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View Full Version : Thingy in the Center of the Blast Deflector


Jeff Walther
10-02-2008, 12:33 PM
I recently acquired two blast deflectors as part of a small lot I bought on Ebay and neither one has the doohickey which goes in the center of the blast deflector so that it fits closely over the launch rod. So currently, the blast deflectors have a hole shaped like a circle with a longer rectangle laid over it, IIRC.

Where can I get those things that go in the center and what are they called?

I guess there are probably different ones depending on the launch rod thickness. I'm just using a plain old 1/8" launch rod.

My need is not urgent as the bottom and top of the old style fruit juice cans (or old Hawaiian Punch cans) with a hole drilled in the middle serve well as a blast deflectors.

Rocket Doctor
10-02-2008, 01:40 PM
I recently acquired two blast deflectors as part of a small lot I bought on Ebay and neither one has the doohickey which goes in the center of the blast deflector so that it fits closely over the launch rod. So currently, the blast deflectors have a hole shaped like a circle with a longer rectangle laid over it, IIRC.

Where can I get those things that go in the center and what are they called?

I guess there are probably different ones depending on the launch rod thickness. I'm just using a plain old 1/8" launch rod.

My need is not urgent as the bottom and top of the old style fruit juice cans (or old Hawaiian Punch cans) with a hole drilled in the middle serve well as a blast deflectors.

Send my a PM and I will send a couple of those "thinggys" to you.

RD

Give full name and address with PM (snail mail)

luke strawwalker
10-02-2008, 02:33 PM
I recently acquired two blast deflectors as part of a small lot I bought on Ebay and neither one has the doohickey which goes in the center of the blast deflector so that it fits closely over the launch rod. So currently, the blast deflectors have a hole shaped like a circle with a longer rectangle laid over it, IIRC.

Where can I get those things that go in the center and what are they called?

I guess there are probably different ones depending on the launch rod thickness. I'm just using a plain old 1/8" launch rod.

My need is not urgent as the bottom and top of the old style fruit juice cans (or old Hawaiian Punch cans) with a hole drilled in the middle serve well as a blast deflectors.

THe old Estes blast deflectors from the 80's used a steel roll pin... they're available at most hardware stores and auto parts places...

They switched to some kind of plastic doo-dad that was custom made to twist-lock into the steel plate on the newer ones I've seen... Sorta like the old 45 to 33 RPM adapters used back in the old vinyl record player days... That you won't likely find anywhere else. You might have to adapt a 1/4 inch steel close pipe nipple to the deflector to replace the plastic chingaderra.

If it has a ROUND hole it's for a steel roll pin, if it has a LARGER round hole with 3 'notches' around the hole, it's for the plastic chingaderra....

Hope this helps! OL JR :)

Shreadvector
10-02-2008, 03:19 PM
THe old Estes blast deflectors from the 80's used a steel roll pin... they're available at most hardware stores and auto parts places...

They switched to some kind of plastic doo-dad that was custom made to twist-lock into the steel plate on the newer ones I've seen... Sorta like the old 45 to 33 RPM adapters used back in the old vinyl record player days... That you won't likely find anywhere else. You might have to adapt a 1/4 inch steel close pipe nipple to the deflector to replace the plastic chingaderra.

If it has a ROUND hole it's for a steel roll pin, if it has a LARGER round hole with 3 'notches' around the hole, it's for the plastic chingaderra....

Hope this helps! OL JR :)

2 notches, not 3. DFMA.

Rocket Doctor
10-02-2008, 07:50 PM
The Doctor has filled the prescription and they will be on their way.

Jeff Walther
10-02-2008, 08:55 PM
Thank you, gentlemen. These blast deflectors are the newer type with two notches. They (the holes) look a bit like an old air force (?) emblem, like a circle overlaid by a rectangle which is much shorter than the circle in one dimension and much longer in the other dimension. I guess that would also be described as two notches.

Anyway, the Rocket Doctor has me covered for which I am very grateful.

