo rep suggested. This will give you what you want.  You could probably brush and sand the primary coats with no problem.

Of course, doing the prep yourself and finding someone at a body shop that does side work to spray the final coat would be best. Then you have no issues with dust.

Good luck.

[Captainhemo]

Just a thought, but if you have one,  I'd use a  3/4" or even 1"  roundover for the back of the woofer holes  on  that 1.5" thick front baffle.  I think generally  the thicker the baffle,  the larger the roundover

-jay

[slosjo]

Chippeman - thanks for the great info on wood finishing.  I will research this further.

Captainhemo - The 3/4" radius bit was pricey and I don't think my router has the guts to get it done so I stuck with 1/2".   

Danny - I will confess that despite your advice via email, I made the front baffle 9" wide to allow a 1/4" radius on each side of the back.  This is mainly because of my lack of ability to build a perfectly square box.  It's close, but not perfect.  Perhaps the X-statik was a bit ambitious for my first woodworking project.  If you think that .25" on each side will make a big difference, I may reconsider. 

Has anyone wrapped a MDF box with vinyl before?  3M makes some pretty cool vinyl wraps.  They seem to have a nice finish.  Wondering if that is a viable option for the box portion that I want to be gloss white.

Thanks again

[bladesmith]

Your speakers are looking good. Keep up the good work.

And keep sending pics.

Bladesmith...

[Danny Richie]

Danny - I will confess that despite your advice via email, I made the front baffle 9" wide to allow a 1/4" radius on each side of the back.  This is mainly because of my lack of ability to build a perfectly square box.  It's close, but not perfect.  Perhaps the X-statik was a bit ambitious for my first woodworking project.  If you think that .25" on each side will make a big difference, I may reconsider. 

Funny how just an additional 1/4" to each side made it look so much wider. Put a big radius on it and then it will be okay.

[Peter J]

You're right about ambering of oil & solvent based  finishes. On many woods it's not all that noticeable and imparts a warmth that's even appealing. On really light woods like BB and maple, it can look downright bad over time if that's not the look one was shooting for.

 Water borne finishes can prevent this to a great extent but have two drawbacks that should be considered. First is appearance; water white finishes can give wood an almost stark quality. It can look good with what you're suggesting with the white box, but I'd give it a whirl first before you commit.

Second is application, best is to spray, but I hate running water borne through my guns. If I did it all the time, I'd have a dedicated set up.

Another consideration is repairs and "finishing" the finish. Most water bornes dry via coalescing as opposed to solvent evaporation. You can sand and buff many solvent finishes, but because successive coats don't "burn in" on water bornes like they do on lacquers and such, it's not usually viable with wb. Your last coat is what it'll look like. There's lots to know about the chemistry, but I dirgress. Water bornes also have the not so nice quality of grain raising.

If you want a glassy smooth finish, the ply edge will give you fits. One either has to fill it with grain filler or finish. It will take many, many coats of finish with sanding in between to achieve.  I have some water based grain filler I got from Homestead, but have yet to try it. This may be helpful.

http://www.homesteadfinishingproducts.com/htdocs/ChoosingFinish.htm

I've also hand finished with this stuff from Mohawk, but it takes 10 or 15 coats to get any build. Not a quick method, but perhaps that's not important. If I were trying to achieve what you're suggesting. I might try the Chrystalac Grain Filler and follow with Finish Up.


http://www.homesteadfinishingproducts.com/htdocs/Pastewoodglazes.htm

http://www.mohawk-finishing.com/catalog_browse.asp?ictNbr=145

[chipperman]

The better so called "water based finishes" are primarily alcohol based, so they don't raise the grain as much, and after the first coat is sanded it is not a problem.  They do sand cleanly and don't gum up as much as varnishes. Nothing blends like laquer, and if you want a rock hard clear finish look at some Ikea furniture. Those are catalyzed polyester, the same kind of stuff as piano black that you have a hard time finding here, and it's priced likke liquid gold.

God bless those Chinese with no pollution controls; they can use the kind of finishes that made America great.
We can't even buy the mdf for what they can sell a finished cabiner for.

I have had no problems spraying water borne finishes with the HVLP gun as long as the needle size and viscosity is correct.. Acyrlic latex (like house paint) is another issue; it chews up the internals like rubbing compound.

[bdp24]

You're right about ambering of oil & solvent based  finishes. On many woods it's not all that noticeable and imparts a warmth that's even appealing. On really light woods like BB and maple, it can look downright bad over time if that's not the look one was shooting for.

 Water borne finishes can prevent this to a great extent but have two drawbacks that should be considered. First is appearance; water white finishes can give wood an almost stark quality. It can look good with what you're suggesting with the white box, but I'd give it a whirl first before you commit.

Second is application, best is to spray, but I hate running water borne through my guns. If I did it all the time, I'd have a dedicated set up.

Another consideration is repairs and "finishing" the finish. Most water bornes dry via coalescing as opposed to solvent evaporation. You can sand and buff many solvent finishes, but because successive coats don't "burn in" on water bornes like they do on lacquers and such, it's not usually viable with wb. Your last coat is what it'll look like. There's lots to know about the chemistry, but I dirgress. Water bornes also have the not so nice quality of grain raising.

