2011 Hallmark JD 4020 ornament, anyone have one?

[wcfn100]

Another thread got me searching for JD 4020 tractors and Hallmark made an ornament in 2011.  Anyone have it or know what it scales out to?


Jason

[jimmo]

One listing for the Hallmark Keepsake ornament I found gave it's length as 3-1/2 inches.

Kinda huge.

[wcfn100]

Oh my! Nevermind.

Thanks.

Looking at the Hydrospan info, looks like ~40% reduction isn't anything special.  I have a three pack of the 4020 in 1/64, 1 narrow tread, 2 wide - one with the cab.

Someday.

Someday.

Jason

[jimmo]

Shrinking a tractor model has it's own set of challenges as casting it in an open mold is impossible. It would only be feasible you were attempting to cast one half at a time. Unless one was thoroughly experienced in such practices, I wouldn't recommend taking the challenge.

[wcfn100]

I don't see where an open mold fits into any of this.


Jason

[peteski]

The way I understand Jimmo is that the tractor shape has all sorts of protrusions on it (axles, wheels, seat, etc). It would be difficult to shrink that complex-shaped item as a single piece (in a closed mold).

[wcfn100]

Okay.  I'm definitely a mold making novice but I figured it would be assumed that the tractor would be taken apart.

Jason

[jimmo]

Like Peteski said, it would have to be stripped down to it's base form in order to do any molding. HydroSpan 400 in tricky enough in an open mold let alone trying to use it in a two-piece closed mold. If you've never used it before, then there's a long road of learning ahead.

If you are working with a 1/64 scale model then you will be making two shrink molds in order to step it down to 1/160. There are HO-scale models available of the 4020. But your biggest challenge is still going to be getting the HS400 into the mold before it sets.

[wcfn100]

Like Peteski said, it would have to be stripped down to it's base form in order to do any molding.

I never thought differently.

If you are working with a 1/64 scale model then you will be making two shrink molds in order to step it down to 1/160.

That would remain to be seen.  It looks like I can get to 177th in one step and that may be good enough for flat car loads.

This is probably all moot, as I'll probably just draw it, but it would seem to be a good candidate for shrinking.

Jason

[sirenwerks]

I would be all over a large handful of these.

[jimmo]

I never thought differently.

That would remain to be seen.  It looks like I can get to 177th in one step and that may be good enough for flat car loads.

This is probably all moot, as I'll probably just draw it, but it would seem to be a good candidate for shrinking.

Jason

How are you figuring on getting to 1/177 in one shrink step? Any shrink over a four-to-one ratio (51%) starts getting unstable. Trying to make a mold using a sticky, floppy master is an exercise in frustration (voice of experience).

If you can produce a suitable model in CAD and have it rendered by Shapeways, that's what I would recommend.

[wcfn100]

How are you figuring on getting to 1/177 in one shrink step? Any shrink over a four-to-one ratio (51%) starts getting unstable. Trying to make a mold using a sticky, floppy master is an exercise in frustration (voice of experience).

I went by the chart on the Hydrospan site.  But maybe I'm reading it wrong.

It says a 1:3 ratio of resin and water will yield a part 36% the size when compared to the original.  That's 1/177th in my book (from 1/64th).  I'm clearly missing something in the math I guess.

Jason

[peteski]

The chart on Hydrospan's site seems to be incorrect.  Funny, because their demo video which shows them shrinking a gun states the correct mixing ratio. I think that I pointed that out to them, when I bought a quart.  Or maybe I just thought of doing that. There is a vendor who sells the stuff re-branded as Hydroshrink. They also show a chart which is done correctly.

How do I know all this?  Because I asked few people who actually used that stuff (jimmo is one of them).

[wcfn100]

The chart on Hydrospan's site seems to be incorrect. 

I'll buy that.  I called the company but the 'technician is out for the holiday'.  The receptionist offered to help but I'll probably have to wait until next week to get an answer.

I'll point out the confusion with the chart and see if they'll fix it.


Jason

[jimmo]

When I first found out about shrink resin, it was a company called "The Compleat Sculptor" selling it as "Hydroshrink". Later I discovered that under the label was the original label for the actual company that makes it, Industrial Polymers. The chart that CS included with their product was correct and worked well, but when I purchased the same product (HydroSpan 400) from IP their chart was different. Thinking it was a different formula, I tried their ratios and was very disappointed in the results. I too contacted their tech department and basically got nowhere.

Basically, the four-to-one (51%) ratio is the best, most reliable reduction. Three-to-one is not too bad, as a matter of fact the way I reduce from 1/64 is a slight variance of three-to-one plus three-to-one to step down to 1/160 in two steps. Five-to-one doesn't set up as stiff and never seems to lose it's tackiness. Obviously, beyond five-to-one is ridiculous to even attempt. In the other direction, two-to-one usually results in a lumpy shrink model as it seems to generate bubbles at that ratio.

On top of all that you still have the task of getting the stuff into the mold before it sets up. Pot time is very short, usually less than a minute.