Duplicating Moulding / Trim Work

[Luxury Architectural]

Has anyone duplicated molding or mill work by using a mold making style technique..

Example:

Customer has small detailed molding that is too small to accurately duplicate using a digitizer and no sample can be removed, area is too tight for a profile gauge...

So I am thinking about using a RTV putty type of product to cast a negative of the trim, then use that to cast a prototype of the molding which i can cut then scan and trace it out in the computer?

Anyone do this, any product recommendations, things to consider, and best putty to use on wood trim, without damage.

Thanks guys!

[billp]

A few years ago I tried this technique and used regular modeling clay, which I was then able to scan on my Roland Picza. Afterwards I learned about "Sculpy" - http://www.sculpey.com/products/clays which I think would give even better definition because you can "bake" the product until it's hard, and then go in and do some further 'editing' with hand tools before scanning.

[Luxury Architectural]

I will check that out, but I was thinking a RTV Silicone type of product would work best, because it will dry and harden while on the wall, on the trim, so that way when I peel it off, the design will stay in tact...

[Brady Watson]

Use Smooth-On's PoYo Putty (http://www.smooth-on.com/Silicone-Rubber-an/c2_1113_1137/index.html) It works really well - just make sure you have enough of it (thick enough) to prevent distortion when you pull it off.

Then cast resin into it or just laser scan as is & invert Z to get the positive.

If the molding doesn't have relief to it (like flowers etc) a regular old pencil tracing + flatbed scanner works just fine.

-B

[Luxury Architectural]

Use Smooth-On's PoYo Putty (http://www.smooth-on.com/Silicone-Rubber-an/c2_1113_1137/index.html) It works really well - just make sure you have enough of it (thick enough) to prevent distortion when you pull it off.

Then cast resin into it or just laser scan as is & invert Z to get the positive.

If the molding doesn't have relief to it (like flowers etc) a regular old pencil tracing + flatbed scanner works just fine.

-B


I don't have a sample that isn't attached, because it is actually cast iron, a stringer from a ooooold staircase.

I have a laser scanner and I can bring it to the job site, but I don't know how I will be able to simply get a profile shot from the scan, I usually just throw stuff into cut 3d, maybe rhino? Any tips?

I am looking at that Poyo stuff and it looks promising, how long does it take to cure enough to pull off?

[Brady Watson]

If you have a portable scanner, then you can scan it & then just get a cross section of it. Not sure if Rhino can do this, but ArtCAM can.

The lowtech way to do this would be to set a piece of stiff cardboard or luan against the profile, preferably so that it doesn't move around on you when you trace. Then just take a pencil tracing of it. Measure top and bottom thickness of actual molding as a gauge for checking your profile. Then just trace vectors from the template, or cut it out with jigsaw and 2D probe on Bot to get DXF. Cleanup tracing in software & verify top & bottom real world measurements to get it right. Then 2-rail sweep in Rhino to get the whole thing in 3D.

A protractor with a point & pencil will function as a stylus for tracing the molding. You have to get creative.

-B

[Luxury Architectural]

Thanks guys, very helpful stuff!

[jsooter]

I am anxious to hear how you end up doing it and seeing the outcome you produce. I really like the moulding you are copying