Enlarger head mixing box foam for Ilford 400 HL

I am thinking of acquiring an older Ilford 400HL (precursor to the 500) which appears to be functional. I have it on loan for evaluation and testing, but I need to fabricate an adapter plate for the Beseler 45MX.

However, the 4x5 mixing box has a very thin, white polystyrene (?) liner that is somewhat deformed from sitting a long time or long term heat damage. The sides protrude a bit into the light path; it may not matter much but I would prefer it to be better.

It is simply an open ended box of 1/8 inch sheets, taped with ancient masking tape on all seams and "C" shaped cut-outs on the edge to allow the light on each side to enter the mixing box. The box itself rests on an about 1.5 inch lower frame of mirrors; also taped with what appears to be masking tape.

Anyone know definitively if a special grade of foam was used? This head is passively cooled, so I know the chamber will get quite hot during long exposures. The masking tape construction makes me wonder if this is even an original foam part and not a homebrew replacement.

Has anyone built their own replacement mixing chambers? I have found and downloaded the manual; which is about as helpful as any consumer manual beyond basic functionality...

Invariably someone will bring up the shortcomings of this unit, but I understand the perils of adopting such ancient technology. The upside is it is local, affordable and appears to work fine.

If I do get it, I will explore upgrading the dichroic filters to the new version offered on Ebay and try to reconcile the 0-4 grade range to these new filters. I would assume each grade button on the controller has an adjustment to balance lamp output for that particular grade, but I may be wrong.

That looks homebrew to me.
I have an Ilford 400 head on my D5XL.
I'll take some pics this evening when I get home.

AnselMortensen said:

That looks homebrew to me.
I have an Ilford 400 head on my D5XL.
I'll take some pics this evening when I get home.

Click to expand...

Thank you!

PM sent to @Kino .

That doesn't look at all like the mixing boxes that I had in my Ilford Multigrade 400 head.

This illustration from the manual shows how the mixing boxes appear, although the version pictured is most likely the smaller 35mm one:


The shape and configuration of the 4x5 mixing box is similar to that one, just wider. It fits in because the light sources slide along the Lamp tracks in order to match the size of the mixing box.
IIRC, the mixing boxes were black metal on the outside - save the bottom.

Also from the manual - FWIW:

Matt,

The mixing box I have appears to be the M3, 4x5 box; shorter and wider.

AnselMortensen's box looks the same as mine, minus the masking tape.

It is a black metal box, but highly perforated.

Maybe our units are very early models and the mixing boxes were redesigned later...

The 4x5 box is the same height as the 35mm box - just wider.
And the 6x7 box is also the same height - its width is halfway between the two.
On mine there might have been masking tape, but it would have been hard to tell, because the sides were solid, not perforated, and the tape would have been between the white reflector material and the outside.
On mine that reflector material was not as white and reflective as I would have preferred, but still usable.
I have no idea whether the solid side units or followed the perforated ones. I believe that the mixing boxes for the later 500 series were solid.

Back when dinosaurs roamed the Earth, I printed in a lab that used an Ilford 500/D5XL setup...
If I recall correctly, the 500-type mixing boxes were solid, and powder-coated white on the outside.

AnselMortensen said:

Back when dinosaurs roamed the Earth, I printed in a lab that used an Ilford 500/D5XL setup...
If I recall correctly, the 500-type mixing boxes were solid, and powder-coated white on the outside.

Click to expand...

Well, if that's the case, these 400HL heads must have been developed about the time the first reptile struggled-up on the beach!

Thanks @AnselMortensen and @MattKing for the solid information.

Back when amphibians first pulled themselves onto land, perforated metal was used for lighter weight and strength. Dinosaurs may not have appreciated the added cost...