Jump to content


Photo

Sachtler legs - plastic repair

crack plastic welding

  • Please log in to reply
10 replies to this topic

#1 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 29 November 2012 - 03:13 PM

I have a spare set of Sachtler legs, 100mm bowl, 16mm aluminum legs. One of the plastic brackets with the leg locks has a crack, see photo. The crack doesn't open like that untill the lock is tightened quite hard. Can these be welded? Does anyone know the type of plastic?

Alternatively does anyone have this part, used, cheap?
If I am removing the aluminum legs from the plastic moldings, is that a glued connection, a tight press fit or something else?

Thanks for any advice,
Gregg.
  • 0

#2 Dom Jaeger

Dom Jaeger
  • Basic Members
  • PipPipPipPip
  • 1599 posts
  • Other
  • Melbourne, Australia

Posted 29 November 2012 - 11:32 PM

Hi Gregg,

I don't know what particular plastic it is, could possibly be welded but I've never tried.. I'd just replace the part. I think Panavision are the Sachtler agents in NZ, have you asked them for a price? Might not be overwhelming.

I used to work on the Sachtler carbon fibre ones, on those the legs were glued in. Sometimes hard work getting them out, I had to use a lot of heat, but the glue is probably different for the aluminium ones.
  • 0

#3 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 30 November 2012 - 04:05 AM

Hey Dom,
Thanks. I was wondering if you might notice this post. Yea I spotted today that Panavision were agents. They've been quite nice sofar. Didn't get to ask yet.

Carbon glued into plastic must have been fun to get out. If the carbon was cured quite hot then I guess you can heat that untill you melt the glue which should be a much lower temp. Even with aluminum legs I worry that the plastic mouldings will overheat. But it must be easier and safer than doing the carbon ones.

Does the replacement plastic part come complete with the locking parts or do you normally switch those over?
  • 0

#4 Mark Dunn

Mark Dunn
  • Basic Members
  • PipPipPipPip
  • 2422 posts
  • Other
  • London

Posted 30 November 2012 - 02:34 PM

If it's a fairly fresh crack, I might try Araldite, or even glass right around the section in a sort of C shape.

Edited by Mark Dunn, 30 November 2012 - 02:36 PM.

  • 0

#5 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 30 November 2012 - 03:57 PM

If it's a fairly fresh crack, I might try Araldite, or even glass right around the section in a sort of C shape.


I don't know the history of these to know when the crack happened. They may not have been used for a while. A guy who was buying them from me was testing his light weight jib on them and reported the crack. I wasn't there. It's possible he grossly overtightened the lock and made the crack without even knowing, So yes that could be a fresh crack.

Intuitively. that cracked area is under tension with tension grading higher towerds the outer surface, so I'm not a fan of a glue fix, although I know in practic a rubbery and aggressively sticky epoxy might work. But if highly loaded the glue will just peel or separate from the plastic. Some kind of welding or gluiung prcess where the molecules melt together might be OK. Wrapping something like glass, carbon or a piece of aluminum around the area would do it. The glue joint is then in shear.

I'll see what the part costs first.

Cheers,
Gregg.
  • 0

#6 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 05 December 2012 - 08:19 PM

.....I used to work on the Sachtler carbon fibre ones, on those the legs were glued in. Sometimes hard work getting them out, I had to use a lot of heat, but the glue is probably different for the aluminium ones.


Dom,
I got the new part, old stock from Panavision Auckland for about US$39 before tax, old stock. Talking to Gary Oliver there, he soakes the glue joint in acetone and knocks the part off. He uses Locktite 480 for the glue. When I look at the gluing surface in the new part it is ribbed. Maybe the Sachtler design engineer was being kind. This is somewhere for the acetone to go. But when I remove the old part I may find those ribs full of epoxy (laughing).

The insert thread that the twist lock screws into. It's screwed into a threaded sleeve in the plastic. Is the insert thread just kept with locktite or is there something else holding it.

Cheers,
Gregg
  • 0

#7 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 11 December 2012 - 04:48 PM

Does anyone know how to remove the treaded insert (sst12e0110)? It's the part that the lock screw itself screws into. It's threaded inside and out and may be glued with Locktight into the threaded sleeve in the plastic part. My guess is I will have to cut away the plastic and cut the sleeve lengthwise to break it off the threaded insert.

If I need to remove the blind roll pin (d148103161) holding the plastic thumb screw. The only idea I had was to drill a hole in the plastic the pin and pull it out. Cosmetics are not really a big deal. Any better ideas?

I had another chat to Gary at Panavision Auckland but it is a long time since he has done one of these.

I attached the schematic showing those parts but it does not seem to show. I may try again.

Thanks for any ideas.
Gregg.

PS the plastic to aluminum joints separated easily. General purpose thinners (couldn't find the acetone) were dripped onto the edge of the joint several times, left an hour or so, then the plastic parts were just tapped off. I saw two different types of glue, one greyish looking type that filled the ribs in the plastic. One would think that the solvent would not get much access, but I think there was some softening.

Edited by Gregg MacPherson, 11 December 2012 - 04:50 PM.

