V-weight for a backplate

[Rudebob]

I have been messing around trying to come up with some simple molds so I can make v-weights to go on backplates. This very simple design worked pretty slick. I've have already drilled and installed one on my SS halcyon. This weight easily added 7 balanced pounds that would of been on my waist before. I have a little more room if I want to repour a little larger weight, but this is already vast improvement when extra weight is needed for drysuit diving. I use tin-lead solder materials (I get remnants free from work), but pure lead would be slightly heavier for the same volume.

The one shown is sized for a dive rite plate. Basically, I took 1.5" thin walled steel square tubing (aluminum would obviously be better but I don't weld aluminum). I cut one side off the tube as close to the edge of the wall as possible to make a U-shaped channel. Then on the opposing side of the tube I ground each corner down to reduce the wall thickness (don't grind through) to a point less that was less the wall thickness of the tube. I then put each end in a large vise and gently bent the walls outward until reaching the correct angle of the dive rite plate. Because the corners of the tube were ground thinner than the rest of the tube the bend radius was formed in the corner only.

I then further flared the end of the mold out slightly and welded on some sheet metal tabs to close off each end of the mold. Because all surfaces are flare outward somewhat the weight easily drops out after cooling.

Then it is just a matter of drilling the mount holes and grinding out a recess for tank straps or you can use spacers to provide enough clearance.

I may tweak the design a little more. If anyone has any ideas for further improvement please comment.

mg

 

[lucca brassi]

first: this is a P- weight ( V- weight is installed between doubles )

This weight easily added 7 balanced pounds that would of been on my waist before.

I do the same thing but unlucky me - P weight spoiled me a trim (obligatory buddy has to check you because you will hard find out yourself that you swiming with head a little down , with exception of neck pain and more consumed air)

Mold it is very well done but you have to heat it hard between instilling and very slow cooling after process. ( Maybe to done some grill or barbecue for keeping constant heat and slow cooling down )

I use tin-lead solder materials (I get remnants free from work), but pure lead would be slightly heavier for the same volume

.

I have tought that this is problematic because of salt water galvanic series but I see from the table that Pb and Sn are close together in the middle of table (not anodic or cathodic orientated metal) and next is SS 316 so no problem at all!

 

[divepig2]

That looks nice. I think you're better off with a steel mold anyway......aside from not welding alu (I don't either) I think you'll get more pours from steel before you'll have trouble.
I'd like to see what your melting setup looks like.
H

 

[Rudebob]

I'd like to see what your melting setup looks like.
H

I just use the propane stove from my turkey fryer. Takes less than 5 minutes to melt 7 lbs. I melt in a medium size aluminum cooking pot that was from a garage sale (not teflon) with a vise-grip clamped on to use a secondary handle. Of course protective clothing is also a neccessary.

 

[HenrikBP]

Doing the melting outside or in a well ventilated area I hope

Henrik

 

[AZ_ROB]

FYI don't get it too hot it will explode all over the place.....

 

[MaxBottomtime]

I made mine using the backplate itself as the mold. I covered the channel with aluminum foil, packing more foil at the ends of the channel, rolled two pins in aluminum foil for the holes so I wouldn't have to drill later and poured the lead directly into the channel.
I found that small chips of lead in the pot melted quickly. The molten lead coming in contact with the larger pieces sped up the melting process. I was able to melt the lead over my stove in less than two minutes. All doors and windows were open and vents were on.

 

[mksmith713]

Why not just buy a 5 pound 3 ounce STA from Hammerhead?
Saves you all the hassle......and it's alot of hassle.....I know.

Hammerhead Scuba - Hammerhead II Backplate.

 

[bmoraes]

After drilling the holes, did you get enough clearance between the plate/nuts and your back?

 

[T. Bix]

How about totally adjustable soft weights for your backplate? I used to reload so I had bunches of .45 laying around not being used for anything. I (my wife) sewed up a pouch that fits between the tanks with a flap to adjust the amount of lead up to six pounds. and a smaller one that holds three pounds that goes against my spine. I just put a couple of gromets 11" apart and it installs on the studs. I will be in the water this weekend so I haven't checked the trim but I'm thinking I have a pretty good starting point maybe three pounds heavy at the safety stop. We'll sse