Repairing a crack in a hard nylon part

.

RknRusty wrote:Can you drill a couple of tiny holes in it and splint it with a strip of aluminum, or 1/16" ply or stainless steel wire? I was about to suggest plastic welding until you mentioned you'd thought already of that .

That's an idea. I'll have to look into that.

LOL, I currently have a little bit of JB Weld on it with a little weight pressing the crack together just because its going to be sitting overnight. If it holds, it holds, if it doesn't then I guess I'll have to try something else. LOL

Mudhen wrote:I've had weird stuff to fix as well.
I called 3M. You can try them here: 1-800-234-8068
Web Page: Here
Hope it helps.
As a last resort, you might try the manufacturer. They may have the part available...even if it is old.

LOL, I could drive over to 3M. I did find the exact part I needed... http://www.surplusshed.com/pages/item/r3074.html but I slept too long to buy it. I was going to buy a few of these units awhile back just for spare parts or projects but I never got around to doing it. That unit is the exact unit that is in my player.


Usually it is hard to find parts for these old players, there were so many different players that had different designed parts. Parts are usually available for the most popular players but most of those parts were from players that people parted out.

The mention of plastic brazing brought back the memories of a toy I had as a kid and built lotsa stuff with.

Gentlemen, I give you a pic of the 1974 Mattel Spinwelder.
http://www.ebay.com/itm/1974-Mattel-SPINWELDER-toy-ad-page-9x12-/350567502018?pt=LH_DefaultDomain_0&hash=item519f7390c2

Little plastic welding rod that you set on the end of the gun tool to friction weld plastic kits together. Very doubtful that it would hold your nylon high stress head piece together.

Nylon is tough and nothing will stick to it.
Your only option is a mechanical splice.

My solution would be to drill a couple of tiny holes on either side of the break and blob some JB weld across the break and into the holes.

The JB Weld will not bite on the nylon unless it is roughed up and your part is too small to endure the grinding process.

Yes, nylon lacks the porousity to absorb an adhesive to create a firm bond.

The above split idea has merit IMO.

But it really depends on how badly you want to revive an $8 thrift shop 8 track. Personally. I wouldn't bother.

PV Pilot wrote:The mention of plastic brazing brought back the memories of a toy I had as a kid and built lotsa stuff with.

Gentlemen, I give you a pic of the 1974 Mattel Spinwelder.
http://www.ebay.com/itm/1974-Mattel-SPINWELDER-toy-ad-page-9x12-/350567502018?pt=LH_DefaultDomain_0&hash=item519f7390c2.

Back from the days when we and toy manufacturers both pointed our kids toward developing fun and useful skills.

lousyflyer wrote:My solution would be to drill a couple of tiny holes on either side of the break and blob some JB weld across the break and into the holes.

Good idea, the same effect as the splinting idea but simpler.

SuperDave wrote:...But it really depends on how badly you want to revive an $8 thrift shop 8 track. Personally. I wouldn't bother.

Dave, I don't think it's about the value, it's about the nostalgia and the challenge.

"And that" as Yoda would say, "is why you fail"

Besides that, chicks dig 8 tracks.

lousy:

Yeah but the "chicks" are now in their late seventies.

Rusty:

"Dave, I don't think it's about the value, it's about the nostalgia and the challenge."

Last time I tried something like that was on a AM/FM tape deck in my '65 Mustang convertible. I wound up with a pile of parts and a fevered mind.

Not wanting to crowd my "envelope" and further I pacified myself by purchasing a NEW unit. And so it is with ALL electronic devises today except if you are some sort of masochist and actuall y ENJOY punishing yourself.

Why bother with vintage reed valve engines?

Because it's fun.

Matt:

Because parts are available from our great vendors like Bernie at Cox International and Matt at EX Model Engines.

Parts for old eight-tracks aren't available to my knowledge but MAYBE....SOMEWHERE.. there's an undiscovered "stash". I'll stick with old Cox "reedies" thank you.

