Restoring a McIntosh 40

[hatrack71]

So I got this from another AKer in hopes of restoring it. As you can see the chassis has a lot of surface rust but the chrome is still shiny in a lot of spots. Believe it or not- as rough as it looks- there are no dents or dings anywhere. Everything damage wise is only paint deep. I am thankful for that. I am not going to take steel wool or anything abrasive in hopes of preserving the lettering. I was thinking taking a paintbrush and brushing on an oxalic acid solution. Or buying the naval jelly rust remover spray. Does anyone have thoughts about which would do the least damage to lettering? Is there a better way? This is just the start. It will most likely find it's way to Terry D if he has an open spot for it in the future. I notice someone modified the chassis on the right for bias adjustment? and also installed a pilot light next to the rca input. Is it best to get those filled and rechrome the whole chassis and worry about lettring later. I need your thoughts.

 

[CountD]

The chrome looks pretty beat. I have a Mc40 that is completely non-stock but was done to a very high standard and is beautiful. I would strip it down to the chassis, have someone blast it and do a re-chrome. It looks like most of the original chrome is gone. A lot of Mc40s I see are like this - I am not sure if it is because they were hidden in places because they were utility amps or the chroming was shoddy. Either way, it is a basis for a sweet resto.

 

[hatrack71]

Kind of what I was figuring but I thought I would see if anyone had a trick up their sleeve for this situation. I know a replacement chassis is out of the question- I have looked exhaustively. If anybody knows where to source one, I'm all ears.

 

[CountD]

I'll post some pics as to what this very talented guy did with my 40. It will blow your mind, and although it is not chrome, it is so well done I do not miss it at all. The chassis doesn't need to be replaced, just redone.

 

[dshoaf]

Agreed on someone supplying replacement chassis - wouldn't be worth the set up/manufacturing cost vs demand from restorers.

For me, I don't mind the poor cosmetics. They'll still operate up to spec just as good as a perfect specimen. If it bothers you, however, I must say I like what Wardsweb did with his: http://www.audiokarma.org/forums/showthread.php?t=367974

Cheers,

David

 

[hatrack71]

What is the best way to remove all the rivets? I have decided to abandon the lost cause of lettering at this point. Just too hard and it will never be right anyway. I have decided to strip this and I will re-chrome the chassis. Does anyone have a way of removing the rivets and what did you use to replace them with to keep a stockish look?

 

[dshoaf]

Sloober and others who have redone MC-30s posted here about replacement rivets.
Removal can be tough but I've found the use of a punch on the rolled side along with a mechanic's socket of just the side of the rivet head works well for drifting out the old ones.

 

[hatrack71]

Paging Sloober!! How did you do it?

 

[titanstats]

If it bothers you, however, I must say I like what Wardsweb did with his: http://www.audiokarma.org/forums/showthread.php?t=367974

+1 on that. The restore on that one was beautiful -- it may not be original, but it sure is gorgeous! His was in worse shape at the beginning of the restore, as well.

 

[hatrack71]

I am definitely getting the chassis re-chromed since there is an industrial plating shop just down the street. He is going to look at filling the extra holes that are not stock as well. I do want to try to re-create the lettering on this chassis. I would like to know how folks are making the stencils or what they are doing- hand painting? Decals? I want the best result with a reasonable amount of time invested. Also which programs are folks using and what sort of medium for the printer. Is there some sort of transferring decal where just the ink goes onto the chassis?

 

[Naptown Rob]

Paging Sloober!! How did you do it?

 

[dshoaf]

Hatrack, you might want to PM Sloober as I'm not sure he checks here until you post in one of his threads or he drops by.

How he did it is pretty well documented here in some threads for the MC-30s. You might want to spend some time running the search engine here at AK.

Cheers,

David

 

[hatrack71]

Keeping track of my progress, I will show pics of what oxalic acid did. Not much better and a lot less lettering. This thing is just too pitted. I am very happy to learn that the chassis is rolled steel. That means I can weld up the extra holes.

 

[BillWojo]

Did you ever finish these? I just picked up a set of MC40's in the same condition.

BillWojo