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01-17-2011, 12:43 PM #1
Casting filler and paint question
Someone suggested some fillers used for smoothing rough castings. Almost anything has to be easier to sand than Bondo, any suggestions? It's going over a pitted "rust converted" iron casting.
Also, I really don't want to shoot Polane in the shop in the winter. Can anyone recommend a paint that'll be better than plain old Rustoleum in a can from the hardware store?
01-17-2011, 12:58 PM #2
Featherfill G2 Gray Gallon by Evercoat can be applied directly to metal and is easy to sand.
Are your working on the Ames Mill you recently acquired?
01-17-2011, 01:27 PM #3
Is Featherfill an auto body product? I've seen something besides Bondo at the auto parts store, but I assumed it was just a different brand of the same thing and didn't pay attention.
01-17-2011, 01:27 PM #4
01-17-2011, 01:32 PM #5
01-17-2011, 01:39 PM #6
I used an automotive product, Swiss brand Green Magic glaze and spot potty.
Thin it with lacquer thinner if needed. Left over from an Opel GT I had years ago.
I used this under Rustoleum paint. This spot putty 'dries' but seems to have a 'plastic' type of hardness.
01-17-2011, 01:51 PM #7
I believe Feather Fill is basically a heavy primer designed to fill small scratches and imperfections, not heavy pitting and casting irregularities. It also requires spraying and all that entails.
I used some heavy cast iron legs off an early American wood lathe for my Ammco shaper base. Had them sandblasted to clean off a few layers of paint and found some good sized casting imperfections that had been filled before painting. I used Bondo to fill them in, and it worked well. I'm not an expert, but what I would do is mix up a batch of Bondo, then quickly spread it on with not much excess. Then in a few minutes as soon as the Bondo started to set, I would shave off the excess with a body file & Surform tool. That left little sanding after the Bondo was fully hardened. After the Bondo work was done, I filled in some small imperfections with glazing putty, then painted the legs.
01-17-2011, 02:48 PM #8
I'll hit the auto paint store tomorrow and see what they have. I'd hoped to paint tomorrow, and I'm already sick of Bondo.
It occurred to me, I've got plenty of old PPG Concept auto paint sitting around, that's probably better than Rustoleum.
I'll take some pics. I hadn't planned on turning this into a "restoration", I started out to just slap some black Rustoleum over pitted cast iron. The saying my wife and I have, from our motorcycle experiences, is "I started out changing a fork seal, next thing I knew I was powdercoating the frame."
01-17-2011, 04:00 PM #9
01-17-2011, 07:09 PM #10
Here are some pictures of the base. The first is after "rust converting", and really I wish I'd stopped there and not had to put up with days of Bondo smell. The second is partially prepped for paint. Hopefully I'll get the paint on tomorrow, I'm really desperate for some heinous petrochemicals to cover up the smell of the Bondo.
Oh yeah, the original mill as I got it can be seen here:
01-17-2011, 08:17 PM #11
FWIW ....brush painted a few circa 1890-1920 machine tools 40 yrs ago w/ central tractor co IH red enamel that i had around..survived 2 moves , 4yrs in a open tobacco barn , & into the basemnt ..been in HSM use since...cant imagine any paint holding up better,,,,BUT ..i was not looking for a "show car" finish either..
i believe tractor suply co ( TSC) has essentially the same paint today
but have not pd much attention , just using it ....have 3 shapers in garage ( open doors ) now waiting for the coats of paint to quit chipping off before brush paintng ...some have no adhesion at all ...must have painted right over the oil .original paint not chipping ...sad!!!
01-17-2011, 08:59 PM #12
Spotted Ames Pufferfish lurks within.
01-18-2011, 12:45 AM #13
Sorry to be late to the party here, but for the next project you do I'll second jhruska's recommendation with using auto body glazing putty. It is tons easier to apply than bondo, no fiddling with mixing and no wastage. It comes in different setup times, the slower ones have less shrinkage than the faster ones do and for these labors of love you don't need to have it set up in 8 minutes anyway. It comes in these elephant-sized toothpaste tubes and is really handy to use.
