AR-11 Restoration

[JKent]

This is going to go slowly, only because I need to do some of the work outside and right now weather doesn't permit.

A friend asked me to do a cosmetic restoration. The woofers were re-foamed by Bill LeGall in 2006 and the speakers have sat in a dry, climate-controlled basement storage room ever since.

These are earlier ones, with brass logos and they're in pretty good shape. Here are the issues:

• Veneer is dry and faded with some water marks
• there are superficial scratches on the bottoms
• One nasty gouge on the front of one, above the logo
• A circular scratch where the one logo was screwed on
• One logo missing
• No grilles

I'm thinking a cleaning with mineral spirits, some light sanding, fill the corners with epoxy. Then maybe Howard Restore-a-Finish? Any thoughts about the water spots welcome. I'll "try" to steam the gouge but am somewhat pessimistic about that.

I'd like to make some grilles. I'm thinking wood frames, beveled, covered with black stretch grille cloth. Vintage-AR sells some like this but I should be able to build my own. Will have to find another brass AR-11 badge.

I pulled one woofer. The original gasket is kind of squooshed so I think I'll replace the gaskets. AND, as I suspected the crossovers are untouched. Caps are Callins--one big can and 2 (I think) of those evil black and red PVC caps. I'll test the cans but they are Callins, not Sprague, so I think all the caps will go. I haven't pulled the xo out yet but the schematic in our Library shows a 50 & 72 in parallel, a 40 and a 10. I'll most likely use NPEs for that ~122uF value on the woofer, maybe for the 40uF midrange cap (have to check my parts box) and film for the 10uF.

Kent

[genek]

No on the Restore a Finish. There is no finish left to restore.

Sand the surfaces and glue down loose pieces. If the first sanding gets out the spots, fill and then sand again until you get a uniformly smooth surface. If there are still spots after the first sanding, bleach them out first and then fill.

Use a stainable wood filler rather than epoxy (I like Famowood, which is made from wood dust and can be gotten in a nominally realistic walnut shade). Epoxy is great if you need to rebuild crushed corners, but you probably don't need to do that here. Remember that epoxy wood filler does not absorb stains or penetrating finishes, and is best used to repair finished surfaces where the repair will be spot finished with a varnish or lacquer touch-up.

Replace or add color with an NGR dye stain. You'll probably get best results if you make it a bit darker than original. Important: if you intend to use a penetrating finish (oil or oil/varnish blends like "Danish oil"), Do NOT use an oil based stain.

Apply a new, REAL finish. For wood that has been filled, a coating will probably be better than a penetrating finish.

 

[JKent]

Thanks for the helpful tips, Gene.

The pics I posted are of the worst areas. I did take some lacquer thinner and cleaned the top, spotty surface of one and it came out almost perfect. But I will skip the Howard's, clean everything thoroughly when I can get outside.

I have tried Famowood but did not care for the color. I prefer JB WeldWood tinted with Mixol.

I did not realize oil-based stain was a problem with Watco Danish Oil. Could you give some more guidance there?

Appreciate the input.

Kent

[genek]

Oil based stains can interfere with wood's ability to absorb penetrating finishes. Watco is an oil varnish blend. It may work fine or it may blotch, depends on what stain you use. On new work, it's easy enough to just test a piece of scrap wood, but you're not going to have that option.

If you use an oil stain, you should follow it with a sealer and then a varnish or lacquer finish.

[lakecat]

Hi Kent....if it was me, I would slap a wet towel over all sides and iron the hell out of it. Let it dry and try sanding the veneer a bit. if water marks disappear...great...but can add bleach if still showing. those water marks aren't bad. That cut in the veneer won't come out from steaming. I would sand all sides with grades of paper starting with 150, 220, and 400. I use Howards as a stain to much disdain here but works well. I would stain before any repairs to cracks. After a through drying of Howards, I would spray one coat of satin poly. After that dries, I would use Mohawks walnut epoxy for all cracks and that cut in the veneer and the coat of poly keeps any oils in the epoxy out of stain.. Roy turned me on to this stuff and I love it...and it matches Howards stain real close. A light sanding of epoxy if needed and add a second coat of poly. The coats of poly must dry for three days between coats. I also have colored pens that I use to make veneer marks over patches like the cut in your veneer. I usually add a third coat of poly then. Of all the refinishing I have done, this is the fastest way I have found to do a cabinet.

