How I solder 6-8mm bullets: simple jig

[JIM MARCUM]

Used to have problems with the silver solder flowing into the contact areas, so I built this simple jig below. Use the mini-torch and regular electrical solder to fill up the connector ends, and 60/40 silver solder on the wires. With the connector in the jig, heat the bullet solder & wire with the mini-torch until the wire can be fully pushed into the bullet. After it cools down, I clip off excess solder leaked out of the holes in the bullets with dikes & use a flap wheel to smooth things up prior to adding the heat shrink. JIM
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NOTE: It's just a piece of >1/2" thick aluminum plate with holes drilled the same size as the "connector" OD part of the bullet to hold them in place & eliminate excess solder flow.

[martin]

Jim do you use any particular 6mm & 8mm conectors or just the various cheapo ones that are around like on Ebay & HK, or do you go for better quality more expensive ones. Thanks Martin.

[JIM MARCUM]

Jim do you use any particular 6mm & 8mm conectors or just the various cheapo ones that are around like on Ebay & HK, or do you go for better quality more expensive ones. Thanks Martin.

Martin, I've bought 8mm bullets from hobby stores in the US and several Chineese dealers. In my opinion, the best I've seen are the ones from Hobby King. They have thicker walls, and larger contact surfaces than any any others. As a result, there is less resistance & therefore less heat.

The pics below show the comparison between "normal" & HK 8mm bullets. JIM
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[tlandauer]

Thanks for the pics, Jim
I realized that also ( thicker walls) but I also noticed the HK alloy has a lighter color, ( was worried that it might be an inferior alloy), at least on the Turnigy battery connectors. But your picture shows exact color so maybe this isn't true on the plugs your buy as supplies. I wanted to try but didn't--- out of this concern.

[JIM MARCUM]

Thanks for the pics, Jim
I realized that also ( thicker walls) but I also noticed the HK alloy has a lighter color, ( was worried that it might be an inferior alloy), at least on the Turnigy battery connectors. But your picture shows exact color so maybe this isn't true on the plugs your buy as supplies. I wanted to try but didn't--- out of this concern.

FYI, by the time my 8mm bullets arrived from HK, I had already put the "normal" sized ones on all of my motors (Leopards 5692-3660) and LIPOs (2s-5S). If any of them incur the dreaded silversolder melt down, I'll replace them with the superior HK bullets. JIM

[Drax21]

Thanks for the great info Jim. I have a jig for 5.5mm bullets and other connectors but not for 6mm. Now I realize I can just drill out the 3.5mm connection slot to 6mm for my connectors. The HK connectors do look a lot better! I didn't think it was that much difference!

[tlandauer]

Jim,
Thanks for the info and now I erased any doubts regarding the quality of HK plugs.

[martin]

Jim are the HK 6mm off equal quality to their 8mm as i need both sizes. Thanks.

[m4a1usr]

Martin, I've bought 8mm bullets from hobby stores in the US and several Chineese dealers. In my opinion, the best I've seen are the ones from Hobby King. They have thicker walls, and larger contact surfaces than any any others. As a result, there is less resistance & therefore less heat.

The pics below show the comparison between "normal" & HK 8mm bullets. JIM

Gotta agree 100%. I began using the larger HK 8mm a couple years ago. All my Lipos, motors and speedos are now 8mm. Took awhile to convert but its been worth it. It took me over a year to buy the various 8mm bullets out on the market and make a comparision between all them. The large HK's will work for anything you have to throw at them. And the price is nice too. I still like the smaller 8mm for my chargers since the load is so small, and the bullets pull off easyier. But for boats. The HK 8mm are more than capable of getting the job done.

John

[m4a1usr]

Oh yeah. Forgot to mention. If you tired of the solder running out those darn side holes in the 8mm bullets buy some 11/32 brass tubing. Cut it at .250 length. Slip it over the wire end of the bullet before soldering. That will make the end into a "cup". Retaining all the solder and it wont run down the bullet. Simple.

John

[martin]

Are the HK 8mm better than Castle 8mm price aside. Thanks Martin.

[dana]

every time i try t solder 8mm bullets standing up like this, the solder just ends up flowing out of the holes and making a mess, so i fight with them laying on their sides and make a mess anyways lol ...im making one.

[JIM MARCUM]

Oh yeah. Forgot to mention. If you tired of the solder running out those darn side holes in the 8mm bullets buy some 11/32 brass tubing. Cut it at .250 length. Slip it over the wire end of the bullet before soldering. That will make the end into a "cup". Retaining all the solder and it wont run down the bullet. Simple.

John

Good idea John. But I'll try aluminum foil instead. My electrical & silversolder sticks to brass.

The OD of the "normal" 8mm bullets at the solder end measure .277". The HK bullets measure .333" - 334". FYI, the OD of the female bullets are .354" for "normal" and .408" for HK respectfully. HK wins.

THX, JIM

[JIM MARCUM]

Jim are the HK 6mm off equal quality to their 8mm as i need both sizes. Thanks.

Martin, I have two types of 6mm bullets. Unfortunately, I don't know where I bought the better of the two. In the pics below, the ones with the smaller solder (.97") holes are superior. I'd just buy a pack from HK and one from OSE. I buy from alot of places so I'm not really sure where I bought these. Maybe you can PM Steven & ask him what the ID of OSE 6mm bullet sloder holes are. If they came from R2hobbies, we're screwed. JIM

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[JIM MARCUM]

Thanks for the great info Jim. I have a jig for 5.5mm bullets and other connectors but not for 6mm. Now I realize I can just drill out the 3.5mm connection slot to 6mm for my connectors. The HK connectors do look a lot better! I didn't think it was that much difference!

Tim, i wouldn't drill out the holes you already have - you might need to use them again. I too have a soldering jig from HK, but it was too limited in size for my larger bullets, and didn't have room to drill additional holes. It was easier for me to just get a piece of 1/2" aluminum scrap & drill the holes to fit the OD of the connector ends. "Letter" drills will work if you don't have metric bits.

One last thing, done right the bullets should have a snug fit in the holes. The aluminum jig acts as a heat sink and will solidify the solder faster. That's a good thing if you don't enjoy burning your fingers on the hot wire.

OK, one more last thing: I use a square of granite flooring tile to solder on, especially when using a mini-toarch. Nobody wants to burn thier house down - so SAFETY FIRST!

JIM