"Hope springs eternal." sayeth Alexander Pope

I see this turned into a "why bother fixing that worthless POS, 8 track is stupid" thread. This was supposed to be about repairing nylon parts, not directly about a busted 8 track head mount.

SuperDave wrote:

But it really depends on how badly you want to revive an $8 thrift shop 8 track. Personally. I wouldn't bother.

It doesn't really matter how much I paid for it or how much its worth. Its just another hobby. The reason I ask about repairing the crack is because I don't want to go find a replacement part or make the effort to recreate the part. Knowing that Soundesign is a "low end" brand and that the player itself looks to have had its day, I really don't want to put much into it until I know what it can already do. Now If this player was a Pioneer H-R100, I would put a lot more work into it.

---

The JB Weld on the head mount did take hold. Its been working so far, but we'll have to see how long it lasts. After I reinstalled and cleaned the head, I popped a tape in to hear how it sounds. While the left channel sounded alright, the right channel was almost dead. I tapped on the right and left head connections on the circuit board to make a little popping noise in the speakers just to ensure there was no electronic problem. I then took a little close look at the head to see the right channel pickup was still a little dirty. I removed the head completely from the player and used some Noxon 7 metal polish to shine the head up. I reinstalled the head and popped a tape in, it sounded much better with the right channel loud and clear again. After a little alignment adjusting, the player actually sounds good, better than some of my others. The JB Welded head mount put up with me installing, removing and then reinstalling the head as well as playing different tapes continuously for the last 3 hours. We'll see how long it lasts. Since I had some JB Weld mixed up, I thought I would put some on a busted nylon gear as a second test. The JB Weld didn't seem to want to come off and it took some force to break it loose from the nylon gear. It did come off but it wasn't like it just fell off.



It could use a little cleaning up and I see one of the dial lights are out but both the tape and radio sound good.

I have a neighbor/friend that has collected over 300 brass garden hose nozzles and I know another guy that collects old flashlights. Both have these "treasures" proudly displayed in their homes. Mind you no two items in these collections are the same.

"Different Strokes for Different Folks" - Sly and the Family Stone

I find that JB weld holds best when the mating parts are roughed up a bit with 120 grit sandpaper. For thin or small parts where you cannot use a lot of glue I will use thread to wrap around the part break to help hold it together. Large flat parts I will use fiberglass cloth or carbon fiber tape to help add strength.

I used Lock-Tite CA for plastics to repair the door handel on a microwave oven. The handel lated longer than the oven.

Check these guys out.
Small family owned business with world class products,-

http://www.shop4glue.com/polyweld-58ml-thin-plastic-plas-weld-glue-adhesive-perspex-polystyrene-acrylic-abs-hips-fivestar-51-p.asp

If this doesn't do the trick they have a cyano type product that
Will bond even PTFE.

I was thinking something along the lines of Oaties PVC pipe primer and glue. I had used that stuff to fix a nylon looking drive wheel inside of a older Mitsubishi VCR player I had. It worked for years after that fix till the power source quit.

John Goddard wrote:Check these guys out.
Small family owned business with world class products,-

http://www.shop4glue.com/polyweld-58ml-thin-plastic-plas-weld-glue-adhesive-perspex-polystyrene-acrylic-abs-hips-fivestar-51-p.asp

If this doesn't do the trick they have a cyano type product that
Will bond even PTFE.

Its unlikely the Polyweld will do it ive tried a few similar bits on old cassette players i use on my 1980s computers and they have been Delrin or Nylon that will not weld , the StarLoc Universal Repair Pack should as it bonds all plastics , the primer makes the plastic bond and the toughened adhesive is also modified to bond with plastics better also has additives to give a high sheer strength to the bond.

http://www.shop4glue.com/universal-glue-bond-adhesive-repair-pack-metal-all-plastics-ptfe-polyethylene-polypropylene-silicone-81-p.asp

The JB Weld is still holding! I have been using it a lot in the last few days and its still going strong!

Ka-chunk...(sound of 8 track)

Very good!