John_M_

No worries Ace, its your boo boo's that make the rest of us look like we know what we're doing... it was meant to happen, or it wouldn't of... this time round should be a winner... the carbon fiber will be a plus, almost a shame to paint over it... carbon fiber in resin has that hi-tech look to it, like those xion propellers.


John M,

TomCrump

I once mixed some custom black paint with bronze flakes for my motorcycle. I had it painted, but took the fenders home, once the paint set up.

Wanting to force the cure, I put the fenders into a "low heat" oven.

I had the fenders repainted, a week later.

Have no fear, my friend. You aren't the first to let impatience cloud better judgement.

Billy J

My Feedback: (4)

how and what to use on Balsa USA on elevator control arm brass to steel? some say silver solder some say brass rod ??? most say do not use rosin core except for wires ! Help my friends ?

WacoNut

Robert,
That is a bummer about the canopy, I know how you feel. Just a real kick in the kahunas I am sure. Kind of like when I knocked my wing over and cut the fabric just after clear coating. . *%*& Happens.
Talking about being cold, -5 deg here tonight.
Later!!
Anthony

Cub Flyer Fresno

A real kick in the - - - cojones - - - is right! Man that sucks! It happens to all of us I guess. When repairing my Cub (the one with the perfectly good fuse, didn't get damaged) I was cutting some balsa with the razor saw. When I went to lay the saw down, I put the end of it into the side of the fuse! It's a small cut though, should repair okay with a small silver dollar patch from PinkIt.

acerc

BillyJ for such an application I would braze it. I use Alfa Fry specialty brazing kits #53500, which contain 56% silver.

John_M_

Billy use silver solder... the proper stuff with the special acid flux... I get my silver solder kits from our local welding supplier... it comes with a small bottle of the special flux and a small quantity of silver solder for like $9 buck... the acid flux is the key to getting a good strong bond to the metals.... clean the parts well with some 600 wet/dry sandpaper... and assemble the pieces, then apply the flux, its a liquid and a small drop goes a long way... when you heat the parts,apply the heat biased to the steel part and away from the joint... gently apply the heat and keep trying to introduce the silver solder until contact with the metal parts start to melt the solder... you will also notice as the parts reach the proper temperature, the flux starts to etch the metals, you'll especially notice it on the brass first... apply one more drop of flux and keep heating until silver flows... as you get experience, you'll see and feel how to control the heat with the torch to were you can create small fillets, that's where the strength of a good bond occurs when the silver flows and capillary action wicks the silver into the joint and forms a fillet... if you apply too much heat too fast you'll burn off the flux and the silver won't flow properly, so its all about taking your time, keep the torch moving to ovoid overheating and then keep introducing the silver with the torch flame away from the joint until it flows... done right silver solder is very strong.


If you're handy with a torch, then you can try your hand at low temperature silver brazing, but its been my experience with small parts, its easy to over temp the small metal parts, especially if it's thin walled tubing brazed to a thicker piece of material, as silver braze requires higher temperatures than silver solder.




John M,

John_M_

Ace this is the stuff I use, .Radnor Stay Clean Silver Solder and Flux




This is their Low Temp Silver Braze Kit




They're are very similar but you can see the color difference of the filler rod on the Silver Brazing kit... low temp brazing requires around 1250F degrees, where as silver solder is between 500-700F degrees.



John M,

acerc

Thanks John, although I'm use to the high silver content, I'll give the Radnor a try. There are many apps where it would be beneficial over the higher silver content.

John_M_

That 56% hi silver brazing kit you are referring to, the one you use is excellent and will work nicely for what Billy is doing, just have to watch the temperature is all... it starts to flow at about 1205F degrees... the Radnor silver 45 braze kit I'm showing is 45% silver, and starts to flow at a little higher temp.1250-1280F... but for small delicate projects, I'd go with the silver solder, its very strong when the metals are properly cleaned and the proper flux is used to get the silver solder to flow and bond properly.


John M,

John_M_

Not to beat a dead horse, but another thing to remember when silver brazing brass tubing... most brass tubing is hardened during the forming process, its actually calculated hardening as its extruded to form the various sizes... when you silver braze hardened brass tube, you run the risk of over temping the brass and annealing it, losing its tensile strength... so in the case of hardened thin wall brass tubing, I will go with the silver solder over brazing, and just make sure everything is cleaned and fluxed properly... a properly silver soldered joint is quite strong.

I believe Leroy used silver soldered on his balsaUSA cub, on the elevator control clevis to brass tie tubes.