[genek]

Here's what the folks at Howard Products say about finishing over Restor-a-Finish:

"Do not use polyurethane over Restor-A-Finish. Keep in mind that the purpose of Restor-A-Finish is to restore an existing finish."

You may get away with not following the manufacturer's instructions, but there is a reason why they say that and I would hate to find out what it is on something that was important to me.

[RoyC]

4 hours ago, genek said:

Here's what the folks at Howard Products say about finishing over Restor-a-Finish:

"Do not use polyurethane over Restor-A-Finish. Keep in mind that the purpose of Restor-A-Finish is to restore an existing finish."

You may get away with not following the manufacturer's instructions, but there is a reason why they say that and I would hate to find out what it is on something that was important to me.

I agree with Gene. While I'm a huge fan of the epoxy putty mentioned in lakecat's post, I believe the Howards stuff is better for temporarily refurbishing an existing finish than anything else. Watco Danish Oil is easy to use, and results in a finish closest to that found on AR cabinets.

Roy

[genek]

The Mohawk sticks have been my go-to for repairs to oil-finished wood for years. Work it into cracks, shave it level and in many cases no sanding is needed. Just grain it, wipe on a bit of flat lacquer with a Q tip and you're done.

[lakecat]

On 1/27/2020 at 4:07 PM, genek said:

Here's what the folks at Howard Products say about finishing over Restor-a-Finish:

"Do not use polyurethane over Restor-A-Finish. Keep in mind that the purpose of Restor-A-Finish is to restore an existing finish."

You may get away with not following the manufacturer's instructions, but there is a reason why they say that and I would hate to find out what it is on something that was important to me.

They are correct....you don't use poly when you are just filling in a cabinet with a finish on it. I am talking about using it as a stain on a completely sanded and unfinished product. It is a breeze to use and better than MinWax stains on this old walnut. The key is to make sure it is completely dry. And...usually use two coats.

I have a pair of 3a's here that are around nine years old that I refinished with Howard's and satin poly. I paste waxed them at about three months old. They still look brand new....and matches the AR color pretty darn close. I have set original pairs of AR's beside these and it passes...:) To each their own...but it works here....and have done dozens with this method. Never had a complaint...and is quick. Screw that eight coats of oil stuff.... that lasts how long?

 

[genek]

Well, if it works for you.

[DavidDru]

Let's see some photos of the cabinets once sanded.  There may be reason to re-veneer the tops or bottoms at this point with what I am seeing.  Hard to tell though.  I think sometimes we all dink around with patches and filling when in the bigger picture it may be better to just cut to the chase and get some new veneer on there.

[JKent]

I'm taking this slowly because other things are going on. Did one xo yesterday with Erse film caps. The biggest job will be building new grilles. As for the cabinets, I appreciate all the input and respect the expertise of guys here but I'm taking a different approach. One cabinet is coming along:

• Washed the surface with Spray Nine
• Steamed the gouge on the front, over the badge.
• Filled gouge with Famowood (thanks Gene)
• Filled small corner gouges with Mohawk epoxy
• Sanded filled areas lightly by hand with a block
• Wiped down entire cabinet with walnut Howard Restore-a-Finish (I agree with lakecat on this but we're in the minority apparently)

It looks very good. I'll do the same treatment on the other one, do any needed touching up, then use Watco Danish Oil, possibly wet-sanding. Stay tuned.....

[JKent]

Not much progress to report--life interferes with my hobby. Painted the bathroom today.

Apparently my new iPhone takes much sharper photos than the old one did. The cabinets were not as hopeless as the photos attached to the first post would suggest. I think these will be fine with minimal cabinet work.

I measured all of the old caps and surprisingly they were all within spec. Even the infamous red & black Callins PVCs. But they've all been replaced with new Erse film caps. Here are the measurements:

Value    Measured    Measured

120uF     121.3            144.5

40uF       43.6               46.9

10uF        11.0               10.7

Also got an original AR-11 badge via a barter with Larrybody. Tomorrow I'll pick up wood for the grille frames, so things are moving along.

