Cone Repair on 602B & 604B

[bowtie427ss]

Get some of those little children's art class paint brushes from your local dollar store [make sure they won't melt with the acetone] and while you're there pick up some flat toothpicks [not the round kind]

Use one brush to gently clean the area with a small amount of acetone. Then apply a small amount of the rubber cement solution with a different brush and lay a small piece of tissue [pre-cut to the required size] over the cement. use the skinny handle part of the paint brush to form the tissue into place in and around the accordion part of the surround. Apply another small amount of cement over the tissue and smooth it out making sure that a little cement is taken beyond the edges of the tissue and feather it out as best you can. Use the blunt end of the toothpicks to remove any excess. More is not better here, just like too little is no good. Make sure you get it looking right before you walk away as once is begins to set, you'll only make a mess if you try and fix anything. When it's dry to the touch, turn the driver over and use a brush to apply a small amount of the solution [no tissue] to the affected area on the front of the cone. Let dry for 24 hours.

This is an excellent method that will last a considerable time. We use thinned rubber cement and talc to seal pneumatic valve pouches in pipe organs and player pianos. They have to remain flexible under stress for years.

If you have an art supply house our good paint center nearby, check for "Best-Test" products. They offer a premium rubber cement and their "Bestine" thinner which is 100% pure heptane.

[slial]

This is an excellent method that will last a considerable time. We use thinned rubber cement and talc to seal pneumatic valve pouches in pipe organs and player pianos. They have to remain flexible under stress for years.

If you have an art supply house our good paint center nearby, check for "Best-Test" products. They offer a premium rubber cement and their "Bestine" thinner which is 100% pure heptane.

That is great info. There are many art supply stores nearby with Rhode Island School of Design not far away. I will look for this stuff. When you say these repairs should last a "considerable" amount of time, what are talking about? Many years I assume?

[bowtie427ss]

When you say these repairs should last a "considerable" amount of time, what are talking about? Many years I assume?

In the closed pneumatic systems where i use it most often, we expect more or less 20 years of reliability minimum with newly installed leather, and a minimum of 5 years when used to rejuvinate pouches(when deemed acceptable condition) that are up to 100 years old.

I can't say with any certainty how long such a repair might last on a speaker cone, but i think similar results could be expected. However, i offer no guarantees.

It's probably reasonable that repairs done by Cal's method will last the remaining life of the cone.

[slial]

In the closed pneumatic systems where i use it most often, we expect more or less 20 years of reliability minimum with newly installed leather, and a minimum of 5 years when used to rejuvinate pouches(when deemed acceptable condition) that are up to 100 years old.

I can't say with any certainty how long such a repair might last on a speaker cone, but i think similar results could be expected. However, i offer no guarantees.

It's probably reasonable that repairs done by Cal's method will last the remaining life of the cone.

I figured as much. I will have to get my hands on a cone I don't need and practice this method. No way I starting cold on a Duplex.

[Cal Weldon]

Hi Scott,

Make the patch slightly larger than the 'wound.'
Yes, align all pieces best you can before starting.
If they lined up perfect and this wasn't in the surround area, I would recommend clear nail polish as you wouldn't even need a patch.
This repair will last indefinitely if:
1. you prep the area well
2. you do a good job with the patch

If you do a lousy job and it falls off, then so what, you start again and do it properly this time, no biggie.

Just go to any electronics repair shop, tell them what you are doing and they might just give you a speaker to try it out on. Try and get one with the same style cone/surround.

Nice to hear bowtie's story.

[slial]

Hi Scott,

Make the patch slightly larger than the 'wound.'
Yes, align all pieces best you can before starting.
If they lined up perfect and this wasn't in the surround area, I would recommend clear nail polish as you wouldn't even need a patch.
This repair will last indefinitely if:
1. you prep the area well
2. you do a good job with the patch

If you do a lousy job and it falls off, then so what, you start again and do it properly this time, no biggie.

Just go to any electronics repair shop, tell them what you are doing and they might just give you a speaker to try it out on. Try and get one with the same style cone/surround.

Nice to hear bowtie's story.

Cal,

If you look at the photo you can see the tear is in the cone area but the original issue was in the surround. So would I use the nail polish as a glue to adhere the seam of the tear and then cover the whole spot with nail polish? This would likely require holding it in place until it sets too.

[Cal Weldon]

That's tough to see in the pics so here's what I suggest and you'll have to take it from there.

If you are doing repairs in the surround then use the rubber cement method. If you are clear of the surround and are working only on the cone and have good alignment of the damaged area, use the clear nail polish straight up, no thinner, no tissue. You still do the repairs on both sides of the cone.

[slial]

Any specifics or preferences for nail polish?

Also, do you have any photos of repairs you have done? This might help me visualize the desired outcome.

[Cal Weldon]

Any specifics or preferences for nail polish?

Also, do you have any photos of repairs you have done? This might help me visualize the desired outcome.

Although I consider myself a modern day sensitive man I don't have a clue as to the nail polish. Here's how I acquire it: "Honey can I borrow some clear nail polish? I don't need much. Thanks Honey, I love you."

Photos? No. Just try it, you'll find you are an expert after just once, trust me, it's not hard. Just pretend they are you're children and you'll do fine. I like the idea of trying it on a spare driver first though.

[VolvoHeretic]

Some have also tried a cut back silicone but I haven't found a good way to clean or prime the cone and the silicone tended to delaminate over time.

I have no idea what you could use to dilute pure Silicone caulking and I can understand why it wouldn't stick not used full strength. Also, caulking must never be feathered at its edges, the feathered edge will always delaminate and once started, will always fail and is why bathtub surround caulking always fails. You would have to mask off the area around the repair, apply the caulk, smooth with your finger to the thickness of the masking tape, and then remove the tape before the caulk sets up.

Probably the same applies to rubber cement.