Marshall JCM 900 412 Slant "Makeover" how-to...

Discussion in 'Amps and Cabs' started by Scumback Speakers, Feb 2, 2006.


  1. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    I was contacted recently by a client to recover their JCM 900 cab, and also make it look older. The client had some specific ideas on what he wanted to do, so we agreed on a price to "makeover" the cab to something a little nicer along the lines of an old Basketweave cab...and he supplied the materials for the recover.

    1) Red tolex... (Big Mike, are you following along here?)
    2) Gold piping over the top and bottom.
    3) Basketweave (Salt & Pepper) grillcloth.
    4) Remove the old logos.
    5) Remove the anit-skid trays and fill them.
    6) Remove the plastic corners and fill the screw holes.

    My job was to strip the cab, get the wood work done, route the channels, and make it look pretty. I dug in yesterday with the following products:

    1) Kleen Strip Aerosol stripper http://www.kleanstrip.com/removers.htm ESR72-18 oz Aerosol available at Home Depot for about $5.39 per can. You'll need two cans to do it right, and you'll use almost all of it.
    2) 1.5" wide metal blade putty knife
    3) A dropcloth or dispostable plastic sheet to put under the cab while you spray the stripper.
    4) Eye goggles (stripper can mess you up, put 'em on!)
    5) Weather in the 65 to 85 degree range.
    6) Good stripping gloves.
    7) Coarse Steel wool.
    8) Sanding block.

    You'll need to remove all of the old plastic corners, tolex and rivets, so refer to this tutorial I did last year on how to get that accomplished, if you need a refresher course.
    http://www.thegearpage.net/board/showthread.php?t=70200&highlight=recover+101

    Put down your dropcloth, put on your gloves, goggles and shake up your aerosol stripper real good and start spraying. Try to do one side at a time only. The fumes are nasty, and moving the cab around with stripper is messy, so try to keep your gloves from getting too gunky so you don't transfer stripper via your gloves back to stripped areas later.

    When you have waited 15-20 minutes, start with the putty knife in the grain direction on the cab, which is from side to side the long way. Use both hands to angle the putty knife at a 30-45 degree angle with the blade TRAILING behind your handle. In other words, lead with your hands and have the angle behind them. You do this so that you don't "gouge" the wood. Lots of times there are imperfections under the tolex from chips in the plywood, or rivet holes, etc. To avoid any unnecessary extra "wood fills" this is the way to do it. You'll see a nice ugly black ball of old Marshall tolex glue form on the edge of your putty knife. Get a plastic grocery bag inside of an old cardboard box and scrape it off as you go, or wipe it on a paper towel, whichever you prefer.

    When you have scraped the excess glue & stripper off, you might get lucky and not have much to do, but there will likely be problem areas where the glue is heavier than others, so spray the stripper again, and wait. Do not proceed to another side till you have it down to a dry surface, otherwise as you flip it you'll collect dirt, dust, crap and corruption and make it harder to finish off with a sander.

    Here's where you'll be at when you're almost done:
    Stripped front:
    [​IMG]
    Stripped rear:
    [​IMG]
    Let it sit overnight (unless you have a nice hot day to dry the leftover stripper fast), and then clean up excess stripper & glue around your anti-skid trays. I find that 50 grit sandpaper does a nice job of removing leftover gunk around the corners, front edges, etc.
    [​IMG]
    [​IMG]
    When you have finished making the wood look white again, you're ready to measure for your piping channels.They come in EXACTLY 1 5/8" in from the sides. You'll need a 5/32 or 3/16" router bit for the piping channel, and it should be about 1/8" deep as well. Your piping should be the standard Marshall thin gold piping available from www.tubesandmore.com as they have the real Marshall replacement gold piping. DO NOT GET THE VOX STRING! The Vox string is the wrong color.

    Here's where you route the piping channels. I use an L square to get it even from back to front.
    [​IMG]
    [​IMG]

    I'll proceed on to the routing and anti-skid plate filling this weekend when my cab maker/fixer can do it and I can take pictures.
     
    Last edited: Aug 13, 2009
  2. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    Had a little time this morning, so I pried out the old staples and the faded black grillcloth and reinstalled some BW/S&P cloth the client supplied.
    [​IMG]
    Routing of the piping channels and filling the anti-skid plates should be going on tomorrow, pics on Monday...assuming I survive the Super Bowl party...
     
