Flashing on 12pt type

[David Bolton]

A different problem, but still bad type. Everything was ok until a month ago. Then 12pt type started to be cast with flashing down one side. Changed the mould, but no improvement. Cleaned the type carrier, as another problem was a small nick down one side. No change, but then changed the movable type channel, and the nick went, which meant the other carrier must be damaged somewhere. But still flashing on one side. Is this a mould problem - crossblock too loose perhaps. I rather suspect it is a temperature problem, as the super caster pot temperature is having to be set manually at the moment, until my SSR control box has been wired up. So the temp can swing between 600 and 750, unless I am careful.

[Jason]

Dave @David Bolton - I have similar issues as well, and for me I'm pretty sure it comes down to old/worn moulds. I clean and snug everything very thoroughly, but still get flash, mainly around the perimeter of the top, but often down one or more side corners, and sometimes on the bottom edge as well.

For me, the top flash is due to misaligned cross-block and mould surfaces. I have dozens of mould insets and 5 bases, but only ONE cross-block (don't ask me how this happened - the haul I got from South Africa seemed like a windfall until I inspected and discovered that amidst all of it there was only one (regular type-high) cross-block). On that one cross-block the face plate is worn, so no matter what inset I use it with none of them create a perfectly level seal for the mat, so I always have some flash around the top edges. (A handful of years ago I had the cross-block worked on, welding and machining a new piece on to level up the casting surface, but that repair has worn rather quickly, so I'm back to where it was. If anyone out there has a spare cross-block, I'd sure like one!)

Normally, this flash around the top of the type just brushes off, but often I have to dress the type to really clean it off, which, in turn, solves any other flash/fins that show up. But, as you can imagine, this makes for a LOT of extra work.

[KPMartin]

... Cleaned the type carrier, as another problem was a small nick down one side. No change, but then changed the movable type channel, and the nick went, which meant the other carrier must be damaged somewhere....

David, I think I'm missing something... If changing the type channel fixed the damaged (nicked) type, why do you think it is the type carrier's fault?

...Then 12pt type started to be cast with flashing down one side. Changed the mould, but no improvement. ... Is this a mould problem - crossblock too loose perhaps. I rather suspect it is a temperature problem, as the super caster pot temperature is having to be set manually at the moment, until my SSR control box has been wired up. So the temp can swing between 600 and 750, unless I am careful.

I suspect that with old worn moulds, the amount of lubrication can affect how much flash you get along the side corners of the type. Is the flash on both corners along the crossblock side of the type or just one? What style of mould are we talking about? Perhaps this should be a separate topic?

New topic - Flashing on 12pt type - created - Admin

[Paul]

David, have you tried scraping the top surface of the mould with a paint scraper?  Use a new blade.  You may find there are tiny residues of metal along the inner edges of the slot.
Also, try cleaning the matrices by placing them flat on some VERY fine emery paper and rubbing in a circular motion. That will remove any small burrs of metal stuck to the sides.
Paul

[Keri Szafir]

Scraping the mould with steel? Definitely NOT! Take the mould apart and remove the blade from the inset, then clean any lead residue by scraping with a piece of lead, wash it down with some gasoline or isopropyl alcohol. This way you won't damage the steel surface.

[David Bolton]

Apologies for typo, small nick was caused by faulty type channel, nothing to do with the type carrier.

The flashing scrapes off happily, either with a bit of brass rule, or with my fingers. The mould is 12pt composition. I should probably remove it and clean up the blades, but having already done that on a different 12pt mould, to cure the same problem, it did not help much. I will try again. Lubrication may have something to do with it, as the mould oiler empties after a few hours running. Happened on the other 12pt mould too, though far worse, with oil dripping into the pot from time to time. My trouble is having all three casters fitted with 12pt moulds, for different jobs, and the super caster has the least used mould (..e. one that is more prone to problems. I have a few more 12pt moulds, but they are very worn, and need matrix descent adjusting to limit the top flashing as much as possible. The moulds on the composition casters do not seem to cause flashing, so it may still be something slightly out of adjustment on the super caster.

Must press on with the super casting - 64% of 3 up of each of some 26732 accented characters now done, all being cast on a 12pt body, or multiples thereof for the display mats...

[KPMartin]

It may also be that the mould has previously been disassembled, removing one or both of the left and right type blocks, and then re-assembled without being scrupulously clean. If the type block is canted a bit due to dirt between it and the mould base plate, the crossblock may not be able to seal the cavity no matter how tight you set the shoe.

I've found that assembling all the non-moving parts of the mould should be done dry, no oil of any kind, with the parts freshly cleaned with a strong solvent (e.g. brake cleaner). The dry surface avoids holding dust, and proper fit cannot be impeded by the thickness of an oil film. The fit should be good enough for the parts to seem to stick together a bit, like machinists' Jo blocks wring together.

Once you start adding parts that are supposed to move (the blade and crossblock) it is OK to oil things, though even there I start with either a very light oil or even a lower-volatility solvent like paint thinner. Of course, it gets a proper oiling before being put into service or storage.

Mind you this is my experience with Lanston composition and display moulds. I have never tried (nor had the need) to disassemble an English composition mould.

[David Bolton]

An update on my flashing problems. Removing the crossblock and cleaning its sides gently with a bit of brass rule, then wiping with clean cloth, and then resetting the gib plate once crossblock back in position seems to have cured the side flashing. (There was a tiny bit of metal stuck on the crossblock side, but that might have got there via a bit too loose a crossblock against the gib plate.)

As for the top flashing, I duly re-set the descent of the matrix holder in accordance with the instruction in the manual. First three casts were fine, then the flashing returned. This is what happened the last time I ran the machine and had to re-set the descent. What is the most likely bit that needs attention, everything seems to still be tight, but it looks as though something is getting pushed out of position.

Not had these problems as bad before, in the 25 years I have been running my casters.

[Jason]

Don't have anything new to contribute Dave, but I appreciate you talking it out here. I'm still getting flash on mine as well, so am now going to strip and clean my mould according to Kevin's suggestions. As I'm getting flash all over the place (around the foot and around the top) I'm pretty sure my issues are a cleanliness/maintenance issue with my mould, along with the worn surface of my crossblock. Because a fair bit of what I cast is from engraved mats, I tend to have to dress the type anyway, but it's a pain in the ass dressing all four sides of every sort to really clear off the flash!

Also, Dave, could you let me know which manual/pages you worked with to adjust the decent of the matrix onto the mould? I'd like to take a look at mine as well, especially with the mats I'm making myself.

[David Bolton]

Adjusting matrix head:
Monotype Super Caster Manual 1953, page 23
Monotype Super Caster Manual 1972, section 11.1

David

[Jason]

Thanks Dave.

[David Bolton]

And a follow-up to my problem with flashing on the tops of 12pt type. After going through the matrix head adjustment procedure several times today, with no obvious improvement, I simply (?) went straight to putting three bits of spool paper between matrix and mould when in casting position, and adjusted the matrix lifter stop collar to very firmly grip those sheets. The flashing became greatly reduced, and indeed absent altogether most of the time, so life is now almost back to normal. However, I did notice a good run of type with no flashing at all, when I had forgotten to move the pump body operating rod lever away from the piston operating rod crosshead stud. Thus a large amount of metal built up under the mould. If this meant that the amount of metal firing into the mould was being slowed/reduced, then maybe I had too much pressure on the piston, thus causing the flashing. We shall see when casting resumes next week...

David