  • 0

#8 Dom Jaeger

Dom Jaeger
  • Basic Members
  • PipPipPipPip
  • 1599 posts
  • Other
  • Melbourne, Australia

Posted 11 December 2012 - 10:14 PM

Hi Gregg,

sorry, can't help but feel a little bit of schadenfreude at your struggle. :rolleyes: Sometimes what looks like the simplest of jobs ends up being a nightmare.. and you can't really charge people for the ten hours it took to replace a $40 part! More and more stuff these days seems made with little regard for future servicing. Maybe it's a deliberate strategy to make repairing old things more expensive than buying new ones.

Sometimes inserts are held in place by pins/splines at the outer edge running down across the threads, or by grub screws, but I'd say your insert is probably glued in. I'd try acetone (nail polish remover from any chemist) and a bit of heat applied with a heat gun or hair dryer. If it's anything like the other legs I've worked on the lock handle should undo until the cone thingy inside backs up against the insert, if you keep trying to undo the handle it should act to unscrew the insert. It's probably glued in solid to stop that happening normally. Or check that the insert doesn't have slots or holes for a tool to undo it with. Maybe it has a back shoulder and needs to be screwed in to remove it. If all else fails, yeah, hacksaw the bastard..

You'll have to drill out the back of the blind pin hole and punch out the roll pin if you need to remove the lock handle.
  • 0

#9 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 12 December 2012 - 02:14 AM

Dom,
I had to google to catch up on what that meant. Is that the slightly cruel version or the empathetic version, like the "I've been there" feeling. Actually it's been a simple, fun and not expensive exercise sofar, just letting the bits fall into place in their own time. But if I was in a hurry I think it would feel very different.

The threaded home for the treaded insert is about 12mm deep. I'm thinking the acetone will not get into all that thred length easily. Probably will cut my way in.

They still make these legs. I saw them for sale on B&H for almost US$1000. Or you can buy what looks like a Proaim copy for about 150 ex India.

Thanks,
Gregg.
  • 0

#10 Gregg MacPherson

Gregg MacPherson
  • Basic Members
  • PipPipPipPip
  • 1880 posts
  • Other
  • New Zealand

Posted 17 December 2012 - 03:20 PM

Hi Gregg,
sorry, can't help but feel a little bit of schadenfreude at your struggle. :rolleyes: Sometimes what looks like the simplest of jobs ends up being a nightmare.. and you can't really charge people for the ten hours it took to replace a $40 part! ......Sometimes inserts are held in place by pins/splines at the outer edge running down across the threads, or by grub screws, but I'd say your insert is probably glued in. I'd try acetone (nail polish remover from any chemist) and a bit of heat applied with a heat gun or hair dryer. If it's anything like the other legs I've worked on the lock handle should undo until the cone thingy inside backs up against the insert, if you keep trying to undo the handle it should act to unscrew the insert. It's probably glued in solid to stop that happening normally....... If all else fails, yeah, hacksaw the bastard..

You'll have to drill out the back of the blind pin hole and punch out the roll pin if you need to remove the lock handle.


Dom,
That was surpisingly easy in the end. The insert I assumed was glued, no signs showing otherwise. Gave it some heat and it didn't move. But, cutting was quick and easy, then splitting the outer sleeve off the insert. Getting the blind roll pin out was ridiculously easy, I'm embarrassed I asked (sort of).
Thanks again for your advice and moral support,
Gregg.
PS. I saw the huge zoom and MBox on the super8 camera photo. This is you enjoying free access to the rental inventory?
  • 0

#11 Dom Jaeger

Dom Jaeger
  • Basic Members
  • PipPipPipPip
  • 1599 posts
  • Other
  • Melbourne, Australia

Posted 17 December 2012 - 08:07 PM

Hi Gregg,

well that's good news, well done. My previous 'schadenfreude' was definitely of the empathetic kind, but unwarranted it seems. I was probably just projecting my own woes, having spent 3 days working on someone's RED zoom - more or less a rehoused Tamron - which was a complete pain in the arse..

Yeah the huge zoom on my little Beaulieu was a bit of a Christmas lark, it gets pretty quiet at the rental house around now. I wanted to try the Optimo 24-290 but it was out on a job. :)
  • 0


Tai Audio

Media Blackout - Custom Cables and AKS

Ritter Battery

Gamma Ray Digital Inc

FJS International, LLC

Wooden Camera

Rig Wheels Passport

Willys Widgets

CineTape

Glidecam

Aerial Filmworks

Abel Cine

Metropolis Post

rebotnix Technologies

Opal

The Slider

Broadcast Solutions Inc

Paralinx LLC

Visual Products

Technodolly

CineLab

Metropolis Post

Broadcast Solutions Inc

The Slider

Visual Products

Media Blackout - Custom Cables and AKS

Wooden Camera

Paralinx LLC

Willys Widgets

Ritter Battery

rebotnix Technologies

CineTape

Gamma Ray Digital Inc

Opal

Aerial Filmworks

FJS International, LLC

Abel Cine

Tai Audio

Glidecam

Technodolly

CineLab

Rig Wheels Passport