  3. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    OK, took the cab guy longer than I thought, but it's back from the shop with the following routes made:
    1) 1 & 5/8" in from the sides on top and bottom, 1/8" wide, and just short of 1/8" deep, with the anti-skid trays filled, and wood putty filling the small gaps that were left. I'm also filling the rivet holes, dings and other anomalies that occur when you move a cab.
    [​IMG]
    [​IMG]
    The typical cutting of the tolex is as follows on a slant cab.
    Top tolex: 26.5" wide x 16" deep.
    Side tolex: 32" long x 18.25" deep
    Bottom tolex: 26.5" wide by 18.25" deep

    Use an "L" square, a sharp razor blade or knife, hold the L square firmly and cut your pieces in advance. Get a 3" paint roller out, and apply (roll) the water based tolex glue on both the wood, and the tolex back side, let it flash off (almost dry/slightly tacky) for 30 minutes then join them together.

    Align the piping channels FIRST, then the front, then the back, then press it down firmly, smoothing out all the bubbles, wrinkles, etc. You can pull the tolex off one or two times to adjust, but no more or it will weaken the glue adhesion.

    Cut the corners at a 45 degree angle back well into the corner, and join the tolex together. Make several very thin small cuts, but keep one perfectly straight and match the other tolex piece up to it by shoving it together to match, then you should wind up with corners like this:
    [​IMG]
    [​IMG]
    [​IMG]
    Rear of cab:
    [​IMG]
     
  4. big mike

    big mike Fixed Bias Moderator Staff Member

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    Be still my beating heart....DAMN I want it!

    must get off ass and do mine!!
     
  5. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    Whoops, sorry Mike, I forgot the front view pic of the completed cab...:Spank
    [​IMG]
     
  6. loudboy

    loudboy Supporting Member

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    My only question is why?

    Also, don't you think he could've dug up a correct logo?

    Loudboy
     
  7. big hair

    big hair Member

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    well because it looks better of course! New logo is the easy bit, the hard work is changing the tolex & piping which looks like it has been done very well - most impressive!

    Thanks for the post :)
     
  8. big mike

    big mike Fixed Bias Moderator Staff Member

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    Because Red sounds better. Besides, I like that logo. Not my cab, but I wish it was!
     
  9. MarkWorth

    MarkWorth Member

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    that's gorgeous...
     
  10. jmp2204

    jmp2204 Supporting Member

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    Awesome! God, that looks great, especially in the kitchen.

    How do you fill the caster tray holes, cut a piece of ply to fit it?
     
  11. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    Yeah, maybe not "quite" the right decor to match our kitchen...but then again, I have seven more of these in the dining room... heh heh heh

    I put my cab fixing/modding guy on the fills, Jon. He used a piece of baltic birch, cut it to fit the hole of the anti-skid tray, then epoxied in the fill piece, plus used wood glue and clamps when he glued it in. I filled in any tell tale stray holes with good old Elmer's wood putty, let it dry, sanded it flat, and then covered it in the red tolex, etc.. Results came out pretty good, I guess?

    I was always kind of put off doing colored tolex on cabs...but now that I've done this one...well...:dude
     
  12. HeeHaw

    HeeHaw Member

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    Good lookin' cab there Jim!
     
  13. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    Thanks, Rich! See ya April 1st at Jimmy's...
     
  14. SteveStrat

    SteveStrat Member

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    Great work, top-notch craftsmanship!!!

    Steve
     
  15. Tone

    Tone Member

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    Southbay Ampworks,Amazing work once again! Do you plan on doing any cabs without the piping channels added? I have a Bogner OS 2x12 that I'm trying to figure out how to do since it looks like the tolex is all just one piece?
     
  16. Scumback Speakers

    Scumback Speakers Gold Supporting Member

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    Tone, sorry I just saw your post. For that style cab, you wrap it in one piece. The tolex seam starts at the bottom, about 2 inches in from the cab side. Usually you line it up with the caster sockets, rubber feet area (where they attach on the bottom. Then you run a single piece of tolex all around and overlap the original starting point, lay down a straight edge and cut through both pieces of tolex to make your seam.
     
  17. Tone

    Tone Member

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    Thanks for the info!
    Do you have any plans to do one similar to the Bogner OS 2x12 in the future? Watching all of your "how to" threads make me want to try it really bad. And you make it seem pretty easy. :)
     

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