John M,

acerc

Like I said, I'm use to the high silver content. It only takes a couple seconds to braze with MAPP/ OXY. By the way both of those products you posted state a silver content of only 4%, much weaker than the 56%.
Now, lets move along for the flies are circling.

acerc

Frequent Flyer tells me this morning another canopy is in the works. I also placed the order this morning for the 46% Pilot from Best Pilots, don't ask what that cost. And my harness material has arrived.

John_M_

You are right, standard "silver bearing solder" sometimes call "lead free solder" has a silver content of around 2%... "silver solder" is around 4-5% silver... 100% silver melts at around 1750F degrees... silver is mixed with other base metals to make an alloy that melts at a spacific temperature... 5% "silver solder" has a working temp at around 480F up to 700F... its the melting temperature properties that makes its preferred use for certain applications, especially where you don't want to over heat certain base metals... but its the silver content plus the right flux that makes it possible to join ferrous metals to non-ferrous metals.

The 56% hi silver braze is much stronger than 5% silver solder, but for our hobby with 5% silver solder is more than strong enough for certain application (as you stated).... like soldering a brass clevis to a piece of thin walled brass tube, with 5% silver solder, the brass tube would distort before the solder bond started to give way.... if you used silver braze for the same pieces, then you risk annealing the thin walled brass tube, so you pick and choose which method will work best for that particular situation... stainless steel to stainless steel, I'd choose the 56% silver braze with out a doubt... for what Billy is doing as long as there is no thin walled brass tubing involved, then go with the 56% silver braze... joining two pieces of thin walled brass tubing, I'd go with the 5% silver solder... its the temperature and the types of metals being joined is the deciding factor... if you're good with the torch and can control the heat, then you can silver braze those delicate materials, just takes practice.

Have you ever tried to pull apart a copper water pipe joint soldered with "silver bearing solder" the 2% stuff... I defy you to separate the joint with out bending or distorting the copper pipe... silver solder done right is very strong... no butt joints of course... the design of the joint is key when welding, brazing, or soldering any materials.


John M,

acerc

I just got home and opened the package from Dynamic Balsa. Their site shows the hardware as metal and what I received was plastic. Very disappointing receiving junk.
I don't think you will have any difficulty distinguishing between the site photo and the stuff I received.

John_M_

Talk about bait and switch, they don't even look like the same design shape... I hope they don't expect you to carve those into shape and then paint them with silver paint.

Try iflytailies site


John M,

FlyerInOKC

My Feedback: (6)

The iflytallies site shows only their 1/2.5 scale harnesses have metal buckles, 1/3 scale and below list plastic buckles.

John_M_

Yep, I just was over there browsing... their 5 point harnesses are plastic 3D printed, they don't look too bad until you use their magnifier to have a closer look, and then you can see the print grain... not many companies making that stuff.


John M,

acerc

I have been emailing with him. He says he has them in metal but thought I'd prefer plastic, "Whaaa"?. Anyway, I think there will be some metal ones on the way, hopefully. I could have just made them but I wanted a few things to be a bit less on the manufacturing side.

Billy J

My Feedback: (4)

Thanks!!! for help

acerc

John, you took a mighty long road to get to the same point. In the pics is a thin walled brass tube cabane I made for my little Pitts. It's not only the materials being used but also the one yielding the materials.

Pic #1 is the mock-up over the plans. The wood spacer is bolted in to hold it for brazing.
#2 Is me and nearly all my weight on this piece.

John_M_

Well I didn't say thin wall brass couldn't be silver brazed, I said you can run the risk over heating and annealing it if you don't control the heat properly... for that particular part you're showing, I think you choose the right method for being a load carrying wing attachment... silver solder would have worked in that situation as well, but you would of had to add some reinforcement to those butt joints, overlapping pieces would work... since you have literally $10k hanging on that part, 56% silver braze was the way to go ... I always try and localize the heat by wrapping the piece in a wet cloth or paper towel to prevent the heat wicking / building in the entire part.

Looking closer at that part with image zoom, you did a nice job silver brazing it; shows very little heat marks which shows good heat control, so the brass tube still has kept its integrity... not that it makes any difference now, and I'm not saying this to be snotty, but I would have chosen some 304 thin walled stainless tube to make that part.. not because I don't trust the brass tubing, I just always over build those types of areas, and I like the way stainless silver brazes... I'm sure if the design calls for the brass tubing then its plenty strong enough... and by the way, you can just as easily anneal stainless steel as you can brass.


John M,

FlyerInOKC

My Feedback: (6)

Robert, on picture #2 my first thought was you have bird legs! I have been banned by the wife from wearing shorts for that reason!

acerc

For what they have supported me through I say thank you.

acerc

Brian from Dbalsa has said metal parts are on their way. Now, if Don would say the same for the canopy and my wheelpants.