Jeff

Mark II
10-02-2008, 10:28 PM
The plastic twist-post on my Porta-Pad II crumbled and broke after several launches. Until luke strawwalker mentioned it, I had forgotten about the steel roll pin that was used in the center of the deflector of my old Electro-Launch Pad, somewhere back near the dawn of time. If you can't find a replacement for the plastic post, you might try replacing it with one of those pins. The one in my old pad worked quite well, as I recall; it didn't fall out all the time, nor did it break down after a just a bit over a dozen launches. ;)

Currently, in my smaller DIY pad, I use a short steel nipple that is threaded just on the ends. One end fits through a hole in my flat blast deflector plate, and is held in place between a pair of electrical conduit nuts that are threaded onto the nipple.

You also might be able to use a brass barbed hose fitting as a replacement for this post. Depending on the diameter of your launch rod, some of the smaller fittings could even center and hold the rod steady without any clamping.

Mark \\.

Royatl
10-03-2008, 12:16 AM
The plastic twist-post on my Porta-Pad II crumbled and broke after several launches. Until luke strawwalker mentioned it, I had forgotten about the steel roll pin that was used in the center of the deflector of my old Electro-Launch Pad, somewhere back near the dawn of time. If you can't find a replacement for the plastic post, you might try replacing it with one of those pins. The one in my old pad worked quite well, as I recall; it didn't fall out all the time, nor did it break down after a just a bit over a dozen launches. ;)

Currently, in my smaller DIY pad, I use a short steel nipple that is threaded just on the ends. One end fits through a hole in my flat blast deflector plate, and is held in place between a pair of electrical conduit nuts that are threaded onto the nipple.

You also might be able to use a brass barbed hose fitting as a replacement for this post. Depending on the diameter of your launch rod, some of the smaller fittings could even center and hold the rod steady without any clamping.

Mark \\.

nah, the hole in the old deflectors is just under 1/4", while the new deflectors are much larger.

I'm thinking about trying to make a mold of the current "thingy" just to see if I can do it and make a few resin copies. Of course, that's one of those things I'm going to try "Real Soon Now, " if you know what I mean!

Mark II
10-03-2008, 12:47 AM
So just reduce the hole with an epoxied or soldered on washer, or make your own deflector! (As in Item 2 or Item 8 in the attachment, taken from page 803 of the McMaster-Carr catalog.)

Mark \\.

gpoehlein
10-03-2008, 06:48 AM
I might add that, "back in the day" we uses the lid or bottom from a coffee can with a hole punched in the center as a blast deflector. Yes, they do eventually burn through, but by that time, hopefully your parents had emptied the next can and you could make another (I was a kid - and I STILL don't like coffee). Some of my friends in the rocket club actually got fancy and used the whole can after cutting the ends out. The cut down the seam, and folded it on the opposite side so they had two semicircles attached at one edge, then flattened it somewhat. They made a hole in the center of the apex and let the motor blast go down one side or the other, re-directing it to the horizontal.

Greg

tbzep
10-03-2008, 07:41 AM
BTW, for a short time, the plastic thingamabob used two screws to hold it in place and the deflector had one large hole and two small ones for the screws. It wasn't long before they advanced to the twist-lock version, cutting the cost of adding a couple of screws. :rolleyes:

Royatl
10-03-2008, 08:13 AM
BTW, for a short time, the plastic thingamabob used two screws to hold it in place and the deflector had one large hole and two small ones for the screws. It wasn't long before they advanced to the twist-lock version, cutting the cost of adding a couple of screws. :rolleyes:

Yea, but I've found it really easy to break the tabs and the flange off, rendering the post useless (probably the same with the screw-on version). I was going to experiment with resin and flocking to see if I could make something stronger.

Solomoriah
10-03-2008, 08:19 AM
None of my twist locks actually lock. I hate them, personally. Part of why I made my own out of ceramic tiles.

Jeff Walther
10-03-2008, 09:37 AM
<chuckle> From the comments here, it sounds like I'm probably better off sticking with my fruit-juice can ends. They haven't burned through yet, and when they do, I saved the body of the can (cut down the seam as an earlier poster mentioned).

There was guy on Ebay who would cut you any (flat) shape of plate steel you wanted on a per pound basis. If he was still selling I'd be tempted to get a couple of 1/8" thick (thinnest he sold) circles from him and then drill a hole in the middle to the size I want--e.g. to match those cold rolled pins mentioned earlier. I wish that guy was still selling. He had the same deal going with plate aluminum. There are an awful lot of things that are easier if you have an affordable source of custom cut plate metal shapes. (had him make me some adapters which I then bent and drilled to convert the weird mounting holes on the back of my ca. 2001 IBM LCD panels to standard VESA mount holes.)

