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Forum topic by 1371Marine posted 09-23-2014 01:56 PM 1171 views 0 times favorited 12 replies Add to Favorites Watch
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1371Marine

23 posts in 802 days


09-23-2014 01:56 PM

I’m not new to woodworking but am new to this game of used equipment. I recently picked up a monster 72A that has some heavy surface rust on the CI top and wings. My first thought is spray it down with Kroil, let it soak, wipe and repeat. In between coats I plan on using some Scotchbrite to lighly scrub the heavier rust off. Finally, once the rust is gone, I plan on clean up with some laquer thinner and a coat of wax. I’m interested on some comments/advice on this being a good or bad path forward. Thanks in advance for the help.
On another note, does anyone know where I could find the 25” CI rounded extension for this beast??


12 replies so far

View Minorhero's profile

Minorhero

372 posts in 2065 days


#1 posted 09-23-2014 02:49 PM

Your plan will work but be very slow. A lot of folk have good luck with using a flat bladed razor to literally scrape rust off. Preserves the flatness and is much quicker. Just remember to wear a respirator.

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1371Marine

23 posts in 802 days


#2 posted 09-23-2014 05:56 PM

I’ll give it a try to speed things up a bit. This saw was built Nov. 2000. I gave $800 for it (well below asking because of the rust). The trunion looks fine, cabinet is in good shape. It has the original accufence etc… Also came with a lot of extras like a Biesemeyer T-square anti kickback spreader, and bladeguard system. I think I did pretty good all things considered. I’m looking into a rotary phase converter in lieu of a motor swap since it’s 3PH. Any advice on these RPC’s as far as brand, size, etc… It has a 7-1/2HP on it now. If I go this route, I’d like to buy it big enough for future equipment. I’m just now starting to put a real shop together and get back into this hobby full swing.

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unbob

718 posts in 1363 days


#3 posted 09-23-2014 06:28 PM

Wow! You certainly made a good move on that.
I just sold a 72A, not because of major problems. I needed right tilt, and already had a 12-14” saw with that.
The PM I had was 5hp 3phase. The other brand saw is 7 1/2hp.
The converters can be put together for low cost, or bought ready to go-I put one to together. A lot of info and help on those at the OWWM site, along with many very happy 72A users.
Using a razor blade to get the bulk of the rust off works good, a little Scotchbrite, then waxing and using the saw, the table will look pretty good in a short time.

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nicksmurf111

361 posts in 911 days


#4 posted 09-23-2014 07:45 PM

First take it apart. Soap, warm water and Scotchbrite. I don’t like using penetrating oils on surfaces. They will soak in, and are not compatible with woodworking finishes. Rust hardeners will leave dark spots if you can’t abrade them off. Then, clean with lacquer thinner, acetone or alcohol. Coat with wax. I must be different, but soap and water works really well…

-- Nicholas

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buildingmonkey

242 posts in 1008 days


#5 posted 09-24-2014 02:39 AM

Grizzly sells converters, might be about the same money to buy a new 5hp motor. I put some miles on one of those old saws, was quite a beast. Quality commercial saw. 5hp should be plenty.

-- Jim from Kansas

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1371Marine

23 posts in 802 days


#6 posted 09-24-2014 10:01 AM

I had ago at it last night . I let the Kroil soak overnight then hit it with a razor blade. Followed up with WD-40 and Scotchbrite and wiped clean with laquer thinner. It turned out better than expected as there was about 30-40 grand of rust on a majority of the surface. Juuust a litle more TLC and it will be GTG. Thanks for all the help gents. Pics below. Still looking into options for the power though.

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nicksmurf111

361 posts in 911 days


#7 posted 09-24-2014 01:49 PM

Where about are you located? I have a used tool store here that has stacks of motors. I’d suggest just swapping to a single phase motor. Then you’ll probably want a starter/contactor to go along with it if you don’t already have an adequate one.

-- Nicholas

View Minorhero's profile

Minorhero

372 posts in 2065 days


#8 posted 09-24-2014 03:37 PM

A 7.5hp is a huge motor. What you do is going to depend a lot on how confident you are in your electrical skills. I would definitely recommend a post on the owwm.org forums. They have a section on motors and wiring.

Bottom line is you have 3 options. 1 wire the rpc up yourself, 2 pay an electrician, 3 swap out the motor.

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nicksmurf111

361 posts in 911 days


#9 posted 09-24-2014 03:46 PM

I’d suggest just swapping to a 3hp motor unless you feel the need for a 5hp. I believe this saw uses a NEMA C face mount motor which can be found used for around $200. I think there are some on Ebay if you don’t have anywhere local to shop for that stuff.

-- Nicholas

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unbob

718 posts in 1363 days


#10 posted 09-24-2014 03:58 PM

Swapping out the 7 1/2hp 3phase motor for a 5hp single phase motor is not a good direction to go.
Just a small amount of research, will show many phase converter options, that cost less then swapping out to a lower quality more trouble prone 1phase motor.
Grizzly does sell the GWM Autogen static phase converters. Those converters have a capacitor run circuit and worked well for me on my 7 1/2hp saw.
Single phase motors are really 3phase motors, except they use a capacitor with a switch to energize the third winding upon starting.
That is, a single phase motor with a bad start capacitor will buzz and not start, just like a 3phase motor without a convertor.
A static converter does the same thing running a 3phase motor on single phase power, except the electronics are in a separate box.

No one on OWWM would recommend swapping out a motor on a fine machine like that to a single phase motor-it just makes no sense.
Basically, a rotary converter is a 3phase motor that is started by a static convertor, that idling motor generates voltage on the third leg-giving near full power to the saw motor.
I would strongly suggest joining the “old wood working machine” forum for further information.

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1371Marine

23 posts in 802 days


#11 posted 09-28-2014 11:13 PM

I managed to get all the rust off the top. It seems there was also some burn off from laminates, plywood etc… on there as well. The Kroil seemed to help a great deal. I used a razor and it worked well. Then some scotchbrite and a little WD40. There are some areas that are stained a bit, not sure from what. The saw was taken out of service a year before the shop closed and I was told it was basically used as a work bench (and it shows) so there may have been some chemicals or stains spilled on there. I’m pretty sold on the RPC to power this as I’ll be getting more 3PH equipment down the road and I’m not too keen on the motor swap. I’m confident I could wire it up if it were a purchased unit ready to go. Building one would take a lot more research for me. I have a buddy that’s a bit of an electrical genius so I’ll be hitting him up for some help. Anyone have a source for that mustard yellow paint on these saws?? Also, does it seem weird that the extension wings are painted on the underside but not the table itself?? Lastly, I’ll be storing/refurbishing this over the winter in an unheated space. Would it be ok to put cosmoline on the table surface to protect it until it is put into operation?

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Minorhero

372 posts in 2065 days


#12 posted 09-28-2014 11:51 PM

All of my machines are in an unheated barn in a high humidity state (maryland to be exact). I use johnsons paste wax to keep rust off. Rub it on, wait 10 minutes, and rub it off. Do this 2 or 3 days in a row and the machined surfaces will be well protected. I would not put cosmoline just because that stuff makes a complete mess.

I don’t know the exact color combination but the folks on owwm.org could help you out there. As for the paint to use. The best paint is either Sherwin Williams Industrial Enamel or Benjamin Moore Super Spec HP Maintenance Coating. The latter is available in pints but the former is only available in gallons. Both are very good. I have used both and would definitely recommend using them in sprayers if at all possible. Keep in mind that that both are going to need temperature of 55 degrees F or higher. So if your winters are cold you won’t be able to paint till spring.

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