Cone Repair on 602B & 604B

[slial]

I have some very small repairs to make on the cones of these two Duplexes. The small holes in the 602 are in the surround and the small tear in the 604 is in the area of the surround, although the cone and surround are of the same material and piece and not separate.

I am wondering about the best way to go about repairing these. The issue of concern on the. 604B was repaired, likely long ago. The small tear has occurred outside the edge of the repair. I wonder and worry that the repair caused stress and ultimately the new damage. And considering this is a 604B, I do not want to do anything to compromise the integrity of the original cone. This cone is really thin, even compared to the 602.

I have reached out with a message to Great Plains Audio requesting advice and guidance on the best process to repairing these. Any advice here would be greatly appreciated as well. I'd also be happy to post photos if that would help matters any, at least in terms of assessing the extent of the issue.

Scott

[juniper]

You may want to post some pictures, so the pros here can evaluate the damage...

[Cal Weldon]

I have reached out with a message to Great Plains Audio requesting advice and guidance on the best process to repairing these.

Hi Scott, sounds like you are taking work away from them so don't be disappointed if they don't reply.

There are any number of ways to do the repairs and, as juniper has said, a picture or two would be very helpful in determining the course of action. It may be as simple as facial tissue and cut back PVA glue.

[slial]

I will upload the photos this evening. As for GPA, they actually replied and indicated they only do full cone replacements and not repairs. At this point I would like to avoid that if possible. The only come they can supply would turn my B into an E.

[slial]

Here are some photos. I have included photos of both obvious areas of some need and some that might be suspect.

604B:

Images reflect 2 older repairs (one of which is near the new tear), a small hole, an older repair, a small spot that seems creased and might be suspect.

Attachment 1904

Attachment 1905

Attachment 1906

Attachment 1907

[slial]

602b:

image-34.jpg

image-35.jpg

image-36.jpg

image-37.jpg

image-38.jpg

[Cal Weldon]

When it's at the surround like that and the surround is paper I would consider using cut back rubber cement. The solvent is acetone and you'll have to be careful how much you thin it. Usually 10:1 is enough. Try even less to start and gradually add acetone until you think it's right. You want it easy to apply thinly but not so runny that it's hard to control. It's hit and miss and there's no way I can help more without being there. I would use facial tissue or TP as a scrim. Do the repair on the back on the cone if possible and just lightly dress the front (no tissue) after the patches on the back have set. 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.