layout lines on rough castings?

Can't you do a first pass of machining to give you flat surfaces to do the layout on (and from)?

I'd pick the best surface to be your reference, machine that flat (or round) and go from there.

Good luck-

Paul T.

I think whiteout fluid would be a good start, with toluene (the solvent used now; 25 years ago whiteout fluid contained 1,1,1-trichloroethane) added to thin it so it doesn't chip off in lumps when you scribe your lines. I think office supply stores still carry White Out, in a variety of colors -- eg pink, blue, canary, etc., to match the colors of different sheets of NCR forms.

-jiw

Grant, Most layout scribing I've seen done involves bluing the casting before scribing. The scribe lines show up very nicely! Unfortunately, I don't know what the blue-colored fluid is called. Years ago, I did a lot of it and it came in spray cans.

I don't know

"DYKEM"

Many years ago when I was an apprentice we used to use chalk on rough castings. Rub the chalk on and then the scribed lines will show through as either grey or orange lines (depending on how rusty the casting is).

Actually, what we used to use were chunks of scrapped pottery molds (plaster of paris) as the company was owned by the worlds largest (at that time) ceramic tile manufacturer and blocks of plaster of paris were easy to come by.

Larry Green

Randy,

Thank you, I was having a semi-senior moment!!

Mike

When I machined castings years ago, they used an opaque white fluid (It just looked like thin white paint to me)to lay it out. When they scribed a line through it with a carbide-tipped scraper, the line was very dark against the white surface. If you have a can of light colored spray paint in your garage, you might experiment with it, or you can get the official stuff at

Under "layout fluids"

Well I am a cheapa SOB, so I usually just use a magic marker. They come in all flavors so find one with a good contrast to suit your vsion and needs. You can even get opaque white paint pencils in Michaels Art Stores, or most hobby shops. The tan or buff colored opaque spray that they use to mark over labels etc on boxes also works well, but IMHO and cheap state of mind magic markers (el Marko's) or Sharpies work best. I prefer red over the traditional blue. Visit my website:

expressed are those of my wife, I had no input whatsoever. Remove "nospam" from email addy.

No one else asked, so I had to bite - what is an MLA kit?

Metal Lathe Accessories:

Jim

Hey Grant,

"Dykem" is a liquid lay-out fluid, available in either a spray-bomb or a bottle with brush.

Have you tried "white-out" or more properly "typing correction fluid"? Originally it came in a little bottle with a brush attached to the lid, but for some years now it also comes in strip paper form, or better yet, in a "liquid pen" form. Mine say "Liquid Paper". "All Purpose Correction Pen" on them, but I'm sure there are other makers. Any stationary store will have them. Very handy for lots of things. I use it a lot to write on dark coloured objects, the counter-part of a black magic marker.

The "pen" version of the white-out goes on in a line as narrow as

3/32" if you are VERY careful.

Take care.

Brian Laws>I'm working on machining an MLA kit. I've very little experience on

Why not use blue Dykem like all the rest of the machining world and then scribe the lines using a carbide tipped scribe? Most height gages have a carbide tipped surface for cases just like this. Leigh at MarMachine

How rough are the surfaces? It occurs to me that you could rub on/in a wet plaster of Paris mix with your thumb, and then do the layout with an ordinary pencil after it sets.

When I had to layout a raw block casting, we're talking a 504 CID engine here, we marked it using ordinary chalk. Just made sure we had a good solid coating and scribed away. Most layout on rough cast, you're not looking for exact locations, you're looking to see if you have any stock left for finishing. Once you have one machined surface, then the whole game changes.

Whiteout also comes in Pens - with a pump bubble on one side - think lines.

Martin

Usually blue or red.

I used to call it "goof paint". :-)

It strikes me as a good choice for rough castings.

Enjoy, DoN.