Hydroforming question

Hey ?Eric,

One of the Members of the MDMC was into hydro-forming for a living. He showed us pictures of the machinery used to hydro-form GM truck frames. Huge, but did do what you are asking.

Take care.

Brian Laws>Can a rectangular shape with rounded corners be hydroformed without

Think Stainless kitchen sink

Are they done all at once? ERS

The Urethane block would, in all probability, compress more than the sheet metal would.

As to the use of Hydroforming, Ford, GM, and Dodge all use this process to make the frames of their pickups - using thicker metal - and, as mentioned earlier in this thread, SS sinks are produced that way.

Of course you realise that you'll need at least 1 die for any kind of mechanical forming - whether Hydroforming or simple stamping (takes 2) - for each shape and size you want.

How many of these boxes would you be wanting to make?

Eric, as I understand, urethane is typically used as the female die cavity, not the punch. There are certain situations where it is used as the punch, namely when trying to expand a vessel without expanding its neck (like a salt shaker cap, for instance).

As far as hydroforming, it's likely that this part could be producing using a hydroforming process. My company built some hydroforming dies to make GM truck frames. This process is a bit different than what you're referring to. With tubular hydroforming, there is no extra material like there is in drawing. Other than some piercings and trimming at the ends of the tube, everything that goes into the die becomes the frame. It would be closer to stretch-forming than drawing. Because the tubes start as round, the corners tend to thin somewhat. I'm not sure this would necessarily be the case in your situation.

As I understand certain panels are actually drawn using a hydroforming process instead of using a solid punch. I'm not sure how such a process would work for the type of work you're talking about, however.

Well, I guess that was kind of useless...

Regards,

Robin

I'm just curious. I have seen sites where people are hydroforming motorcycle mufflers and the like. But I was wondering just how far it could be taken. ERS

Here's one example: My son-in-law laid down his bike a couple of weeks ago. The muffler is apparently a very expensive factory-only item, and was partially crushed by the tip-over. The ding was way too far down inside the welded assembly to get any sort of tool onto, and he really didn't want to drill it, pull it, and weld the hole.

So we slipped the whole muffler housing inside a fairly close-fitting pipe (just to make sure it wouldn't balloon) and explosively inflated it (yes... with explosives... happens to be my business ).

Worked just FINE! It doesn't look exactly factory new, but doing it was FUN!

LLoyd

I did that explosives trick to a motorcycle gas tank once. Very thin light gauge steel. I was going to repaint it but didn't want the seams to split so I wrapped it a few turns with nylon filament packaging tape, followed by some old fiberglass cloth, tossed in a couple of Black-cats and ran like hell. No real drama and the dents were neatly punched out from the inside. DO NOT try this.

Found that brouchure again (Veith Eladur*).

They have the following recommendations:

Material |factor| max. wall thickness

-----------+------+--------------------- Eladur 42 | 1.3 | 0.5mm Eladur 100 | 1.25 | 1.2mm Eladur 167 | 1.2 | 2.0mm Eladur 200 | 1.1 | 3.0mm

factor is how much the diameter or cross-section can be widened.

The types have following propperties: type |shore | elasticity

-----------+------------+------------ Eladur 42 | 80 A | 35% Eladur 100 | 90 A / 40 D| 30% Eladur 167 | 96 A / 50 D| 25% Eladur 200 | 98 A / 60 D| 15%

Don't know how "elasticity" is measured.

If you want, I can scan the 3 sectional drawings they have for that subject. They also say that you can have bigger factors, but the rubber will get kaputt quicker (no mentioning of how many cycles).

You're welcome.

*) My posting a few weeks ago about the press barke that used a PU-stick for the die.

Nick

--Well ya just *know* someone's going to try it, so howzabout an explanation of how you did it so others don't kill themselves? ;-)

How about the links?

The ones I have seen (don't ask me for a link!) were _very_ primitive: Cut out two equal halfes out of sheet metal. Weld them all the way around, except where you weld a short house into it. And pump it up with water. No die needed. They didn't look that bad!

Nick

Wellsir... in my case "a couple of black cats" wouldn't have come close.

50mg common firecrackers have almost no explosive force, and worse, the aluminum-based flash powder they use is what's known as a "negative explosive", in that the combustion products (once cooled) occupy a smaller physical volume than the initial constituents.

What you need for this kind of operation is a gas-producing explosive. It's the rapidly expanding gas - not the shock wave - that forces the metal outward.

We used 1oz of black powder concussively initiated with 5g of common "flash powder". That produces something like 3800 cc of gas in about 2 ms. The muffler housing had a gross capacity of about 1800cc. We didn't want to overpressure it, so we stopped at about a 2:1 volume ratio. In general, you can figure the pressure generated by a partially obturated black powder explosion to be around 160-250 psi, but the initial overpressure wave when it's concussively ignited is around 500psi for a few microseconds. (I don't know these things by personal measurement, it's something that's been tested in the industry, and can be found in tables)

Keep in mind that one ounce of black powder ignited with a fuse can fire a

1-lb, 4" diameter projectile about 400' high.

Actually, we tried the trick with 5g of flash powder (only... no BP), and nothing happened except for a very satisfying BANG!

I really _wouldn't_ try this at home. First of all, you must have a BATFE license _and_a_licensed_site_ to do this. Second, it could be pretty hazardous. We have the place, the license, and the protective bunkers and clothing to do this sort of thing in reasonable safety.

And if it destroyed the muffler? Oh, well... he was gonna have to replace it anyway!

LLoyd

Way cool! Id love to take a tour sometime.

Gunner, once carried a B blasters license, and as a child was known as the Mad Bomber

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."

"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion).

-Buddy Jordan 2001

Leaky diaper?

Two of my friends and I decided to make our own firecrackers when we were in Jr High School, in the aerly '60s. Their mother was a science teacher at our school. They asked her to buy them a 20 pound bag of Sulfur, 20 pounds of Potassium Nitrate. They already had a stack of 10 pound bags of Charcoal, not to mention about 50-100 empty 2 oz glass bottles with metal lids from several chemistry sets. One of them had someone buy some slow burn fuse, and we proceeded to make 5 pounds of black powder, and fill the bottles.

We found a great use for them. They not only blew the trash out of a spiral galvanized culvert under a driveway, but the glass did a decent job of removing the rust. ;-)

Ayup.

Hey..one of the local cranksters walked off with that jack hoist last weekend. I got it back within 24 hours, no harm no foul, and nobody died...(though he did need to change his skivies). So please please please come get that Big Joe and the jack hoist ASAP so I dont have to run a new Forstner 3/8" drill bit up under someones kneecap as I graphicly demonstrated doing, if something else comes up missing again.

We will worry about the details at some other time. I just want em gone, to limit the "bees to honey" factor and frankly..I need the room.

Gunner

"If I'm going to reach out to the the Democrats then I need a third hand.There's no way I'm letting go of my wallet or my gun while they're around."

"Democrat. In the dictionary it's right after demobilize and right before demode` (out of fashion).

-Buddy Jordan 2001

Mark, Snap a few pics and send them. You guys sure do have a lot of crime up there. Glad I'm safe down here in Los Angeles. LOL

Here is a link to a muffler hydroformed.

regards,

John