If you want a glassy smooth finish, the ply edge will give you fits. One either has to fill it with grain filler or finish. It will take many, many coats of finish with sanding in between to achieve.  I have some water based grain filler I got from Homestead, but have yet to try it. This may be helpful.

http://www.homesteadfinishingproducts.com/htdocs/ChoosingFinish.htm

I've also hand finished with this stuff from Mohawk, but it takes 10 or 15 coats to get any build. Not a quick method, but perhaps that's not important. If I were trying to achieve what you're suggesting. I might try the Chrystalac Grain Filler and follow with Finish Up.


http://www.homesteadfinishingproducts.com/htdocs/Pastewoodglazes.htm

http://www.mohawk-finishing.com/catalog_browse.asp?ictNbr=145

Peter, what finish on Baltic Birch makes for a non-yellowed appearance? As close to the unfinished color of BB as possible, but with the protection of a finish?

[slosjo]

Second is application, best is to spray, but I hate running water borne through my guns. If I did it all the time, I'd have a dedicated set up.

Do water based products degrade the internals of a spray gun?  Just curious.  I have a TP HVLP turbine.  I use it to spray water based paints all the time.  I believe all the parts of the gun are stainless.  I haven't noticed any damage from the water based paints, but if I'm ruining my gun by using these paints I'd like to know before it's too late.

I have had no problems spraying water borne finishes with the HVLP gun as long as the needle size and viscosity is correct.. Acyrlic latex (like house paint) is another issue; it chews up the internals like rubbing compound.

Agreed; tip, viscosity, and air flow must be correct.  Same question for you as above though.  Does the paint actually abrade the SS parts in the gun?

I'll look at some of the products available at the aforementioned websites.  Thanks for all the great suggestions.

Any problem with connecting the drivers ( in free air) and crossovers to my receiver as a test?  I just want to make sure everything functions properly before I put it all in the box.  Bass and midrange drivers connected in parallel, correct?

Your speakers are looking good. Keep up the good work.

And keep sending pics.

Bladesmith...

Thanks!
No progress recently, but here are some more photos of the birch baffles, sanded and routed / rounded.








 

[chipperman]

None of the "water based" finishes will hurt your spray gun. The only issue is the mechnical abrasion from using acrylic latex. And, no, they won't corrode anything. The abrasion issue takes a long time to show up anyway, and it doesn't seem like you are doing production house painting with your unit.

Talk with some of the vendors and ask them what they think would work best. You want a water-clear finish.

[mlundy57]

Any problem with connecting the drivers ( in free air) and crossovers to my receiver as a test?  I just want to make sure everything functions properly before I put it all in the box.  Bass and midrange drivers connected in parallel, correct?

No problem with connecting everything up in free air as a test. That's what I do before installing anything.  I made up some test leads out of both red and white 14g stranded wire. I soldered small alligator clips on the ends. I also made up a pair of speaker wires with banana plugs on one end and alligator clips on the other. I clip the speaker wires to the input wires on the crossover networks and use the test leads to connect the hook up wires to the driver tabs or to interconnect  driver tabs if need be.

Nike

[Peter J]

Slosjo, I should clarify about a couple of things.

 My beef with water borne is not that it damages gun somehow, but rather cleaning. Switching back and forth from solvent finishes to water borne and back requires a really thorough disassembly and cleaning of guns in my experience.  In a production environment, that's a PIA. Acrylic (latex) paint is a whole 'nuther story and is indeed abrasive, best thing for that is probably an airless setup but it's not what we're talking about anyway.

By the way, I make a distinction between water borne and water based. I'm nearing the limit of my knowledge, but water borne suggests to me that the delivery vehicle is water, but the actual solvent may be alcohol or perhaps something else, as Chipperman pointed out.  Water based goods actually use water as the solvent...like house paint.

I've used these products with success, but not since General Finishes bought Compliant Spray Systems, who was the developer.

http://generalfinishes.com/professional-products/water-base-topcoats-and-sanding-sealers

 If you're going to spray, this is what I'd recommend for a water clear finish, but honestly, my knowledge is dated. At the time I used it, it handled more like lacquer than anything else I tried.  I'm a solvent finish guy until I can't anymore, I suppose, so that's my benchmark.

[Bob in St. Louis]

Great thread, I love watching the build process. 

[mlundy57]

How did you cut the notch for the tweeter terminals so cleanly?

Mike

[slosjo]

Peter J, thanks for sharing your knowledge.  I'm going to do a bunch of reading and talk to a few vendors.  Hopefully I can decide soon.

How did you cut the notch for the tweeter terminals so cleanly?

Mike

HA! Funny that you ask that.  Well let me tell you, it was not clean like that after the first pass.  It was very much trial and error.
I started with my jig saw with straight cut attachment.  That was fine for cutting directly into the wood on both sides.  Then came the task of cutting out the bottom of the notch.  I figured I would just cut at an angle from each side, and then cut the bottom off clean right between my two vertical cuts  with a straight edge clamped to the baffle.  The results were not so great, I failed to realize that the blade was bending until after I completed the cut.  So, cleaning up the mess basically involved some very careful sanding with a 90 degree block and a builder's square until it was clean  and square.  Actually turned out great, but I managed to do it the caveman way, as usual.

On that same note, that recessed tweeter area is tricky.  You certainly don't want it too big (diameter), but obviously too small and it won't fit.  I ended up being way too conservative on the first one, which lead to probably 4 hours of very careful sanding before it fit.  Once you cut out the circle, I don't believe there is any way to increase the diameter evenly with a router.  A spindle sander would have been useful, but again, one little slip up with a power tool and you've messed up the whole thing.