These two blast deflectors are probably destined for my son's cub scout troop anyway. They were a little short of launchers at the rocket activity a month ago and would have been woefully short if two parents (I was one) hadn't brought launchers. Maybe statistics say that every year parents will have enough extra launchers available, but it seems unlikely. Then again, it's a big enough troop that statistics might apply. Anyway, it won't hurt to give them a couple of launchers provided there's enough institutional organization to not lose them.

Shreadvector
10-03-2008, 09:38 AM
BTW, for a short time, the plastic thingamabob used two screws to hold it in place and the deflector had one large hole and two small ones for the screws. It wasn't long before they advanced to the twist-lock version, cutting the cost of adding a couple of screws. :rolleyes:

DFMA

There were 5 parts replaced by 2 parts. Upper plastic standoff, deflector plate, lower plastic flange and 2 screws. New version has metal plate and twist lock standoff.

Mine last a long time and if they break I use the pipe nipple replacement with a nut to secure it.

luke strawwalker
10-03-2008, 03:01 PM
2 notches, not 3. DFMA.

Sorry... still thinking about the old 45 to 33 LP adapters... LOL:) I don't have a pad/deflector that new, but I've seen them and helped some kids with them. OL JR :)

PS... DFMA?? :)

luke strawwalker
10-03-2008, 03:10 PM
The plastic twist-post on my Porta-Pad II crumbled and broke after several launches. Until luke strawwalker mentioned it, I had forgotten about the steel roll pin that was used in the center of the deflector of my old Electro-Launch Pad, somewhere back near the dawn of time. If you can't find a replacement for the plastic post, you might try replacing it with one of those pins. The one in my old pad worked quite well, as I recall; it didn't fall out all the time, nor did it break down after a just a bit over a dozen launches. ;)

Currently, in my smaller DIY pad, I use a short steel nipple that is threaded just on the ends. One end fits through a hole in my flat blast deflector plate, and is held in place between a pair of electrical conduit nuts that are threaded onto the nipple.

You also might be able to use a brass barbed hose fitting as a replacement for this post. Depending on the diameter of your launch rod, some of the smaller fittings could even center and hold the rod steady without any clamping.

Mark \\.

Hehehe.. yeah I remembered having to install that sucker myself when I was 13-14... just about smashed my fingers trying to get that little b@st@rd started in the hole and pounded halfway thru... Course I was using the farm anvil and a 16 ounce ball peen from the shop :)
Not half as bad as replacing the roll pins in the bar drive gears on a 9900 cotton picker bar-- they use a 1/16 roll pin hammered INTO a 1/8 roll pin-- you hammer/press the gear on, hope the holes line up, and then hammer in the 1/8 roll pin, then hammer a 1/16 roll pin inside it... if you DON'T install the 1/16 roll pin, the 1/8 pin will shear off under the torque... kinda stupid design IMHO...

The best bet for folks that need the newer style, since it's SIGNIFICANTLY larger, is to take the blast deflector plate to the local hardware store and start looking around... a 1/4 inch pipe close pipe nipple comes to mind immediately as a possible replacement, or possibly some 1/4 inch or 3/8 inch plastic tubing about a couple inches long twisted into the hole, perhaps with a slightly larger piece over it if necessary to take up the slack, etc.

Actually just dropping the plate with NO rod chingaderra isn't necessarily a bad thing, as the plate will tilt a little and deflect the blast at an angle, but keeping it from shorting the clips is another matter... :) OL JR :)

tbzep
10-03-2008, 04:56 PM
Sorry... still thinking about the old 45 to 33 LP adapters... LOL:) I don't have a pad/deflector that new, but I've seen them and helped some kids with them. OL JR :)

PS... DFMA?? :)

Design for manufacturing and assembly

MarkB.
10-04-2008, 07:31 PM
Does "chingaderra" have one r or two?

luke strawwalker
10-06-2008, 11:36 AM
Does "chingaderra" have one r or two?

Not sure... I can speak just enough Spanish to get in trouble... can't spell it for scheiss... OL JR :)