Another hint is when you are covering a large flat area such as your base, cover whatever filler you are applying with a sheet of clear plastic and use a plastic squeegee on the top of the plastic to smooth it all down. It does a great job of levelling everything out, you can run your hand over everything to feel high spots, and when cured peel the plastic off and you have a nice flat surface that only needs minimal scuffing for painting.
P.S. Tom- if you still have any of your extra Barnes change gears could you send me a PM please? Thanks, Mark.
01-19-2011, 06:01 AM #14
I used a 14" drywall knife to smooth the Bondo out. It worked well enough, the biggest problem was the set time being too fast. The large flat surfaces were a lot easier than trying to apply it to compound curves. A small propane cylinder made the radius to the bottom flange.
01-19-2011, 08:24 AM #15
Bondo cure time is dependent upon the quantity of hardener and the temperature. Slow down the cure rate by working at a cooler temp. Then bring the temp back up for the cure. At 80 or 95 degrees bondo cures really fast using the recomended proportions of hardener and filler. 55 to 65 degrees slows it down a bit and increases the work time. You could cool the filler too but it may be a bit stiff.
Spot putty can fill up to 1/8 inch. Spot putty is applied to fill small voids and to fill sandscratches left in bondo. Spot putty will sand out to a finer more scratch free surface than bondo.
01-19-2011, 08:43 AM #16
The handy thing about bondo is that you can vary the amount of hardener to to increase/decrease the working time. So the simple answer to your issue is that if it sets up too fast you are using too much hardener, so use less next batch. The big problem I have (still!) is gauging the volume of the bondo to squeeze the blob you get from the can into a large hamburger patty and then make a smiley mouth line on it. If you keep the mouth the same proportion it works for different size hamburger patties, and it makes it easier to fine tune the amount in the following batches.
Another piece of trivia about bondo is you can get spreaders that are pink in color. They are pink for a reason, because that is the same color of bondo mixed in the recommended proportions, so if it is lighter or darker it lets you know if you should be adding more or less hardener to get the standardized proportions.
01-28-2011, 05:04 PM #17
I finally got around to spraying the mill base. We've had some pretty cold weather in Boston lately, and I have to ventilate the shop when I spray. I've got plenty of heat to keep the shop warm, I'm just overly conscious about the amount of heat I have to blow out the exhaust fan to clear the fumes. Today it made it up to freezing, which I deemed warm enough.
It had occurred to me that I've got a cabinet full of PPG Concept auto paint, which has pretty good chemical resistance, and can be sprayed with just an organic solvents respirator, so I picked a bright color and shot it.
01-28-2011, 05:18 PM #18
So, the really funny part about this is that neither of the two cameras I tried (Powershot instamatic and EOS SLR) could come even remotely close to reproducing the color. This thing is purple. The name on the can is "Purple Velvet" - not a light purple, not a dark purple, just a good old fashioned purple that could not be mistaken for anything but purple. You'd never look at it and say "Well, that's sorta blue", kind of like the picture looks like a blue that might be a bit purple. It's not like that, it's purple.
That's gonna look mighty fine with an institutional green Ames mill sitting on top!
I had originally planned to slap some Rustoleum over the rust converter and call it good. At this point I've gone so far overboard I might just wet sand and buff it.
And, I just realized, I forgot to mask the wheels.
01-29-2011, 07:48 AM #19
I used this stuff on my Bridgeport and I was very happy with it HALF TIME® One-Step Filler & Glazing Putty I bought it at my local auto paint supplier. I also invested in a mixing board that has a pad of paper on it so you can mix what you need use it then just tear off the sheet, no scraping the mix board anymore
01-30-2011, 07:18 AM #20
Good color...matches the PM background. A Novel idea putting an aquarium in the base also, much better than letting those stinky fish live in the house.
For mixing Bondo I keep a stack of waxy paper plates in the shop. One batch and in the trash. It works for me. The problem I have is keeping enough plastic spreaders handy, even a small bur on one will leave a streak and lead to more sanding.