Using 300W ELH bulbs in old spec Multigrade 500H

Stuart Richardson · Oct 24, 2009

I was wondering if anyone had any experience in using the newer 300W bulbs in the older version of the Mulitgrade 500 head. My head is older and does not have heat shields, but I am curious if this is a real issue. Or maybe it is just an insurance company mandated precaution? If it is important, is it possible to DIY the heat shields? I have seen the picture of their diagram in another thread, but I have not seen them in an enlarger. Does anyone with a newer Multigrade 500 mind snapping a photo of what they look like installed in head?

Thanks very much,
Stuart

youngrichard · Oct 25, 2009

500h

I've got 2 of these. Greedy I know but I started over 50 years ago with a Johnson and Johnson contact printing frame for 127 film, and only finally got to this sort of gear 3 years ago, just before I retired. Any way I bought them on eBay attached to a Focomat 11c and a Durst DA900, one of the 500ss packed up and I got a replacement from eBay USA. To cut a long story short, neither is a 2nd generation model ie no heat shield blinkers or whatever they are; I know what you mean I've seen pictures. But, they both came with 300 w ELH bulbs fitted, so I am not sure the upgrade from 150 to 300 came with the fitting of blinkers; it may have come earlier. Or, when it came, users decided to fit the 300w bulbs anyway
HST, I do find that despite the fans onto the bulbs down the flexible piping, there is a lot of heat; even 35mm film 'pops' within seconds of lighting up, so I use perforce double glass neg carriers. Might be able to get away with upper AN glass, glassless below - haven't tried yet.
Richard

youngrichard · Oct 26, 2009

Further thought

Come to think of it, maybe the negatives wouldn't 'pop' if I downsized to 150w bulbs; there is power to spare and for a 5" x 7" print from an MF negative I am stopped down to f22 anyway.
Richard

Stuart Richardson · Oct 26, 2009

Thanks Richard. At least it is good to know that the enlarger does not burst into flames if you fit the more powerful bulbs! I will try to find a few of both and see how it goes...I am putting together an order now, as it appears there are not any ELH or ESD bulbs anywhere in this entire country.

L Gebhardt · Oct 26, 2009

I may go to the smaller bulbs. For 4x5 printing I am usually using a 2 stop ND filter too keep the aperture at f/8 or f/11 and the times above a few seconds.

I also have two of the heads. One came with the add on heat shields. They aren't much more than metal plates on clips.

DAP · Oct 28, 2009

There are two types of heat shields for these units. There are little white ones that clip onto the flexible cooling tubes. The other shields are larger black metal plates that screw onto the inside of the plastic endplates of the head. It seems like the white clamp-on shields were only produced for a little while (few heads have them - I have only seen them on the early 300w heads). The larger black metal shields are on every 300w head that I have ever come across (they protect the plastic sides from melting - don't know if you can get by without these...they should be easy to make if your head doesn't have them)

Stuart Richardson · Oct 28, 2009

Thank you all for the information. I think I will try to create some makeshift heatshields -- can't be too hard I think.

rmann · Oct 28, 2009

I have one with the clip on heat shields - they are to protect the wires from direct exposure to the IR from the bulbs - It would not be hard to make your own keeping an air space between the shield and the wiring to the bulb. But, why not just use the 150 watt bulbs - if you have the right mixing box for the format you are using there should be plenty of light.

Stuart Richardson · Oct 28, 2009

The reason I would rather use 300w bulbs is that neither bulb is available in Iceland, so I have to order from the US. At most sources I have seen, the ESD 150W bulbs are 20-35 dollars, the ELH 300w bulbs are 10-12 dollars. The ESD are rated for 12 hours average life, and the ELH bulbs are rated for 35 hours. So using the 300w bulbs saves me a lot of money -- I also have to pay 25% tax on the cost of the bulbs, as well as on the shipping, so it really adds up.

Bob-D659 · Oct 28, 2009

Have a look at topbulb.com, lower prices than what you have found.
Also bulb specs are here Dead Link Removed

And for all their catalog pages,

Dead Link Removed

Stuart Richardson · Oct 29, 2009

Thanks for the help Bob -- that advice is very useful.

youngrichard · Jan 6, 2010

I too found that the 150 watt bulbs are a lot more expensive than the 300w. Then I looked inside the head and found a warning tab "Use only 300 watt bulbs". Inside my other head, same notice. Don't want to risk blowing the electronics - I have had one head conk out on me and pronounced unrepairable, so I think I need an ND filter.
I am not an electronics expert - can anyone comment as to whether a 150w bulb would endanger the circuit whilst 300w is safe? It occurs to me that if 150w is a problem, then the bulb blowing as it will one day must be even more of a threat to the electronics.
Richard

youngrichard · Jan 6, 2010

Sorry, it was the 500s transformer etc unit that failed, not the head.
Richard

Using 300W ELH bulbs in old spec Multigrade 500H

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