 

[lARrybody]

I don't quite understand the 11.3uf value on the 120uf cap. I have used a few Erse PluseX caps and I like them. How do your new caps read? Are they within the + or - 3%. I agree with the phone cameras getting better and better.  Happy Valentines Day everyone.

[JKent]

Whoa! Typo!

Not 11.3, it's 121.3

Funny thing about the Erse caps. I ordered the PEx but they sent the more expensive PuleX, and they're pretty much spot on.

Thanks Larry

[JKent]

Finished up the crossovers. The older I get the harder it is to work inside those cabinets (and the heavier they get) ?

Got outside today and did a coat of Restor-a-Finish. Next time it's nice out I'll do the Watco oil. The cabinets still have a bit of "patina" but I think they look pretty good and I think my friend will be pleased. That nasty gouge on the front isn't 100% fixed but unless you get up very close it disappears.

Waiting for a friend to rip some strips of poplar to make the grille frames, so those may be a while.

 

[Pete B]

They are looking great!  What is the thinking behind RAF then Watco over it, isn't Watco Danish Oil 

also a colored finish?  I have used it but not over RAF.

[JKent]

Thanks Pete

The RAF is really intended to restore an existing finish. My thinking was that the finish was partly still there, partly gone. The RAF serves to even it out, but it's not a finish. The original finish was, I believe, similar to Watco Danish Oil so once the cabinets are thoroughly dry I'll apply the oil.

[DAA]

Great restoration...I just finished my AR11Bs. I decided to use NPE caps bundled with smaller value polys. Left the big bass cap for now.  Give these some clean power from an amp with good headroom and man, they are terrific!   I finished mine with a few coats of Danish oil over a week. Had to lightly sand tops, but overall mine were really clean.  Good original grills too. Enjoy them!  

[GD70]

Hi Kent!

Nice work on the cabs! Don't be daunted by the grill frames and new fabric.

I would make them like I did on my 12s, if you're after the original look with the beveled edges.

The grills took me two days to complete.

Cheers, Glenn

[genek]

On 2/17/2020 at 8:05 PM, JKent said:

The original finish was, I believe, similar to Watco Danish Oil so once the cabinets are thoroughly dry I'll apply the oil.

The original finish was a penetrating oil with a catalyzed drier; no topcoat. Watco is penetrating oil blended with varnish that will have a topcoat. Watco will also dry glossy compared to the original matte finish. You'll need to dull it if you're intending to match the original look.

[GD70]

On March 3, 2020 at 12:11 AM, genek said:

The original finish was a penetrating oil with a catalyzed drier; no topcoat. Watco is penetrating oil blended with varnish that will have a topcoat. Watco will also dry glossy compared to the original matte finish. You'll need to dull it if you're intending to match the original look.

Watcos doesn't dry glossy unless you apply many wet coats beyond what the veneer can absorb. 

All my cab restorations have used Watcos, and all have a nice matt/satin finish. Usually five applications is all the veneer will absorb.

When I apply the oil, I wipe it on with an old sock, or cut up t-shirt. I never apply so much that I need to wipe away extra each application.

[xmas111]

Nice job Kent!  They look awesome and the grills will give them the finishing touch.  

I'll keep watching your progress with these.....

 

John

[JKent]

Thanks John

Don't have the wood for the grilles yet and it may be a month or more before I can get to them but I'll post pics when I start the work.

Kent

[JKent]

On 3/3/2020 at 12:01 AM, GD70 said:

Hi Kent!

Nice work on the cabs! Don't be daunted by the grill frames and new fabric.

I would make them like I did on my 12s, if you're after the original look with the beveled edges.

The grills took me two days to complete.

Cheers, Glenn

Thanks Glenn

Do you have a link to your 12 restoration? I'd like to see how you did the frames. I've built frames from scratch but not with the beveled edge or the stretchy cloth. I'm planning to use 0.75" x 1.5" poplar on edge and use a 45° router around the top edge. And I had planned to use 1/4" Monel staples but maybe glue is better for the stretchy fabric. Any tips?

Kent