Welcome! Need support, you got it. Or share your ideas and experiences.
In Reply to: RE: MG 1.6 loose croosbar posted by Yeang on February 13, 2012 at 18:16:42
Please post pictures as you figure more out.
I wish I could be of some actual help.....others may be along, since some owners seem to have multiple pairs, one of which is always undergoing one mod or another!
Too much is never enough
The same thing happened on my SMGa's, which only have two bars per driver. The bars had sprung loose at the ends, but remained solidly attached in the middle.
I agree with Andyr - that the drivers have to be removed entirely from the speaker frame so you work on them. There is no getting around that.
For mine, I used the 2-part epoxy that you mix up (I got the strongest formulation offered - nothing magical about the brand but get a good name brand in a fresh package). Get some with a longer "working time" so you can take you time and can deal with any mistakes. You also need some of those quick-clamps - two for each bar that you want to fix at a time.
Make sure the surfaces are clean.
The bars are curved, so make sure they are replaced (if you take yours all the way off, or it is comepletely loose) with the curvature correct. If your bars are all the way off, test clamp them to the pole piece prior to applying the glue to assure that your clamping scheme will restore the curvature.
To apply the glue I used a sample plastic credit card (one of those you get in the mail all the time with free offers ans such) to apply the epoxy evenly and get it into the hard to reach areas. Don't go hog-wild with the epoxy, just make sure the surfaces are covered. If you put too much, it'll squeeze out and run all over and make a mess, and could even plug holes on the pole piece near the bar and you don't want that. Also, you could force excess epoxy into the middle of the driver through the pole-piece holes, and you don't want that either.
There may be some narrow strips of tape over portions of the pole-piece holes in the QR section of the driver. Leave them alone.
When I applied the epoxy and clamped the bars back down on the edges of the panels and set them to cure, I placed them flat with the pole pieces DOWN to assure that any possible squeeze-out would not down run the front of the driver and any squeeze-out that might go through the pole piece holes did not get drip onto the mylar in the interior of the driver.
I did this repair to my SMGa's over two years ago and they are still going strong.
Thanks so much for confirming my suspicions that the drivers have to be removed!
What's a good way of putting them back in the MDF frame, assuming that I don't want to go to the trouble of making hardwood frames? The driver side staples look different from the ones holding the sock in!
Sorry to take a couple days to respond. I wanted to think about it a bit. I'd get a staple gun that is capable of driving staples that are comparable to the ones in there now.
Others will likely respond with other ideas, including some form of clamping scheme. You just have to be sure that the means of re-securing the drivers does not draw them out of shape by flattening them. The solution doesn't have to be cosmetically nice if you are going to re=sock them
I have seen posts on here railing against Magnepan's use of staples to secure the panels within the MDF frames. After using screws through holes drilled in the driver edges to secure the driver to a set of oak frames I made for SMGas and seeing the screws flatten it to the point that the curvature is taken out, I am not particularly enamored with that means of attachment. Others really like it though. I may have drilled the holes too far from the edge of the driver.
For fastening to the MDF, staples may remain the best choice if you want to avoid surgery on the frames. Plus, they are adjustable somewhat meaning they can be tapped down to increase the fastening force they apply.
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