Packard Forum Index » Packard Parts & Misc - For Sale, Wanted, Trade

Hello! I'm currently looking for the interior plastic knobs for a 1948 Packard super eight. Air, no air, heat, OD, etc. I need a full set, mine are completely rotted. If I could get a high-quality set too, I could pop off some molds for creating reproductions out of fiberglass. Let me know if you have some!

Thanks,

Icarus

Have you tried Max Merritt for NOS pieces? They’ve surprised me with all the odd bits and pieces that they’ve been able to supply for my Henney-Packard.

Maybe message Crin and see if he wants to design a 3D printed set.

Or check with Lavine Reproductions and see if it is something they have considered adding to their current line of knobs.classiccarreproductions.com

Fiberglas is not the right material to use, an unreinforced material will give a better surface. There are a lot of 22-23rd series cars - a parts car may be the easiest way

Search this topic: This came up not too long ago and someone was trying to remove one(hood pull?) or something and they're molded on.
It doesn't do much good to make the knobs only as they won't fit the shafts.
I don't think there were any repro for that reason.
I tried to get some of the same plastic escutcheon rounds that go under the handles that protect the door panel and had no luck. I'd omit in the "someday" new interior. The plastic was tenite or butyrate pigmented and blended to look like ivory and appears to degrade over time. Maybe marble dust or other fillers. I think epoxy is a better choice if you want to repair. You can make a blank out of turned wood or plastic and make the mold in two parts and encase the old knob and add the epoxy. Turn, sand, and/or polish as needed.
Fiberglass will be hard to match without painting. Not easy to use gel coat in a small item. There are injectible resins that will give the look, but not a pourable entity. Those are usually acrylics. The guy, Dennis, that does steering wheels (quality restorations, ins.) uses it and matches well. I was going to do the wheel, but the price scared me off to get a driver, but probably will put in a new column anyway.

I believe I have the heater and air knobs for both 22nd and 23rd will look tomorrow.

Thanks Dell! Lemme know what you find.

@Fish'N Jim

The reason I wanted to use fiberglass is because a) I'm quite familiar with it, and b) it allows me to make a hollow shell that can be filled. Like you said, the knobs are moulded on; if you take a hollow shell and fill it,you can fairly easily squish it onto the old fitting and paint it in place.

I don't know if it'd be possible to get the fine detail, but I wanted to give it a shot. You are right, it'd be hard to match without painting, but for a small batch it'd be fine (and it'd be an interesting project!).

@humanpotatohybrid

3D printing could be a good choice! I didnt think of that.

Nevertheless, something tells me that I'm barking up a tree that others have already tried, possibly decades before I was born lol.

An insert in the mold, like a straw, could make the hole. If you hand lay some mat to make the hole, that will work too, although wetting it out will be a bit tricky. Fiberglas is chopped glass fiber in a (usually) polyester matrix. The glass fiber will give a rougher surface and is unnecessary for strength in this part.

Another option would be to make a silicone mold and use a casting urethane. Since interiors can get rather hot if the car is standing in the sun use a material with one of the higher temp before it will deform ratings to cast the knob. There are also some casting epoxy materials that will withstand even higher temperatures but that is probably overkill. Smooth-On and others have several options.

For a finish, I don't think paint on casting material or fiberglass would match the original look very well so to my mind, the hardest part would be to match the knob color in the casting material. For that, it will take experimenting, patience, a good eye and being able to duplicate the formula more than once. With my castings, I found I lack some of those qualities but the Yesterdays Radio knobs (now made by Lavine Reproductions) have that part down to almost perfection. Before going to a lot of effort or expense maybe it would be worth touching bases with Lavine to see if those knobs are something they would be interested in doing.

As far as being molded onto the shaft, when Yesterdays Radio made knobs to replace molded originals a simple hole was drilled or maybe cast in the new knob. The knobs were then fastened onto the old shafts using epoxy. Most of the shafts have some kind of knurling or serrations the original plastic grabbed or formed around and if some provisions are made in the replacement knob hole for the epoxy to fill and harden into, it will hold satisfactorily. On a couple of knobs I replaced with repros I used a Dremel tool to make a couple of undercut or angled notches going into the straight sided hole to provide a space the epoxy could key into. With the angle wider at the inside it also made it harder for the knobs to be pulled off.