stunthanger.com

Building Tips and technical articles. => 1/2 A building. => Topic started by: Dane Martin on May 07, 2020, 02:50:22 PM

Title: Cracked Cox backplates peewee 020
Post by: Dane Martin on May 07, 2020, 02:50:22 PM: I'm asking this because I'd really like to fix or salvage this...

So, sometimes you get ahold of a used engine that's warped or cracked, usually from someone over tightening it. Has anyone successfully soldered something like this? I'm not even sure what type of metal it is. In the pic, you can see the light in the bolt hole where the crack is.
Title: Re: Cracked Cox backplates peewee 020
Post by: Fredvon4 on May 08, 2020, 08:20:15 AM: sorry.....pot metal with a coating that changed over the years...sometimes the pot metal was refered as zmack or something similar

do self favor...ask your friends...hint hint for a few old bees-------or bid on odd lots with a few metal back plates

Bernie and Matt are nearing a run of CNC machined aluminum back plates....
Title: Re: Cracked Cox backplates peewee 020
Post by: Dane Martin on May 08, 2020, 08:38:09 AM: Quote from: Fredvon4 on May 08, 2020, 08:20:15 AM

do self favor...ask your friends...hint hint for a few old bees-------or bid on odd lots with a few metal back plates

I have a bunch of complete engines. I really don't "need" this... but I can't stand the thought of a dead one just because of a back plate! Lol.

I pressed it out pretty straight, and soaked it in CLR. Cleaned it out real nice with a tooth brush. It's really clean and kinda straight now. I might try a cleverly placed dab of JB. It certainly can't be any worse
Title: Re: Cracked Cox backplates peewee 020
Post by: 944_Jim on May 08, 2020, 09:51:24 AM: This may be the time to go "externally tanked" without drilling the factory tank. One of the guys on CEF 3d printed a short run of plastic backplates that makes the Pee Wee look like a mini product engine.

There are test videos of converted engines, so this is a proven solution...that, and the Pee Wee is just so cute with only a backplate on it!

I bought two, but have yet to play with them.
The next run was a wholesale run for Bernie to retail through Cox Intl. You may want to watch CEF and Cox Intl for availability.
Title: Re: Cracked Cox backplates peewee 020
Post by: Fredvon4 on May 08, 2020, 09:56:08 AM: Hey Dane old guy here...sorry missed the peewee 20

new back plates are for 049s

the printed items Jim is touting are trick and you NEED two....grin
Title: Re: Cracked Cox backplates peewee 020
Post by: Dane Martin on May 08, 2020, 12:23:25 PM: Well would you look at that? It's live now!

https://coxengines.ca/product.php?productid=2117&cat=3&page=1
Title: Re: Cracked Cox backplates peewee 020
Post by: Dave Hull on May 10, 2020, 11:50:54 PM: Danish,

We had a guy making solid aluminum "backer plates" that would go behind the factory plate to solve the warp/leak/break problem with .049's. You could do the same for the .020 if you want to keep the integral tank and would rather cobble something up rather than hunt for a good one. They work fine, but you need longer screws. If you are interested, I can text you a picture.

The Divot
Title: Re: Cracked Cox backplates peewee 020
Post by: Dane Martin on May 13, 2020, 08:13:36 AM: So... I ended up pressing mine "straight" and with some clever dollops of jb weld, it's leak free. Whilst being impatient, I had emailed Matt at EX models. He was able to procure a back plate that wasn't listed on his site. So now i have a really nice one, and a JB welded back up